Salt intake assessed by spot urine on physical examination in Hunan, China

Excessive salt intake is a major public health problem in several countries, especially in China. However, few people are aware of their salt intake. The purpose of this study is to carry out salt intake test in routine physical examination, and to explore the salt intake of different populations and their correlation with diet.

Spot urine sample was collected to test urinary sodium and creatinine excretions for each participant recruited from physical examinations at the Third Xiangya Hospital. The Tanaka formula was used to estimate 24-h urinary sodium excretion, which reflects salt intake. In addition to physical and laboratory examination, information including personal details, health-related habits, and selfreported disease histories was obtained from the National Physical Examination Questionnaire.

In total, 26,406 people completed the salt intake evaluation. After data cleansing, the average salt intake was 8.39±1.80 g/d. Male, middle-aged, overweight and obese, hypertensive, and dyslipidaemic populations, as well as those with non-cardiovascular diseases were more likely to have excessive salt intake. Dietary sources had an effect on salt intake. Salt intake was lower in those who consumed more milk and fruit (both p and p trend<0.01) but was higher in those who consumed more lean meat (both p and p trend<0.05), fatty meat (both p and p trend<0.01) and animal organs (both p and p trend<0.01).

The salt intake in this population far surpasses the recommended amount. We strongly recommend salt intake assessment as routine test into physical examination center.