摘要：Objectives. To review the contribution of the Nurses’ Health Studies (NHS and NHS II) in addressing hypotheses regarding risk factors for and consequences of obesity. Methods. Narrative review of the publications of the NHS and NHS II between 1976 and 2016. Results. Long-term NHS research has shown that weight gain and being overweight or obese are important risk factors for type 2 diabetes, cardiovascular diseases, certain types of cancers, and premature death. The cohorts have elucidated the role of dietary and lifestyle factors in obesity, especially sugar-sweetened beverages, poor diet quality, physical inactivity, prolonged screen time, short sleep duration or shift work, and built environment characteristics. Genome-wide association and gene–lifestyle interaction studies have shown that genetic factors predispose individuals to obesity but that such susceptibility can be attenuated by healthy lifestyle choices. This research has contributed to evolving clinical and public health guidelines on the importance of limiting weight gain through healthy dietary and lifestyle behaviors. Conclusions. The NHS cohorts have contributed to our understanding of the risk factors for and consequences of obesity and made a lasting impact on clinical and public health guidelines on obesity prevention. Over the past 40 years, few health topics have engendered as much concern, controversy, or debate as obesity. Once a rarity, obesity is now epidemic, and major health organizations consider it a disease. Obesity rates have climbed across the decades despite increasing knowledge about obesity’s health risks and strategies for prevention. When the Nurses’ Health Study (NHS) began in 1976, the national prevalence of overweight (body mass index [BMI; defined as weight in kilograms divided by the square of height in meters] of ≥ 25 to < 30) in women was 24.8%, and obesity (BMI ≥ 30) was 16.8%. 1 When NHS II launched in 1989, overweight prevalence in US women still hovered around 25%, but obesity prevalence had climbed to nearly match it. 1 Today, approximately two thirds of US women are overweight or obese. The findings from NHS cohorts have greatly contributed to our understanding of the etiology of obesity, as well as its consequences. Among key findings are the effects of excess weight, even in normal BMI ranges, on the risk of chronic disease morbidity and mortality, the importance of limiting weight gain, and dietary, lifestyle, and genetic determinants of obesity, as well as gene–environment interactions. We have reviewed these and related findings and how they have contributed to obesity knowledge and public health approaches regarding obesity prevention. (For a more inclusive list of NHS and NHS II publications, see the Appendix, available as a supplement to the online version of this article at http://www.ajph.org , and the 2008 textbook Obesity Epidemiology . 2 )
