ROCHESTER, N.Y., Feb. 13 (UPI) -- A U.S. study has found a defect in a gene determines why some people can smoke until old age, and others can suffer a heart attack in their 50s.

Dr. Arthur Moss of the University of Rochester Medical Center in New York said the answer lies in a common deviation of the gene CETP -- cholesterol ester transfer protein -- a protein found in all people that controls cholesterol metabolism.

The study, published in the Annals of Noninvasive Electrocardiology, found smokers with a common form of CETP are likely to suffer a heart attack 12 years earlier than a non-smoker, while smokers who do not carry this variant appear to be "protected" and have the same risk of heart attack as non-smokers.

CETP has a common defect, it makes the protein controlling high-density lipoproteins, or HDL, the "good cholesterol" work on overdrive, attacking HDL and breaking it into smaller particles that are more easily cleared from the blood, leading to decreased HDL levels and less good cholesterol.

"The problem only gets worse for smokers who have this form of CETP, because smoking is known to also lower HDL levels," Moss said in a statement."The cumulative effect is a dramatic drop in the age such smokers are likely to experience a heart attack."