An Indian man enjoys a cigarette on a covered pavement in New Delhi. People native to South Asia are at greater risk of heart attack at a younger age than other people because of factors that include lifestyle choices such as smoking, a study published in the US journal JAMA said. [Photo: AFP/File/Prakash Singh]

People native to South Asia are at greater risk of heart attack at a younger age than other people because of factors that include lifestyle choices such as smoking, a study published in the US journal JAMA said.

India, Pakistan, Bangladesh, Sri Lanka and Nepal account for about a quarter of the world's population and have the highest proportion of cardiovascular diseases compared with any other region globally.

Deaths related to cardiovascular diseases occur between five and 10 years earlier in these South Asian countries than in Western countries, according to background in the article published in the Journal of the American Medical Association.

An international team of researchers led by Dr. Prashant Joshi of the Government Medical College, Nagpur, India, looked at the possibility that South Asians have a special susceptibility for acute myocardial infarction (AMI, or heart attack) that was not explained by traditional risk factors.

The study included 1,732 heart attack patients and 2,204 controls from 15 medical centers in five South Asian countries and 10,728 heart attack cases and 12,431 controls from other countries.

The researchers found that the average age for a first heart attack was lower in South Asian countries, 53.0 years, than in other countries, 58.8 years. Protective risk factors, such as leisure time, physical activity, regular alcohol intake, and daily intake of fruits and vegetables, were markedly lower in South Asian study participants compared with those from other countries.

Some harmful factors were more common in native South Asians than in individuals from other countries: history of diabetes, current and former smoking, history of hypertension, psychosocial factors such as depression and stress at work or home, and an elevated ratio of ApoB/ApoA-I ratio, a protein/lipid.

When looked at by age, South Asians had more risk factors at ages younger than 60 years.

"The younger age of first AMI among the South Asian cases in our study appears to be largely explained by the higher prevalence of risk factors in native South Asians," the authors write.

"These data suggest that lifestyle changes implemented early in life have the potential to substantially reduce the risk of AMI in South Asians."