Lifetime history of gestational diabetes and cognitive function in parous women in midlife

We conducted a secondary data analysis of the prospective Nurses’ Health Study II. From 1989 to 2001, and then in 2009, participants reported their history of GDM. A subset participated in a cognition sub-study in 2014–2019 (wave 1) or 2018–2022 (wave 2). We included 15,906 parous participants (≥1 birth at ≥18 years) who completed a cognitive assessment and were free of CVD, cancer and diabetes before their first birth. The primary exposure was a history of GDM. Additionally, we studied exposure to GDM and subsequent type 2 diabetes mellitus (neither GDM nor type 2 diabetes, GDM only, type 2 diabetes only or GDM followed by type 2 diabetes) and conducted mediation analysis by type 2 diabetes. The outcomes were composite z scores measuring psychomotor speed/attention, learning/working memory and global cognition obtained with the Cogstate brief battery. Mean differences (β and 95% CI) in cognitive function by GDM were estimated using linear regression.

The 15,906 participants were a mean of 62.0 years (SD 4.9) at cognitive assessment, and 4.7% (n=749) had a history of GDM. In models adjusted for age at cognitive assessment, race and ethnicity, education, wave of enrolment in the cognition sub-study, socioeconomic status and pre-pregnancy characteristics, women with a history of GDM had lower performance in psychomotor speed/attention (β −0.08; 95% CI −0.14, −0.01) and global cognition (β −0.06; 95% CI −0.11, −0.01) than those without a history of GDM. The lower cognitive performance in women with GDM was only partially explained by the development of type 2 diabetes.