Data from a long-term prospective study of healthy, middle-aged Norwegian men suggests that a low heart rate during moderate-intensity exercise is linked with future risk of AF.
"We found that the men who did not exceed 100 bpm at the end of six minutes of workload had a significantly increased AF risk," write Dr Irene Grundvold (Oslo University Hospital, Norway) and colleagues in the paper published July 21, 2013 inCirculation: Arrhythmia and Electrophysiology. In an analysis by tertile, those with heart rates <110 bpm after six minutes of moderate-intensity exercise had a significantly increased risk of AF compared with those with a heart rate >125 bpm.
There is evidence that individuals who participate in longstanding endurance training might have an increased risk of AF as they get older, according to the researchers. One other study of Norwegian master cross-country skiers found that a low resting heart rate was a long-term predictor of AF.
With this background, Grundvold et al wanted to determine if a low heart rate during moderate-intensity exercise predicted incident AF in healthy middle-aged Norwegian men. Slightly more than 2000 men participated in the prospective cardiovascular health survey between 1972 and 1975. All men were healthy and had no evidence of cardiovascular disease.
During a median of 30 years of follow-up, 13% of the men developed AF at a mean age of 71 years. In a multivariate analysis, age, resting systolic blood pressure, relative heart volume, left ventricular hypertrophy, and a low heart rate when engaged in moderate-intensity cycling on a stationary bike (100 W) were all predictors of AF. For those with a heart rate >100 bpm during exercise, the risk of AF decreased by 15% (hazard ratio 0.85; p=0.04) compared with those with lower heart rates.
"The present main results--an increased AF risk associated with low heart rate at moderate exercise in healthy men--might suggest involvement of an inappropriate heart rate response to exercise with prolonged parasympathetic activation," suggest Grundvold and colleagues. "Vagally mediated paroxysmal AF may be particularly important in athletic men without apparent heart disease."
Welcome to my collection of health articles. Most of them contain little nuggets of health wisdom that we can easily apply to our daily lives. As you can gather, I've been consuming all sorts of supplements over the years, most of them from iherb. They deliver on time (DHL), and prices are good. If you're a first-time buyer, use my code 'pot089' to enjoy up to $10 off.
Sunday, 4 August 2013
Friday, 19 July 2013
Air Pollution, Even at Low Levels, Tied to Lung Cancer
Prolonged exposure to air pollution is significantly associated with an increased risk for lung cancer, according to the results of a new meta-analysis.
The study adds "substantially to the weight of epidemiological evidence" that links the 2 phenomena, say the authors, led by Ole Raaschou-Nielsen, PhD, from the Danish Cancer Society Research Center, in Copenhagen.
The researchers, who synthesized data from 17 cohort studies in 9 European countries, found that the risk exists even when the levels of particulate matter (PM) air pollution were below the current European limit values.
Sources of PM air pollution include traffic, industry, and domestic heating.
"We found no threshold below which there was no risk; the results showed a picture that 'the more the worse, the less the better,' " said Dr. Raaschou-Nielsen in a press statement.
"Particulate matter air pollution contributes to lung cancer incidence in Europe," the study authors conclude.
The study, which is one of the largest studies of its kind, included data on more than 300,000 individuals and 2095 lung cancer cases and had a median follow-up of 12.8 years. It was published online July 10 in the journal Lancet Oncology.
"At this stage, we might have to add air pollution, even at current concentrations, to the list of causes of lung cancer," write Takashi Yorifuji MD, PhD, from Okayama University Graduate School of Environmental and Life Science, and Saori Kashima, PhD, from Hiroshima University, in Japan, in an accompanying editorial.
Air pollution is not recognized by medical practitioners as a cause of lung cancer, the pair say. For instance, it is not listed in the iconic Harrison's Principles of Internal Medicine as a cause.
It may also be time to "recognise that air pollution has large effects on public health," the Japanese editorialists state.
Evidence for an association between air pollution exposure and lung cancer is "accumulating," they say. Still, the lung cancer risk associated with air pollution is much lower than that associated with smoking. For instance, in the current study, there was a hazard ratio [HR] of 1.22 (per 10 μg/m³ increase in PM10). By contrast, other research indicates that the relative risk [RR] of developing lung cancer is 23.3 for currently smoking men and 12.7 for currently smoking women compared with nonsmokers. However, the editorials point out that 'everybody is exposed to air pollution." Thus, "the public health effect is quite large."
The editorialists also point out that the World Health Organization has estimated that smoking caused 5.1 million deaths and 71% of lung cancer worldwide in 2004, whereas air pollution caused 1.2 million deaths and 8% of lung cancer worldwide in the same year.
Greater Risk for Adenocarcinomas
In the new study, the authors assessed the impact of long-term exposure to nitrogen oxides and particulate matter with a diameter of less than 2.5 micrometers (PM2.5) and less than 10 micrometers (PM10) on the risk for lung cancer.
Air pollution concentration was estimated at individuals' home addresses using land-use regression models. Participants were tracked for new lung cancer diagnoses in cancer registries. The researchers also applied statistical modeling to control for other factors like smoking, diet, and occupation.
The analysis found that for every increase of 5 micrograms per cubic meter of PM2.5 pollution, the risk for lung cancer rose by 18%, and for every increase of 10 micrograms per cubic meter in PM10pollution, the risk increased by 22%.
The risk/HRs were even higher for the lung cancer subtype, adenocarcinomas. The same increments of PM10 and PM2.5 were associated with HRs for adenocarcinomas of the lung of 1.51 and 1.55, respectively.
However, other studies have not found that there is a pronounced relation between air pollution and any particular lung cancer subtype, the authors and editorialists point out.
No association between lung cancer and nitrogen oxides was found.
