Ethnic Differences in Weight Category Transition and Body Mass Index Trajectories from Adolescence to Young Adulthood...

To assess ethnic differences in the transition of weight categories and in BMI trajectories from adolescence to young adulthood between Jewish and Arab populations.

A retrospective cohort study, based on the centralized computerized database of 'Clalit Health Services', the major health service organization that insures 52% of the Israeli population. The study population consisted of 99,741 adolescents born from 1988 to 1992 who had at least one BMI measurement in the exposure (ages 17-19 years) and follow-up (age 20 to <30 years) periods. We examined differences in weight categories in young adulthood (ages 20 to <30 years), by ethnic group, and assessed whether ethnicity moderated BMI trajectories from 20 to <30 years of age. Multilevel models were applied to examine BMI trajectories.

A higher percentage of Arab than Jewish adolescents from the 'underweight', 'normal', and 'overweight' categories moved to one of the higher weight categories in young adulthood (p < 0.001 for all). In the 'underweight', 'normal', 'overweight', and 'obese' weight categories, the increase in BMI with increasing age was lower for Jews (p < 0.001 for all).

Many adolescents, even if not obese, have increasing BMI trajectories at ages 17-19 and move to a higher weight category in adulthood. Arab adolescents constitute a risk group for rapid BMI increase as they transition to adulthood. The present study could contribute to a better understanding of BMI dynamics and, in turn, to the development of more effective public health and policy interventions.