Determinants and Consequences of Obesity

Abstract

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.

FIGURE 1—

Relationships Between Changes in Food and Beverage Consumption and Weight Change Every 4 Years in the Nurses’ Health Study (NHS; 1986–2006), the NHS II (1991–2003), and the Health Professionals Follow-up Study (HPFS; 1986–2006): United States Note. Weight changes are shown per increase in daily serving of the food or beverage. All weight changes were adjusted simultaneously for age, baseline body mass index, sleep duration, smoking status, physical activity, television watching, alcohol use, and all the dietary factors shown. Source. Adapted from Mozaffarian et al.

FIGURE 2—

Percentage Changes in the Risk of Developing Obesity Associated With Television Watching, Other Sedentary Behaviors, and Walking Among Nonobese Women in the Nurses’ Health Study: United States, 1992–1998 Note. Analyses were adjusted for age, smoking, alcohol consumption, and dietary covariates. All sedentary behavior variables were included simultaneously in the model. Other sitting included reading, mealtime, and at a desk. Vertical bars indicate 95% confidence intervals. Source. Adapted from Hu et al.

FIGURE 3—

Relative Risk of Developing Obesity Among Nonobese Men and Women, per Increment of 10 Obesity Risk Alleles, According to Intake of Sugar-Sweetened Beverages in the Nurses’ Health Study (1980–1998), Health Professionals Follow-up Study (1986–1998), and Women’s Genome Health Study (1992–1998): United States Note. Shown are the relative risks of incident obesity, adjusted for age, source of genotyping data, physical activity, time spent watching television, smoking, alcohol intake, and other dietary covariates. Horizontal bars indicate 95% confidence intervals. Source. Reprinted with permission from Qi et al.

FIGURE 4—

Relative Risk of Death From (a) Cardiovascular Disease, (b) Cancer, and (c) Other Causes According to Body Mass Index Among Women in the Nurses’ Health Study Who Had Never Smoked: United States, 1976–2000 Note. Analyses were adjusted for age, parental history of coronary heart disease, menopausal status, hormone use, physical activity, and alcohol intake. Vertical bars indicate 95% confidence intervals. Source. Reprinted with permission from Hu et al.