The HRs for lung cancer were similar with and without restriction to study participants below most of the predefined public safety threshold values, say the authors. This suggests that "exposure of populations to particulate matter air pollution even at concentrations below the existing European Union air quality limit values for PM10 (40 ug/m³) and PM2.5 (25 ug/m³) might increase the risk for lung cancer," they write.
The new study is "sophisticated and overcame several limitations of previous air pollution studies," the editorialists say.
They point out that earlier studies examined the effect of air pollution on lung cancer by assessing the geographical correlations between air pollution concentration data in communities and aggregate data on lung cancer. However, this method is subject to exposure misclassification and confounding, especially by tobacco smoking.
The new study takes advantage of the fact that researchers subsequently tried to reduce these systematic errors by shifting to case-control or cohort studies with area-level exposure assessment.
Dr. Raaschou-Nielsen and colleagues took the next step by conducting a meta-analysis of these newer studies.
The new study also benefited from a high follow-up rate and adjustment of potential confounders, including a set of smoking variables, the editorialists emphasize.
The study adds "substantially to the weight of epidemiological evidence" that links the 2 phenomena, say the authors, led by Ole Raaschou-Nielsen, PhD, from the Danish Cancer Society Research Center, in Copenhagen.
The researchers, who synthesized data from 17 cohort studies in 9 European countries, found that the risk exists even when the levels of particulate matter (PM) air pollution were below the current European limit values.
Sources of PM air pollution include traffic, industry, and domestic heating.
"We found no threshold below which there was no risk; the results showed a picture that 'the more the worse, the less the better,' " said Dr. Raaschou-Nielsen in a press statement.
"Particulate matter air pollution contributes to lung cancer incidence in Europe," the study authors conclude.
The study, which is one of the largest studies of its kind, included data on more than 300,000 individuals and 2095 lung cancer cases and had a median follow-up of 12.8 years. It was published online July 10 in the journal Lancet Oncology.
"At this stage, we might have to add air pollution, even at current concentrations, to the list of causes of lung cancer," write Takashi Yorifuji MD, PhD, from Okayama University Graduate School of Environmental and Life Science, and Saori Kashima, PhD, from Hiroshima University, in Japan, in an accompanying editorial.
Air pollution is not recognized by medical practitioners as a cause of lung cancer, the pair say. For instance, it is not listed in the iconic Harrison's Principles of Internal Medicine as a cause.
It may also be time to "recognise that air pollution has large effects on public health," the Japanese editorialists state.
Evidence for an association between air pollution exposure and lung cancer is "accumulating," they say. Still, the lung cancer risk associated with air pollution is much lower than that associated with smoking. For instance, in the current study, there was a hazard ratio [HR] of 1.22 (per 10 μg/m³ increase in PM10). By contrast, other research indicates that the relative risk [RR] of developing lung cancer is 23.3 for currently smoking men and 12.7 for currently smoking women compared with nonsmokers. However, the editorials point out that 'everybody is exposed to air pollution." Thus, "the public health effect is quite large."
The editorialists also point out that the World Health Organization has estimated that smoking caused 5.1 million deaths and 71% of lung cancer worldwide in 2004, whereas air pollution caused 1.2 million deaths and 8% of lung cancer worldwide in the same year.
Greater Risk for Adenocarcinomas
In the new study, the authors assessed the impact of long-term exposure to nitrogen oxides and particulate matter with a diameter of less than 2.5 micrometers (PM2.5) and less than 10 micrometers (PM10) on the risk for lung cancer.
Air pollution concentration was estimated at individuals' home addresses using land-use regression models. Participants were tracked for new lung cancer diagnoses in cancer registries. The researchers also applied statistical modeling to control for other factors like smoking, diet, and occupation.
The analysis found that for every increase of 5 micrograms per cubic meter of PM2.5 pollution, the risk for lung cancer rose by 18%, and for every increase of 10 micrograms per cubic meter in PM10pollution, the risk increased by 22%.
The risk/HRs were even higher for the lung cancer subtype, adenocarcinomas. The same increments of PM10 and PM2.5 were associated with HRs for adenocarcinomas of the lung of 1.51 and 1.55, respectively.
However, other studies have not found that there is a pronounced relation between air pollution and any particular lung cancer subtype, the authors and editorialists point out.
No association between lung cancer and nitrogen oxides was found.
The HRs for lung cancer were similar with and without restriction to study participants below most of the predefined public safety threshold values, say the authors. This suggests that "exposure of populations to particulate matter air pollution even at concentrations below the existing European Union air quality limit values for PM10 (40 ug/m³) and PM2.5 (25 ug/m³) might increase the risk for lung cancer," they write.
The new study is "sophisticated and overcame several limitations of previous air pollution studies," the editorialists say.
They point out that earlier studies examined the effect of air pollution on lung cancer by assessing the geographical correlations between air pollution concentration data in communities and aggregate data on lung cancer. However, this method is subject to exposure misclassification and confounding, especially by tobacco smoking.
The new study takes advantage of the fact that researchers subsequently tried to reduce these systematic errors by shifting to case-control or cohort studies with area-level exposure assessment.
Dr. Raaschou-Nielsen and colleagues took the next step by conducting a meta-analysis of these newer studies.
The new study also benefited from a high follow-up rate and adjustment of potential confounders, including a set of smoking variables, the editorialists emphasize.
Stop idling, move more to avoid diabetes
Time spent in sedentary behavior — sitting or lying down — has a stronger impact on diabetes risk than does moderate to vigorous physical activity (MVPA) in adults, new research shows.
"This is the first work to demonstrate that sedentary behavior might have a greater bearing on diabetes risk factors than exercise in adults at risk of the disease," said lead author Joseph Henson, a PhD student from the Leicester Diabetes Center, United Kingdom.
Mr. Henson stressed, however, that sedentary behavior "is not simply a lack of exercise," and trying to reduce it "shouldn't be used as a substitute for exercise; they should be treated independently.
