Objectives Assessment of knowledge, attitude and practice (KAP) is a crucial element. By performing a cross-sectional survey, we aimed to investigate KAP regarding dietary sodium intake in Shandong residents aged 18-year-old and above, and provide baseline data to develop public education campaigns to reduce dietary sodium intake.

Methods A close-ended questionnaire was applied to assess KAP. With a response rate of 98.4%, a representative sample of 15350 residents were interviewed between June and July 2011. Difference in proportions of understanding the link between salt and hypertension, intention to reduce salt, and being currently take action to reduce salt were compared using the χ² test. Predicators for intention and take action to reduce salt were determined by multivariate logistic regression with adjustment for potential confounders.

Results Dietary sodium intake KAP of urban residents was generally better than rural counterparts. Although residents lacked knowledge on recommended limit of sodium, good knowledge and a favourable attitude towards low sodium diet was seen. Residents seemed ready for sodium reduction: Vast majority of residents (85.3% for urban; 86.7% for rural) reported intention to reduce salt; About four fifth of residents reported agreeing with the low sodium diet and food labelling. However, urban residents seemed more likely to be ready for sodium reduction than rural counterparts: Majority of urban residents (60.4%) reported understanding the relationship of sodium intake and hypertension, while 48.2% of the rural counterparts did so; 46.2% of urban residents reported currently taking actions to reduce salt, while 34.9% of rural counterparts did so. Comparing to residents with low education level, those with high education level were more likely to intend to reduce salt (OR=3.33, 95% CI 2.31 to 4.81, p for trend <0.001 for urban; OR=2.80, 95% CI 1.87 to 4.20, p for trend <0.001 for rural), and take action to reduce salt (OR=1.44, 95% CI 1.16 to 1.78, p for trend <0.001 for urban; OR=1.31, 95% CI 1.12 to 1.52, p for trend=0.001 for rural), after adjusting for potential confounders. Similarly, increased likelihood was observed among household income, intention and take action to reduce salt. Misperception seemed prevalent among residents: Vast majority of residents (82.1% for urban; 76.1% for rural) reported that food will lose its taste; many residents (28.4% for urban; 31.8% for rural) reported low sodium intake reduces strength. There was significantly independent association among favourable attitude toward low-sodium diet, intention and take action to reduce salt, while those who perceive low sodium reducing strength, were less likely to intend to reduce salt (OR=0.85, 95% CI 0.77 to 0.95 for urban; OR=0.78, 95% CI 0.69 to 0.89 for rural) and to take action to reduce salt (OR=0.91, 95% CI 0.79 to 1.04 for urban; OR=0.89, 95% CI 0.81 to 0.98 for rural). TV/radio was the most frequently reported source of information on salt and health (60.5% for urban; 54.9% for rural), doctors stood next in the line (29.4% for urban; 23.1% for rural).

Conclusions The majority of Shandong residents recognise the health consequences of high-sodium diet and are interested in reducing their sodium intake. Expanded educational efforts are needed to broaden awareness of the health impact of a high-sodium diet, and address misperception of low sodium diet. Salt media campaign should be considered to achieve desirable salt consumption. The findings of this study suggest that socio-economic status (education and income) should be considered during the development of strategies for effective public education campaign.