Drinking habits and water sources with the incidence of cognitive impairment in Chinese elderly population: The Chinese Longitudinal Healthy Longevity Survey

•Subjects drinking un- boiled water were more likely to develop cognitive impairment.•Drinking from tap water was associated with a lower risk of cognitive impairment.•Drinking surface water at childhood decreased the incidence of cognitive impairment. Little was known on whether drinking habits and water sources affected cognitive function. This study aimed to examine the associations of drinking habits and water sources with the incidence of cognitive impairment in the Chinese elderly population. Data were drawn from the Chinese Longitudinal Healthy Longevity Survey. All participants aged ≥ 60 years at baseline were potential eligible. Cognitive function was measured using the Chinese version of the Mini-Mental State Examination (CMMSE). Participants with the CMMSE score ≤ 24 were identified as cognitive impairment. Drinking habits included preferring to drink boiled water or un-boiled water. Water sources included well, surface water, spring, and tap water. This study included 18034 participants. Participants drinking un- boiled water were more likely to develop cognitive impairment than those drinking boiled water (P< 0.001; HR: 1.269; and 95% CI: 1.128-1.427). Compared to drinking from a well, drinking from tap water at childhood, around aged 60 years, and present was associated with a lower incidence of cognitive impairment (all P< 0.001; HR: 0.672, 0.735, and 0.765; and 95% CI: 0.540-0.836, 0.686-0.788, and 0.723-0.810, respectively). The underline mechanisms behind the associations of drinking habits and water sources with the incidence of cognitive impairment were not fully explained. Participants drinking un- boiled water were more likely to develop cognitive impairment. Meanwhile, compared to drinking from a well, drinking from tap water was associated with a lower incidence of cognitive impairment.