"This requires a paradigm shift, so that people at high risk of developing type 2 diabetes think about the balance of sedentary behavior and physical activity throughout the day," he added, noting that sedentary time occupies a much larger portion of the day than time spent in physical activity.
Sedentary Time Affects Glucose, TGs, and HDL Cholesterol
In their study, Mr. Henson and colleagues analyzed individuals with known risk factors for type 2 diabetes from 2 ongoing diabetes-prevention programs in the UK: 153 from the Sedentary Time and Diabetes (STAND) study (mean age, 33 years; 29% men) and 725 from the Walking Away from Diabetes study (mean age, 64 years; 65% men).
They examined the extent to which sedentary time, breaks in sedentary time, MVPA, and total physical activity were independently associated with cardiometabolic risk factors. Accelerometers were used to assess sedentary time, MVPA, and total physical activity. Breaks in sedentary time were defined as a transition from a sedentary to an active state.
Following adjustment for various covariates, including MVPA and body mass index (BMI), there were detrimental linear associations of sedentary time with 2-hour plasma glucose (P < .001), triglycerides (P= .001), and HDL cholesterol (P = .029).
Breaks in sedentary time, total physical activity, and MVPA were significantly inversely associated with measures of adiposity, but not with any other cardiometabolic variables after adjustment for sedentary time and BMI.
The findings were consistent across a diverse age range, providing evidence that the negative consequences of excess sedentary time exist from young adulthood through older ages (ages 18 to 74 years), another unique aspect of the study, said Mr. Henson. He noted that previous studies that have shown detrimental effects of sedentary behavior have been performed in older adults in the general population.
"The findings from this study may have important methodological and public-health implications," he and his colleagues point out. "This…provides novel objective evidence that, in individuals at high risk of type 2 diabetes mellitus, sedentary time may be a more important indicator of cardiometabolic health than MVPA."
Diabetes Prevention Should not Overlook Sedentary Time
The results also have implications for diabetes and cardiovascular disease prevention programs, they say.
"This may raise questions regarding the prescription of optimal daily human movement for health. As such, diabetes and cardiovascular [disease] prevention programs concentrating solely on MVPA may overlook an area that is of fundamental importance to cardiometabolic health.
"Along with messages related to accumulating at least 150 min/week of MVPA, which forms the cornerstone of diabetes-prevention programs, such interventions may be more effective if individuals are further encouraged to simply sit less and move more, regardless of the intensity level," they add.
Future Study Will Try to Tease out Biological Mechanism
Mr. Henson stresses nevertheless that the research "is still only a cross-sectional, observational study," which should serve as a stimulus for further work, including tightly controlled experimental studies in different populations.
To this end, he and his colleagues plan to conduct another study, assessing individuals at risk of diabetes who will be assigned to 1 of 3 groups: sitting all day, walking about for 5-minute intervals twice an hour, and standing for 5-minute intervals twice an hour. They plan to try to tease out the biological mechanisms that are at play, Mr. Henson explained.
"This is the first work to demonstrate that sedentary behavior might have a greater bearing on diabetes risk factors than exercise in adults at risk of the disease," said lead author Joseph Henson, a PhD student from the Leicester Diabetes Center, United Kingdom.
Mr. Henson stressed, however, that sedentary behavior "is not simply a lack of exercise," and trying to reduce it "shouldn't be used as a substitute for exercise; they should be treated independently.
"This requires a paradigm shift, so that people at high risk of developing type 2 diabetes think about the balance of sedentary behavior and physical activity throughout the day," he added, noting that sedentary time occupies a much larger portion of the day than time spent in physical activity.
Sedentary Time Affects Glucose, TGs, and HDL Cholesterol
In their study, Mr. Henson and colleagues analyzed individuals with known risk factors for type 2 diabetes from 2 ongoing diabetes-prevention programs in the UK: 153 from the Sedentary Time and Diabetes (STAND) study (mean age, 33 years; 29% men) and 725 from the Walking Away from Diabetes study (mean age, 64 years; 65% men).
They examined the extent to which sedentary time, breaks in sedentary time, MVPA, and total physical activity were independently associated with cardiometabolic risk factors. Accelerometers were used to assess sedentary time, MVPA, and total physical activity. Breaks in sedentary time were defined as a transition from a sedentary to an active state.
Following adjustment for various covariates, including MVPA and body mass index (BMI), there were detrimental linear associations of sedentary time with 2-hour plasma glucose (P < .001), triglycerides (P= .001), and HDL cholesterol (P = .029).
Breaks in sedentary time, total physical activity, and MVPA were significantly inversely associated with measures of adiposity, but not with any other cardiometabolic variables after adjustment for sedentary time and BMI.
The findings were consistent across a diverse age range, providing evidence that the negative consequences of excess sedentary time exist from young adulthood through older ages (ages 18 to 74 years), another unique aspect of the study, said Mr. Henson. He noted that previous studies that have shown detrimental effects of sedentary behavior have been performed in older adults in the general population.
"The findings from this study may have important methodological and public-health implications," he and his colleagues point out. "This…provides novel objective evidence that, in individuals at high risk of type 2 diabetes mellitus, sedentary time may be a more important indicator of cardiometabolic health than MVPA."
Diabetes Prevention Should not Overlook Sedentary Time
The results also have implications for diabetes and cardiovascular disease prevention programs, they say.
"This may raise questions regarding the prescription of optimal daily human movement for health. As such, diabetes and cardiovascular [disease] prevention programs concentrating solely on MVPA may overlook an area that is of fundamental importance to cardiometabolic health.
"Along with messages related to accumulating at least 150 min/week of MVPA, which forms the cornerstone of diabetes-prevention programs, such interventions may be more effective if individuals are further encouraged to simply sit less and move more, regardless of the intensity level," they add.
Future Study Will Try to Tease out Biological Mechanism
Mr. Henson stresses nevertheless that the research "is still only a cross-sectional, observational study," which should serve as a stimulus for further work, including tightly controlled experimental studies in different populations.
