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Meir J Stampfer

Publications and source records attributed to Meir J Stampfer.

At least 37 records · Page 2Linked to original sources
PubMed2006

Physical exertion, exercise, and sudden cardiac death in women.

CONTEXT: Exercise is associated with a lower risk of cardiovascular events but may transiently increase the risk of ventricular arrhythmias. Its short-term and long-term associations with risk of sudden cardiac death among women are unclear. OBJECTIVES: To compare the risk of sudden cardiac death in women during moderate to vigorous exertion with the risk of sudden cardiac death during lighter or no exertion; and to assess the long-term association between moderate to vigorous exercise and sudden cardiac death. DESIGN, SETTING, AND PARTICIPANTS: Prospective, nested case-crossover study of 288 cases of sudden cardiac death within the Nurses' Health Study (1980-2004); and a prospective cohort analysis of 69,693 participants without prior cardiovascular disease followed up from 1986-2004. MAIN OUTCOME MEASURE: Risk of sudden cardiac death associated with moderate to vigorous exertion. RESULTS: The absolute risk of sudden cardiac death associated with moderate to vigorous exertion was exceedingly low at 1 per 36.5 million hours of exertion. In case-crossover analyses, the risk of sudden cardiac death was transiently elevated during moderate to vigorous exertion (relative risk [RR], 2.38; 95% confidence interval [CI], 1.23-4.60; P = .01) compared with the risk during lesser or no exertion. Habitual moderate to vigorous exertion modified this transient risk (P = .005 for interaction) and the risk was no longer significantly elevated among those who exercised 2 or more hours per week. In the cohort analyses, an increasing amount of moderate to vigorous exercise was associated with a lower long-term risk of sudden cardiac death in age-adjusted and multivariable models that excluded biological intermediates (P = .006 for trend). This relationship was attenuated when biological intermediates were included (P = .06 for trend); however, the reduction in risk remained significant among women who exercised 4 or more hours per week (adjusted RR, 0.41; 95% CI, 0.20-0.83; P = .01) compared with women who did not exercise. CONCLUSIONS: These prospective data suggest that sudden cardiac death during exertion is an extremely rare event in women. Regular exercise may significantly minimize this small transient risk and may lower the overall long-term risk of sudden cardiac death.

Adult↗
PubMed2006

Obesity as compared with physical activity in predicting risk of coronary heart disease in women.

BACKGROUND: The comparative importance of physical inactivity and obesity as predictors of coronary heart disease (CHD) risk remains unsettled. METHODS AND RESULTS: We followed 88 393 women, 34 to 59 years of age, in the Nurses' Health Study from 1980 to 2000. These participants did not have cardiovascular disease and cancer at baseline. We documented 2358 incident major CHD events (including nonfatal myocardial infarction and fatal CHD) during 20 years of follow-up, including 889 cases of fatal CHD and 1469 cases of nonfatal myocardial infarction. In a multivariate model adjusting for cardiovascular risk factors, overweight and obesity were significantly associated with increased risk of CHD, whereas increasing levels of physical activity were associated with a graded reduction in CHD risk (P<0.001). In joint analyses of body mass index (BMI) and physical activity in women who had a healthy weight (BMI, 18.5 to 24.9 kg/m2) and were physically active (exercise > or =3.5 h/wk) as the reference group, the relative risks of CHD were 3.44 (95% confidence interval [CI], 2.81 to 4.21) for women who were obese (BMI > or =30 kg/m2) and sedentary (exercise <1 h/wk), 2.48 (95% CI, 1.84 to 3.34) for women who were active but obese, and 1.48 (95% CI, 1.24 to 1.77) for women who had a healthy weight but were sedentary. In combined analyses of waist-hip ratio and physical activity, both waist-hip ratio and physical activity were significant predictors of CHD, and the highest risk was among women in the lowest category of physical activity and the highest tertile of waist-hip ratio (relative risk=3.03; 95% CI, 1.96 to 4.18). Even a modest weight gain (4 to 10 kg) during adulthood was associated with 27% (95% CI, 12% to 45%) increased risk of CHD compared with women with a stable weight after adjusting for physical activity and other cardiovascular risk factors. CONCLUSIONS: Obesity and physical inactivity independently contribute to the development of CHD in women. These data underscore the importance of both maintaining a healthy weight and regular physical activity in preventing CHD.

