Association between relative fat mass and periodontitis: results from NHANES 2009-2014

Relative fat mass (RFM) is a novel indicator for measuring body fat. This cross-section study aims to explore the association between RFM and periodontitis and to investigate possible effect modifiers in U.S. adults based on the National Health and Nutrition Examination Survey 2009-2014. The category of periodontitis was defined by the CDC/AAP. Mean clinical attachment loss and mean pocket probing depth (PPD) were calculated. The RFM formula is: 64 - (20 × height/WC) + (12 × sex), with sex coded as 1 for female and 0 for male. Natural cubic spline and weighted multivariable regression analyses were conducted to investigate the relationship between RFM and periodontal status. Subgroup and interaction analyses were also employed to assess the moderating roles of age, gender, and race. A total of 10,307 participants were included in our study. Compared to the lowest quartiles, individuals in the highest quartiles of RFM levels were more likely to have moderate/severe periodontitis (OR_Q4vs1 = 1.64, 95% CI 1.30-2.06) and had a higher mean PPD (β_Q4vs1 = 0.15, 95% CI 0.09-0.22). This association was particularly stronger in populations under the age of 60, with significant interactions. Taken together, RFM is positively associated with periodontitis, particularly in those under 60 years old.