To this end, he and his colleagues plan to conduct another study, assessing individuals at risk of diabetes who will be assigned to 1 of 3 groups: sitting all day, walking about for 5-minute intervals twice an hour, and standing for 5-minute intervals twice an hour. They plan to try to tease out the biological mechanisms that are at play, Mr. Henson explained.
Friday, 28 June 2013
Eczema: Evening Primrose Oil, Borage Oil not helpful
Evening primrose oil (EPO) and borage oil (BO) provide little benefit for the relief of atopic eczema compared with placebo, according to a new review published in the April issue of the Cochrane Database of Systematic Reviews.
Joel Bamford, MD, from the University of Minnesota Medical School in Duluth, and colleagues identified 27 studies (19 EPO and 8 BO; 1596 adults and children overall) that evaluated the use of oral EPO or BO for treatment of eczema compared with placebo. The review authors searched the main scientific literature databases up to August 29, 2012.
A meta-analysis of 7 EPO studies showed no significant increase in symptom relief compared with placebo. Studies of BO also failed to show any significant symptom improvement; however, a meta-analysis of studies was not performed because of differences in study reporting.
Adverse effects were mild but similar for EPO and BO, were primarily gastrointestinal in nature, and ranged in frequency from 7% to 15%. One study reported that EPO may increase bleeding risk among patients receiving warfarin.
According to the researchers, 67% of the included studies were judged as having a low risk of bias for random sequence generation, 44% had a low risk of bias for allocation concealment, and 59% had a low risk of bias for blinding.
"[EPO and BO] do not seem to add any benefit to eczema as measured in this systematic review," Dr. Bamford and colleagues write.
"Noting that the confidence intervals between the active and placebo treatments are so narrow to exclude the possibility of any clinically useful difference, we conclude that further studies [of] EPO or BO for eczema would be hard to justify," they write.
Hywel Williams, PhD, FRCP, from the Center of Evidence Based Dermatology, University of Nottingham, United Kingdom, wrote: "Although some of us always suspected that EPO was not especially useful in atopic eczema, this study provides robust evidence from the totality of evidence to suggest that it is of very little value, if any."
Dr. Williams agreed with the review authors that more research in this area is not needed and that "research monies should be spent elsewhere on eczema, such as finding out how best to prevent it."
Joel Bamford, MD, from the University of Minnesota Medical School in Duluth, and colleagues identified 27 studies (19 EPO and 8 BO; 1596 adults and children overall) that evaluated the use of oral EPO or BO for treatment of eczema compared with placebo. The review authors searched the main scientific literature databases up to August 29, 2012.
A meta-analysis of 7 EPO studies showed no significant increase in symptom relief compared with placebo. Studies of BO also failed to show any significant symptom improvement; however, a meta-analysis of studies was not performed because of differences in study reporting.
Adverse effects were mild but similar for EPO and BO, were primarily gastrointestinal in nature, and ranged in frequency from 7% to 15%. One study reported that EPO may increase bleeding risk among patients receiving warfarin.
According to the researchers, 67% of the included studies were judged as having a low risk of bias for random sequence generation, 44% had a low risk of bias for allocation concealment, and 59% had a low risk of bias for blinding.
"[EPO and BO] do not seem to add any benefit to eczema as measured in this systematic review," Dr. Bamford and colleagues write.
"Noting that the confidence intervals between the active and placebo treatments are so narrow to exclude the possibility of any clinically useful difference, we conclude that further studies [of] EPO or BO for eczema would be hard to justify," they write.
Hywel Williams, PhD, FRCP, from the Center of Evidence Based Dermatology, University of Nottingham, United Kingdom, wrote: "Although some of us always suspected that EPO was not especially useful in atopic eczema, this study provides robust evidence from the totality of evidence to suggest that it is of very little value, if any."
Dr. Williams agreed with the review authors that more research in this area is not needed and that "research monies should be spent elsewhere on eczema, such as finding out how best to prevent it."
Vitamin D levels linked to respiratory disease
Having severe vitamin D deficiency may put people aged 65 years and older at more than twice the risk of having self-reported respiratory disease, according to an article published online May 6 in theJournal of the American Geriatrics Society.
However, the question remains as to whether respiratory disease is a cause rather than a consequence of low vitamin D concentrations.
Vasant Hirani, PhD, from the Department of Epidemiology and Public Health, University College London Medical School, United Kingdom, analyzed the records of 2070 people (1120 women) who participated in the 2005 Health Survey for England and who were also interviewed by a nurse and had a blood sample taken.
Dr. Hirani found that after adjusting for age, sex, season, smoking status, and social class, people with less than 35 nmol/L serum 25(OH)D were more than twice as likely to report having respiratory disease as those individuals with a serum level of 64 nmol/L or higher. Individuals with intermediate serum levels also had greater risk compared with those with levels above 64 nmol/L.
Prevalence of respiratory disease among the study population ranged from 8.9% for people with vitamin D levels of 75 nmol/L and greater to 45.5% for people with levels of 25.0 to 49.9 nmol/L. The association was not consistent, however, as only 14.7% of individuals with serum 25(OH)D levels lower than 25 nmol/L reported having respiratory disease.
Although Dr. Hirani found associations in unadjusted analyses between low vitamin D levels and smoking tobacco, lower social class, fair or poor general health, and self-reported heart disease, cancer, and pain, she found no associations between low vitamin D levels and age, sex, body mass index, alcohol consumption, or use of vitamin supplements.
It is "biologically plausible" for vitamin D to be associated with respiratory health, she writes, because of vitamin D's role in the lung's immunity response to virus infection.
"It is also likely that individuals with a respiratory condition are less likely to spend time outdoors and may also limit their activities, resulting in less sunlight exposure and thus vitamin D deficiency," she writes. More research is needed to clarify the cause and effect of the association, she notes.
