Background Excessive intake of sugar-sweetened beverages (SSBs) is harmful to health. In recent decades, the consumption of SSBs by Chinese residents has increased rapidly, increasing the risk of death and burden of disease.

Objective To analyze the knowledge level and influencing factors of SSBs for Chinese residents aged 18-64 years in 2021.

Methods A multi-stage cluster random sampling approach was used to conduct a questionnaire survey among residents aged 18-64 years in 302 survey sites across the country in 2021, and 98567 valid questionnaires were obtained. Four questions are about SSBs among the questionnaire's 5 dimensions. Respondents who answered 3 or more questions correctly were considered to have a basic understanding of SSBs. Frequency and weighted proportion were used for description. With individual as level 1 and resident council (village council) as level 2, a two-level logistic regression model was applied to examine the influencing factors. A null model was used to determine whether the two-level logistic regression model was appropriate.

Results The knowledge awareness rate of SSBs was 57.0% among the Chinese residents aged 18-64 years in 2021. The knowledge point with the lowest correct rate was "It is best to consume no more than 25 grams of added sugar per day" (22.6%), while the one with the highest correct rate was "Excessive intake of SSBs can increase the risk of obesity and diabetes" (81.1%). The results of the null model showed that SSBs knowledge level had a clustering effect at resident council (village council) level (t=25.00, P<0.0001), so a two-level model fit better than a one-level model. The results of the two-level logistic model revealed that residents who were female (OR=1.14, 95%CI: 1.11, 1.18) or working in medical and health (OR=1.36, 95%CI: 1.27, 1.45) and education institutions (OR=1.16, 95%CI: 1.07, 1.24) had a higher knowledge level compared to males or residents of other occupations. The knowledge level was lower among residents in central (OR=0.87, 95%CI: 0.77, 0.97) and western (OR=0.85, 95%CI: 0.75, 0.94) areas than in eastern areas. Those with chronic diseases (OR=0.81, 95%CI: 0.78, 0.84) and who did not know if they had a chronic disease (OR=0.75, 95%CI: 0.72, 0.78) had a lower knowledge level than those without chronic diseases. Compared with 18-24 years, the knowledge level was higher in ages 35-44 years (OR=1.07, 95%CI: 1.02, 1.12) and lower in ages 55-64 years (OR=0.92, 95%CI: 0.86, 0.97), and not different from the ages 25-34 years and 45-54 years. The knowledge level increased with the level of education, the trend was statistically significant (P＜0.001).

Conclusion Only about half of Chinese adults aged 18-64 years had a basic understanding of SSBs in 2021. The awareness rate of added sugar intake was low in particular. The knowledge levels of male, central and western, or less educated populations were even lower. Awareness of the negative health outcomes of SSBs was high among the population.