Adult↗
PubMed2006

Diet after diagnosis and the risk of prostate cancer progression, recurrence, and death (United States).

OBJECTIVES: We examined post-diagnostic diet and risk of cancer progression in a cohort of men with prostate cancer from the Health Professionals Follow-up Study. METHODS: We observed 392 progression outcomes among 1,202 men diagnosed with incident localized/regional prostate cancer between 1986 and 1996. Men completed prospective dietary surveys before and after diagnosis and were followed through 2000. We examined post-diagnostic consumption of red meat, grains, vegetables, fruits, milk, tomatoes, tomato sauce, and fish as predictors of progression using Cox proportional hazard regression models adjusted for total energy, age, clinical factors, and pre-diagnostic diet. RESULTS: Men in the highest versus lowest quartile of post-diagnostic fish consumption had a multivariate hazard ratio (HR) of progression of 0.73 (95% CI 0.52-1.02); the comparable HR for tomato sauce was 0.56 (95% CI 0.38-0.82). We observed inverse linear relationships for fish and tomato sauce and risk of progression (HR = 0.83, p-value = 0.006 and HR = 0.80, p-value = 0.04 for a two serving/week increase of fish and tomato sauce, respectively). Milk and fresh tomato consumption were associated with small elevations in risk. CONCLUSIONS: These data suggest that diet after diagnosis may influence the clinical course of prostate cancer, and fish and tomato sauce may offer some protection against disease progression.

Adult↗
PubMed2006

Relation of anthropometric measurements to ovarian cancer risk in a population-based case-control study (United States).

OBJECTIVE: To examine the relationship between anthropometric measures and ovarian cancer by menopausal status. METHODS: We analyzed data from a population-based case-control study comprised of 700 incident cases of epithelial ovarian cancer and 5,943 population controls from Massachusetts and Wisconsin enrolled between 1993 and 2001. In a telephone interview, information was gathered on established ovarian cancer risk factors, as well as adult height and age-specific body weight. Logistic regression was used to estimate multivariate-adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for body mass index (BMI) throughout life. RESULTS: Recent BMI had no significant association with ovarian cancer risk (P-trend 0.14 for continuous BMI), after adjustment for age and other ovarian cancer risk factors. However, a non-significant positive association (overall P-trend 0.08) was observed for BMI at age 20; the risk estimate comparing a body mass of >25 kg/m2 to the lowest quintile (<or=18.88 kg/m2) was moderately but non-significantly elevated (OR 1.46; 95% CI 0.92, 2.31). CONCLUSION: Results of this study suggest that maintenance of a lean body mass, particularly in early adult life, may decrease ovarian cancer risk.

Adult↗
PubMed2006

A prospective study of fish, marine fatty acids, and bladder cancer risk among men and women (United States).

OBJECTIVE: To evaluate prospectively the association between intakes of fish, marine fatty acids, and bladder cancer risk in two ongoing cohorts, the Health Professionals Follow-up Study and the Nurses' Health Study. METHODS: During 16 and 18 years of follow-up, 501 and 235 incident cases of bladder cancer were diagnosed among men and women, respectively. Cox proportional hazard models were used to estimate incidence rate ratios (RR) and 95% confidence intervals (CI) between fish intake and bladder cancer risk adjusting for age, total caloric intake, pack-years of cigarette smoking, and current smoking. RESULTS: We observed no significant overall association between total fish intake and bladder cancer risk, even when we compared >/=1 servings of fish per day to fish intake </=1-3 servings per month. Among men, a statistically significant lower risk of bladder cancer was observed among men consuming fish or high marine fatty acid, after excluding the first 4 years of follow-up (MV RR = 0.60; 95% CI, 0.38-0.94, for >/=1 total fish servings per day compared to </=1-3 servings per month). CONCLUSIONS: Overall, these findings suggest that fish intake is not likely to be appreciably associated with the risk of bladder cancer.

Adult↗
PubMed2006

Potato and french fry consumption and risk of type 2 diabetes in women.

