Development and Validation of Chinese Health Literacy Scale for Low Salt Consumption - Hong Kong Population (CHLSalt-HK)

Globally, sodium intake far exceeds the level recommended by the World Health Organization. Assessing health literacy related to salt consumption among older adults could guide the development of interventions that target their knowledge gaps, misconceptions, or poor dietary practices. This study aimed to develop and validate the Chinese Health Literacy Scale for Low Salt Consumption - Hong Kong population (CHLSalt-HK). Based on previous studies on salt intake and nutrition label reading in other countries, we developed similar questions that were appropriate for the Chinese population in Hong Kong. The questions covered the following eight broad areas: functional literacy (term recognition and nutrition label reading), knowledge of the salt content of foods, knowledge of the diseases related to high salt intake, knowledge of international standards, myths about salt intake, attitudes toward salt intake, salty food consumption practices, and nutrition label reading practices. Eight professionals, including doctors, nurses, and dietitians, provided feedback on the scale. The psychometric properties of the scale were assessed based on data collected from a convenience sample of 603 Chinese elderly adults recruited from Elderly Health Centres in Hong Kong. The 49-item CHLSalt-HK had a possible score range of 0 to 98, with a higher score indicating higher health literacy related to salt intake. The CHLSalt-HK had acceptable content validity; the item-level Content Validity Index ranged from 0.857 to 1.000, and the scale-level Content Validity Index was 0.994. Additionally, it had good internal consistency (Cronbach's alpha of 0.799) and good test-retest reliability (intraclass correlation coefficient of 0.846). The mean CHLSalt-HK score among those who were aware of the public education slogan about nutrition labels and sodium intake was higher by 3.928 points (95% confidence interval: 1.742 to 6.115) than that among those who were not aware of the slogan, which supports adequate discriminant validity. The validated CHLSalt-HK had acceptable content validity, acceptable construct validity, good internal consistency, good test-retest reliability, and adequate discriminant validity. The scale could be completed in 10-15 minutes and is easy to administer compared with the collection of biomarkers or food diaries. Further research should investigate its concurrent validity and predictive validity. The development of this scale supports the first step in salt intake reduction among older Chinese adults in Hong Kong by enabling the assessment of their health literacy related to salt consumption in health screenings or health assessments, and it can be used to evaluate salt reduction interventions.