Cumulative Smoking Exposure In The Non-Demented Older People And The Risk Of Cognitive Decline (NEDICES)

Background: Whether cumulative smoking exposure is a risk factor for cognitive decline among older adults remains majorly unresolved. We assessed whether cumulative smoking exposure in non-demented older people was associated with a higher risk of cognitive decline. Methods: : Baseline cigarette smoking habits were assessed in 2,624 non-demented elderly (≥65 years) Spanish participants. A 37-item version of the Mini-Mental State Examination (MMSE) was administered at two visits (baseline and follow-up, approximately three years later). Change in 37-MMSE (baseline 37-MMSE score − follow-up 37-MMSE score) was divided into tertiles (lower tertile ≥2 points improvement in score, higher tertile ≥2 point decline in score). We dichotomized this variable into higher (cognitive decline) vs. middle and lower tertiles for the current analyses. Results: : Any cumulative smoking exposure, regardless of intensity, was associated with a higher risk of cognitive decline, with a non-linear dose-response. Multivariable-adjusted hazard ratios for higher risk of cognitive decline were 1.00 (reference) in the never smokers, 1.32 (95% confidence interval 1.0-1.74) in the lower tertile of pack-years (47). Multivariable-adjusted hazard ratios for higher risk of cognitive decline were 1.00 (reference) in the never smokers, 1.37 (1.03-1.83) in former smokers, and 1.57 (1.23-2.02) in current smokers. Conclusions: and relevance: The association between cumulative smoking exposure and cognitive decline in the elderly population was dose-dependent. Results underscore the cognitive health risk of smoking and the potential benefits of quitting it.