BACKGROUND: Potatoes, a high glycemic form of carbohydrate, are hypothesized to increase insulin resistance and risk of type 2 diabetes. OBJECTIVE: The objective was to examine prospectively the relation between potato consumption and the risk of type 2 diabetes. DESIGN: We conducted a prospective study of 84,555 women in the Nurses' Health Study. At baseline, the women were aged 34-59 y, had no history of chronic disease, and completed a validated food-frequency questionnaire. The participants were followed for 20 y with repeated assessment of diet. RESULTS: We documented 4496 new cases of type 2 diabetes. Potato and french fry consumption were both positively associated with risk of type 2 diabetes after adjustment for age and dietary and nondietary factors. The multivariate relative risk (RR) in a comparison between the highest and the lowest quintile of potato intake was 1.14 (95% CI: 1.02, 1.26; P for trend = 0.009). The multivariate RR in a comparison between the highest and the lowest quintile of french fry intake was 1.21 (95% CI: 1.09, 1.33; P for trend < 0.0001). The RR of type 2 diabetes was 1.18 (95% CI: 1.03, 1.35) for 1 daily serving of potatoes and 1.16 (95% CI: 1.05, 1.29) for 2 weekly servings of french fries. The RR of type 2 diabetes for substituting 1 serving potatoes/d for 1 serving whole grains/d was 1.30 (95% CI: 1.08, 1.57). The association between potato consumption and risk of type 2 diabetes was more pronounced in obese women. CONCLUSIONS: Our findings suggest a modest positive association between the consumption of potatoes and the risk of type 2 diabetes in women. This association was more pronounced when potatoes were substituted for whole grains.

Adult↗
PubMed2006

Meat intake and bladder cancer risk in 2 prospective cohort studies.

BACKGROUND: Nitrosamines, which are known bladder carcinogens, or their precursors are found in certain meat items, and concentrations of these compounds are especially high in bacon. Only 3 cohort studies, all with <100 case subjects, have examined the relation between meat intake and bladder cancer, and few studies have examined the relation of different meat types with bladder cancer. OBJECTIVE: The aim was to examine the association between specific meat items and bladder cancer in 2 large prospective studies. DESIGN: We analyzed data from 2 cohorts with up to 22 y of follow-up and 808 incident bladder cancer cases. Detailed data on meat were obtained from multiple food-frequency questionnaires administered over time. Multivariate relative risks (RRs) and 95% CIs were estimated by using Cox proportional hazards models with control for potential confounders, including detailed smoking history. RESULTS: Men and women with a high intake of bacon (>/=5 servings/wk) had an elevated risk of bladder cancer compared with those who never ate bacon (multivariate RR = 1.59; 95% CI = 1.06, 2.37), although the overall association was not statistically significant (P for trend = 0.06). However, the association with bacon was stronger and became statistically significant after the removal of individuals who indicated having "greatly" changed their red meat (men) or bacon (women) intake during the 10 y before baseline (multivariate RR = 2.10; 95% CI = 1.24, 3.55; P for trend = 0.006). A positive association was also detected for intake of chicken without skin, but not for chicken with skin or for other meats, including processed meats, hot dogs, and hamburgers. CONCLUSIONS: In these 2 cohorts combined, frequent consumption of bacon was associated with an elevated risk of bladder cancer. Other studies with data on specific meat items are necessary to confirm our findings.

Adult↗
PubMed2006

Plasma C-peptide and cognitive performance in older men without diabetes.

BACKGROUND: Emerging evidence suggests that type 2 diabetes may be related to diminished cognition, but little data are available directly regarding the role of insulin levels. OBJECTIVE: The objective of this prospective cohort study was to examine the relation of insulin secretion to cognitive function among men without diabetes. SETTING: The study setting was the Physicians' Health Study-U.S. male physicians. PARTICIPANTS: Three hundred sixty-seven men who provided blood samples in 1982, when they had no lifetime history of diabetes and ranged in age from 47-65 years (mean age: 57 years). MEASUREMENTS: The authors assayed plasma C-peptide, reflecting insulin secretion, in the stored blood samples. Beginning in 2001, an average 18 years after blood collection, the authors administered telephone interviews, including tests of general cognition (Telephone Interview of Cognitive Status [TICS]), verbal memory, and category fluency. The authors used regression models to estimate mean differences in cognitive performance across levels of C-peptide controlling for a wide variety of potential confounding factors. RESULTS: On the TICS, men in the top tertile of C-peptide performed significantly worse than those in the bottom (multivariable-adjusted mean difference: -1.01 points, 95% confidence interval: -1.78 to -0.24); this apparent impact of C-peptide on cognition was equivalent to the cognitive differences the authors observed between men 6 years apart in age. Performance on the global score (combining results from all the individual tests) and verbal memory score (combining results from four tests of verbal memory) appeared lower among men in the highest C-peptide tertile, but results were not statistically significant. CONCLUSION: Higher midlife insulin secretion may be related to decreased later-life cognitive function, even among men without diabetes.

