Physical activity and risk of stroke in women

BACKGROUND AND PURPOSE

Physical activity has generally been inversely related to the risk of developing stroke, but details regarding the amount and kinds of activity required are unclear as are associations for specific stroke subtypes.

METHODS

Eligible subjects were 39 315 healthy US women, > or =45 years of age, from the Women's Health Study. Women reported physical activity at baseline (1992 to 1995) and at 36, 72, 96, 125, and 149 months' follow-up. During an average follow-up of 11.9 years, 579 women developed incident stroke (473 ischemic, 102 hemorrhagic, and 4 of unknown type). Proportional hazards models related physical activity, updated over time, to the risk of incident stroke.

RESULTS

The multivariable relative risks associated with <200, 200 to 599, 600 to 1499, and > or =1500 kcal/week of leisure-time physical activity were 1.00 (referent), 1.11 (95% CI, 0.87 to 1.41), 0.86 (95% CI, 0.67 to 1.10), and 0.83 (95% CI, 0.63 to 1.08), respectively (P trend=0.06). Similar results were observed for ischemic stroke, whereas no associations were observed for hemorrhagic stroke. Vigorous physical activity was not related to stroke risk (P trend=0.50); however, walking time and walking pace were inversely related, either significantly or with borderline significance, to total, ischemic, and hemorrhagic stroke risks (P trend between 0.002 and 0.07).

CONCLUSIONS

This study shows a tendency for leisure-time physical activity to be associated with lower stroke risk in women. In particular, walking was generally associated with lower risks of total, ischemic, and hemorrhagic stroke.

Lipoprotein(a) and risk of type 2 diabetes

BACKGROUND

Previous studies have demonstrated that cardiovascular risk is higher with increased lipoprotein(a) [Lp(a)]. Whether Lp(a) concentration is related to type 2 diabetes is unclear.

METHODS

In 26 746 healthy US women (mean age 54.6 years), we prospectively examined baseline Lp(a) concentrations and incident type 2 diabetes (n = 1670) for a follow-up period of 13 years. We confirmed our findings in 9652 Danish men and women with prevalent diabetes (n = 419). Analyses were adjusted for risk factors that included age, race, smoking, hormone use, family history, blood pressure, body mass index, hemoglobin A(1c) (Hb A(1c)), C-reactive protein, and lipids.

RESULTS

Lp(a) was inversely associated with incident diabetes, with fully adjusted hazard ratios (HRs) and 95% CIs for quintiles 2-5 vs quintile 1 of 0.87 (0.75-1.01), 0.80 (0.68-0.93), 0.88 (0.76-1.02), and 0.78 (0.67-0.91); P for trend 0.002. The association was stronger in nonfasting women, for whom respective HRs were 0.79 (0.58-1.09), 0.78 (0.57-1.08), 0.66 (0.46-0.93), and 0.56 (0.40-0.80); P for trend 0.001; P for interaction with fasting status 0.002. When we used Lp(a) > or =10 mg/L and Hb A(1c) <5% as reference values, the adjusted HRs were 1.62 (0.91-2.89) for Lp(a) <10 mg/L and Hb A(1c) <5%, 3.50 (3.06-4.01) for Lp(a) > or =10 mg/L and Hb A(1c) 5%-<6.5%, and 5.36 (4.00-7.19) for Lp(a) <10 mg/L and Hb A(1c) 5%-<6.5%. Results were similar in nonfasting Danish men and women, for whom adjusted odds ratios were 0.75 (0.55-1.03), 0.64 (0.46-0.88), 0.74 (0.54-1.01), and 0.58 (0.42-0.79) for Lp(a) quintiles 2-5 vs quintile 1; P for trend 0.002.

CONCLUSIONS

Our results indicated that Lp(a) was associated inversely with risk of type 2 diabetes independently of risk factors, in contrast to prior findings of positive associations of Lp(a) with cardiovascular risk.

A multimarker approach to assess the influence of inflammation on the incidence of atrial fibrillation in women

AIMS

To assess the joint influence of inflammatory biomarkers on the risk of incident atrial fibrillation (AF) in women.

METHODS AND RESULTS

We performed a prospective cohort study among women participating in the Women's Health Study. All women were free of AF at study entry and provided a baseline blood sample assayed for high-sensitivity C-reactive protein, soluble intercellular adhesion molecule-1, and fibrinogen. To evaluate the joint effect of these three biomarkers, an inflammation score was created that ranged from 0 to 3 and reflected the number of biomarkers in the highest tertile per individual. During a median follow-up of 14.4 years, 747 of 24,734 women (3.0%) experienced a first AF event. Assessed individually, all three biomarkers were associated with incident AF, even after adjustment for traditional risk factors. When combined into an inflammation score, a strong and independent relationship between inflammation and incident AF emerged. Across increasing inflammation score categories, there were 1.66, 2.22, 2.73, and 3.25 AF events per 1000 person-years of follow-up. The corresponding hazard ratios (95% confidence intervals) across inflammation score categories were 1.0, 1.22 (1.00-1.49), 1.32 (1.06-1.65), and 1.59 (1.22-2.06) (P for linear trend 0.0006) after multivariable adjustment.

CONCLUSION

In this large-scale prospective study among women without a history of cardiovascular disease, markers of systemic inflammation were significantly related to AF even after controlling for traditional risk factors.

