Frailty and its combined effects with lifestyle factors on cognitive function: a cross-sectional study

BACKGROUND: Frailty describes an age-related state of deterioration in biological function. This study aimed to investigate the association between frailty and cognitive function and its combined effects with lifestyles. METHODS: A total of 3,279 participants from the Dongfeng-Tongji (DFTJ) cohort were tested the cognitive function by using the Chinese version of Mini-mental State Examination (MMSE). Frailty was evaluated based on a 35-item frailty index (FI). Frailty status was dichotomized into robust (FI < 0.15) and frail (FI ≥ 0.15). Multivariate generalized linear regression models and logistic regression models were used to estimate the associations of frailty with MMSE score and cognitive impairment. We also analysed the modification and combined effects of lifestyle factors, including smoking status, drinking status, and regular physical exercise, on the above associations. RESULTS: FI was significantly associated with lower MMSE score [β (95%Cl) = -0.28 (-0.43, -0.13)] and cognitive impairment [OR (95%Cl) = 1.19 (1.04, 1.35)]. The association of frailty status with MMSE were found to be stronger among ever smokers [β(95%Cl) = -1.08 (-1.64, -0.51)] and physical inactive individuals [β(95%Cl) = -1.59 (-2.63, -0.54)] while weaker or not significant among never smokers [β(95%Cl) = -0.30 (-0.62, 0.01)] and physical active individuals [β(95%Cl) = -0.37 (-0.65, -0.08))]. There were significant combined effects of frailty status with unhealthy lifestyles including smoking, alcohol drinking, and physical inactive on cognitive impairment. CONCLUSIONS: Frailty was associated with cognitive impairment among Chinese middle-aged and elderly people, while smoking cessation and regular physical exercise could attenuate the above associations, which highlight the potential preventive interventions. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12877-023-03761-0.