Nicotine Content In Womens’ Toenails Can Predict Heart Disease

The level of nicotine in womens’ toenails can predict the risk of coronary heart disease, say researchers from the University of California, San Diego.

By analyzing the nicotine levels in the toenails of more than 60,000 women, the researchers found that those who had suffered heart disease had on average twice the levels of nicotine in their toenails than women without heart disease.

“Using toenail nicotine is a novel way to objectively measure exposure to tobacco smoke, and ultimately, to increase our understanding of tobacco-related illnesses,” explained Wael Al-Delaimy, Ph.D., Department of Family and Preventive Medicine, UC San Diego School of Medicine. “It has advantages over using other biomarkers and could become a useful test to identify high-risk individuals in the future. This would be especially helpful in situations where smoking history is not available or is biased.”

Researchers found no difference in age, body mass index, aspirin use, or history of high cholesterol corresponding to the toenail nicotine levels. Women with the highest toenail nicotine levels were physically less active, had a lower body mass index, drank a higher amount of alcohol, and were more likely to have histories of high blood pressure, diabetes, and family history of heart attack than women with lower levels.

Why toenails? The toenails have an advantage over other existing biomarkers of smoking because they grow more slowly. The levels detected in the nails represent nicotine taken up from blood by nails during growth. The slow growth rates of toenails provide a more stable estimate of average exposure, which is most relevant for illnesses related to tobacco smoke, such as heart disease. Using toenail samples in epidemiological studies is also an attractive concept because they’re easy to collect and store for relatively low cost.

The study was conducted by researchers at University of California, San Diego, School of Medicine, in collaboration with colleagues from Harvard University, and published in the April, 2008 issue of the American Journal of Epidemiology.

Quitting Smoking Leads to Significant Reduction in Mortality Risks After 5 Years

Women smokers who quit reduce the risk of death from heart disease within 5 years, and their risk of any other smoking-related death by 20%, according to a recent study.

"Tobacco use remains the leading preventable cause of death in the United States. Globally, approximately 5 million premature deaths were attributable to smoking in 2000. The World Health Organization projects by 2030 that tobacco-attributable deaths will annually account for 3 million deaths in industrialized countries and 7 million in developing countries," the authors write. They add that the rate of mortality risk reduction after quitting compared with continuing to smoke is uncertain.

By analyzing data from the Nurses’ Health Study, an observational study of 104,519 female participants, with follow-up from 1980 to 2004, Stacey A. Kenfield, Sc.D., of the Harvard School of Public Health, Boston and his colleagues measured the relationship between cigarette smoking and quitting smoking on mortality in women. 12,483 deaths were recorded in this group, of which 4,485 (35.9%) had never smoked, 3,602 (28.9%) were current smokers, and 4,396 (35.2%) were among past smokers.

A 13% risk reduction in mortality from any cause within the first 5 years of stopping smoking (compared with continuing to smoke), with the excess risk falling to the level of someone who had never smoked 20 years after quitting.

According to the study, "Significant trends were observed with increasing years since quitting for all major cause-specific outcomes. A more rapid decline in risk after quitting smoking compared with continuing to smoke was observed in the first 5 years for vascular diseases compared with other causes."

In regard to coronary heart disease, 61% of the full benefit of quitting was realized within the first 5 years; similarly for cerebrovascular mortality where 42% of the potential benefit was realized within the first 5 years after quitting. Death due to respiratory disease showed an 18% reduction in risk within 5 to 10 years of quitting.

Lung cancer mortality showed a 21% risk reduction during the first 5 years compared with people who did not quit, but the excess risk remained for 30 years. Past smokers with 20 to less than 30 years of not smoking showed an 87% reduction in risk of lung cancer mortality compared with continuing smokers. The researchers also found that approximately 64 percent of deaths among current smokers and 28 percent of deaths among former smokers were attributable to cigarette smoking.

"Early age at initiation is associated with an increased mortality risk so implementing and maintaining school tobacco prevention programs, in addition to enforcing youth access laws, are key preventive strategies. Effectively communicating risks to smokers and helping them quit successfully should be an integral part of public health programs," the authors conclude.

Source: Journal of the American Medical Association (JAMA), April 7, 2008 – 2008;299[17]:2037-2047