New Delhi, June 19: Excess fat in the liver raises the risk of symptom-less blockages of the arteries even among people with no diabetes and no history of heart disease, a new research study in India has shown.
The study by a team of doctors at the All India Institute of Medical Sciences, New Delhi, has suggested that people with non-alcoholic fatty liver (NAFL) and no obvious health trouble should be investigated for risks of cardiovascular disease.
The doctors have said this is the first demonstration of the link between NAFL and sub-clinical, or silent, atherosclerosis among Indians, although this association has previously been observed mainly in Caucasian populations.
“It’s possible that the complications of NAFL on the heart occur much earlier than its complications on the liver,” said Naval Vikram, associate professor of medicine at the AIIMS, and lead author of the study to appear in the journal Atherosclerosis.
Doctors have known for long that NAFL may sometimes lead to inflammation, chronic liver damage and cirrhosis. Abdominal fat, obesity and diabetes are among risk factors associated with NAFL.
Community surveys, including one in Bengal two years ago by doctors at the Institute of Postgraduate Medical Education and Research (IPMER), Calcutta, have indicated that NAFL is an emerging public health problem.
The survey in a pocket of rural Bengal by hepatologist Abhijit Chowdhury and his colleagues from the IPMER had found 8 per cent of the population sample had NAFL, and five out of 10 persons with NAFL were neither overweight nor had abdominal obesity. A survey in an urban locality of Mumbai five years ago had revealed an even higher prevalence of NAFL — 16 per cent.
“Such prevalence figures would mean hundreds of thousands of people across the country with NAFL who face the risk of liver complications are also at risk of silent atherosclerosis,” Vikram told The Telegraph.
The AIIMS researchers measured the thickness of the inner lining of the carotid artery, the main blood vessel that carries blood to the brain, and found that people with NAFL had a five-fold increased risk of a thickened arterial wall. Their study also showed that people with NAFL had a 12-fold higher risk of having impaired blood flow behaviour in their arteries than people without NAFL.
“This is a significant study as the association between NAFL and atherosclerosis had remained to be proven in Indians — until now,” said Anoop Misra, a diabetes specialist and director of the Centre for Diabetes, Obesity and Cholesterol, New Delhi, who was earlier at the AIIMS.
Doctors believe NAFL — which may be quantitatively measured through magnetic resonance spectroscopy imaging — is reversible through rigorous diet and exercise. “Reducing a lot of weight is the main prescription for patients with NAFL,” said Misra, who was not involved in the new study.
But a liver specialist in Mumbai said long-term follow-up studies would be required to determine whether the sub-clinical atherosclerosis actually led to cardiovascular events in patients with NAFL.
“We may view NAFL as a manifestation of the metabolic syndrome on the liver,” said Deepak Amrapurkar, a hepatologist at the Bombay Hospital, Mumbai, who had led the 2007 survey of NAFL in a city suburb. The metabolic syndrome is marked by obesity, high cholesterol levels and diabetes.
“Patients in whom NAFL has been detected during abdominal ultrasound scans are already being recommended further investigations for the metabolic risk factors,” said Amrapurkar. Practice guidelines from professional associations of gastroenterologists in the US recommend that patients with unsuspected NAFL detected in scans should be assessed for obesity, glucose intolerance and high lipid levels.
