The Association Between Serum C-Reactive Protein Levels and Body Fat Parameters: Results from the Korean National...

Background and Objectives: C-reactive protein (CRP), a marker of systemic inflammation, is frequently elevated in individuals with excessive adiposity. However, the relationship between specific body fat parameters and CRP levels across sexes and age groups remains unclear. This study aimed to investigate the association between CRP levels and body fat parameters using data from the 2022 Korea National Health and Nutrition Examination Survey. Methods: A total of 3369 participants (representing 32,635,626 Korean adults) were included. Demographic, lifestyle, and clinical data were collected, and body composition parameters were measured using bioelectrical impedance analysis. The primary exposure variables included fat mass index (FMI; total body fat mass/height²) and trunk fat mass. The primary outcome was log-transformed high-sensitivity CRP (ln[hsCRP]). Pearson correlation and sex-stratified multivariate linear regression analyses were performed. Results: The mean age of participants was 49.6 years, and 53.3% were male. ln[hsCRP] was positively associated with body mass index, waist circumference, total body fat mass, FMI, appendicular fat mass, and trunk fat mass in both sexes (all p < 0.001). FMI showed a stronger association with ln[hsCRP] in females (r = 0.373) than in males (r = 0.232). In multivariable analyses, FMI remained independently associated with ln[hsCRP] in both males (β = 0.10) and females (β = 0.14), with a stronger effect observed in females. Trunk fat mass was also independently associated with ln[hsCRP] (β = 0.06 in males; β = 0.10 in females). Age-stratified analyses demonstrated that these associations were more pronounced in younger adults (19-40 years old) than in those aged 41-70 years. Conclusions: In Korean adults, total and truncal fat masses were independently associated with systemic inflammation, and this association was stronger among females and younger adults.