The long- and short-term impact of elevated body mass index on the risk of new atrial fibrillation the WHS (women's health study)

OBJECTIVES

The purpose of this study was to characterize the relationship between changes in body mass index (BMI) and incident atrial fibrillation (AF) in a large cohort of women.

BACKGROUND

Obesity and AF are increasing public health problems. The importance of dynamic obesity-associated AF risk is uncertain, and mediators are not well characterized.

METHODS

Cases of AF were confirmed by medical record review in 34,309 participants in the Women's Health Study. Baseline and updated measures of BMI were obtained from periodic questionnaires.

RESULTS

During 12.9 +/- 1.9 years of follow-up, 834 AF events were confirmed. BMI was linearly associated with AF risk, with a 4.7% (95% confidence interval [CI]: 3.4 to 6.1, p < 0.0001) increase in risk with each kilogram per square meter. Adjustment for inflammatory markers minimally attenuated this risk. When updated measures of BMI were used to estimate dynamic risk, overweight (hazard ratio [HR]: 1.22; 95% CI: 1.02 to 1.45, p = 0.03), and obesity (HR: 1.65; 95% CI: 1.36 to 2.00; p < 0.0001) were associated with adjusted short-term increases in AF risk. Participants becoming obese during the first 60 months had a 41% adjusted increase in risk of the development of AF (p = 0.02) compared with those maintaining BMI <30 kg/m(2). The prevalence of overweight and obesity increased over time. The adjusted proportion of incident AF attributable to short-term elevations in BMI was substantial (18.3%).

CONCLUSIONS

In this population of apparently healthy women, BMI was associated with short- and long-term increases in AF risk, accounting for a large proportion of incident AF independent of traditional risk factors. A strategy of weight control may reduce the increasing incidence of AF. (Women's Health Study [WHS]: A Randomized Trial of Low-Dose Aspirin and Vitamin E in the Primary Prevention of Cardiovascular Disease and Cancer; NCT00000479).

Low-dose aspirin in the primary prevention of rheumatoid arthritis: the Women's Health Study

OBJECTIVE

Low-dose aspirin may reduce the risk of developing rheumatoid arthritis (RA) through its effect on cyclooxygenase activity and its antioxidant pathways. Previous randomized trial data have demonstrated a beneficial effect of low-dose aspirin in reducing other inflammatory diseases, such as asthma and colorectal adenomas, but no trial has evaluated the role of aspirin in RA prevention.

METHODS

The Women's Health Study is a randomized, double-blind, placebo-controlled trial conducted between 1992 and 2004 designed to evaluate the risks and benefits of low-dose aspirin (100 mg every other day) and vitamin E in the primary prevention of cardiovascular disease and cancer among 39,876 female health care professionals age > or =45 years throughout the US. After excluding women with RA at baseline, 39,144 women were evaluated for the present study. A definite diagnosis of RA was assessed during followup by self-report and confirmed using a connective tissue disease screening questionnaire, followed by a medical record review by a rheumatologist for American College of Rheumatology criteria.

RESULTS

During an average followup of 10 years, 106 women developed definite RA (48 women in the aspirin group and 58 in the placebo group). There was a nonsignificant risk for RA (relative risk [RR] 0.83, 95% confidence interval [95% CI] 0.56-1.21; P = 0.33) associated with aspirin. There were 64 seropositive RA cases (60%) and 42 seronegative RA cases (40%). Aspirin also had no significant effect on either seropositive RA (RR 1.0, 95% CI 0.61-1.63) or seronegative RA (RR 0.62, 95% CI 0.33-1.15).

CONCLUSION

One hundred milligrams of aspirin taken every other day was not associated with a significant reduction in the risk of developing RA among women in a randomized, double-blind, placebo-controlled trial.

Anthropometric measures, body mass index, and pancreatic cancer: a pooled analysis from the Pancreatic Cancer Cohort Consortium (PanScan)

BACKGROUND

Obesity has been proposed as a risk factor for pancreatic cancer.

METHODS

Pooled data were analyzed from the National Cancer Institute Pancreatic Cancer Cohort Consortium (PanScan) to study the association between prediagnostic anthropometric measures and risk of pancreatic cancer. PanScan applied a nested case-control study design and included 2170 cases and 2209 control subjects. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using unconditional logistic regression for cohort-specific quartiles of body mass index (BMI [calculated as weight in kilograms divided by height in meters squared]), weight, height, waist circumference, and waist to hip ratio as well as conventional BMI categories (underweight, <18.5; normal weight, 18.5-24.9; overweight, 25.0-29.9; obese, 30.0-34.9; and severely obese, > or = 35.0). Models were adjusted for potential confounders.

RESULTS

In all of the participants, a positive association between increasing BMI and risk of pancreatic cancer was observed (adjusted OR for the highest vs lowest BMI quartile, 1.33; 95% CI, 1.12-1.58; P(trend) < .001). In men, the adjusted OR for pancreatic cancer for the highest vs lowest quartile of BMI was 1.33 (95% CI, 1.04-1.69; P(trend) < .03), and in women it was 1.34 (95% CI, 1.05-1.70; P(trend) = .01). Increased waist to hip ratio was associated with increased risk of pancreatic cancer in women (adjusted OR for the highest vs lowest quartile, 1.87; 95% CI, 1.31-2.69; P(trend) = .003) but less so in men.