C-Peptide↗
PubMed2006

A prospective study of calcium intake and incident and fatal prostate cancer.

Prostate cancer is the most common incident cancer and the second leading cause of cancer mortality in U.S. males. Higher milk intake has been relatively consistently associated with an increased risk of prostate cancer, especially advanced prostate cancer. Some data suggest that high intake of calcium might account for this association, but this relationship remains controversial. We hypothesized that high calcium intake, possibly by lowering 1,25(OH)2 vitamin D levels, is associated with poorer differentiation in prostate cancer and thereby with fatal prostate cancer. We examined calcium intake in relation to prostate cancer risk using data from the Health Professionals Follow-up Study, a prospective cohort study of 47,750 male health professionals with no history of cancer other than nonmelanoma skin cancer at baseline. We assessed total, dietary, and supplementary calcium intake in 1986, 1990, 1994, and 1998, using a validated food frequency questionnaire. We calculated the multivariable relative risk (RR) and 95% confidence intervals (95% CI) using Cox proportional hazards regression. Over 16 years of follow-up, we identified 3,544 total cases of prostate cancer, 523 advanced (extraprostatic) cases, and 312 fatal cases. Higher calcium intake was not appreciably associated with total or nonadvanced prostate cancer but was associated with a higher risk of advanced and fatal prostate cancer [for fatal prostate cancer, compared with men whose long-term calcium intake was 500-749 mg/d (excluding supplement use of <5 years); those with intakes of 1,500-1,999 mg/d had a RR, 1.87; 95% CI, 1.17-3.01; and those with > or = 2,000 mg/d had a RR, 2.43; 95% CI, 1.32-4.48; P(trend) = 0.003]. Dietary calcium and supplementary calcium were independently associated with an increased risk. For high-grade prostate cancer (Gleason > or = 7), an association was observed for high versus low calcium intake (RR, 1.89; 95% CI, 1.32-2.71; P(trend) = 0.005), but a nonsignificant, inverse association was observed for organ-confined, low-grade prostate cancer (RR, 0.79; 95% CI, 0.50-1.25; P(trend) = 0.09). In a sample of this cohort, higher calcium intake was associated with lower circulating 1,25(OH)2 vitamin D levels. Our findings suggest that calcium intakes exceeding 1,500 mg/d may be associated with a decrease in differentiation in prostate cancer and ultimately with a higher risk of advanced and fatal prostate cancer but not with well-differentiated, organ-confined cancers.

Adult↗
PubMed2006

Ethnicity, obesity, and risk of type 2 diabetes in women: a 20-year follow-up study.

OBJECTIVE: To examine ethnic differences in risk of type 2 diabetes, taking dietary and lifestyle risk factors into account. RESEARCH DESIGN AND METHODS: A prospective (1980-2000) cohort (from The Nurses' Health Study) including 78,419 apparently healthy women (75,584 whites, 801 Asians, 613 Hispanics, and 1,421 blacks) was studied. Detailed dietary and lifestyle information for each participant was repeatedly collected every 4 years. RESULTS: During 1,294,799 person-years of follow-up, we documented 3,844 incident cases of diabetes. Compared with whites, the age-adjusted relative risks (RRs) were 1.43 (95% CI 1.08-1.90) for Asians, 1.76 (1.32-2.34) for Hispanics, and 2.18 (1.82-2.61) for blacks. After adjustment for BMI, the RRs changed to 2.26 (1.70-2.99) for Asians, 1.86 (1.40-2.47) for Hispanics, and 1.34 (1.12-1.61) for blacks. For each 5-unit increment in BMI, the multivariate RR of diabetes was 2.36 (1.83-3.04) for Asians, 2.21 (1.75-2.79) for Hispanics, 1.96 (1.93-2.00) for whites, and 1.55 (1.36-1.77) for blacks (P for interaction <0.001). For each 5-kg weight gain between age 18 and the year 1980, the risk of diabetes was increased by 84% (95% CI 58-114) for Asians, 44% (26-63) for Hispanics, 38% (28-49) for blacks, and 37% (35-38%) for whites. A healthy diet high in cereal fiber and polyunsaturated fat and low in trans fat and glycemic load was more strongly associated with a lower risk of diabetes among minorities (RR 0.54 [95% CI 0.39-0.73]) than among whites (0.77 [0.72-0.84]). CONCLUSIONS: The risk of diabetes is significantly higher among Asians, Hispanics, and blacks than among whites before and after taking into account differences in BMI. Weight gain is particularly detrimental for Asians. Our data suggest that the inverse association of a healthy diet with diabetes is stronger for minorities than for whites.

