Association of low birth weight with high blood pressure among adolescents in Kerala, South India: an unmatched case control study

To determine the association of Low Birth Weight (LBW) and other factors with high blood pressure (BP) among adolescents in Kerala, India. A case control study was conducted among school- going adolescents from classes 6–12 in selected schools of Ernakulam and Kannur districts in kerala. BP was measured using standard protocols, and data on birth weight and other risk factors were collected using a structured questionnaire. Logistic regression analyses were performed to identify predictors of high BP. A total of 560 adolescents were included, comprising 140 cases (high BP) and 420 controls (normal BP). LBW (< 2500 g) was significantly associated with high BP (AOR: 2.52, 95% CI: 1.48–4.30, p = 0.001). Other significant factors included family history of hypertension (AOR: 2.08, 95% CI: 1.32–3.27, p = 0.001), overweight/obesity (AOR: 2.62, 95% CI: 1.53–4.48, p < 0.001), lack of fruit consumption in the previous week (AOR: 2.73, 95% CI: 1.21–6.11, p = 0.015), absence of active commuting to school (AOR: 2.48, 95% CI: 1.55–3.96, p < 0.001) and performing muscle- strengthening exercises only 1–3 days a week (AOR: 2.17, 95% CI: 1.06–4.46, p = 0.03). A gradient was observed with vegetable intake and high BP, with the highest risk among those reporting no consumption (AOR: 10.12, 95% CI 2.67–38.35, p = 0.001). Underweight status was protective (AOR: 0.29, 95% CI: 0.12–0.73, p = 0.008). Short sleep duration (4–6 h per night) showed borderline significance (AOR: 1.93, 95% CI: 1.00–3.73, p = 0.050). Early-life factors, particularly birth weight, may play an important role in the development of high BP. However, prospective longitudinal studies are needed to clarify the long-term effects of fruit and vegetable intake and other modifiable lifestyle factors on BP.