Background: Overweight and obesity in childhood have been linked to an increased risk of adult mortality, but evidence is still scarce.
Methods: We identified trajectories of body mass index (BMI) development in early life and investigated their mortality risk. Data come from the Helsinki Birth Cohort Study, in which 4943 individuals, born 1934-1944, had serial measures of weight and height from birth to 11 years extracted from health care records, weight and height data in adulthood, and register-based mortality data for 2000-2010.
Results: Three early BMI trajectories (increasing, average, and average-to-low for men and increasing, average, and low-to-high BMI for women) were identified. Women with an increasing or low-to-high BMI (BMI lower in early childhood, later exceeded average) trajectory had an increased risk of all-cause mortality compared to those with an average BMI trajectory (HR 1.55, 95% CI 1.07-2.23; and HR 1.57, 95% CI 1.04-2.37, respectively). Similar associations were observed for cancer mortality. Among men, BMI trajectories were not associated with all-cause mortality, but those with average-to-low BMI (BMI first similar then dropped below average) had an increased risk of cancer mortality.
Conclusions: An increasing BMI in early life may shorten the lifespan of maturing cohorts as they age, particularly among women.
Keywords: Aging; birth size; body mass index; developmental origins of adult health and disease; growth mixture models; life-course epidemiology; mortality.