Weight, Weight Gain, Activity, and Major Illnesses: The Nurses' Health Study

Brigham and Women's Hospital, Boston, Massachusetts, United States
International Journal of Sports Medicine (Impact Factor: 2.07). 08/1997; 18 Suppl 3(S 3):S162-70. DOI: 10.1055/s-2007-972709
Source: PubMed


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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    • "The consequences of being overweight or obese have been described in a number of studies (Colditz and Coakley, 1997). Findings regarding shift work mostly indicate that night-shift workers alter their eating habits rather than calorie intake, i.e. there is higher consumption of cold rather than hot food, they eat rather by habit and time availability and less by appetite and are more likely to nibble between main meals (Waterhouse et al., 2003; Pasqua and Moreno, 2004; Rohmer et al., 2004). "
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    ABSTRACT: Recent health care organizational changes have been associated with stress and musculoskeletal disorders in nurses. However, studies are lacking on what factors are the most important predictors of poor self-assessed health among nurses. To describe and identify the self-assessed predictors of physical and mental health of nurses. A cross-sectional design was used with a sample of 394 nurses, drawn from the registry of the Icelandic Nurses' Association, representing 17% of the workforce of Icelandic nurses. Data were collected with a self-administered questionnaire, addressing symptoms, illness and treatment, lifestyle and sleep, work and working environment, family and quality of family life. Data were analysed according to nurses' assessment of their physical and mental health (very good/good; poor/very poor) by use of analysis of variance, chi-square and stepwise multiple linear regression. 21.7% of participants assessed their physical health as poor or very poor and 14.3% assessed their mental health as such. Those who assess their physical or mental health poor/very poor, as compared to the others, reported more symptoms in general, less regular exercise, as well as more use of medication, more visits to physicians, trouble with sleeping, conflicts between work and family life, work absence, and they experience their work as more strenuous. Experiencing symptoms is an important predictor of both physical and mental health of nurses. Various factors, including work-, family- and socio-cultural environment, play a role in how nurses assesses their health. During our present time of nurse shortage it is imperative that the authorities take special measures in order to improve the work environment of nurses.
    International Journal of Nursing Studies 04/2008; 45(10):1479-89. DOI:10.1016/j.ijnurstu.2008.01.007 · 2.90 Impact Factor
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    • "Several studies support the important role of PA for both primary and secondary prevention of cardiovascular diseases [2]. There is also evidence that regular PA may prevent osteoporosis [3], some forms of cancer [4], type 2 diabetes [5,6], and may increase longevity [7]. "
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    ABSTRACT: Information on correlates of total physical activity (PA) levels among middle-aged and elderly women is limited. This article aims to investigate whether total daily PA levels are associated with age, body mass index, smoking, drinking status, and sociodemographic factors. In a cross-sectional study of 38,988 women between the ages of 48 and 83 years residing in central Sweden, information on PA, weight, height, smoking, drinking, and sociodemographic factors was collected through a self-administered questionnaire. Total daily PA levels were measured as metabolic equivalents (MET-h/day). Odds ratios (OR) and 95% confidence intervals (CI) were estimated by ordinal logistic regression models. We observed decreasing level of total PA with increasing age (for 5-year increase: OR = 0.87; 95% CI: 0.85–0.89) and body mass index (for 5-unit, kg/m2, increase: OR = 0.81; 95% CI: 0.79–0.84). Multivariable adjusted correlates of total PA level were smoking (current vs. never: OR = 0.83; 95% CI: 0.79–0.88), drinking (current vs. never: OR = 0.88; 95% CI: 0.82–0.94), educational level (university vs. primary: OR = 0.54; 95% CI: 0.51–0.58), employment status (housewife vs. full-work: OR = 2.59; 95% CI: 2.25–2.98), and childhood environment (city vs. countryside: OR = 0.62; 95% CI: 0.59–0.65). In the present investigation, among middle-aged and elderly women, the likelihood of engaging in higher total daily PA levels decreased with age, body mass index, educational level, smoking, drinking, and growing up in urban places.
    International Journal of Behavioral Nutrition and Physical Activity 02/2007; 4(1):16. DOI:10.1186/1479-5868-4-16 · 4.11 Impact Factor
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    • "Inconsistencies in results for risk factor-disease associations for colon cancer have been attributed to a variety of non-biological factors. Since earlier results for colon cancer came primarily from case-control studies, while cohort studies contributed more to the recent literature, study design, i.e. the potential biased reporting in case-control studies, has been cited as a potential explanation for differences between results of older and more recent studies[15]. However, results of cohort studies may be affected by measurement error from imprecise exposure assessment when data are collected using a self-administered format. "
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    ABSTRACT: Epidemiologic studies have identified a number of lifestyle factors, e.g. diet, obesity, and use of certain medications, which affect risk of colon cancer. However, the magnitude and significance of risk factor-disease associations differ among studies. We propose that population trends of changing prevalence of risk factors explains some of the variability between studies when factors that change prevalence also modify the effect of other risk factors. We used data collected from population-based control who were selected as study participants for two time periods, 1991-1994 and 1997-2000, along with data from the literature, to examine changes in the population prevalence of aspirin and non-steroidal anti-inflammatory medication (NSAID) use, obesity, and hormone replacement therapy (HRT) over time. Data from a population-based colon cancer case-control study were used to estimate effect-measurement modification among these factors. Sizeable changes in aspirin use, HRT use, and the proportion of the population that is obese were observed between the 1980s and 2000. Use of NSAIDs interacted with BMI and HRT; HRT use interacted with body mass index (BMI). We estimate that as the prevalence of NSAIDs use changed from 10% to almost 50%, the colon cancer relative risk associated with BMI >30 would change from 1.3 to 1.9 because of the modifying effect of NSAIDs. Similarly, the relative risk estimated for BMI would increase as the prevalence of use of HRT among post-menopausal women increased. In conclusion, as population characteristics change over time, these changes may have an influence on relative risk estimates for colon cancer for other exposures because of effect-measure modification. The impact of population changes on comparability between epidemiologic studies can be kept to a minimum if investigators assess exposure-disease associations within strata of other exposures, and present results in a manner that allows comparisons across studies. Effect-measure modification is an important component of data analysis that should be evaluated to obtain a complete understanding of disease etiology.
    Epidemiologic Perspectives & Innovations 02/2007; 4(1):10. DOI:10.1186/1742-5573-4-10 · 1.58 Impact Factor
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