Weight gain and hypertension at three years of age and older in extremely low birth weight infants

OBJECTIVE: To determine the prevalence and weight gain as a risk factor of hypertension (HTN) at three years of age and older among extremely low birth weight (ELBW) infants. STUDY DESIGN: Retrospective cohort study of all ELBW infants born and followed up at our institution over 15 years. RESULTS: 204 infants were followed up for [median (inter-quartile range)] 10.2 years (6.9-13.0). Their birth weight and gestational age were (mean±standard deviation) 758±149 g and 26.4±2.1 weeks respectively. At 3 years of age and older, the prevalence of HTN was 7.3% (15/204), and the prevalence of obesity was 13.2% (27/204). Obesity was more prevalent in children with than without HTN [33% (5/15) vs. 12% (22/189); p = 0.01]. In a regression analysis, body mass index (BMI) percentile at 3 years of age and older (p = 0.04) and increase in weight Z scores since birth (p = 0.008) were associated with a higher systolic blood pressure (SBP; R = 0.386, p < 0.001). CONCLUSION: Obesity is prevalent in ELBW infants at three years of age and older, and it is significantly associated with hypertension. An increase in BMI percentile at ≥3 years of age, and the rate of weight gain since birth among ELBW infants are associated with an increase in SBP.