Potential impact of maternal nighttime light exposure and its interaction with sociodemographic characteristics on the risk of various congenital heart diseases.

Background: Although maternal exposure to artificial light at night has shown negative associations with pregnancy outcomes, its impact on risk of congenital heart disease remains unclear. This study examined the association between maternal exposure to artificial light at night during pregnancy and occurrence of congenital heart disease in offspring, considering potential interactions with sociodemographics.

Methods: We included newborns diagnosed prenatally with congential heart disease and healthy volunteers from 21 cities in Southern China. Using satellite data, we estimated annual exposure to artificial light at night at maternal residential addresses during pregnancy. We evaluated associations using marginal structural logistic models and assessed multiplicative and additive interaction between sociodemographics and light exposure.

Results: Each one-unit increase in light at night during pregnancy was associated with elevated risk of total congenital heart disease (OR: 1.2, 95% CI: 1.2-1.3), and of almost all specific disease subtypes, in offspring. Using quartiles of light at night confirmed a monotonic dose-response relationship between exposure and disease. The association was more pronounced in severe disease. Some sociodemographic characteristics modified associations between light at night and congenital heart disease, with detrimental associations more pronounced among offspring of mothers with lower education (OR: 1.3, 95% CI: 1.2-1.3), lower income (OR: 1.2, 95% CI: 1.1-1.3), or being usual residents (OR: 1.3, 95% CI: 1.2-1.4), based on the continuous model.

Conclusions: Maternal exposure to artificial light at night during pregnancy was substantially associated with elevated risk of congenital heart disease in offspring. This association was more pronounced among some sociodemographic groups.