Abstract
BACKGROUND: Evaluating lifelong weight trajectories is challenging due to the high costs of studies that follow individuals from childhood to adulthood. The use of silhouette scales has been a new approach to assess the body shape trajectory across life as a proxy for body weight trajectory. Depending on body shape trajectories, individuals may be more prone to develop diseases in adulthood. Therefore, identifying factors related to them is essential for public health. This study aimed to evaluate body shape trajectories across the lifespan and to verify associations between them, birth weight, body mass index, and sociodemographic conditions in a Brazilian cohort. METHODS: This is a cross-sectional analysis conducted with 14,014 participants of first follow-up data collection of Longitudinal Study of Adult Health (ELSA-Brasil). ELSA-Brasil is a multicentric prospective cohort study initiated in 2008 with civil servants of six public institutions in the Northeast, South and Southeast regions of Brazil. We applied a clustering method to longitudinal data to identify body shape trajectories from 5 to 40 years of age and assessed the associations between these trajectories and birth weight, body mass index and sociodemographic conditions (race, education, maternal education and monthly per capita family income) using multiple correspondence analysis. RESULTS: We found five body shape trajectories for women and three for men. Low birth weight was associated with a slight to moderate increase in shape. High birth weight was associated with maintaining large body size in both sexes and markedly increased body shape in women. Higher sociodemographic status and white race were associated with marked increases in body shape in men and maintenance of medium body shape in women. CONCLUSIONS: The study shows that variables related to worse lifetime weight status (evaluated by anthropometry), such as presence of obesity, are also associated with worse body shape trajectories, as assessed with silhouette scales. Our results suggest that body shape trajectories are a good indicator of body weight trajectories and may be used when cohort studies are not possible.