CONCLUSIONS

These findings provide strong support for a positive association between BMI and pancreatic cancer risk. In addition, centralized fat distribution may increase pancreatic cancer risk, especially in women.

Lipoprotein particle size and concentration by nuclear magnetic resonance and incident type 2 diabetes in women

OBJECTIVE

Diabetic dyslipoproteinemia is characterized by low HDL cholesterol and high triglycerides. We examined the association of lipoprotein particle size and concentration measured by nuclear magnetic resonance (NMR) spectroscopy with clinical type 2 diabetes.

RESEARCH DESIGN AND METHODS

This was a prospective study of 26,836 initially healthy women followed for 13 years for incident type 2 diabetes (n = 1,687). Baseline lipids were measured directly and lipoprotein size and concentration by NMR. Cox regression models included nonlipid risk factors (age, race, smoking, exercise, education, menopause, blood pressure, BMI, family history, A1C, and C-reactive protein). NMR lipoproteins were also examined after further adjusting for standard lipids.

RESULTS

Incident diabetes was significantly associated with baseline HDL cholesterol, triglycerides, and NMR-measured size and concentration of LDL, IDL, HDL, and VLDL particles. The associations of these particles differed substantially by size. Small LDL(NMR) and small HDL(NMR) were positively associated with diabetes (quintile 5 vs. 1 [adjusted hazard ratios and 95% CIs], 4.04 [3.21-5.09] and 1.84 [1.54-2.19], respectively). By contrast, large LDL(NMR) and large HDL(NMR) were inversely associated (quintile 1 vs. 5, 2.50 [2.12-2.95] and 4.51 [3.68-5.52], respectively). For VLDL(NMR), large particles imparted higher risk than small particles (quintile 5 vs. 1, 3.11 [2.35-4.11] and 1.31 [1.10-1.55], respectively). Lipoprotein particle size remained significant after adjusting for standard lipids and nonlipid factors.

CONCLUSIONS

In this prospective study of women, NMR lipoprotein size and concentrations were associated with incident type 2 diabetes and remained significant after adjustment for established risk factors, including HDL cholesterol and triglycerides.

Mean leukocyte telomere length and risk of incident colorectal carcinoma in women: a prospective, nested case-control study

BACKGROUND

To date, no prospective epidemiological data are available, particularly in women, on mean leukocyte telomere length as a risk predictor.

METHODS

Using leukocyte DNA samples collected at baseline in a prospective cohort of over 28,000 initially healthy women, we examined the relationship between mean leukocyte telomere repeat copy number to single gene copy number (TSR) in 134 incident cases of colorectal carcinoma (CRC), and 357 matched controls; all were Caucasian.

RESULTS

The observed log(e)-transformed TSRs were similar between cases and controls (p=0.79). Using an adjusted analysis, we found no evidence for an association of the log(e)-TSRs with CRC risk [adjusted odds ratio (OR)=0.943, 95% confidence interval (CI)=0.647-1.376, p=0.762]. Stratified analysis by median follow-up time, or postmenopausal status also showed similar null findings.

CONCLUSIONS

In concordance with our previous findings in Caucasian men, the present study in Caucasian women found no evidence for an association of mean leukocyte telomere length with risk of incident CRC, further suggesting that leukocyte telomere length may not be a useful indicator for risk assessment.

Common variants in cardiac ion channel genes are associated with sudden cardiac death

BACKGROUND

Rare variants in cardiac ion channel genes are associated with sudden cardiac death in rare primary arrhythmic syndromes; however, it is unknown whether common variation in these same genes may contribute to sudden cardiac death risk at the population level.

METHODS AND RESULTS

We examined the association between 147 single nucleotide polymorphisms (SNPs) (137 tag, 5 noncoding SNPs associated with QT interval duration, and 5 nonsynonymous SNPs) in 5 cardiac ion channel genes, KCNQ1, KCNH2, SCN5A, KCNE1, and KCNE2, and sudden and/or arrhythmic death in a combined nested case-control analysis among 516 cases and 1522 matched control subjects of European ancestry enrolled in 6 prospective cohort studies. After accounting for multiple testing, 2 SNPs (rs2283222 located in intron 11 in KCNQ1 and rs11720524 located in intron 1 in SCN5A) remained significantly associated with sudden/arrhythmic death (false discovery rate=0.01 and 0.03, respectively). Each increasing copy of the major T-allele of rs2283222 or the major C-allele of rs1172052 was associated with an odds ratio of 1.36 (95% confidence interval, 1.16 to 1.60; P=0.0002) and 1.30 (95% confidence interval, 1.12 to 1.51; P=0.0005), respectively. Control for cardiovascular risk factors and/or limiting the analysis to definite sudden cardiac death did not significantly alter these relationships.

CONCLUSION

In this combined analysis of 6 prospective cohort studies, 2 common intronic variants in KCNQ1 and SCN5A were associated with sudden cardiac death in individuals of European ancestry. Further study in other populations and investigation into the functional abnormalities associated with noncoding variation in these genes may lead to important insights into predisposition to lethal arrhythmias.

Alcohol consumption, weight gain, and risk of becoming overweight in middle-aged and older women

BACKGROUND

The obesity epidemic is a major health problem in the United States. Alcohol consumption is a source of energy intake that may contribute to body weight gain and development of obesity. However, previous studies of this relationship have been limited, with inconsistent results.

