Sex differences in the association between self-rated health and high-sensitivity C-reactive protein levels in Koreans: a cross-sectional study using data from the Korea National Health and Nutrition Examination Survey

BACKGROUND: No studies have investigated the association between self-rated health (SRH) and high-sensitivity C-reactive protein (hs-CRP) levels in South Koreans. We explored this association and analyzed differences between sexes. METHODS: Using cross-sectional data from the 2015-2017 Korea National Health and Nutrition Examination Survey, we analyzed the association between SRH and high hs-CRP levels (> 1.0 mg/L) in 14,544 Koreans aged ≥ 19 years who responded to the SRH survey and had available hs-CRP test results. Differences in sociodemographic factors were analyzed using the Pearson's chi-square test for categorical variables or the Mann-Whitney U test for continuous variables. Multiple logistic regression analysis was used to measure the association between hs-CRP levels and SRH according to sex while adjusting for other possible confounders. RESULTS: The percentage of very poor to poor SRH was higher in the high hs-CRP group (22.4%) than in the low hs-CRP group (17.66%). Among men, the risk of a high hs-CRP level increased with worse SRH (adjusted for confounders; P for trend < 0.001). After adjusting for all confounders, including chronic diseases, men with very poor SRH showed a higher odds ratio (OR) for high hs-CRP levels than those with very good SRH (fully adjusted OR, 1.74; 95% CI, 1.04-2.90). Significant correlations were absent among women. CONCLUSIONS: Poor SRH was correlated with low-grade inflammation (high hs-CRP levels) among Korean male adults. These findings could be useful for developing health improvement programs and in goal setting at a national scale.