Sex differences in dementia risk and risk factors: Individual-participant data analysis using 21 cohorts across six continents from the COSMIC consortium.
Level 3 - non-randomized controlled study
Individual-participant data meta-analysis of prospective observational cohorts
PubMed 36790027 · doi:10.1002/alz.12962
What was done
Individual-participant data meta-analysis pooling 29,850 participants (58% women) across 21 cohorts from six continents within the COSMIC consortium. Mixed-effect Cox proportional hazards models were used to calculate sex-specific hazard ratios (HRs) and women-to-men ratio of hazard ratios (RHRs) for associations between risk factors and incident all-cause dementia.
What was found
Over a median follow-up of 4.6 years, 2,089 participants (66% women) developed incident dementia. Women had a higher overall dementia risk than men (HR 1.12, 95% CI [1.02, 1.23]), particularly in low- and lower-middle-income countries. Associations between longer education (RHR 1.01, 95% CI [1.00, 1.03] per year) and former alcohol use (RHR 0.55, 95% CI [0.38, 0.79]) with dementia risk were stronger in men than in women. Other examined risk factors showed no discernible sex differences.
Why it matters
Provides large-scale, multi-continental evidence that while women experience a modest elevation in dementia risk in lower-income settings, most conventional risk factors affect men and women similarly.
Limits
Follow-up was relatively short (median 4.6 years) to assess late-life cognitive decline. The abstract does not detail specific harmonization methods, variations in dementia diagnostic criteria across cohorts, or the complete list of non-differential risk factors tested.
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