Longitudinal association between pulmonary function and incident cognitive decline : Results of the SONIC cohort...

Reduced pulmonary function may contribute to cognitive decline in older adults; however, few longitudinal studies adjust for frailty, lifestyle, and comorbidities. This study examined whether baseline spirometry predicts 3-year cognitive decline in community-dwelling older Japanese adults. Data were derived from the SONIC Study, a longitudinal cohort of older Japanese adults. This 3-year follow-up included community-dwelling adults in their 70 s and 80 s, stratified by age and sex. Baseline and follow-up assessed anthropometry, physical frailty indicators (grip strength and gait speed), cognition (Montreal Cognitive Assessment, Japanese version [MoCA-J]) and pulmonary function (percent vital capacity [%VC], percent forced vital capacity [%FVC], percent forced expiratory volume in one second [%FEV₁], forced expiratory volume in one second / forced vital capacity ratio [FEV₁/FVC], and percent peak expiratory flow [%PEF]). Associations with mild cognitive decline were examined using logistic regression, adjusted for comorbidities, health behaviors, and frailty. Most pulmonary function measures markedly decreased over 3 years, whereas the FEV₁/FVC ratio remained stable. MoCA-J scores markedly declined among adults in their 80 s but remained stable in those in their 70 s. Reduced %PEF was markedly associated with cognitive decline only in participants in their 70 s, in males and females. Additionally, reduced FEV₁/FVC ratio was associated with increased cognitive decline in females in their 70 s. No significant associations were found in participants in their 80 s. In older adults, declines in %PEF and FEV₁/FVC ratio increased cognitive decline in the 70 s age group, with sex differences noted. Simple pulmonary measures may help identify those at risk.