A greater ratio of thigh subcutaneous fat to abdominal fat is associated with protection against non-alcoholic fatty liver disease

BACKGROUND & AIMS: No prospective studies have examined the association between thigh subcutaneous fat distribution and non-alcoholic fatty liver disease (NAFLD). We investigated the associations of thigh subcutaneous fat distribution with incidence and remission of NAFLD in a community-based prospective cohort. METHODS: We followed 1,787 subjects, who underwent abdominal ultrasonography, abdominal and femoral magnetic resonance imaging scans, and anthropometric assessments. Associations of thigh subcutaneous fat area/abdominal fat area ratio and thigh circumference/waist circumference ratio with incidence and remission of NAFLD were estimated using the modified Poisson regression model. RESULTS: Over a mean 3.6-year follow-up, 239 incident cases of NAFLD and 207 regressed cases of NAFLD were identified. Increasing thigh subcutaneous fat area/abdominal fat area ratio was associated with a lower risk of incident NAFLD and a higher likelihood of remission of NAFLD [risk ratio (RR) per SD: 0.69, 95% CI 0.59-0.81; 1.20, 95% CI 1.07-1.34, respectively). Each one SD increase in thigh circumference/waist circumference ratio was associated with a 16% lower risk of incident NAFLD (RR 0.84, 95% CI 0.76-0.94) and a 22% higher likelihood of remission of NAFLD (RR 1.22, 95% CI 1.11-1.34). Additionally, the effects of thigh subcutaneous fat area/abdominal fat area ratio on the incidence and remission of NAFLD were mediated through adiponectin (14.9% and 26.6%), homeostasis model assessment of insulin resistance (9.5% and 23.9%), and triglyceride (7.5% and 19.1%). CONCLUSIONS: These results demonstrated that a favourable fat distribution, characterised by a greater ratio of thigh subcutaneous fat to abdominal fat, had a protective role against NAFLD. IMPACT AND IMPLICATIONS: The associations of thigh subcutaneous fat distribution with NAFLD incidence and remission have not been prospectively examined in a community-based cohort. Our findings suggest that greater thigh subcutaneous fat relative to a given amount of abdominal fat has a protective effect against NAFLD among the middle-aged and older Chinese populations.