The association between all-cause mortality with drinking habits and water sources: a nationwide longitudinal study...

Few studies have reported on the association between drinking habits, water sources and all-cause mortality among the elderly, who are susceptible to toxic environmental factors. We aimed to address this gap by conducting a longitudinal study among the Chinese population.

We conducted a 16-year longitudinal study using data of individuals aged >65 years at baseline enrolled in the Chinese Longitudinal Healthy Longevity Study. A formal questionnaire was used to collect data on drinking habits and water sources. The former to whether participants consumed boiled or unboiled water, while the latter queried the use of well water, surface water, spring water, and tap water. We used Cox proportional hazard adjusted for sociodemographic factors, lifestyle, and common diseases to calculate the risk of all-cause mortality associated with drinking water. We further conducted subgroup analyses to evaluate potential interaction effects.

We used data on 15 664 individuals, among whom 4472 men and 6166 women died from any reason. Participants who drank unboiled water were more likely than those who drank boiled water to eventually reach a high risk of all-cause mortality (hazard ratio (HR) = 1.14; 95% confidence interval (CI) = 1.06-1.23). Compared to drinking well water, drinking tap water in childhood (HR = 0.80; 95% CI = 0.68-0.95), being around 60 years of age (HR = 0.81; 95% CI = 0.76-0.86), and at present (HR = 0.90; 95% CI = 0.86-0.95) were all associated with lower risks of all-cause mortality. Drinking surface water in childhood was also related to a lower risk of all-cause mortality (HR = 0.94; 95% CI = 0.90-0.98). However, drinking spring water was not associated with all-cause mortality across the entire lifespan in the total sample.

Drinking unboiled water was associated with a higher risk of all-cause mortality. In comparison to well water, tap water emerged as a safer and healthier option for the elderly Chinese population throughout their whole life cycle.