Salt-Related Knowledge, Attitudes, and Behaviors and Their Relationship with 24-Hour Urinary Sodium Excretion in Chinese Adults

Abstract

Salt intake in China is very high, which increases the risk of hypertension and cardiovascular disease. This study aimed to assess the levels of salt-related knowledge, attitudes, and behaviors (KABs) and the factors that influence them and to explore the relationship between the scores of salt-related KAB and 24-h urinary sodium excretion. In 2018, we collected data from 5453 individuals aged 18-75 years from six provinces in China. A face-to-face survey was carried out, focusing on the KAB related to salt reduction. All participants were asked to collect one 24-h urine sample. Of the 5453 participants, 5352 completed urine collection. The mean score for overall KAB was 31.27 (SD = 9.18), which was composed of three elements: knowledge 4.80 (SD = 5.14), attitude 9.33 (SD = 3.93), and behavior 17.14 (SD = 4.43). The average 24-h urinary sodium excretion was 187.70 (SD = 77.48) mmol, which was equivalent to a urinary sodium excretion of 4.32 (SD = 1.78) g/d. We found that salt-related knowledge, attitude, behavior, and overall KAB scores were all inversely associated with 24-h urinary sodium excretion. For every one-point increase in the KAB score, the 24-h urinary sodium excretion decreased by 0.851 mmol (95% CI: -1.095, -0.602). We also found that location (rural/urban), sex, age, and education are associated with salt-related KAB scores. These results suggest that large-scale health education is needed to reduce salt intake in the Chinese population. In particular, efforts should be focused on reaching those who live in rural areas with low educational levels and older people.