(P18-065-23) Life-Course Physical Growth Trajectories From Birth to Two Years of Age and Blood Pressure at Early Adolescence: A Birth Cohort

Objectives: To examine the associations of life-course physical growth trajectories from birth to two years of age with adolescent blood pressure (BP), and the causal mediating role of adolescent current adiposity and puberty onset.

Methods: We analyzed data from a prospective birth cohort of children born to mothers who participated in a randomized controlled trial of antenatal micronutrient supplementation in China. We measured infant weight and length at birth, 1, 3, 6, 9, 12, 18, and 24 months of age, which were then converted into z scores by the INTERGROWTH-21^st and WHO standards. We assessed adolescent BP using a validated electronic sphygmomanometer, which was then transferred into percentiles by sex, age, and height. We used group-based trajectory modeling to identify infant weight-, length-, BMI- and weight-for-length-for-age and sex z score (WAZ, LAZ, BAZ, WFL) trajectories during the first two years of life, and then examined their associations with adolescent BP using generalized estimating equations. The natural indirect effects and corresponding proportions mediated (PM) through adolescent BAZ and puberty onset were estimated by using inverse odds ratio weighting.

Results: Among 1388 infants enrolled for long-term follow-up, 745 (60.9% male) adolescents aged 10-14 were followed, with a mean age of 11.26 (SD, 0.57). Distinct growth trajectories were identified, implying catch-up growth after birth. BAZ and WFL trajectories were associated with adolescent systolic and diastolic BP and BP percentiles, with adjusted mean differences ranging from 2.10 to 5.38 mmHg. In addition, these relationships between growth trajectories and adolescent systolic BP were largely mediated by adolescent BAZ with PMs of around 70%, while the corresponding PMs of jointed mediations with puberty onset only slightly increased. The natural indirect effects were not statistically significant for adolescent diastolic BP with much smaller PMs, around 20%.

Conclusions: Early-life growth trajectories from birth may have causal relationships with adolescent systolic BP. Routine monitoring of infant growth has the potential utility to predict the life-long risk of hypertension and other cardiovascular diseases.

Funding Sources: This work was supported by the National Natural Science Foundation of China and the China Postdoctoral Science Foundation.