The Association Between Total Percent Fat and Serum Uric Acid in Adults

Abstract

Background: Serum uric acid (SUA) has been proven to be closely associated with metabolic abnormalities, including obesity. This study aimed to investigate the detailed relationship between total percent fat (TPF) and SUA among adults.

Methods: Briefly, 23,715 adults aged 18-59 years in the National Health and Nutrition Examination Survey (NHANES) 1999-2018 were included in this study. Multivariable linear regression models were used to examine the association between TPF and SUA. Subgroup analyses stratified by sex and obesity status were also performed by multivariable linear regression. Then, fitted smoothing curves and generalized additive models were also applied to address the non-linear relationship between TPF and SUA. Finally, a recursive algorithm was used to calculate the inflection point in the non-linear relationship and a two-segment piecewise linear regression model was used to analyze the relationship between TPF and SUA on both sides of the inflection point.

Results: There were 15,808 (66.7%) obese individuals in all 23,715 participants. In the fully adjusted model, there was a positive association between TPF and SUA (β = 0.99, 95% CI: 0.73-1.26). Besides, this positive association remained statistically significant in subgroup analyses stratified by sex and obesity status. Interestingly, in males, the association of TPF and SUA was an inverted U-shaped curve (inflection point: 34.3%).

Conclusion: Our study revealed a significant positive relationship between TPF and SUA among adults and this association remained statistically significant when stratified by sex and obesity status, but the shape of the smoothing curve in males differed from that in females.

Keywords: NHANES; hyperuricemia; obesity; serum uric acid; total percent fat.

FIGURE 1

The association between total percent fat (%) and serum uric acid (μmol/L). (A) Each black point represents a sample. (B) Solid red line represents the smooth curve fit between variables. Blue bands represent the 95% confidence bands derived from the fit. (C) Stratified by sex. (D) Stratified by obesity status. Age, sex, race, smoking status, heavy alcohol consumption, vigorous work activity, hypertension, diabetes, weak/failing kidneys, body mass index, blood urea nitrogen, cholesterol, triglycerides, education level, ratio of family income to poverty, dietary intakes of energy and nutrients (protein, carbohydrate, and fat), and prescription medication use were adjusted (C was not sex-adjusted).