Open AccessPregnancy loss and risk of later dementia: A nationwide cohort study, Denmark, 1977–2017
Author(s) -
Basit Saima,
Wohlfahrt Jan,
Boyd Heather A.
Publication year - 2019
Publication title -
alzheimer's and dementia: translational research and clinical interventions
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.49
H-Index - 30
ISSN - 2352-8737
DOI - 10.1016/j.trci.2019.02.006
Subject(s) - dementia , medicine , hazard ratio , pregnancy , miscarriage , proportional hazards model , cohort study , cohort , confidence interval , obstetrics , pediatrics , disease , biology , genetics
Pregnancy losses may be associated with increased risks of dementia. Methods We conducted a register‐based cohort study in 1,243,957 women with ≥1 pregnancy in Denmark in the period 1977–2015. Using Cox regression, we estimated hazard ratios (HRs) comparing risks of dementia in women with and without pregnancy losses. Results During 21,672,433 person‐years of follow‐up, 261,279 women experienced a pregnancy loss, and 2188 women were diagnosed with dementia. Stillbirth was associated with an 86% increased risk of dementia overall (HR 1.86, 95% confidence interval [CI] 1.28–2.71). By contrast, miscarriage was not associated with later risk of dementia overall (single miscarriage, HR 0.99, 95% CI 0.87–1.12; recurrent miscarriages, HR 1.06, 95% CI 0.84–1.35). Adjustment for cardiovascular disease, hypertension, and diabetes did not meaningfully alter the association magnitudes. Discussion Stillbirth and dementia may share underlying mechanisms, suggesting that a history of stillbirth should be considered when assessing dementia risk in women.