Lean non-alcoholic fatty liver disease (Lean-NAFLD): characteristics and risk factors from a community cohort follow up study

Abstract

INTRODUCTION AND OBJECTIVES: Non-alcoholic fatty liver disease (NAFLD) is usually associated with obesity. However, some NAFLD patients are lean. We assessed the characteristics and risk factors for lean-NAFLD. METHOD: In a community cohort follow up study (initial screening-2007, re-evaluation-2014), NAFLD was established on USS criteria and exclusion of alcohol overuse and secondary causes. Lean (BMI <23 kg/m2) and non-lean (BMI ≥23 kg/m2) NAFLD were compared. The two groups were compared for differences in gender, diabetes, hypertension, hypertriglyceridemia, low-HDL, weight and waist circumference (WC) at baseline. They were also compared for differences in development of incident diabetes, hypertension, hypertriglyceridemia, low-HDL, and change in weight and WC. RESULTS: 678 (69.6%) individuals with NAFLD detected in 2007 presented for follow up in 2014. 78(11.5%) [males-32(41%); mean-age 53.7(SD-7.1) years] were lean and 600(88.5%) [males-191(31.8%); mean-age 52.3(SD-7.5) years] were non-lean. Hypertension (p=0.007) and a smaller WC (<90cm for males, <80cm for females) (p<0.001) were associated with lean-NAFLD. After 7 years, change in BMI was less (p=0.022) among lean-NAFLD. There were no differences in change in WC or incident metabolic co-morbidities. Of those who did not have NAFLD in 2007, 746 developed incident NAFLD in 2014; lean-NAFLD 193/746 (25.9%) [males-100(51.8%); mean age 59.6(SD-7.5)], non-lean-NAFLD 553/746 (74.1%) [males-201(36.3%); mean age 58.2(SD-7.7)]. On logistic regression analysis, presence of diabetes (p=0.002, OR 2.1) and raised WC (p=0.003, OR 1.7) were associated with incident lean-NAFLD. CONCLUSIONS: Among individuals with NAFLD, lean-NAFLD is associated with hypertension and smaller WC. In the community, diabetes and bigger WC predict incident lean-NAFLD.