Emerging data from one of the large population-based studies in , designed to examine the interaction between genetic and lifestyle factors and its hepatic manifestations, has shown the prevalence of non-alcoholic fatty liver disease (NAFLD) amongst the population to be a whopping 49.8%. Researchers say that even this rate, significantly higher than the global pooled prevalence of 25%, is likely to be an underestimation in a cohort chosen to be representative of a large Indian population.
‘Cohort profile: the Trivandrum NAFLD cohort’ appeared in BMJ Open in May this year. It is a project supported and funded by the Nottingham Digestive Diseases Biomedical Research Unit, Nottingham University, U.K. The cohort was selected by the city-based Population Health and Research Institute.
Rising levels of obesity, Type 2 diabetes and metabolic syndrome (MetS, a cluster of conditions such as elevated blood sugar, blood pressure, triglyceride levels and abdominal obesity that occur together and can increase one’s risk of heart disease and stroke) amongst Indian population have been a matter of grave concern.
NAFLD is believed to the hepatic manifestation of MetS. It encompasses a spectrum of diseases from mild steatosis (fatty changes in the liver) to non-alcoholic steatohepatitis (NASH or aggressive fatty liver disease), inflammation which may progress to cirrhosis and liver failure. This damage is similar to the damage caused by heavy alcohol use.
“The global prevalence of NAFLD is about 25%. Population-based studies on NAFLD prevalence in India are scarce. The Trivandrum NAFLD cohort of 2,158 individuals above 25 years from both urban and rural areas in the district represents the full spectrum of the demography of a large Indian State,” says K.T. Shenoy, former Professor of Gastroenterology, Government Medical College Thiruvananthapuram, one of the investigators of the study.
Apart from clinical data, blood samples were collected from the cohort for assessment of liver function, platelet count, fasting glucose insulin and lipids. The participants also underwent abdomen ultrasound scans to assess the presence and grade of fatty infiltration in the liver.
“What is interesting is that obesity turned out to be more of a risk factor for NAFLD than diabetes within the cohort. But even at lower BMI, a significant number of individuals had fatty liver. Accumulation of visceral fat (fat around internal organs inside the abdominal cavity) seems to be high amongst Keralites,” says Dr. Shenoy.
“A decade ago, 85-90 % of cirrhosis cases at the OP in Medical Colleges was linked to alcohol use. However, in the last 7-8 years, we have been seeing a shift, with only 60% cirrhosis cases linked to alcohol use, while over 30% of the cases are linked to fatty liver and non-alcoholic steatohepatitis. The mechanism seems to be almost the same as that we see in alcohol users, but the progression to liver failure seems to be more aggressive in the case of NASH,” he points out.
Researchers feel that NAFLD prevalence even at 49.8% could be an underestimation as ultrasound scan (rather than liver biopsy) was the diagnostic tool for NAFLD in this study.