Adult↗
PubMed2005

Dyslipidemia and the risk of incident hypertension in men.

Evidence suggests that hypertension may share a similar pathophysiology with cardiovascular disease (CVD). Thus, dyslipidemia, a strong predictor of CVD, may also predict incident hypertension. We analyzed 3110 men free of hypertension, CVD, and cancer from the Physicians' Health Study, who provided baseline blood samples from which we measured total cholesterol (TC) and HDL cholesterol (HDL-C), and calculated non-HDL-C and the TC/HDL-C ratio. We categorized each lipid parameter into quintiles and considered National Cholesterol Education Project clinical cut points. Other risk factor information was provided from self-reports on the baseline questionnaire. Incident hypertension was defined as either the initiation of antihypertensive treatment, self-reported systolic blood pressure > or =140 mm Hg, or diastolic blood pressure > or =90 mm Hg. Over a mean follow-up of 14.1 years, 1019 men developed hypertension. In Cox proportional hazards models adjusted for lifestyle and clinical risk factors, men in the highest quintile of TC, non-HDL-C, and TC/HDL-C ratio had increased risks of developing hypertension of 23%, 39%, and 54%, respectively, compared with participants in the lowest quintile. Furthermore, men in the highest quintile of HDL-C had a 32% decreased risk of developing hypertension compared with those in the lowest quintile. Models using National Cholesterol Education Project cut points demonstrated similar associations with hypertension. Models excluding men with diabetes and obesity maintained an independent association between baseline lipids and hypertension. These prospective cohort data suggest that dyslipidemias may lead to the subsequent development of hypertension. Thus, plasma lipids may be useful in the identification of men at risk for hypertension.

Adult↗
PubMed2005

Non-high-density lipoprotein cholesterol and apolipoprotein B in the prediction of coronary heart disease in men.

BACKGROUND: Apolipoprotein B (apoB) plasma levels reflect the concentration of proatherogenic lipoproteins very low-density lipoprotein and low-density lipoprotein (LDL), whereas non-high-density lipoprotein cholesterol (non-HDL-C) levels reflect the concentration of cholesterol transported by these particles. METHODS AND RESULTS: The aim of our study was to compare apoB, non-HDL-C, LDL cholesterol (LDL-C), and other lipid markers as predictors of coronary heart disease (CHD) in a nested case-control study among 18 225 participants in the Health Professionals Follow-up Study. Among men who were free of diagnosed cardiovascular disease at the time of blood collection, 266 had nonfatal myocardial infarction or fatal CHD during 6 years of follow-up. Through the use of risk set sampling, control subjects were selected at a 2:1 ratio and matched with regard to age, date of blood collection, and smoking status. After adjustment for matching factors, the relative risk of CHD in the highest quintile compared with the lowest quintile was 2.76 (95% confidence interval [CI], 1.66 to 4.58) for non-HDL-C, 3.01 (95% CI, 1.81 to 5.00) for apoB, 1.81 (95% CI, 1.12 to 2.93) for LDL-C, 0.31 (95% CI, 0.18 to 0.52) for HDL-C, 2.41 (95% CI, 1.43 to 4.07) for triglycerides (all P trend <0.001), and 1.42 (95% CI, 0.86 to 2.32, P trend =0.19) for lipoprotein(a). When non-HDL-C and LDL-C were mutually adjusted, only non-HDL-C was predictive of CHD. When non-HDL-C and apoB were mutually adjusted, only apoB was predictive; the relative risk was 4.18 (95% CI, 1.30 to 13.49; P trend =0.02) for apoB compared with 0.70 (95% CI, 0.21 to 2.27; P trend =0.72) for non-HDL-C. Triglycerides added significant information to non-HDL-C but not to apoB for CHD risk prediction. CONCLUSIONS: Although non-HDL-C and apoB were both strong predictors of CHD in this male cohort, more so than LDL-C, the findings support the concept that the plasma concentration of atherogenic lipoprotein particles measured by apoB is more predictive in development of CHD than the cholesterol carried by these particles, measured by non-HDL-C.

