Predictors of blood pressure at 7-13 years: The "new millennium baby" study

Abstract

Background and aims: The purpose of this study is to evaluate the association between blood pressure (BP) at 7-13 years of age and body mass index (BMI), early feeding, lifestyle indicators, and parental characteristics.

Methods and results: Retrospective plus cross-sectional cohort study was started in 1294 children born in 2000-2004, right from their birth in primary care settings. Early feeding was estimated by measuring breast-feeding (BF) duration, complementary feeding (CF) introduction time, and lifestyle indicators such as daily screen time and weekly extracurricular sports activity time. Parental education, smoking, and obesity-related diseases were also considered. Multivariable linear regression and mediation analysis were used. CF introduction at 5-6 months of age was a negative predictor of systolic and diastolic BP (mean systolic BP-standard deviation score (SDS) -0.38 [95% CI: -0.47, -0.29] (p < 0.001); mean diastolic BP-SDS -0.32 [95% CI: -0.40, -0.24]) (p < 0.001); BMI was a positive predictor of systolic and diastolic BP (p < 0.001); and parental hypertension was a positive predictor of diastolic BP (p < 0.05). Predictors of mean BMI-SDS at 7-13 years of age were birth weight, screen time, and parental obesity and smoking (p < 0.001). BF had no effect on BP or BMI. Mediation analysis showed virtually no indication of the effect of CF on BP mediated by BMI.

Conclusions: CF introduction between 5 and 6 months of age could be associated with low BP at 7-13 years. The effect of CF on BP seems to be independent of BMI. Low screen time is associated with low BMI. CF time may play a role in the occurrence of surrogates of noncommunicable disorders in future.

Keywords: Blood pressure; Body mass index; Breast-feeding; Complementary feeding; Family history; Lifestyle.