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Disproportionate Climate Burden of Rising Temperature on Low Birth Weights in a Health-Compromised Nation
25 Pages Posted: 30 Jan 2025
More...Abstract
Background: Warming temperatures add to the global health burden, with profound implications for vulnerable populations including pregnant women and newborns. Low birth weight is a major neonatal health issue in Pakistan leading to neonatal mortality and impaired long-term health. This study assessed the impact of extreme temperatures on low birth weights, developed heat vulnerability index at district-level, identified high-risk subgroups, estimated heat-attributable burden, and projected future risks.
Methods: We constructed a space-time series study using national survey data from 2008–2017 across Pakistan. Distributed-lag nonlinear models within a generalised linear mixed-effects framework accounted for provincial variation. We modelled nonlinear and lagged associations between temperature and low birth weights using quadratic functions, and model-averaged predictions addressed uncertainty. Province-level risk estimates combined with district-level indicators, such as live births, child mortality, poverty index, and heat index, developed the heat vulnerability index.
Findings: The study included 85,017 participants, with 15,920 (18·72%) infants identified as having low birth weights. Heat-related risks for low birth weights varied across provinces, with relative risks ranging from 1·30 (1·07–1·57, 95% confidence interval) to 1·74 (1·16–2·59). The heat-related population attributable fraction ranged from 8·95 to 10·91%, translating to 1·12 million heat-related low birth-weight cases over the study period. Projections estimate that heat-related population attributable fractions will increase by 1·23–2·36% by the 2060s. Subgroup analysis showed that the risk of heat-related low birth weight was associated with hazardous air pollution, women with both lower or higher education, and those living in urban areas. Women in southern Punjab, northern Baluchistan, and Sindh faced the highest risks.
Interpretation: Our findings identify Pakistan’s districts most vulnerable to heat-related low birth weight and highlight contributing factors. These insights can drive targeted interventions to mitigate risks. The study advances understanding of global impacts of rising temperatures, particularly in resource-limited and high-risk settings.
Keywords: child health, climate change, extreme heat, global health, heat-related population attributable fraction, heatwaves, infants, pregnant women, relative risk
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