Educational gradients and sex-by-education differences in environmental health literacy among adults from selected urban communities in Nanning, China.

BACKGROUND

Environmental health literacy (EHL) is essential for recognizing environmental risks and adopting health-protective behaviors. This study assessed EHL among adults recruited from selected urban communities in Nanning, Guangxi, China, examined sociodemographic correlates with emphasis on educational attainment and sex, and explored whether basic concepts were statistically linked to the association from environmental health knowledge to practical skills.

METHODS

A cross-sectional survey using non-probability, site-based convenience recruitment was conducted from November to December 2024 among eligible adults present at two selected urban community survey sites in Nanning, Guangxi, China. EHL was measured using a standardized 30-item instrument covering basic concepts, basic knowledge, and basic skills. Multivariable linear and logistic regression models were used to identify correlates of EHL and to test sex-by-education interactions. An exploratory bootstrap indirect-association analysis with 5,000 resamples assessed whether the association between basic knowledge and basic skills was statistically consistent with an indirect link through basic concepts.

RESULTS

Among 1,773 participants, 953 (53.75%) were female, and the mean total EHL score was 83.34 ± 10.91. In the analytic community sample, 1,574 participants (88.8%) met the 70-point criterion for sufficient EHL; the total-score distribution was left-skewed and concentrated above this threshold. Internal consistency was acceptable for the total instrument (Cronbach's alpha = 0.718), whereas domain-specific coefficients were interpreted descriptively. Educational attainment showed the strongest and most consistent association with EHL. Compared with participants with primary school education or below, those with a master's degree or above had an 11.32-point higher total score (95% CI: 7.84 to 14.80) and higher odds of sufficient EHL (aOR = 10.06; 95% CI: 3.82 to 28.98). Significant sex-by-education interactions were observed for total EHL, basic knowledge, and basic skills. The exploratory indirect association from basic knowledge to basic skills through basic concepts was small but statistically evident in the total sample and among women.

CONCLUSION

Educational attainment was the strongest correlate of EHL in this selected urban community sample. The findings should be interpreted as sample-specific associations rather than population-representative estimates for all adults in Nanning. The observed sex-by-education heterogeneity and exploratory knowledge-concept-skill association suggest that EHL promotion should prioritize residents with limited education and use concept-centered, skill-oriented communication strategies.