How do the drinking habits and water sources influence all-cause mortality? A nation-wide longitudinal study on Chinese elderly

Abstract BackgroundFew studies reported the association between water quality with all-cause mortality among the elderly and vulnerable groups susceptible to toxic environmental factors. This study aimed to examine the effect of drinking habits and kinds of water sources on the risk of all-cause mortality in the Chinese elderly population.MethodsData were drawn from the China Longitudinal Healthy Longevity Survey (CLHLS), and a longitudinal study for 16 years was conducted in this study. All participants aged ≥ 65 years at baseline were potentially eligible. The information on drinking habits and water sources was recorded via a structured questionnaire. The drinking habits referred to drinking boiled or un-boiled water, and the types of water sources included well water, surface water, spring water, and tap water. Cox proportional hazard models, adjusting socio-demographics, lifestyle, and common diseases, were used to estimate the risk of all-cause mortality by drinking water. The subgroup analyses were performed to assess potential interaction effects.ResultsA total of 15,663 participants were included in the study, among whom 4,472 males and 6,166 females died from any causes. Participants drinking un-boiled water were more likely to progress to high risk of all-cause mortality than those drinking boiled water (HR:1.14; 95% CI: 1.06-1.23). Compared to drinking well water, drinking tap water in childhood, around aged 60 years, and at present were all associated with lower risks of all-cause mortality (HR: 0.80, 0.81, and 0.90; and 95% CI: 0.68-0.95, 0.76-0.86, and 0.86-0.94, respectively); drinking surface water in childhood was related to a lower risk of all-cause mortality (HR:0.94, 95%CI:0.90-0.98); drinking spring water was not found to be associated with all-cause mortality in the total sample across all the life span.ConclusionDrinking un-boiled was associated with higher risk of all-cause mortality. Tap water was a safe and healthy source to drink compared with well water in the entire life cycle for the Chinese elderly.