Although definitive conclusions as to whether low vitamin D is truly linked to respiratory disease, she writes, the study population is nationally representative of people of that age in England.
She concludes, "Regardless of the direction of causation, the higher-than-expected co-occurrence of vitamin D deficiency and respiratory conditions is an important public health question for older populations living in northern latitudes because both are common, and both have substantial adverse health consequences."
Dr. Hirani is currently funded by the National Health Services Information Centre and is an editor and chapter author on the Health Survey for England, funded by the English Department of Health.
However, the question remains as to whether respiratory disease is a cause rather than a consequence of low vitamin D concentrations.
Vasant Hirani, PhD, from the Department of Epidemiology and Public Health, University College London Medical School, United Kingdom, analyzed the records of 2070 people (1120 women) who participated in the 2005 Health Survey for England and who were also interviewed by a nurse and had a blood sample taken.
Dr. Hirani found that after adjusting for age, sex, season, smoking status, and social class, people with less than 35 nmol/L serum 25(OH)D were more than twice as likely to report having respiratory disease as those individuals with a serum level of 64 nmol/L or higher. Individuals with intermediate serum levels also had greater risk compared with those with levels above 64 nmol/L.
Prevalence of respiratory disease among the study population ranged from 8.9% for people with vitamin D levels of 75 nmol/L and greater to 45.5% for people with levels of 25.0 to 49.9 nmol/L. The association was not consistent, however, as only 14.7% of individuals with serum 25(OH)D levels lower than 25 nmol/L reported having respiratory disease.
Although Dr. Hirani found associations in unadjusted analyses between low vitamin D levels and smoking tobacco, lower social class, fair or poor general health, and self-reported heart disease, cancer, and pain, she found no associations between low vitamin D levels and age, sex, body mass index, alcohol consumption, or use of vitamin supplements.
It is "biologically plausible" for vitamin D to be associated with respiratory health, she writes, because of vitamin D's role in the lung's immunity response to virus infection.
"It is also likely that individuals with a respiratory condition are less likely to spend time outdoors and may also limit their activities, resulting in less sunlight exposure and thus vitamin D deficiency," she writes. More research is needed to clarify the cause and effect of the association, she notes.
Although definitive conclusions as to whether low vitamin D is truly linked to respiratory disease, she writes, the study population is nationally representative of people of that age in England.
She concludes, "Regardless of the direction of causation, the higher-than-expected co-occurrence of vitamin D deficiency and respiratory conditions is an important public health question for older populations living in northern latitudes because both are common, and both have substantial adverse health consequences."
Dr. Hirani is currently funded by the National Health Services Information Centre and is an editor and chapter author on the Health Survey for England, funded by the English Department of Health.
Low back pain linked to bacterial infection
New research suggests that some 40% of chronic lower back pain (CLBP) could be caused by bacteria, and that a significant percentage of people with lower back pain following a herniated disc and swelling in the spine could find relief by taking an antibiotic.
Investigators from the Research Department of the Spine Center of Southern Denmark, University of Southern Denmark, Odense, led by Hanne B. Albert, PhD, conclude that antibiotics may be considered as a treatment option for patients with chronic low back pain, but with caution.
The authors suggest that long-term antibiotics should not be prescribed "without due consideration." Low back pain is so common in the community that there could be hazards if used indiscriminately, they write.
"However, as many patients, as in this trial, are on sick leave at risk of losing their jobs and have a high analgesic intake, we suggest that antibiotics, when applied along the lines of this MAST [Modic antibiotic spine therapy] protocol may be appropriate in this subgroup, i.e., CLBP with Modic type 1 changes. We do not support the proposition that all patients with lumbar pain should have a trial course of antibiotics."
Their findings, published in 2 papers, 1 a randomized trial of antibiotics for low back pain, are published in the April issue of the European Spine Journal.
Positive cultures
An estimated 80% of Americans have low back pain at some point in their life, the authors write, and back pain is the most common reason for workplace absence.
The first of 2 studies shows that patients with an anaerobic infected disc are more likely to develop Modic change (MC) (bone edema) in the adjacent vertebrae after disc herniation, suggesting a role of bacteria in developing Modic changes.
The study included 61 adults (mean age, 46.4 years; 27% female) who had MRI-confirmed lumbar disc herniation and were undergoing surgery. All patients were immunocompetent. No patient had received a previous epidural steroid injection or had previous back surgery.
Using stringent antiseptic sterile protocols, researchers collected 5 tissue samples from each patient. In total, microbiological cultures were positive in 46% of the patients. Anaerobic cultures were positive in 43% of patients, and of these, 7% had dual microbial infections, containing 1 aerobic and 1 anaerobic culture. No tissue specimens had more than 2 types of bacteria.
The anaerobic microorganism Propionibacterium acnes was found in 40% of the total cohort and in 86% of those with positive microbiology. These bacteria typically live in human skin and hair follicles and gums.
The results showed that in the discs with a nucleus with anaerobic bacteria, 80% developed new MC in the vertebrae adjacent to the previous disc herniation. In contrast, none of the patients with aerobic bacteria and only 44% of those with negative cultures developed new MC.
The association between an anaerobic culture and new MCs was highly statistically significant.
The authors said that the detected bacteria are unlikely the result of intraoperative skin contamination. They pointed out that the procedures were conducted under the strictest of sterile conditions. As well, if skin contamination was the cause of the infection, a pattern of multiple skin bacteria cultures would be observed, which was not the case.
Why would some patients develop MC when no microorganisms are present in their herniated nuclear tissue? The authors speculate this could be due to a biochemical effect reflecting edema secondary to microfractures and subsequent inflammation, or the result of an inflammatory process from proinflammatory chemicals penetrating through the microfractures from the nucleus pulposus.