METHODS

We conducted a prospective cohort study among 19 220 US women aged 38.9 years or older who were free of cardiovascular disease, cancer, and diabetes mellitus and had a baseline body mass index (BMI; calculated as weight in kilograms divided by height in meters squared) within the normal range of 18.5 to less than 25. Alcoholic beverage consumption was reported on a baseline questionnaire. Body weight was self-reported on baseline and 8 annual follow-up questionnaires.

RESULTS

There was an inverse association between amount of alcohol consumed at baseline and weight gained during 12.9 years of follow-up. A total of 7942 (41.3%) initially normal-weight women became overweight or obese (BMI > or =25) and 732 (3.8%) became obese (BMI > or =30). After adjusting for age, baseline BMI, smoking status, nonalcohol energy intake, physical activity level, and other lifestyle and dietary factors, the relative risks of becoming overweight or obese across total alcohol intake of 0, more than 0 to less than 5, 5 to less than 15, 15 to less than 30, and 30 g/d or more were 1.00, 0.96, 0.86, 0.70, and 0.73, respectively (P( )for trend( )<.001). The corresponding relative risks of becoming obese were 1.00, 0.75, 0.43, 0.39, and 0.29 (P( )for trend( )<.001). The associations were similar by subgroups of age, smoking status, physical activity level, and baseline BMI.

CONCLUSION

Compared with nondrinkers, initially normal-weight women who consumed a light to moderate amount of alcohol gained less weight and had a lower risk of becoming overweight and/or obese during 12.9 years of follow-up.

Association of resistin promoter polymorphisms with plasma resistin levels and type 2 diabetes in women and men

This study's objective was to examine the associations between resistin (RETN) polymorphisms, plasma resistin levels, and type 2 diabetes risk. We conducted two nested case-control studies in postmenopausal women (359 incident cases and 359 controls) and middle-aged/elderly men (170 incident cases and 170 controls). Controls were matched (1:1) to cases by age, race, duration of follow-up, and time of blood draw. Circulating resistin levels were higher among carriers of the variant allele for rs34861192 (p<0.0001 for women, p=0.002 for men) but not rs1862513 (p=0.15 for women, p=0.14 for men). Neither polymorphism was significantly associated with risk of type 2 diabetes after adjusting for diabetes risk factors (exercise, smoking status, alcohol intake, family history of diabetes, and matching factors) among women (rs1862513: OR=1.19, 95% CI=0.80-1.77; rs34861192: OR=0.41, 95% CI=0.14-1.19) and men (rs1862513: OR=1.05, 95% CI=0.57-1.95; rs34861192: OR=0.64, 95% CI=0.14-2.89). In conclusion, RETN promoter polymorphism rs34861192 was associated with elevated circulating resistin levels, but rs1862513 was not. Neither polymorphism was associated with an increased risk for type 2 diabetes.

Physical activity and weight gain prevention

CONTEXT

The amount of physical activity needed to prevent long-term weight gain is unclear. In 2008, federal guidelines recommended at least 150 minutes per week (7.5 metabolic equivalent [MET] hours per week) of moderate-intensity activity for "substantial health benefits."

OBJECTIVE

To examine the association of different amounts of physical activity with long-term weight changes among women consuming a usual diet.

DESIGN, SETTING, AND PARTICIPANTS

A prospective cohort study involving 34,079 healthy US women (mean age, 54.2 years) from 1992-2007. At baseline and months 36, 72, 96, 120, 144, and 156, women reported their physical activity and body weight. Women were classified as expending less than 7.5, 7.5 to less than 21, and 21 or more MET hours per week of activity at each time. Repeated-measures regression prospectively examined physical activity and weight change over intervals averaging 3 years.

MAIN OUTCOME MEASURE

Change in weight.

RESULTS

Women gained a mean of 2.6 kg throughout the study. A multivariate analysis comparing women expending 21 or more MET hours per week with those expending from 7.5 to less than 21 MET hours per week showed that the latter group gained a mean (SD) 0.11 kg (0.04 kg; P = .003) over a mean interval of 3 years, and those expending less than 7.5 MET hours per week gained 0.12 kg (0.04; P = .002). There was a significant interaction with body mass index (BMI), such that there was an inverse dose-response relation between activity levels and weight gain among women with a BMI of less than 25 (P for trend < .001) but no relation among women with a BMI from 25 to 29.9 (P for trend = .56) or with a BMI of 30.0 or higher (P for trend = .50). A total of 4540 women (13.3%) with a BMI lower than 25 at study start successfully maintained their weight by gaining less than 2.3 kg throughout. Their mean activity level over the study was 21.5 MET hours per week (approximately 60 minutes a day of moderate-intensity activity).

CONCLUSIONS

Among women consuming a usual diet, physical activity was associated with less weight gain only among women whose BMI was lower than 25. Women successful in maintaining normal weight and gaining fewer than 2.3 kg over 13 years averaged approximately 60 minutes a day of moderate-intensity activity throughout the study.

Genetic loci associated with plasma concentration of low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, triglycerides, apolipoprotein A1, and Apolipoprotein B among 6382 white women in genome-wide analysis with replication

BACKGROUND

Genome-wide genetic association analysis represents an opportunity for a comprehensive survey of the genes governing lipid metabolism, potentially revealing new insights or even therapeutic strategies for cardiovascular disease and related metabolic disorders.

