Incidence and risk factors for non-alcoholic fatty liver disease in an urban, adult Sri Lankan population – a community cohort follow-up study

Abstract

INTRODUCTION: In 2007, we reported a 33% prevalence of non-alcoholic fatty liver disease (NAFLD) and its association with PNPLA3(rs738409) gene polymorphism in an urban, adult Sri Lankan population. OBJECTIVES: This study investigated incidence and risk factors for NAFLD after seven years follow-up. METHOD: The study population (42-71-year-olds, selected by age-stratified random sampling from the Ragama MOH area) was screened initially in 2007 and re-evaluated in 2014. On both occasions they were assessed by structured interview, anthropometric measurements, liver ultrasound, biochemical and serological tests. NAFLD was diagnosed on established ultrasound criteria, safe alcohol consumption and absence of hepatitis B/C markers. Non-NAFLD controls did not have any ultrasound criteria for NAFLD. An updated case-control genetic association study for 10 selected genetic variants and incident NAFLD was also performed. RESULTS: 2155/2985 (72.2%) of the original cohort attended follow-up [1244-women, 911-men; mean-age 59.2(SD, 7.7) years]. 1322 [839 women; mean-age 58.9 (SD, 7.6) years] had NAFLD. Out of 795 [466 women] who initially did not have NAFLD, 365 [226 women, mean-age 58.6(SD,7.9) years] had developed NAFLD after 7 years (annual incidence-6.6%). Increased waist circumference [p=0.001], BMI>23kg/m2 [p<0.001] and raised plasma triglycerides [p<0.05] independently predicted incident NAFLD. The updated genetic association study (1310 cases, 427 controls) showed borderline association with NAFLD at 2/10 candidate loci: PPP1R3B(rs4240624), PNPLA3(rs738409) (one-tailed p=0.044 and 0.033, respectively). CONCLUSIONS: In this community cohort follow-up study, the annual incidence of NAFLD was 6.6%. Incident NAFLD was associated with features of metabolic syndrome, and showed tendency of association with PNPLA3 and PPP1R3B gene polymorphisms.