Weight change across adulthood in relation to all cause and cause specific mortality: prospective cohort study

Abstract

Objective: To investigate the association between weight changes across adulthood and mortality.

Design: Prospective cohort study.

Setting: US National Health and Nutrition Examination Survey (NHANES) 1988-94 and 1999-2014.

Participants: 36 051 people aged 40 years or over with measured body weight and height at baseline and recalled weight at young adulthood (25 years old) and middle adulthood (10 years before baseline).

Main outcome measures: All cause and cause specific mortality from baseline until 31 December 2015.

Results: During a mean follow-up of 12.3 years, 10 500 deaths occurred. Compared with participants who remained at normal weight, those moving from the non-obese to obese category between young and middle adulthood had a 22% (hazard ratio 1.22, 95% confidence interval 1.11 to 1.33) and 49% (1.49, 1.21 to 1.83) higher risk of all cause mortality and heart disease mortality, respectively. Changing from obese to non-obese body mass index over this period was not significantly associated with mortality risk. An obese to non-obese weight change pattern from middle to late adulthood was associated with increased risk of all cause mortality (1.30, 1.16 to 1.45) and heart disease mortality (1.48, 1.14 to 1.92), whereas moving from the non-obese to obese category over this period was not significantly associated with mortality risk. Maintaining obesity across adulthood was consistently associated with increased risk of all cause mortality; the hazard ratio was 1.72 (1.52 to 1.95) from young to middle adulthood, 1.61 (1.41 to 1.84) from young to late adulthood, and 1.20 (1.09 to 1.32) from middle to late adulthood. Maximum overweight had a very modest or null association with mortality across adulthood. No significant associations were found between various weight change patterns and cancer mortality.

Conclusions: Stable obesity across adulthood, weight gain from young to middle adulthood, and weight loss from middle to late adulthood were associated with increased risks of mortality. The findings imply that maintaining normal weight across adulthood, especially preventing weight gain in early adulthood, is important for preventing premature deaths in later life.

Fig 1

Associations between weight change patterns across adulthood and risk of all cause mortality stratified by baseline age, smoking status, and sex in NHANES 1988-2014. Risk estimates were adjusted for baseline age (not adjusted in subgroup analysis by age), sex (not adjusted in subgroup analysis by sex), race/ethnicity, education level, family income-poverty ratio level, marital status, drinking status, smoking status (not adjusted in subgroup analysis by smoking status), leisure time physical activity level, healthy eating index scores, self reported general health, and family history of diabetes or heart attack. All estimates accounted for complex survey design of NHANES. In analysis of weight change from age 25 years to 10 years before baseline, P for interaction was <0.001 for baseline age group (<60 and ≥60 years old), 0.97 for smoking status (never and ever smokers), and 0.84 for sex. In analysis of weight change from age 25 years to baseline, corresponding P values for interaction were <0.001, 0.68, and 0.86. In analysis of weight change in 10 year period before baseline, corresponding P values for interaction were <0.001, 0.44, and 0.77

Fig 2

Dose-response association between absolute weight change across adulthood and risk of all cause mortality. Associations were examined by multivariable Cox regression models based on restricted cubic splines. Solid line represents estimates of hazard ratios and dashed line represents 95% CIs. Risk estimates were adjusted for baseline age, sex, race/ethnicity, education level, family income-poverty ratio level, marital status, drinking and smoking status, leisure time physical activity level, healthy eating index scores, self reported general health, and family history of diabetes or heart attack. For weight change from age 25 years to 10 years before baseline or to baseline, weight at age 25 and baseline height were also adjusted for. For weight change from 10 years before baseline to baseline, weight at 10 years previously and baseline height were also adjusted for. P values for overall association and P values for non-linear association were all <0.001 in three periods