METHODS AND RESULTS

We have performed large-scale, genome-wide genetic analysis among 6382 white women with replication in 2 cohorts of 970 additional white men and women for associations between common single-nucleotide polymorphisms and low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, triglycerides, apolipoprotein(Apo) A1, and ApoB. Genome-wide associations (P < 5 x 10(-8)) were found at the PCSK9 gene, the APOB gene, theLPL gene, the APOA1-APOA5 locus, the LIPC gene, the CETP gene, the LDLR gene, and the APOE locus. In addition,genome-wide associations with triglycerides at the GCKR gene confirm and extend emerging links between glucose and lipid metabolism. Still other genome-wide associations at the 1p13.3 locus are consistent with emerging biological properties for a region of the genome, possibly related to the SORT1 gene. Below genome-wide significance, our study provides confirmatory evidence for associations at 5 novel loci with low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, or triglycerides reported recently in separate genome-wide association studies. The total proportion of variance explained by common variation at the genome-wide candidate loci ranges from 4.3% for triglycerides to 12.6% for ApoB.

CONCLUSION

Genome-wide associations at the GCKR gene and near the SORT1 gene, as well as confirmatory associations at 5 additional novel loci, suggest emerging biological pathways for lipid metabolism among white women.

Plasma homocysteine and cysteine and risk of breast cancer in women

Homocysteine and cysteine are associated with oxidative damage and metabolic disorders, which may lead to carcinogenesis. Observational studies assessing the association between circulating homocysteine or cysteine and breast cancer are very limited, and findings have been inconsistent. We prospectively evaluated plasma levels of homocysteine and cysteine in relation to breast cancer risk among 812 incident cases of invasive breast cancer and 812 individually matched control subjects from 28,345 women in the Women's Health Study; these women were >or=45 years old, provided blood samples, and had no history of cancer and cardiovascular disease at baseline. Logistic regression controlling for matching factors and risk factors for breast cancer was used to estimate relative risks (RR) and 95% confidence intervals (95% CI). All statistical tests were two sided. Homocysteine levels were not associated with overall risk for breast cancer. However, we observed a positive association between cysteine levels and breast cancer risk; the multivariate RR for the highest quintile group relative to the lowest quintile was 1.65 (95% CI, 1.04-2.61; P for trend = 0.04). In addition, women with higher levels of homocysteine and cysteine were at a greater risk for developing breast cancer when their folate levels were low (P for interaction = 0.04 and 0.002, respectively). Although our study offers little support for an association between circulating homocysteine and overall breast cancer risk, higher homocysteine levels may be associated with an increased risk for breast cancer among women with low folate status. The increased risk of breast cancer associated with high cysteine levels warrants further investigation.

Tai Chi for osteopenic women: design and rationale of a pragmatic randomized controlled trial

Background

Post-menopausal osteopenic women are at increased risk for skeletal fractures. Current osteopenia treatment guidelines include exercise, however, optimal exercise regimens for attenuating bone mineral density (BMD) loss, or for addressing other fracture-related risk factors (e.g. poor balance, decreased muscle strength) are not well-defined. Tai Chi is an increasingly popular weight bearing mind-body exercise that has been reported to positively impact BMD dynamics and improve postural control, however, current evidence is inconclusive. This study will determine the effectiveness of Tai Chi in reducing rates of bone turnover in post-menopausal osteopenic women, compared with standard care, and will preliminarily explore biomechanical processes that might inform how Tai Chi impacts BMD and associated fracture risks.

Methods/Design

A total of 86 post-menopausal women, aged 45-70y, T-score of the hip and/or spine -1.0 and -2.5, have been recruited from primary care clinics of a large healthcare system based in Boston. They have been randomized to a group-based 9-month Tai Chi program plus standard care or to standard care only. A unique aspect of this trial is its pragmatic design, which allows participants randomized to Tai Chi to choose from a pre-screened list of community-based Tai Chi programs. Interviewers masked to participants' treatment group assess outcomes at baseline and 3 and 9 months after randomization. Primary outcomes are serum markers of bone resorption (C-terminal cross linking telopeptide of type I collagen), bone formation (osteocalcin), and BMD of the lumbar spine and proximal femur (dual-energy X-ray absorptiometry). Secondary outcomes include health-related quality-of-life, exercise behavior, and psychological well-being. In addition, kinetic and kinematic characterization of gait, standing, and rising from a chair are assessed in subset of participants (n = 16) to explore the feasibility of modeling skeletal mechanical loads and postural control as mediators of fracture risk.

Discussion

Results of this study will provide preliminary evidence regarding the value of Tai Chi as an intervention for decreasing fracture risk in osteopenic women. They will also inform the feasibility, value and potential limitations related to the use of pragmatic designs for the study of Tai Chi and related mind-body exercise. If the results are positive, this will help focus future, more in-depth, research on the most promising potential mechanisms of action identified by this study.

Trial registration

This trial is registered in Clinical Trials.gov, with the ID number of NCT01039012.

Association between a literature-based genetic risk score and cardiovascular events in women

CONTEXT

While multiple genetic markers associated with cardiovascular disease have been identified by genome-wide association studies, their aggregate effect on risk beyond traditional factors is uncertain, particularly among women.

OBJECTIVE

To test the predictive ability of a literature-based genetic risk score for cardiovascular disease.

