OBJECTIVETo investigate intake of water in different periods of a day of primary and middle school students in Beijing, Shanghai, Guangzhou and Chengdu of China.

METHODSA total of 5914 primary and middle school students from Beijing, Shanghai, Guangzhou and Chengdu were recruited using multiple-stage random sampling method from September to October 2011. Among them, 5868 students completed the survey. The information of amounts and types of drinking in 8 time periods, morning, afternoon, night as well as in meal and non-meal time in 24 hours of a day was recorded by subjects for seven consecutive days using a quantitative measurement. This information was analyzed by different periods.

RESULTSThe amount of drinking water among 8 periods of a day was (99 ± 101), (130 ± 106), (191 ± 155), (96 ± 107), (246 ± 172), (90 ± 101), (188 ± 135) and (50 ± 81) ml, respectively for before breakfast, during breakfast, after breakfast, during lunch, after lunch, during dinner, after dinner, and midnight (F = 1679.77, P < 0.01). Based on three periods of a day, the amount of drinking water in the morning (420 ± 242) ml was the statistically significantly most, followed by afternoon (341 ± 199) ml, and the least in the evening (327 ± 195) ml (F = 325.23, P < 0.01). The distribution trend of plain water in three periods was the same as total drinking water, with (270 ± 209), (250 ± 179) and (224 ± 177) ml, respectively (F = 84.89, P < 0.01) ; but beverage consumption was the most in the morning(151 ± 133) ml, then in the evening (103 ± 122) ml, and the least in the afternoon (91 ± 199) ml (F = 373.56, P < 0.01). The daily plain water consumption in meal time was (316 ± 247) ml, while it in non-meal time was (773 ± 445) ml with statistically significant difference (Z = 65.2, P < 0.01). There was no significant difference in meal time between plain water (165 ± 194) ml and beverage (151 ± 152) ml (Z = 0.59, P = 0.56) whilst plain water (579 ± 408) ml in non-meal time was significantly higher than beverages (194 ± 204) ml (Z = 64.5, P < 0.01).

CONCLUSIONThe amount of drinking water of primary and middle school students in different periods of a day was different in four cities of China.