Work

Prenatal heat exposure and childhood cardiovascular development: evidence from a prospective birth cohort in Shanghai

Year: 2025

Type: article

Abstract: Background Early-life heat exposure is increasing due to climate change and has been linked to impaired cardiovascular development, yet its long-term effects remain unclear. This study investigated the association between early-life heat exposure and blood pressure (BP), cardiac structure and function in early childhood. Methods We analyzed data from the Shanghai Birth Cohort with cardiovascular assessments at age 4 years (2018–2021). Daily ambient temperatures were assigned using a 1-km spatiotemporal model based on participants’ residence. Extreme heat events were defined as days exceeding local temperature thresholds, with heatwaves characterized by intensity-duration criteria and quantified by frequency (total number of heatwave events) and cumulative days (total days within heatwaves). Adjusted associations between long-term heat exposure (pregnancy through age 4 years) and cardiovascular parameters were analyzed using distributed lag nonlinear models. Logistic regression was applied to evaluate the risk of left ventricular hypertrophy (LVH), and restricted cubic splines were employed to characterize the exposure–response relationships within the identified windows. All models were adjusted for maternal, child, and environmental covariates. Results Among 1,100 children (525 girls [47.7 %]), 56 [5.1 %] had LVH. Gestational weeks 9–16 were identified as the critical window of susceptibility, during which heat exposure above the 95 th percentile was associated with an increased risk of LVH (OR = 1.37, 95 % CI 1.26–1.50). While heat exposure showed minimal impact on BP, a J-shaped relationship was observed for cardiac structure, with temperatures above 18.7 °C and 17.4 °C linked to increases of 0.70 g/m 2.7 (95 % CI 0.46–0.93) in left ventricular mass index (LVMI) and 0.47 % (95 % CI 0.34–0.59) in relative wall thickness (RWT), respectively. Heatwave frequency was more strongly associated with LVH risk than cumulative days. Sensitivity analyses confirmed these findings. Conclusion Prenatal heat exposure during gestational weeks 9–16 was associated with increased risk of LVH in children, underscoring the need for early-life adaptation strategies.

Source: Environment International

DOI: 10.1016/j.envint.2025.109895