DESIGN, SETTING, AND PARTICIPANTS

Prospective cohort of 19,313 initially healthy white women in the Women's Genome Health Study followed up over a median of 12.3 years (interquartile range, 11.6-12.8 years). Genetic risk scores were constructed from the National Human Genome Research Institute's catalog of genome-wide association study results published between 2005 and June 2009.

MAIN OUTCOME MEASURE

Incident myocardial infarction, stroke, arterial revascularization, and cardiovascular death.

RESULTS

A total of 101 single nucleotide polymorphisms reported to be associated with cardiovascular disease or at least 1 intermediate cardiovascular disease phenotype at a published P value of less than 10(-7) were identified and risk alleles were added to create a genetic risk score. During follow-up, 777 cardiovascular disease events occurred (199 myocardial infarctions, 203 strokes, 63 cardiovascular deaths, 312 revascularizations). After adjustment for age, the genetic risk score had a hazard ratio (HR) for cardiovascular disease of 1.02 per risk allele (95% confidence interval [CI], 1.00-1.03/risk allele; P = .006). This corresponds to an absolute cardiovascular disease risk of 3% over 10 years in the lowest tertile of genetic risk (73-99 risk alleles) and 3.7% in the highest tertile (106-125 risk alleles). However, after adjustment for traditional factors, the genetic risk score did not improve discrimination or reclassification (change in c index from Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults [ATP III] risk score, 0; net reclassification improvement, 0.5%; [P = .24]). The genetic risk score was not associated with cardiovascular disease risk (ATP III-adjusted HR/allele, 1.00; 95% CI, 0.99-1.01). In contrast, self-reported family history remained significantly associated with cardiovascular disease in multivariable models.

CONCLUSION

After adjustment for traditional cardiovascular risk factors, a genetic risk score comprising 101 single nucleotide polymorphisms was not significantly associated with the incidence of total cardiovascular disease.

Vitamin E and age-related macular degeneration in a randomized trial of women

OBJECTIVE

To test whether alternate day vitamin E affects the incidence of age-related macular degeneration (AMD) in a large-scale randomized trial of women.

DESIGN

Randomized, double-masked, placebo-controlled trial.

PARTICIPANTS

Thirty-nine thousand eight hundred seventy-six apparently healthy female health professionals aged 45 years or older.

INTERVENTION

Participants were assigned randomly to receive either 600 IU of natural-source vitamin E on alternate days or placebo.

MAIN OUTCOME MEASURES

Incident AMD responsible for a reduction in best-corrected visual acuity to 20/30 or worse based on self-report confirmed by medical record review.

RESULTS

After 10 years of treatment and follow-up, there were 117 cases of AMD in the vitamin E group and 128 cases in the placebo group (relative risk, 0.93; 95% confidence interval, 0.72-1.19).

CONCLUSIONS

In a large-scale randomized trial of female health professionals, long-term alternate-day use of 600 IU of natural-source vitamin E had no large beneficial or harmful effect on risk of AMD.

MTHFR 677C->T and ACE D/I polymorphisms and migraine attack frequency in women

Data on the association of the MTHFR 677C→T and ACE D/I polymorphisms with migraine severity, measured by attack frequency, are scarce. We performed an association study among 24 961 women participating in the Women's Health Study. Migraine, aura status and attack frequency were self-reported. Multinomial logistic regression was used to investigate the genotype-migraine association. Among the 3186 migraineurs with complete genotype and attack frequency data, 1270 reported migraine with aura (MA) (attack frequency 76 ≥ weekly; 219 monthly; 123 every other month; 852 fewer than six times/year) and 1916 migraine without aura (MoA) (attack frequency: 85 ≥ weekly; 414 monthly; 208 every other month; 1209 fewer than six times/year). The MTHFR 677TT genotype was associated with a reduced risk for MA, which only appeared for attacks fewer than six times/year (age-adjusted odds ratio 0.78; 95% confidence interval 0.61, 0.99). We did not find a specific pattern of association of the ACE D/I polymorphism with attack frequency for MA or MoA.

Pancreatic cancer risk and ABO blood group alleles: results from the pancreatic cancer cohort consortium

A recent genome-wide association study (PanScan) identified significant associations at the ABO gene locus with risk of pancreatic cancer, but the influence of specific ABO genotypes remains unknown. We determined ABO genotypes (OO, AO, AA, AB, BO, and BB) in 1,534 cases and 1,583 controls from 12 prospective cohorts in PanScan, grouping participants by genotype-derived serologic blood type (O, A, AB, and B). Adjusted odds ratios (ORs) for pancreatic cancer by ABO alleles were calculated using logistic regression. Compared with blood type O, the ORs for pancreatic cancer in subjects with types A, AB, and B were 1.38 [95% confidence interval (95% CI), 1.18-1.62], 1.47 (95% CI, 1.07-2.02), and 1.53 (95% CI, 1.21-1.92), respectively. The incidence rates for blood types O, A, AB, and B were 28.9, 39.9, 41.8, and 44.5 cases per 100,000 subjects per year. An increase in risk was noted with the addition of each non-O allele. Compared with OO genotype, subjects with AO and AA genotype had ORs of 1.33 (95% CI, 1.13-1.58) and 1.61 (95% CI, 1.22-2.18), whereas subjects with BO and BB genotypes had ORs of 1.45 (95% CI, 1.14-1.85) and 2.42 (1.28-4.57). The population attributable fraction for non-O blood type was 19.5%. In a joint model with smoking, current smokers with non-O blood type had an adjusted OR of 2.68 (95% CI, 2.03-3.54) compared with nonsmokers of blood type O. We concluded that ABO genotypes were significantly associated with pancreatic cancer risk.

