Abstract Body (Do not enter title and authors here): Background: Few studies have examined associations of BMI trajectories from childhood with CVD events.
Aims: To describe BMI trajectories from childhood to midlife and their associations with CVD morbidity and mortality.
Methods: Data were from the International Childhood Cardiovascular Cohort Consortium of 7 cohorts from Australia, Finland, and the USA. Participants (n=21,410) had ≥2 measures of height and weight prior to CVD events, including ≥1 in childhood (3-19 years) and ≥1 in adulthood (≥20 years). Age-sex-standardised BMI-z scores in childhood were estimated using WHO Child Growth Standards, and in adulthood using the internal reference. Group-based trajectory modelling identified BMI-z score trajectories. Outcomes were physician-adjudicated fatal and non-fatal CVD events in adulthood. Cox proportional hazards models estimated the risk of CVD outcomes, adjusted for mean age and calendar year at childhood visits, sex, race, cohort, and childhood smoking, accounting for competing risk.
Results: Six trajectories were identified, differing by attained adult BMI category: persistently low (10.3%, adult normal weight), persistently average (35.1%, normal/overweight), moderately high decreasing (29.2%, overweight), high decreasing (12.1%, class I obesity), moderately high increasing (8.7%, class II/III obesity) and persistently high (4.6%, class III obesity). Over a median follow-up of 38.1 years, 98 fatal CVD events occurred among 20,821 participants and 388 fatal or nonfatal CVD events occurred among 18,069 participants with available covariates. Compared to the persistently average trajectory, high decreasing, moderately high increasing and persistently high trajectories were associated with higher risks of fatal CVD events (adjusted hazard ratios [aHRs]: 1.88-4.16, all p<0.05) and fatal or nonfatal CVD events (aHRs: 1.76-3.27, all p<0.05). A higher risk of fatal and nonfatal CVD events was found for the moderately high decreasing trajectory (aHR: 1.33, 95% CI: 1.02-1.74).
Conclusions: BMI z-score trajectories that started moderately high or high in childhood, even if with z-score decrease over time, were associated with overweight and obesity in adulthood and increased risks of CVD morbidity and mortality.