Temperature variability and birthweight: Epidemiological evidence from Africa

Area of Science:

• Environmental Epidemiology
• Reproductive Health
• Climate Change Research

Background:

• Nonoptimal ambient temperatures are linked to low birthweight (LBW).
• The impact of temperature variability (TV) on LBW risk remains largely unknown.
• Africa faces significant climate change vulnerability.

Purpose of the Study:

• To quantify the association between temperature variability (TV) and the risk of low birthweight (LBW) in Africa.
• To investigate the effects of overall, intraday, and interday TV on LBW.
• To assess the public health implications of TV in a vulnerable region.

Main Methods:

• Utilized birthweight data from 37 African countries (1990-2020) via Demographic and Health Surveys.
• Calculated TV metrics (overall, intraday, interday) using high-resolution hourly temperature data (ERA5-Land).
• Employed generalized linear mixed logistic regression to model LBW risk associated with TV.

Main Results:

• 10.2% of 333,618 births were LBW.
• A J-shaped association was observed between TV and LBW risk.
• Extreme TV (97.5th percentile) increased LBW odds by 37.3% (overall), 24.1% (intraday), and 15.1% (interday).
• Elevated overall TV accounted for 7.3% of all LBW births in Africa, particularly in dry climate zones.

Conclusions:

• Temperature variability poses an adverse risk to low birthweight outcomes in Africa.
• Findings underscore the importance of climate-health risk assessments for vulnerable populations.
• Different TV metrics demonstrate consistent adverse associations with LBW.