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Compelling New Evidence on the Benefits of Quitting Smoking

August 07, 2000|THOMAS H. MAUGH II

You've heard plenty about the health benefits of quitting smoking. Now British researchers have provided more compelling evidence of just how significant those benefits can be.

Researchers at Oxford University found that people who quit smoking before age 35 can reduce their risk of developing lung cancer by more than 90%. And giving up smoking even late in life eliminates most of the risk.

While previous studies of quitting have shown the effect on lung cancer rates can be dramatic, the Oxford report in Saturday's British Medical Journal (http://www.bmj.com) gives the clearest evidence yet.

The project, led by Sir Richard Peto, also provides the first prediction of the number of tobacco-related deaths that will occur worldwide in the next 100 years if smoking patterns persist--1 billion deaths, contrasted with 100 million in the last century.

Peto's research found there already are 1 billion smokers in the world and that, by 2030, another billion or so young adults will have started to smoke. If current smoking patterns continue, tobacco-related deaths worldwide will rise from 4 million a year now to about 10 million a year around 2030, an increase of about 100 million a decade, he estimated.

If trends continue, he predicted that about 15% of all adult deaths worldwide in the second half of the 21st century will be due to tobacco.

No matter how early in life a smoker quits, some of the damage done is irreversible and the risk of lung cancer never declines to normal. Recent research has shown that starting smoking before age 18 is particularly harmful to the lungs.

The Oxford study found that only 2% of those who quit by age 30 developed the disease by age 75, compared to a 0.4% chance for people who have never smoked. It also found that 10% of those who quit at 60 will die of lung cancer, and that continuing to smoke into old age results in a 16% risk.

Abuse Tied to Stress and Depression in Women

Women who were sexually or physically abused as children have abnormally elevated hormonal responses to stress, a chemical imbalance that predisposes them to mood and anxiety disorders, according to researchers from Emory University in Atlanta. The scars of their childhood persist throughout life, according to Dr. Charles B. Nemeroff, leaving them vulnerable to a wide variety of psychiatric disorders.

The Emory team studied 49 adult women, age 18 to 45 years, who were divided into four groups: those who were sexually or physically abused as children and were diagnosed with depression in adulthood; those who were abused in childhood but had not developed depression; depressed women who had not suffered child abuse; and a control group of women with no history of either abuse or depression.

The women underwent a variety of stress tests during which levels of hormones, such as cortisol and ACTH, were measured. The researchers reported in Wednesday's Journal of the American Medical Assn. (http://jama.ama-assn.org) that both groups of women who were abused in childhood showed exaggerated stress responses, with those who were depressed showing the greatest increase. On some measures, their output of stress hormones was six times as great as that of the control group. The women who were depressed but had no history of abuse showed the same hormone response as the control group, however. The team is now looking for ways to minimize that elevated response.

Dual Therapy Tests Well on Head, Neck Cancers

A combination of chemotherapy and gene therapy has proved effective in preliminary trials on a group of patients with head and neck cancers, which are particularly hard to treat, according to researchers from the M.D. Anderson Cancer Clinic in Houston. Dr. Fadlo Khuri and his colleagues reported in the August Nature Medicine (http://www.medicine.nature.com) that the treatment caused tumors to shrink in 25 of 30 patients tested. Conventional chemotherapy, in contrast, normally produces results in only 30% to 40% of similar patients, they said.

The Khuri team used a genetically engineered virus called ONYX-015, which destroys cells containing a mutated tumor suppressor gene called p53. That gene occurs in as many as 70% of head and neck cancers. The virus was injected directly into the tumor. Patients also received the anti-cancer drugs cisplatin and 5-fluorouracil.

Hand Disorder Most Common Among Whites

Contrary to previous belief, the disabling hand disorder Dupuytren's disease does affect African-Americans, but it is much more common in whites, according to researchers at St. Louis University. Dupuytren's occurs when the fibrous tissue under the skin of the hand becomes scarred and thickened, causing fingers to be stuck in a bent position. The cause is unknown, but it is most common in people over the age of 60 and is more likely to occur in patients with medical conditions such as diabetes and hypertension, and in smokers. Researchers had previously believed it did not affect blacks.

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