Analysis of urine volume and dietary salt intake assessed by two 24 hours urine specimens / 中华疾病控制杂志

ABSTRACT

@#Objective To analyze urine volume and dietary salt intake assessed by two 24 h urine specimens，to discuss its application value for evaluating population level and individual level dietary salt intake． Methods The subjects aged 18-69 years were selected from four counties in Shandong Province and Jiangsu Province from 2013 to 2014 by using multi-stage stratified cluster random sampling method． A questionnaire survey was conducted and two 24 h urine with an interval of one day were collected． The differences between two 24 h urine volume，and the dietary salt intake between two 24 h urine were assessed at individual level and population level． Ｒesults A total of 1 288 subjects was( 42．3± 14．0) years old，of which 626( 48．6%) were males． The average urine volume of the subjects was ( 1 462±437) ml． The first 24 h urine volume ( 1 427±488) ml was lower than the second 24 h urine volume ( 1 498± 552) ml ( t = -4．439，P＜0．001) ． The dietary salt intake was ( 9．8±3．3) g，and the dietary salt intake of males ( 10．1±3．5) g was higher than that of females ( 9．5±3．1) g ( t = 3．09，P= 0．002) ． There was a significant difference in dietary salt intake among different age groups ( F= 7．57，P＜0．001) ． The dietary saltintake of 1 136 ( 88．2%) subjects was higher than the recommended level． At the individual level，the participants with the absolute difference with 1g between the subjects’two 24 h urinary salt excretion was 279 ( 21．7%) ，and the participants with the absolute difference with ＞3 g was 48．5%． At the population level，the first 24 h urinary salt excretions ( 9．9 ± 4．1) g was similar to that in the second 24 h urine and ( 9．7±4．0) g ( P= 0．1021) ． The intraclass correlation coefficients between salt excretions in the two 24 h urine was 0．508( 95% CI 0．451-0．559) ． Conclusion The results of this study suggest that 24 h urinary salt excretion can better assess the salt intake at population level，but cannot accurately reflect the individual’s salt intake．