Adult↗
PubMed2005

Genetic variation in the HSD17B1 gene and risk of prostate cancer.

Steroid hormones are believed to play an important role in prostate carcinogenesis, but epidemiological evidence linking prostate cancer and steroid hormone genes has been inconclusive, in part due to small sample sizes or incomplete characterization of genetic variation at the locus of interest. Here we report on the results of a comprehensive study of the association between HSD17B1 and prostate cancer by the Breast and Prostate Cancer Cohort Consortium, a large collaborative study. HSD17B1 encodes 17beta-hydroxysteroid dehydrogenase 1, an enzyme that converts dihydroepiandrosterone to the testosterone precursor Delta5-androsterone-3beta,17beta-diol and converts estrone to estradiol. The Breast and Prostate Cancer Cohort Consortium researchers systematically characterized variation in HSD17B1 by targeted resequencing and dense genotyping; selected haplotype-tagging single nucleotide polymorphisms (htSNPs) that efficiently predict common variants in U.S. and European whites, Latinos, Japanese Americans, and Native Hawaiians; and genotyped these htSNPs in 8,290 prostate cancer cases and 9,367 study-, age-, and ethnicity-matched controls. We found no evidence that HSD17B1 htSNPs (including the nonsynonymous coding SNP S312G) or htSNP haplotypes were associated with risk of prostate cancer or tumor stage in the pooled multiethnic sample or in U.S. and European whites. Analyses stratified by age, body mass index, and family history of disease found no subgroup-specific associations between these HSD17B1 htSNPs and prostate cancer. We found significant evidence of heterogeneity in associations between HSD17B1 haplotypes and prostate cancer across ethnicity: one haplotype had a significant (p < 0.002) inverse association with risk of prostate cancer in Latinos and Japanese Americans but showed no evidence of association in African Americans, Native Hawaiians, or whites. However, the smaller numbers of Latinos and Japanese Americans in this study makes these subgroup analyses less reliable. These results suggest that the germline variants in HSD17B1 characterized by these htSNPs do not substantially influence the risk of prostate cancer in U.S. and European whites.

17-Hydroxysteroid Dehydrogenases↗
PubMed2005

Dietary alpha-linolenic acid intake and risk of sudden cardiac death and coronary heart disease.

BACKGROUND: Alpha-linolenic acid, an intermediate-chain n-3 fatty acid found primarily in plants, may decrease the risk of fatal coronary heart disease (CHD) through a reduction in fatal ventricular arrhythmias and sudden cardiac death (SCD). METHODS AND RESULTS: We prospectively examined the association between dietary intake of alpha-linolenic acid assessed via updated food-frequency questionnaires and the risk of SCD, other fatal CHD, and nonfatal myocardial infarction (MI) among 76,763 women participating in the Nurses' Health Study who were free from cancer and completed a dietary questionnaire at baseline in 1984. During 18 years of follow-up, we identified 206 SCDs, 641 other CHD deaths, and 1604 nonfatal MIs. After controlling for coronary risk factors and other fatty acids, including long-chain n-3 fatty acids, the intake of alpha-linolenic acid was inversely associated with the risk of SCD (P for trend, 0.02) but not with the risk of other fatal CHD or nonfatal MI. Compared with women in the lowest quintile of alpha-linolenic acid intake, those in the highest 2 quintiles had a 38% to 40% lower SCD risk. This inverse relation with SCD risk was linear and remained significant even among women with high intakes of long-chain n-3 fatty acids. CONCLUSIONS: These prospective data suggest that increasing dietary intake of alpha-linolenic acid may reduce the risk of SCD but not other types of fatal CHD or nonfatal MI in women. The specificity of the association between alpha-linolenic acid and SCD supports the hypothesis that these n-3 fatty acids may have antiarrhythmic properties.

