To examine the association of water intake with risk of mortality from CVD.

Prospective cohort study.

A total of 22 939 men and 35 362 women aged 40–79 years enrolled in the Japan Collaborative Cohort (JACC) Study with available data regarding water intake from foods and beverages. The underlying causes of death were determined based on the International Classification of Diseases.

During the median 19·1 years of follow-up, 1637 men and 1707 women died from CVD. There was an inverse trend between high water intake and risk of CVD in both sexes. Compared with participants in the lowest quintile of water intake, the multivariable-adjusted hazard ratios (95 % CI) for mortality from total CVD in the highest quintile of water intake were 0·88 (0·72, 1·07; P for trend=0·03) in men and 0·79 (0·66, 0·95; P for trend=0·10) in women. Those for CHD were 0·81 (0·54, 1·21; P for trend=0·06) in men and 0·60 (0·39, 0·93; P for trend=0·20) in women. Reduced risk of mortality from ischaemic stroke was also observed among women in the highest water intake quintile: 0·70 (0·47, 0·99; P for trend=0·19). There was no association between water intake and mortality from haemorrhagic stroke in either sex.

Higher intake of fluids from foods and beverages was associated with reduced risk of cardiovascular mortality in both sexes and reduced risk of ischaemic stroke in women in Japan.