Antibiotic randomized trial
The second study, a double-blind, randomized trial, showed that an antibiotic protocol was significantly more effective than placebo in reducing pain and disability. This study included 162 adults who had chronic lower back pain that had developed after a previous disc herniation and had lasted more than 6 months.
These patients also had bone edema, as shown by Modic type 1 changes in the vertebrae adjacent to the previous herniation. Such changes in the vertebrae are present in 6% of the general population and 35% to 40% of those with low back pain.
The patients were randomly assigned to amoxicillin-clavulanate (500 mg/125 mg;Bioclavid) or identical placebo 3 times daily for 100 days and were blindly evaluated at baseline, end of treatment, and 1 year.
The analysis included 144 patients who completed the 1-year follow-up. The antibiotic group improved on all primary outcome measures, including disease-specific score on Roland Morris Disability Questionnaire (RMDQ), and lumbar pain. The improvement continued from the 100-day follow-up until the 1-year follow up.
The improvements in the antibiotic group were highly statistically significant on all outcomes measured, including secondary outcomes of leg pain, number of hours with pain in the last 4 weeks, global perceived health, and days with sick leave, among others.
For example, at baseline, 100 days, and 1 year, the disease-specific disability-RMDQ scores for the antibiotic group were 15.0, 11.5, and 7.0, and for placebo they were 15.0, 14.0, and 14.0 (P = .0001 for the difference between placebo and antibiotic group at 1 year follow up). For back pain, the figures for the antibiotic group were 6.7, 5.0, and 3.7 and for placebo they were 6.3, 6.3, and 6.3. (P = .0001 for difference).
For low back pain, which was experienced by all patients at the beginning of the study, 67.5% of the antibiotic group reported this pain after 1 year compared with 94.0% of the placebo group (P = .0001 for difference). The percentage of those with constant pain was reduced from 73.5% to 19.5% in the antibiotic group and from 73.1% to 67.2% in the placebo group (P = .0001 for difference).
There was a trend toward a dose-response relationship, with double-dose antibiotics being more effective; however, this was not statistically significant because the study was not powered for this comparison.
Adverse events were more common in the antibiotic group (65% of participants) than in the placebo group (23%).
Surgical setting
In an editorial accompanying the publication, Max Aebi, MD, from the MEM Research Center for Orthopaedic Surgery, Institute for Evaluative Research in Orthopedic Surgery, University of Berne, Switzerland, and editor-in-chief of the European Spine Journal, points out that previous studies have shown that MC I occurs 6 times more frequently in the low back pain population than the general population. The relationship may be mechanical, he writes, "but under certain circumstances, low virulent infections may play a key role."
These new papers not only demonstrate that patients infected with herniated nucleus material by anaerobic bacteria in lumbar disc herniation develop new MC I in adjacent vertebrae but also that patients with low back pain and MC I after lumbar disc herniation improved significantly with an antibiotic protocol, Dr. Aebi writes.
"This strongly suggests one cause of low back pain in combination of MC I to be of low-grade infectious nature in case of previous disc herniation," he said.
However, he cautions that it is ethically impossible to take biopsy samples from all of these patients; this could be done only those who have surgery subsequent to disc herniation. The authors ask "the obvious key question" of whether the bacteria found in the nuclear material results from infection or could be due to intraoperative contamination, he writes, and then provide a "plausible" answer as to why such contamination is "highly improbable."
"Nevertheless," Dr. Aebi writes, "further research is necessary to show what exactly happens in patients with disc herniation who develop MC I and low back pain and who have not been operated on. How could we show that in this fraction of patients there could be the same number of anaerobic infections of the nucleus material? By markers of the anaerobic bacteria or of specific infectious tissue, which could be made visible in imaging? By fine needle biopsy?"
Knowing these answers would make the current study results "even more explosive" in terms of better understanding low back pain and corresponding MRI changes, said Dr. Aebi. "We are keen to wait for further innovative research in this field."
Investigators from the Research Department of the Spine Center of Southern Denmark, University of Southern Denmark, Odense, led by Hanne B. Albert, PhD, conclude that antibiotics may be considered as a treatment option for patients with chronic low back pain, but with caution.
The authors suggest that long-term antibiotics should not be prescribed "without due consideration." Low back pain is so common in the community that there could be hazards if used indiscriminately, they write.
"However, as many patients, as in this trial, are on sick leave at risk of losing their jobs and have a high analgesic intake, we suggest that antibiotics, when applied along the lines of this MAST [Modic antibiotic spine therapy] protocol may be appropriate in this subgroup, i.e., CLBP with Modic type 1 changes. We do not support the proposition that all patients with lumbar pain should have a trial course of antibiotics."
Their findings, published in 2 papers, 1 a randomized trial of antibiotics for low back pain, are published in the April issue of the European Spine Journal.
Positive cultures
An estimated 80% of Americans have low back pain at some point in their life, the authors write, and back pain is the most common reason for workplace absence.
The first of 2 studies shows that patients with an anaerobic infected disc are more likely to develop Modic change (MC) (bone edema) in the adjacent vertebrae after disc herniation, suggesting a role of bacteria in developing Modic changes.
The study included 61 adults (mean age, 46.4 years; 27% female) who had MRI-confirmed lumbar disc herniation and were undergoing surgery. All patients were immunocompetent. No patient had received a previous epidural steroid injection or had previous back surgery.
Using stringent antiseptic sterile protocols, researchers collected 5 tissue samples from each patient. In total, microbiological cultures were positive in 46% of the patients. Anaerobic cultures were positive in 43% of patients, and of these, 7% had dual microbial infections, containing 1 aerobic and 1 anaerobic culture. No tissue specimens had more than 2 types of bacteria.
The anaerobic microorganism Propionibacterium acnes was found in 40% of the total cohort and in 86% of those with positive microbiology. These bacteria typically live in human skin and hair follicles and gums.
