Light Exposure Before Sleep May Raise Gestational Diabetes Risk

Greater exposure to light before sleep during pregnancy is associated with an increased risk for gestational diabetes, according to study results presented at the 2023 Annual Meeting of the American Academy of Sleep Medicine and the Sleep Research Society, held from June 3 to 7 in Indianapolis, Indiana.

Previous research has found a link between mistimed light exposure and impaired glucose regulation in nonpregnant women. However, research is scarce when it comes to the effect of evening light exposure during pregnancy. For the study, researchers sought to assess the relationship between evening light exposure prior to sleep, during pregnancy, and the incidence of gestational diabetes.

The researchers conducted a prospective cohort study that included 741 nulliparous women from 8 clinical sites, excluding women with pregestational diabetes.

Participants kept a daily sleep diary and wore a wrist actigraphy monitor for 7 days between 160- and 216-weeks’ gestation. The primary exposure variable was time spent above 10 lux (dim light) during the 3 hours preceding sleep onset. The time was averaged over valid days of recording and participants were categorized to 3 groups according to time exposed to light (“high”, “medium”, and “low”).

Compared with women with a low duration of presleep light exposure, women in the high and medium groups had an increased risk for gestational diabetes (high group: odds ratio [OR], 5.49; 95% CI, 1.8-23.84 and medium group: OR, 4.05; 95% CI, 1.27–17.94). Moreover, women in the high group had more daytime light and were less likely to be late (midpoint > 5AM) or fragmented (wake after sleep onset ≥ 75th percentile) sleepers.

“Increased evening light exposure in pregnancy may be an under-recognized, potentially modifiable risk factor for GDM [gestational diabetes]. Future research should investigate light-targeted interventions as a potential preventive strategy for GDM,” the researchers concluded.