New Delhi, Jan. 16: Medical scientists today said they have resolved the long-standing puzzle of why heart attacks typically tend to strike Indians five or 10 years earlier than Europeans or North Americans.
The early heart attacks in Indians and other South Asians, first noticed nearly 20 years ago, had triggered speculation that people in the subcontinent may carry certain genes that make them vulnerable to heart disease.
Now, an international research team has shown that the early heart attacks are linked to well-known, traditional risk factors such as bad diet, lack of exercise and diabetes — and may have little to do with genes or other unknown factors.
“It’s the price South Asians are paying for eating less fruits and vegetables and exercising less than other countries,” said team member K. Srinath Reddy, the president of the Public Health Foundation of India, in New Delhi.
“The early heart attacks are driven mainly by risk factors linked to behaviour and are thus easily preventable,” Reddy told The Telegraph. “The idea that Indians — and South Asians — are different should no longer be an alibi for inaction.”
The researchers from India, Pakistan, Bangladesh and Canada compared the lifestyles of 1,730 patients of first-time heart attacks from South Asia with the lifestyles of 15,000 patients from 47 other countries.
Their study, which will appear in the Journal of the American Medical Association tomorrow, has shown that the traditional risk factors are more common in young people from South Asia than in their counterparts from other countries.
The proportion of the population in South Asia that consumes fruits and vegetables at least twice a day is half what it is in the other 47 countries. The proportion of South Asian population that engages in exercise is three times lower than that in the other countries. The prevalence of diabetes and harmful fats in blood was also higher in young South Asians than in other populations.
“In the transition to a modern lifestyle, these risk factors have been picked up rapidly by South Asians,” said Prabhakaran Dorairaj, a cardiologist at the All India Institute of Medical Sciences in New Delhi.
Nearly nine out of 10 heart attacks could be explained through these traditional risk factors. “However, there may be some genetic role underlying risk factors such as diabetes,” Prabhakaran said.
The study showed that the average age of first-time heart attacks in South Asia was 53 years compared to 58 years in the other countries. Previous studies have indicated that heart attacks may occur up to 10 years earlier in South Asians.
“Until now, no one really knew why heart attacks were common in young people in their 40s and early 50s in South Asia,” said Prashant Joshi, a cardiologist at the Government Medical College in Nagpur.
“There was speculation that genes or narrow coronary arteries, or shorter life-spans in South Asia may be making people here susceptible to early heart attacks,” he said.
While regular and moderate alcohol consumption had a protective effect in the other countries, this effect was absent in South Asia. Doctors suspect that this is because of distinct drinking patterns observed in South Asia compared to other parts of the world.
“Unlike in the western countries where people drink very moderately and regularly, here there is excessive, binge drinking,” Joshi said.
“While regular and moderate drinking has been shown to be protective, irregular but excessive drinking at one go does not appear to have any protective effect,” he said.