Weight, weight gain, activity, and major illnesses: the Nurses' Health Study.
ABSTRACT The Nurses' Health Study was initiated in 1976 to study the relation between oral contraceptives and breast cancer. Subsequent funding was available to follow the cohort to address relations between cigarette smoking, postmenopausal hormones, hair dyes, and a range of cancers including breast, endometrial, ovarian, and lung cancer. The 121,700 participating nurses are followed up every 2 years via mail questionnaire to update exposure information to identify incident cancers and other illnesses. Follow-up through 1994 has achieved 90% response from living cohort members. Over the course of the study, additional exposures have been added and refined, including weight at age 18, current weight, height, waist and hip measurements and history of major voluntary weight loss among others. Our focus has been on the health effects of weight gain during middle age. The results relating to diabetes, coronary heart disease, certain types of cancer and total mortality are reviewed. Our primary analytic tools have been multiple logistic regression and Cox proportional hazards models. These methods allow for flexibility in defining the exposures of interest as well as determining their relative importance while controlling for key risk factors. Our models show that even moderate weight gain after age 18 increases risk of each condition. The benefits of physical activity include reduced risk of disease. Issues in the measurement and validation of weight and activity highlight the complexities that are inherent in observational studies addressing the health consequences of lifestyles and anthropometric variables. Our experience of working with repeated measures of body weight and recreational activity are described. Recreational activity has been ascertained in various ways on several questionnaires and may be subject to misclassification. For both weight and activity it may be the pattern of these values that is of importance (e.g. "weight cycling") for some outcomes or conditions. Our research in this area is ongoing. These issues regarding longitudinal measurement will never be completely resolved because weight and activity are intrinsically complex concepts. For these and other such variables, the primary solution is to minimize the problems associated with longitudinal studies. This is best accomplished by developing and maintaining a very strong study design/protocol, including: careful consideration of the sample frame and sample size; maintenance of a high response rate; and continuous monitoring and improvement of the survey/interview instrument(s).
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ABSTRACT: The relative importance of overweight after childhood and excess weight gain during adulthood remains unclear. In 39,909 male participants of the Health Professionals Follow-Up Study who were 40-75 years of age in 1986 and were followed until 2008, we documented 8,755 incident cases of obesity-related chronic diseases (type 2 diabetes mellitus, cardiovascular diseases, and colorectal, renal, pancreatic, and esophageal cancers). We calculated composite and cause-specific hazard ratios using a model that included body mass index (BMI; weight (kg)/height (m)(2)) at 21 years of age, weight change since age 21 years, smoking, alcohol consumption, and family histories of myocardial infarction, colon cancer, and diabetes. Compared with a BMI at 21 years of 18.5-22.9, the composite hazard ratio for a BMI of 23-24.9 was 1.22 (95% confidence interval (CI): 1.16, 1.29), that for a BMI of 25.0-27.4 was 1.57 (95% CI: 1.48, 1.67), that for a BMI of 27.5-29.9 was 2.40 (95% CI: 2.17, 2.65), and that for a BMI ≥30.0 was 3.15 (95% CI: 2.76, 3.60). The composite hazard ratios for adult weight gain compared with a stable weight were 1.12 (95% CI: 1.03, 1.22) for a gain of 2.5-4.9 kg, 1.41 (95% CI: 1.31, 1.52) for a gain of 5-9.9 kg, 1.72 (95% CI: 1.59, 1.86) for a gain of 10-14.9 kg, and 2.45 (95% CI: 2.27, 2.63) for a gain ≥15 kg. Adiposity in early adulthood and adult weight gain were both associated with marked increases in the risk of major chronic diseases in middle-aged and older men, and these associations were already apparent at modest levels of overweight and weight gain.American journal of epidemiology 04/2014; · 4.98 Impact Factor
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ABSTRACT: Weight change during adult life may reflect metabolic changes and influence colorectal cancer (CRC) development, but such role is not well established. We aimed to explore the association between adult weight change (from age 20 to 50) and CRC risk. In particular, we investigated differences according to colon and rectal cancer, sex and measures of attained adiposity. We included 201,696 participants from six participating countries in the European Prospective Investigation into Cancer and Nutrition (1992-2010). During a mean follow-up of 11.2years 2384 (1194 in men and 1190 in women) incident CRC cases occurred. Cox proportional hazard models adjusted for body mass index at age 20 and lifestyle factors at study recruitment were used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs). After multivariable adjustment, each kg of weight gained annually from age 20 to 50 was associated with a 60% higher risk of colon cancer (95% CI 1.20-2.09), but not rectal cancer (HR 1.13, 95% CI 0.79-1.62, Pinteraction=0.04). The higher risk of colon cancer was restricted to people with high attained waist circumference at age 50 (HR 1.82, 95%CI 1.14-2.91, Pinteraction=0.02). Results were not different in men and women (Pinteraction=0.81). Adult weight gain, as reflected by attained abdominal obesity at age 50, increases colon cancer risk in both men and women. These data underline the importance of weight management and metabolic health maintenance in early adult life years for colon cancer prevention.European journal of cancer (Oxford, England: 1990) 07/2013; · 4.12 Impact Factor
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ABSTRACT: Coronary disease is the leading cause of death in women, responsible for 2-4 times more deaths than breast cancer. The clinical picture of coronary heart disease in women is often different than that in men, evidence of a particular pathophysiology: it is most often identified when acute, as non-ST-elevated acute coronary syndrome, and involves a higher frequency than among men of normal coronary arteries, microvascular damage, and endothelial dysfunction. The risk factors for woman are also distinctive: a higher risk profile, older age, and higher frequency of lack of exercise and its consequences (abdominal obesity, metabolic syndrome, diabetes). Smoking is a major risk factor in young women. Stress tests are less useful for diagnosis in women than in men, essentially because of the higher rate of false positives. On the other hand, the diagnostic value of myocardial scintigraphy and stress ultrasound testing differs little from that in men. Coronary revascularization by angioplasty or bypass classically yields poorer results in women than men, probably because of their smaller arteries. These differences are nonetheless fading as techniques improve. The impact of active stents in women remains to be determined. The prognosis of myocardial infarction in women remains poorer than in men, but appropriate and early management, especially by angioplasty, seems to be smoothing out this difference in recent studies. Women on the whole receive less good treatment than men (delayed management and less frequent drug and interventional treatment), which contributes to their poorer prognosis. Simple means of prevention have proved effective in women: regular physical activity thus reduces the risk of infarction by 50% (and also reduces the incidence of diabetes); the effect of aspirin as primary prevention remains controversial.La Presse Médicale 02/2010; 39(2):242-248. · 1.17 Impact Factor