P-252: The relationship between free fatty acids and whole body fat mass varies by ancestry and sex: the CHAriSmA study
T Hitt, D Stefanovski, R McCarter, L Yanek, B Zemel, A Kelly, S MaggeAbstract
Introduction
Conventional thinking suggests that fasting free fatty acids are positively correlated with adiposity. However, there are adiposity differences by sex and ancestry.
Objectives
We evaluated the relationship between fasting free fatty acids and adiposity in in South Asian adolescents and young adults compared with White and African American peers.
Methods
We measured fasting free fatty acids and total fat mass (Hologic DXA scan) among South Asian, White, and African American adolescents and young adults with BMI ≥ 80%ile (≥ 23kg/m2 if ≥ 18y) without diabetes. Ancestry differences in the fasting free fatty acid - fat mass association were tested using generalized linear models with interaction analysis between ancestry groups, sex, and fasting free fatty acids adjusted for age, pubertal stage, and height-squared.
Results
Adolescents and young adults [51 South Asian, mean age: 19.8y, 54 White: 18.9y, 49 African American: 18.8y, p=0.02] did not differ by sex, BMI, pubertal stage, or fat mass [mean: South Asian 31219g, African American 31964g, White 29733g, p=0.5]. In males, White adolescents and young adults had a positive relationship between fasting free fatty acids and fat mass (β=0.07%, p<0.001), but differed by ancestry: South Asian vs White, -0.08%, p<0.000; African American vs White, -0.12%, p<0.001 (See Figure). Among females, there were no significant differences.
Conclusions
In our cohort, the fasting free fatty acid - fat mass relationship varied by sex and ancestry. Among males, fasting free fatty acids were positive correlated with fat mass only in the White group. Thus, a positive relationship between fasting free fatty acids and fat mass may be specific to White males.