Heart link to chewing tobacco

Indian cardiologists have produced what they say is the first evidence to show that chewing tobacco can constrict the blood vessels of the heart within minutes and possibly raise the risk of heart attacks.

Their study on men who volunteered to chew a single gram of tobacco while having their hearts monitored has revealed significant reductions in the diameters of coronary arteries within 10 minutes after they began chewing.

The cardiologists from the All India Institute of Medical Sciences (AIIMS), New Delhi, say their findings highlight the rapidity with which a habit long associated with mouth cancer can also put the heart in danger by constricting coronary arteries.

“This is the first hard evidence that chewing tobacco harms the heart,” Balram Bhargava, professor of cardiology at AIIMS, and lead author of the study said. The findings have appeared in the American Journal of Cardiovascular Drugs.

Public health experts believe the results are significant because the public as well as doctors appear inadequately informed about cardiovascular risks of tobacco chewing. “Tobacco chewing is often not viewed as harmful for the heart, even doctors forget to advise heart patients to stop chewing tobacco,” said Sivasubramanian Ramakrishnan, assistant professor of cardiology at AIIMS, the study’s first author.

More men and women in India use smokeless tobacco which is mainly chewed. Nearly four in 10 men consume smokeless tobacco, while three in 10 smoke, and 9 in 100 women chew tobacco in contrast to 2 in 100 who smoke.

In their study, AIIMS cardiologists examined the effect of chewing tobacco on 12 habitual male tobacco chewers who were undergoing coronary angiography for diagnosis. Each man volunteered to chew one gram of crushed tobacco leaves during the procedure.

One section of a coronary artery constricted from an average diameter of 3.17 mm to 2.79 mm within 10 minutes. “The effect peaked within 12 to 13 minutes, the tobacco absorbed through the buccal mucosa,” said Bhargava.

The cardiologists have called this a “striking transient narrowing” of the coronary arteries. In line with previous studies on tobacco, their observations show that chewing tobacco increased the heart rate and the workload on the heart.

The findings add fresh evidence of the risks of chewed tobacco to organs other than the mouth. Last year, biophysicist Krishan Khanduja and his colleagues at the Postgraduate Institute of Medical Education and Research in Chandigarh had shown that chewed tobacco disrupts the normal functions of a key family of enzymes active in almost every organ of the body.

Their study indicated that chewed tobacco can also damage genetic material in the liver, kidneys and lungs. “The earlier myth was that chewed tobacco affects only the oral cavity,” Khanduja said.

source: www.telegraphindia.com