Childhood BMI trajectories predict cardiometabolic risk and stress at age 13 years. The STARS cohort

BACKGROUND: Research on BMI trajectory focuses mainly on childhood and adolescence, missing birth and infancy, which are also relevant in the development of cardiometabolic disease. We aimed to identify trajectories of BMI from birth throughout childhood, and to examine whether BMI trajectories predict health at age13 years; and, if so, whether differences exist among trajectories regarding timeframes during which early life BMI influences health. METHODS: Participants from Western Sweden (n = 1902, 44% males, 13.5±0.4 years) completed questionnaires assessing perceived stress and psychosomatic symptoms and examined for waist circumference (WC), systolic blood pressure (SBP), pulse wave velocity, and white blood cell counts (WBC). They had at least 5 retrospective measures of weight and height covering birth, infancy, childhood to early adolescence. We used group-based trajectory modeling to identify BMI trajectories and linear regression to assess associations, which are presented as estimated mean differences with 95% CI between trajectories. RESULTS: We identified three BMI trajectories: normal, moderate, and excessive gain. Differences distinguishing these trajectories were established before 2 years of age. After adjusting for sex, age, migrant background, and parental income, adolescents with excessive gain had higher WC (19.2 [18.4-20.0} cm), SBP (3.6 [2.4-4.4] mmHg), WBC (0.7 [0.4-0.9] x109/L) and stress (1.1 [0.2-1.9]) than adolescents with normal gain. Increased levels of WC (6.4 [5.8-6.9] cm), SBP (1.8 [1.0-2.5] mmHg) and stress (0.7 [0.1-1.2]) were found in adolescents with moderate gain. The observed significant positive correlation of early life BMI with SBP started approximately at age 6 years for participants with excessive gain, much earlier than for participants with normal and moderate gain, for which it started at age 12 years. CONCLUSIONS: Excessive gain BMI trajectory from birth predicts cardiometabolic risk and stress in adolescents before age 13 years. KEY MESSAGES: • Differences distinguishing childhood BMI trajectories were established before age 2 years. • In excessive gain group, influence of early life BMI on SBP started already around age 6 years.