Childhood occasional hypertension and its association with size at birth and early growth: a population-based retrospective cohort study from China.

Background: Hypertension has recently shown a rapid rise in prevalence among children and adolescents. It can track into adulthood and tend to manifest at an earlier age. It should be prevented urgently and efficiently.

Methods: This study assesses the prevalence of occasional hypertension (OHTN) at 5 ~ 6 years old and evaluates its association with size at birth and BMI at 2 and 5 ~ 6 years old in full-term children. We conducted a population-based cohort study of 12,564 children from 66 kindergartens in Tianjin, China. Information on birth weight, body mass index (BMI) at 2 and 5 ~ 6 years old, and blood pressure at 5 ~ 6 years old was retrospectively collected.

Results: The prevalence of childhood OHTN (SBP or DBP ≥ P₉₅ percentile for sex, age, and height) was 17.0%. At birth, SGA has a high risk of OHTN (AOR 1.36, 95%CI 1.10-1.68). In the SGA subgroup, although children are of normal weight at 5 ~ 6 years old, excessive catch-up growth (BMI ≥75th at 2 years old) was still attributed to OHTN (OR 1.51, 95%CI 1.03-2.24). Obesity (BMI ≥2SD at 5 ~ 6 years old) was a vital risk factor for OHTN (AOR 2.93, 95%CI 2.56-3.36) unregarding with birthweight (OR 95%CI: SGA 3.23(1.66 ~ 6.27), AGA 2.83 (2.42-3.31), LGA 3.52 (2.65-4.68)). The co-presence of moderate or excessive catch-up growth before 2 years old and obesity at 5 ~ 6 years old significantly increased the risk of childhood OHTN (OR from 2.74 (1.65-4.54) to 6.53 (2.68-15.90)).

Conclusions: Preschool obesity, low birth weight, and excessive catch-up growth increased the risk of OHTN in childhood.