Greater Light Exposure Before Bed Linked to Increased Risk for GDM

WEDNESDAY, March 29, 2023 (HealthDay News) — Greater light exposure in the three hours before bed is associated with an increased risk for gestational diabetes mellitus (GDM), according to a study published online March 10 in the American Journal of Obstetrics & Gynecology: Maternal-Fetal Medicine.

Minjee Kim, M.D., from the Northwestern University Feinberg School of Medicine in Chicago, and colleagues examined the association between objectively measured evening light exposure before sleep during pregnancy and the risk for GDM in a prospective cohort study conducted at eight clinical sites between 2011 and 2013. The primary exposure variable was minutes of light exposure during the three hours preceding sleep onset, averaged across all valid days of recording and categorized into terciles (dim, moderate, and bright). The final analysis included 741 women with a median gestational age of 20 weeks and five days on the first day of actigraphy recording.

The researchers found that GDM occurred in 4.2 percent of participants. Greater presleep light exposure was associated with increased GDM risk (odds ratios, 5.49 and 4.05 for bright and moderate, respectively, versus dim). Presleep light exposure remained significantly associated with GDM after adjusting for multiple confounding variables. Compared with those who did not develop GDM, women who developed GDM had greater light exposure in the three hours before sleep onset, but did not differ in terms of light exposure during daytime or sleep, or in their activity levels.

“Our study suggests that light exposure before bedtime may be an underrecognized yet easily modifiable risk factor of gestational diabetes,” Kim said in a statement.