Migraine, migraine features, and cardiovascular disease

BACKGROUND

Many studies support an association between migraine and cardiovascular disease (CVD). This association appears particularly in migraine with aura and is also modified by additional factors.

OBJECTIVE

We sought to investigate whether the association between migraine and CVD in addition to aura status is affected by certain migraine features.

METHODS

Cohort study among 27,840 women, participating in the Women's Health Study. We had detailed self-reported information on migraine and migraine features among women with active migraine (migraine during the year prior to baseline). Incident CVD events were confirmed after medical record review. We used Cox proportional hazards models to evaluate the association between migraine and incident CVD. The results have been presented in part before. We ran additional analyses according to migraine features.

RESULTS

At baseline, 5125 (18.4%) women reported history of migraine; 39.7% of the 3610 women with active migraine indicated aura. During a mean of 11.9 years of follow-up, 708 CVD events occurred. Migraine with aura doubled the risk for CVD, ischemic stroke, and myocardial infarction. With regard to ischemic stroke, this association seemed stronger in the absence than in the presence of migraine features. This was most pronounced in the absence (hazard ratio = 3.27; 95% CI = 1.93-5.51; P < .0001) than in the presence of nausea/vomiting (hazard ratio = 0.91; 95% CI = 0.43-1.93; P = .80). In contrast, the association with myocardial infarction did not reveal a certain pattern.

CONCLUSIONS

These data suggest that the association between migraine with aura and ischemic stroke may differ by absence or presence of migraine features.

Alcohol consumption and functional outcome after stroke in men

BACKGROUND AND PURPOSE

Light-to-moderate alcohol consumption has been associated with reduced risk of total and ischemic stroke. However, data on the relationship between alcohol consumption and functional outcomes from stroke are sparse.

METHODS

Prospective cohort study among 21 860 men enrolled in the Physicians' Health Study who provided information on alcohol consumption at baseline and had no prior history of stroke or transient ischemic attack (TIA). Alcohol consumption was divided into 5 categories: <1 drink/wk, 1 drink/wk, 2 to 4 drinks/wk, 5 to 6 drinks/wk, and >/=1 drink/d. Possible functional outcomes included TIA, modified Rankin Scale (mRS)=0 to 1, mRS=2 to 3, and mRS=4 to 6. We used multinomial logistic regression to evaluate the relationship between levels of alcohol consumption and functional outcomes from stroke.

RESULTS

During a mean of 21.6 years of follow-up, 766 TIAs and 1393 strokes (1157 ischemic, 222 hemorrhagic, and 14 unknown type) occurred. Men who consumed 1 drink/wk had lowest associated odds for any outcome. Compared with men who did not experience a TIA or stroke and who consumed <1 drink/wk, men who consumed 1 drink/wk had odds ratio (95% CI) for total stroke of 0.85 (0.60 to 1.21) for mRS=0 to 1, 0.84 (0.64 to 1.10) for mRS=2 to 3, and 0.60 (0.37 to 0.97) for mRS=4 to 6. The odds ratio for TIA was 0.95 (0.73 to 1.23). The pattern of association did not substantially differ for ischemic and hemorrhagic stroke. Higher alcohol consumption showed no association with functional outcome after stroke.

CONCLUSIONS

Our data do not show strong associations between alcohol consumption and functional outcome after stroke. Modest beneficial associations exist with low alcohol consumption.

Migraine and cardiovascular disease: systematic review and meta-analysis

OBJECTIVE

To evaluate the association between migraine and cardiovascular disease, including stroke, myocardial infarction, and death due to cardiovascular disease.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

Electronic databases (PubMed, Embase, Cochrane Library) and reference lists of included studies and reviews published until January 2009. Selection criteria Case-control and cohort studies investigating the association between any migraine or specific migraine subtypes and cardiovascular disease. Review methods Two investigators independently assessed eligibility of identified studies in a two step approach. Disagreements were resolved by consensus. Studies were grouped according to a priori categories on migraine and cardiovascular disease.

DATA EXTRACTION

Two investigators extracted data. Pooled relative risks and 95% confidence intervals were calculated.

RESULTS

Studies were heterogeneous for participant characteristics and definition of cardiovascular disease. Nine studies investigated the association between any migraine and ischaemic stroke (pooled relative risk 1.73, 95% confidence interval 1.31 to 2.29). Additional analyses indicated a significantly higher risk among people who had migraine with aura (2.16, 1.53 to 3.03) compared with people who had migraine without aura (1.23, 0.90 to 1.69; meta-regression for aura status P=0.02). Furthermore, results suggested a greater risk among women (2.08, 1.13 to 3.84) compared with men (1.37, 0.89 to 2.11). Age less than 45 years, smoking, and oral contraceptive use further increased the risk. Eight studies investigated the association between migraine and myocardial infarction (1.12, 0.95 to 1.32) and five between migraine and death due to cardiovascular disease (1.03, 0.79 to 1.34). Only one study investigated the association between women who had migraine with aura and myocardial infarction and death due to cardiovascular disease, showing a twofold increased risk.

