Association between 24 h urinary sodium excretion and microalbuminuria among Chinese people aged from 18 to 69 years old

Objective To analyze the association between 24 h urinary sodium excretion and microalbuminuria (MAU) among Chinese people aged from 18 to 69 years old. Methods 2 400 subjects aged from 18 to 69 years old were selected form Gaomi and Fushan sites of Shandong Province and Xinyi and Ganyu sites of Jiangsu Province in 2013 by using multi-stage stratified cluster random sampling method. Questionnaire survey, physical measurement and 24 h urine collection were conducted. 2 262 subjects were finally included in the analysis. According to the quartile of 24 h urinary sodium, all subjects were divided into Q1-Q4 groups and the levels of urinary microalbumin and MAU among different groups were compared. The relationship between urinary sodium and MAU was analyzed by multivariate logistic regression analysis. Results The age of subjects was (42.1±13.5) years old, including 1 124 males (49.7%). The 24 h urine volume, urinary sodium, urine albumin M (P25, P75) and MAU detection rate were (1 411±495) ml, (166.4±71.6) mmol/d, 12.5 (9.6, 17.4) mg/d and 9.0% (203 cases), respectively. With the increase of urinary sodium level, the level of urinary albumin increased (Ptrend<0.001), and the prevalence of MAU also showed an upward trend (Ptrend<0.001). Multivariate logistic regression analysis showed that after adjusting for age, gender, smoking, alcohol consumption, BMI, hypertension and diabetes, the risk of MAU in Q4 group increased by 174% compared with Q1 group, and OR (95%CI) value was 2.74 (1.80-4.16). Conclusion 24 h urinary sodium is associated with the prevalence of MAU and salt reduction can help reduce MAU. Key words: Urine; Sodium; Albuminuria; Cross-sectional studies