The results showed that in the discs with a nucleus with anaerobic bacteria, 80% developed new MC in the vertebrae adjacent to the previous disc herniation. In contrast, none of the patients with aerobic bacteria and only 44% of those with negative cultures developed new MC.
The association between an anaerobic culture and new MCs was highly statistically significant.
The authors said that the detected bacteria are unlikely the result of intraoperative skin contamination. They pointed out that the procedures were conducted under the strictest of sterile conditions. As well, if skin contamination was the cause of the infection, a pattern of multiple skin bacteria cultures would be observed, which was not the case.
Why would some patients develop MC when no microorganisms are present in their herniated nuclear tissue? The authors speculate this could be due to a biochemical effect reflecting edema secondary to microfractures and subsequent inflammation, or the result of an inflammatory process from proinflammatory chemicals penetrating through the microfractures from the nucleus pulposus.
Antibiotic randomized trial
The second study, a double-blind, randomized trial, showed that an antibiotic protocol was significantly more effective than placebo in reducing pain and disability. This study included 162 adults who had chronic lower back pain that had developed after a previous disc herniation and had lasted more than 6 months.
These patients also had bone edema, as shown by Modic type 1 changes in the vertebrae adjacent to the previous herniation. Such changes in the vertebrae are present in 6% of the general population and 35% to 40% of those with low back pain.
The patients were randomly assigned to amoxicillin-clavulanate (500 mg/125 mg;Bioclavid) or identical placebo 3 times daily for 100 days and were blindly evaluated at baseline, end of treatment, and 1 year.
The analysis included 144 patients who completed the 1-year follow-up. The antibiotic group improved on all primary outcome measures, including disease-specific score on Roland Morris Disability Questionnaire (RMDQ), and lumbar pain. The improvement continued from the 100-day follow-up until the 1-year follow up.
The improvements in the antibiotic group were highly statistically significant on all outcomes measured, including secondary outcomes of leg pain, number of hours with pain in the last 4 weeks, global perceived health, and days with sick leave, among others.
For example, at baseline, 100 days, and 1 year, the disease-specific disability-RMDQ scores for the antibiotic group were 15.0, 11.5, and 7.0, and for placebo they were 15.0, 14.0, and 14.0 (P = .0001 for the difference between placebo and antibiotic group at 1 year follow up). For back pain, the figures for the antibiotic group were 6.7, 5.0, and 3.7 and for placebo they were 6.3, 6.3, and 6.3. (P = .0001 for difference).
For low back pain, which was experienced by all patients at the beginning of the study, 67.5% of the antibiotic group reported this pain after 1 year compared with 94.0% of the placebo group (P = .0001 for difference). The percentage of those with constant pain was reduced from 73.5% to 19.5% in the antibiotic group and from 73.1% to 67.2% in the placebo group (P = .0001 for difference).
There was a trend toward a dose-response relationship, with double-dose antibiotics being more effective; however, this was not statistically significant because the study was not powered for this comparison.
Adverse events were more common in the antibiotic group (65% of participants) than in the placebo group (23%).
Surgical setting
In an editorial accompanying the publication, Max Aebi, MD, from the MEM Research Center for Orthopaedic Surgery, Institute for Evaluative Research in Orthopedic Surgery, University of Berne, Switzerland, and editor-in-chief of the European Spine Journal, points out that previous studies have shown that MC I occurs 6 times more frequently in the low back pain population than the general population. The relationship may be mechanical, he writes, "but under certain circumstances, low virulent infections may play a key role."
These new papers not only demonstrate that patients infected with herniated nucleus material by anaerobic bacteria in lumbar disc herniation develop new MC I in adjacent vertebrae but also that patients with low back pain and MC I after lumbar disc herniation improved significantly with an antibiotic protocol, Dr. Aebi writes.
"This strongly suggests one cause of low back pain in combination of MC I to be of low-grade infectious nature in case of previous disc herniation," he said.
However, he cautions that it is ethically impossible to take biopsy samples from all of these patients; this could be done only those who have surgery subsequent to disc herniation. The authors ask "the obvious key question" of whether the bacteria found in the nuclear material results from infection or could be due to intraoperative contamination, he writes, and then provide a "plausible" answer as to why such contamination is "highly improbable."
"Nevertheless," Dr. Aebi writes, "further research is necessary to show what exactly happens in patients with disc herniation who develop MC I and low back pain and who have not been operated on. How could we show that in this fraction of patients there could be the same number of anaerobic infections of the nucleus material? By markers of the anaerobic bacteria or of specific infectious tissue, which could be made visible in imaging? By fine needle biopsy?"
Knowing these answers would make the current study results "even more explosive" in terms of better understanding low back pain and corresponding MRI changes, said Dr. Aebi. "We are keen to wait for further innovative research in this field."
Eating peppers may help ward off Parkinson's Disease
Eating foods that contain even a small amount of nicotine, such as peppers, may reduce the risk for Parkinson's disease (PD), new research hints.
Peppers are in the same botanical family as tobacco — the Solanaceae family. In a population-based study, researchers found that increasing consumption of edible forms of Solanaceae plants was associated with a lower risk of developing PD, with peppers displaying the strongest association.
"If our results are confirmed in similar studies, and we also learn more about why peppers might be protective, then the research may be of particular interest to people who want to eat foods that might benefit their health, especially people without PD already," Susan Searles Nielsen, PhD, who led the study, told Medscape Medical News.
"We weren't able to explore whether peppers or other foods slow progression of the disease once you have it, although research to address that question might be a natural extension," added Dr. Searles Nielsen, research scientist in the Department of Environmental and Occupational Health Sciences, University of Washington, Seattle.
The study was published online May 9 in Annals of Neurology
Consistent inverse association with tobacco
Research has consistently shown an inverse association between PD and tobacco use, with people who have ever regularly smoked cigarettes less likely to develop PD than others. Some animal studies indicate that nicotine might help protect neurons. "However, it's unclear whether nicotine or something else in tobacco is actually protective, or whether people predisposed to PD simply don't respond well to tobacco smoke and therefore avoid it," Dr. Searles Nielsen explained.
