Raw Water Consumption Does Not Affect All-Cause or Cardiovascular Mortality: A Secondary Analysis

Previous studies have examined water quality and its association with all-cause and cardiovascular mortality. However, there is a lack of data regarding association between the amount of water consumption and risk of mortality. We used the third National Health and Nutrition Examination Survey (NHANES III) database and its subsequent follow-up data. Only patients older than 45 years who reported amount of average water consumption and for whom follow-up mortality data were available were included in the study. Patients were stratified into following groups of average daily raw water consumption: (1) no water consumption, (2) ≤2 cups, (3) >2 to ≤ 4 cups, (4) >4 to ≤6 cups, (5) >6 to ≤8 cups, and (6) ≥8 cups. End points studied were all-cause mortality, ischemia-related mortality, congestive heart failure-related mortality, and stroke-related mortality. Baseline characteristics were compared using t tests and Mann-Whitney U tests. Odds ratios, 95% confidence intervals, and P values were calculated for univariate analysis using >6 cups to ≤8 cups of water a day group as reference. Multivariate analysis was then performed adjusting for various factors. P values of less than 0.05 were considered statistically significant. A total of 7666 patients were ultimately included in the study. Multivariate analysis demonstrated no significant differences in all-cause, ischemia-related, heart failure-related, or stroke-related mortality among various raw water intake groups when compared with the reference group. The significance noted for all-cause mortality in >2 glasses to ≤4 glasses a day group in the univariate analysis was not seen with multivariate analysis (odds ratio: 0.747; 95% confidence interval: 0.437-1.276; P = 0.285). Daily raw water consumption does not seem to impact all-cause mortality or cause-specific cardiovascular mortality.