[Water intake sources analysis of adults in four cities of China in summer]

To investigate the water intake sources of adults in the four cities of China in summer.

A total of 64 adults aged 18 - 60 yrs from the four cities (Beijing, Shanghai, Chengdu and Guangzhou) were selected using convenient sampling method. The information on amounts and types of daily drinking water was recorded by subjects for three consecutive days using a quantitative measurement. The food samples were collected by using duplicate portion method and the water content of food samples were determined.

The median of daily total water intake of 63 subjects was 3045 ml, while daily total drinking water was 1600 ml, the median ratio of which accounting for 55.8% of total water intake. Water from food was 1157 ml, the median ratio of which accounting for 41.4% of total water intake. The median of daily total water intake (3566 ml) and the ratio of water from food (55.3%) of subjects in Chengdu was significantly higher than subjects in Guangzhou (2929 ml, 45.4%), Shanghai (2748 ml, 33.1%) and Beijing (2743 ml, 31.3%) (daily total water intake: χ² = 10.42, P = 0.015;the proportion of water: χ² = 28.48, P < 0.01). Daily total water intake in men (3302 ml) was significantly higher than that in women (2900 ml) (Z = 2.35, P = 0.019).

Daily total water intake of subjects in summer was more than the current Chinese recommended total water intake (2200 ml), with the main part of drinking water and water from food.