"A few studies suggest that secondhand smoke might be associated with a reduced risk of PD, so that prompted us to look at another source of a relatively small amount of nicotine — foods in the same plant family as tobacco," she added.
The researchers assessed whether nicotine from edible Solanaceae influences risk for PD in 490 adults with newly diagnosed PD and 644 unrelated, neurologically healthy controls. They used questionnaires to assess participants' lifetime diets and tobacco use.
They report that PD was inversely associated with consumption of all edible Solanaceae combined (relative risk [RR], 0.81; 95% confidence interval [CI], 0.65 - 1.01), but not consumption of all other vegetables combined (RR, 1.00; 95% CI, 0.92 - 1.10).
They found that the trend "strengthened" when they weighted edible Solanaceae by nicotine concentration.
An inverse association was also evident for peppers specifically. Eating peppers 2 to 4 times per week was "consistently" associated with a 30% reduction in risk for PD the researchers report.
The potentially protective effect of peppers was mainly in people who had little or no prior tobacco use, which is "intriguing," Dr. Searles Nielsen said. "That is where you would expect to see the clearest association if something in both tobacco and peppers, such as nicotine, is protective."
"This lends strength to our findings, along with our observations that the association grew stronger with greater consumption of peppers and that there was no association between PD and eating vegetables outside this plant family. However, more research is needed to fully understand whether eating peppers might help prevent PD," Dr. Searles Nielsen said.
Novel approach, new evidence
The observation that smokers have a lower risk for PD has been "consistently reported in more than 60 epidemiological studies," Honglei Chen, MD, PhD, from the National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, who wasn't involved in the study, told Medscape Medical News.
"All previous studies on this topic have focused on analysis of smoking behaviors, while this study took a very different and novel approach by examining nicotine from diet in relation to Parkinson risk. Although this study did not settle the controversies regarding smoking and PD, it offers new evidence that supports a causal explanation," Dr. Chen said.
He cautioned, however, that this is a "preliminary finding that needs to be replicated, particularly from prospective studies that assess dietary habit before PD diagnosis.
"This study, however, is an excellent example of a novel approach for studying the relationship between smoking and PD. Further, if this finding could be confirmed, it adds to the health benefits of eating tomatoes and green peppers," Dr. Chen said.
Peppers are in the same botanical family as tobacco — the Solanaceae family. In a population-based study, researchers found that increasing consumption of edible forms of Solanaceae plants was associated with a lower risk of developing PD, with peppers displaying the strongest association.
"If our results are confirmed in similar studies, and we also learn more about why peppers might be protective, then the research may be of particular interest to people who want to eat foods that might benefit their health, especially people without PD already," Susan Searles Nielsen, PhD, who led the study, told Medscape Medical News.
"We weren't able to explore whether peppers or other foods slow progression of the disease once you have it, although research to address that question might be a natural extension," added Dr. Searles Nielsen, research scientist in the Department of Environmental and Occupational Health Sciences, University of Washington, Seattle.
The study was published online May 9 in Annals of Neurology
Consistent inverse association with tobacco
Research has consistently shown an inverse association between PD and tobacco use, with people who have ever regularly smoked cigarettes less likely to develop PD than others. Some animal studies indicate that nicotine might help protect neurons. "However, it's unclear whether nicotine or something else in tobacco is actually protective, or whether people predisposed to PD simply don't respond well to tobacco smoke and therefore avoid it," Dr. Searles Nielsen explained.
"A few studies suggest that secondhand smoke might be associated with a reduced risk of PD, so that prompted us to look at another source of a relatively small amount of nicotine — foods in the same plant family as tobacco," she added.
The researchers assessed whether nicotine from edible Solanaceae influences risk for PD in 490 adults with newly diagnosed PD and 644 unrelated, neurologically healthy controls. They used questionnaires to assess participants' lifetime diets and tobacco use.
They report that PD was inversely associated with consumption of all edible Solanaceae combined (relative risk [RR], 0.81; 95% confidence interval [CI], 0.65 - 1.01), but not consumption of all other vegetables combined (RR, 1.00; 95% CI, 0.92 - 1.10).
They found that the trend "strengthened" when they weighted edible Solanaceae by nicotine concentration.
An inverse association was also evident for peppers specifically. Eating peppers 2 to 4 times per week was "consistently" associated with a 30% reduction in risk for PD the researchers report.
The potentially protective effect of peppers was mainly in people who had little or no prior tobacco use, which is "intriguing," Dr. Searles Nielsen said. "That is where you would expect to see the clearest association if something in both tobacco and peppers, such as nicotine, is protective."
"This lends strength to our findings, along with our observations that the association grew stronger with greater consumption of peppers and that there was no association between PD and eating vegetables outside this plant family. However, more research is needed to fully understand whether eating peppers might help prevent PD," Dr. Searles Nielsen said.
Novel approach, new evidence
The observation that smokers have a lower risk for PD has been "consistently reported in more than 60 epidemiological studies," Honglei Chen, MD, PhD, from the National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, who wasn't involved in the study, told Medscape Medical News.
"All previous studies on this topic have focused on analysis of smoking behaviors, while this study took a very different and novel approach by examining nicotine from diet in relation to Parkinson risk. Although this study did not settle the controversies regarding smoking and PD, it offers new evidence that supports a causal explanation," Dr. Chen said.
He cautioned, however, that this is a "preliminary finding that needs to be replicated, particularly from prospective studies that assess dietary habit before PD diagnosis.
"This study, however, is an excellent example of a novel approach for studying the relationship between smoking and PD. Further, if this finding could be confirmed, it adds to the health benefits of eating tomatoes and green peppers," Dr. Chen said.
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