Adult↗
PubMed2005

Habitual caffeine intake and the risk of hypertension in women.

CONTEXT: Caffeine acutely increases blood pressure, but the association between habitual consumption of caffeinated beverages and incident hypertension is uncertain. OBJECTIVE: To examine the association between caffeine intake and incident hypertension in women. DESIGN, SETTING, AND PARTICIPANTS: Prospective cohort study conducted in the Nurses' Health Studies (NHSs) I and II of 155,594 US women free from physician-diagnosed hypertension followed up over 12 years (1990-1991 to 2002-2003 questionnaires). Caffeine intake and possible confounders were ascertained from regularly administered questionnaires. We also tested the associations with types of caffeinated beverages. MAIN OUTCOME MEASURE: Incident physician-diagnosed hypertension. RESULTS: During follow-up, 19,541 incident cases of physician-diagnosed hypertension were reported in NHS I and 13,536 in NHS II. In both cohorts, no linear association between caffeine consumption and risk of incident hypertension was observed after multivariate adjustment (NHS I, P for trend = .29; NHS II, P for trend = .53). Using categorical analysis, an inverse U-shaped association between caffeine consumption and incident hypertension was found. Compared with participants in the lowest quintile of caffeine consumption, those in the third quintile had a 13% and 12% increased risk of hypertension, respectively (95% confidence interval in NHS I, 8%-18%; in NHS II, 6%-18%). When studying individual classes of caffeinated beverages, habitual coffee consumption was not associated with increased risk of hypertension. By contrast, consumption of cola beverages was associated with an increased risk of hypertension, independent of whether it was sugared or diet cola (P for trend <.001). CONCLUSION: No linear association between caffeine consumption and incident hypertension was found. Even though habitual coffee consumption was not associated with an increased risk of hypertension, consumption of sugared or diet cola was associated with it. Further research to elucidate the role of cola beverages in hypertension is warranted.

Caffeine↗
PubMed2005

Vitamin Intervention For Stroke Prevention trial: an efficacy analysis.

BACKGROUND AND PURPOSE: The Vitamin Intervention for Stroke Prevention trial (VISP) intention-to-treat analysis did not show efficacy of combined vitamin therapy for recurrent vascular events in patients with nondisabling stroke. Reasons for lack of efficacy may have included folate fortification of grain products, inclusion of the recommended daily intake for B12 in the low-dose arm, treatment with parenteral B12 in patients with low B12 levels in both study arms, a dose of B12 too low for patients with malabsorption, supplementation with nonstudy vitamins, and failure of patients with significant renal impairment to respond to vitamin therapy. We conducted an efficacy analysis limited to patients most likely to benefit from the treatment, based on hypotheses arising from evidence developed since VISP was initiated. The criteria for this subgroup were defined before any data analysis. METHODS: For this analysis, we excluded patients with low and very high B12 levels at baseline (<250 and >637 pmol/L, representing the 25th and 95th percentiles), to exclude those likely to have B12 malabsorption or to be taking B12 supplements outside the study and patients with significant renal impairment (glomerular filtration rate <46.18; the 10th percentile). RESULTS: This subgroup represents 2155 patients (37% female), with a mean age of 66+/-10.7 years. For the combined end point of ischemic stroke, coronary disease, or death, there was a 21% reduction in the risk of events in the high-dose group compared with the low-dose group (unadjusted P=0.049; adjusted for age, sex, blood pressure, smoking, and B12 level P=0.056). In Kaplan-Meier survival analysis comparing 4 groups, patients with a baseline B12 level at the median or higher randomized to high-dose vitamin had the best overall outcome, and those with B12 less than the median assigned to low-dose vitamin had the worst (P=0.02 for combined stroke, death, and coronary events; P=0.03 for stroke and coronary events). CONCLUSIONS: In the era of folate fortification, B12 plays a key role in vitamin therapy for total homocysteine. Higher doses of B12, and other treatments to lower total homocysteine may be needed for some patients.

Aged↗