BACKGROUND: Poor respiratory function, including low peak expiratory flow (PEF), is a risk factor for dementia. Motoric cognitive risk syndrome (MCR) is a predementia syndrome characterized by slow gait and subjective cognitive complaints. However, the association between PEF and MCR remains unclear. This study examined the cross-sectional and longitudinal association between PEF and MCR. METHODS: The National Health and Aging Trends Study (NHATS), which is a nationally representative cohort of adults ≥65 years of age in the United States, was analyzed from 2011 to 2017. Logistic regression and discrete-time proportional hazards models tested the association of PEF standardized residuals (SR) at baseline with prevalent and incident MCR, respectively. The models adjusted for multiple sociodemographic and health-related covariates. RESULTS: Among 5328 participants (57% women) included at baseline, lower PEF SR was associated with higher prevalence of MCR. Compared with the ≥80 PEF SR percentile group, the <
30 and 30-50 percentile groups had significantly higher odds of prevalent MCR (OR 3.04 [95% CI 1.85, 5.01]
OR 2.06 [95% CI 1.19, 3.54], respectively). Over six years of follow-up, lower PEF SR was also associated with higher incidence of MCR. Compared with the ≥80 PEF SR percentile group, the <
30 and 30-50 percentile groups had significantly higher risk of incident MCR (HR 1.81 [95% CI 1.24, 2.66]
HR 1.55 [95% CI 1.02, 2.34], respectively). CONCLUSIONS: Lower PEF was associated with higher prevalence and incidence of MCR. Poor respiratory function should be further investigated as a potentially modifiable risk factor for MCR and cognitive decline.