Sex-specific Associations of Body Mass Index With Inflammatory Biomarkers (Interleukin-1 Beta and C-reactive Protein) in Healthy Adults

Background: Obesity-related inflammation may exhibit sex-specific patterns due to differences in adipose tissue distribution and immune regulation. This study investigated sex-specific associations between body mass index (BMI) and circulating interleukin-1β (IL-1β) and C-reactive protein (CRP) levels in healthy adults.
Materials and Methods: This cross-sectional study included 119 healthy adults (49 females and 70 males). Serum IL-1β and CRP concentrations were measured using ELISA. BMI was analyzed as a continuous variable and categorized as normal, overweight, or obese. Age-adjusted multiple linear regression and analysis of covariance were performed to examine sex-specific associations.
Results: IL-1β levels increased progressively across normal, overweight, and obese BMI categories in males (P<0.05), whereas females showed no significant variation in IL-1β levels across BMI subgroups (P>0.05). BMI was positively associated with IL-1β in the overall population (R²=0.105; P=0.039), males (R²=0.142; P=0.018), and females (R²=0.115; P=0.041), with stronger effects in males. No significant BMI-CRP associations were found in either sex. Females had significantly higher IL-1β levels than males, particularly in normal and overweight subgroups, but this difference disappeared in obesity. No sex differences in CRP were observed across BMI subgroups.
Conclusion: BMI was positively associated with IL-1β in healthy adults, with stronger effects in males, while no significant BMI-CRP associations were found. These findings highlight sex-specific obesity-related inflammation patterns and suggest IL-1β may be a more sensitive biomarker for adiposity-related inflammation in healthy populations.