CONCLUSION

Migraine is associated with a twofold increased risk of ischaemic stroke, which is only apparent among people who have migraine with aura. Our results also suggest a higher risk among women and risk was further magnified for people with migraine who were aged less than 45, smokers, and women who used oral contraceptives. We did not find an overall association between any migraine and myocardial infarction or death due to cardiovascular disease. Too few studies are available to reliably evaluate the impact of modifying factors, such as migraine aura, on these associations.

Mean telomere length and risk of incident colorectal carcinoma: a prospective, nested case-control approach

Recent studies have shown telomere length shortening in colorectal carcinoma (CRC). However, to date, no prospective, epidemiologic data are available on examining mean leukocyte telomere length as a risk predictor. Using leukocyte DNA samples collected at baseline in a prospective cohort of 14,916 initially healthy American men, we examined the relationship of mean telomere repeat copy number to single gene copy number (T/S ratio), using a modified quantitative PCR protocol, among 191 incident CRC cases (all white males), matched to 306 controls by age, smoking status, and length of follow-up. An inverse correlation between T/S ratio and age was observed in our sample population (P = 0.038). However, the T/S ratios were similar between cases and controls (P = 0.650). Furthermore, in a multivariable adjusted analysis, we found no evidence for an association of the observed T/S ratios with CRC risk (adjusted odds ratio, 1.249; 95% confidence interval, 0.863-1.808; P = 0.238). In summary, the present investigation found no evidence for an association of leukocyte mean telomere length with risk of incident CRC and further suggests that leukocyte mean telomere length may not be a useful indicator for risk assessment.

Low-dose aspirin and medical record-confirmed age-related macular degeneration in a randomized trial of women

OBJECTIVE

To test whether alternate-day low-dose aspirin affects incidence of age-related macular degeneration (AMD) in a large-scale randomized trial of women.

DESIGN

Randomized, double-masked, placebo-controlled trial.

PARTICIPANTS

Thirty-nine thousand eight hundred seventy-six healthy female health professionals aged 45 years or older.

INTERVENTION

Participants were assigned randomly to receive either 100 mg aspirin on alternate days or placebo and were followed up for the presence of AMD for an average of 10 years.

MAIN OUTCOME MEASURES

Incident AMD responsible for a reduction in best-corrected visual acuity to 20/30 or worse based on self-report confirmed by medical record review.

RESULTS

After 10 years of treatment and follow-up, there were 111 cases of AMD in the aspirin group and 134 cases in the placebo group (hazard ratio, 0.82; 95% confidence interval, 0.64-1.06).

CONCLUSIONS

In a large-scale randomized trial of female health professionals with 10 years of treatment and follow-up, low-dose aspirin had no large beneficial or harmful effect on risk of AMD.

Sex hormone-binding globulin and risk of type 2 diabetes in women and men

BACKGROUND

Circulating sex hormone-binding globulin levels are inversely associated with insulin resistance, but whether these levels can predict the risk of developing type 2 diabetes is uncertain.

METHODS

We performed a nested case-control study of postmenopausal women in the Women's Health Study who were not using hormone therapy (359 with newly diagnosed type 2 diabetes and 359 controls). Plasma levels of sex hormone-binding globulin were measured; two polymorphisms of the gene encoding sex hormone-binding globulin, SHBG, that were robustly associated with the protein levels were genotyped and applied in mendelian randomization analyses. We then conducted a replication study in an independent cohort of men from the Physicians' Health Study II (170 with newly diagnosed type 2 diabetes and 170 controls).

RESULTS

Among women, higher plasma levels of sex hormone-binding globulin were prospectively associated with a lower risk of type 2 diabetes: multivariable odds ratios were 1.00 for the first (lowest) quartile of plasma levels, 0.16 (95% confidence interval [CI], 0.08 to 0.33) for the second quartile, 0.04 (95% CI, 0.01 to 0.12) for the third quartile, and 0.09 (95% CI, 0.03 to 0.21) for the fourth (highest) quartile (P<0.001 for trend). These prospective associations were replicated among men (odds ratio for the highest quartile of plasma levels vs. the lowest quartile, 0.10; 95% CI, 0.03 to 0.36; P<0.001 for trend). As compared with homozygotes of the respective wild-type allele, carriers of a variant allele of the SHBG single-nucleotide polymorphism (SNP) rs6259 had 10% higher sex hormone-binding globulin levels (P=0.005), and carriers of an rs6257 variant had 10% lower plasma levels (P=0.004); variants of both SNPs were also associated with a risk of type 2 diabetes in directions corresponding to their associated sex hormone-binding globulin levels. In mendelian randomization analyses, the predicted odds ratio of type 2 diabetes per standard-deviation increase in the plasma level of sex hormone-binding globulin was 0.28 (95% CI, 0.13 to 0.58) among women and 0.29 (95% CI, 0.15 to 0.58) among men, a finding that suggests that sex hormone-binding globulin may have a causal role in the risk of type 2 diabetes.

CONCLUSIONS

Low circulating levels of sex hormone-binding globulin are a strong predictor of the risk of type 2 diabetes in women and men. The clinical usefulness of both SHBG genotypes and plasma levels in stratification and intervention for the risk of type 2 diabetes warrants further examination.