Mutation May Increase Risk From Secondhand Smoke

Secondhand cigarette smoke may be more dangerous than believed, researchers say. Their study found that some women are as much as six times more likely to develop lung cancer if they live with smokers.

An examination of tissue from a group of Missouri women who lived with smokers found that those with a common gene mutation (in this case, the absence of a gene) were 2.6 to six times more likely to develop lung cancer, researchers report.

Clarice R. Weinberg of the National Institute of Environmental Health Sciences said the study is intriguing because it supports the idea that a gene deletion and environmental tobacco smoke work together to increase the risk of lung cancer. However, Weinberg said the study has a weakness because it only examined lung cancer patients. To validate the conclusions for the general population, she said, a larger environmental tobacco smoke study is needed that compares lung cancer patients with a randomly selected group of people without the disease.

The study, led by William P. Bennett of the City of Hope National Medical Center in Los Angeles, is based on the analysis of tissue samples from 106 Missouri women who had never smoked but who had lung cancer diagnosed.

How to Add Six Years

What's a healthful life style worth? Maybe six to 10 extra years of life, new research suggests.

Dramatic benefits are shown for people who don't smoke and who maintain low cholesterol and blood pressure levels.

The research, appearing in today's Journal of the American Medical Association, found life-extending benefits for adults of all ages who have low heart disease risk factors, including not smoking cigarettes.

Jeremiah Stamler of Northwestern University, lead author, said the study evaluated more than 366,000 people over many years and determined the health outcome for those considered at low risk of heart disease.

The results, he said, show that an American life style that includes smoking, little exercise, obesity and poor diet "creates havoc in the cardiovascular system," while healthy habits can extend life substantially.

The study, he said, marks the first time data have been collected for how low-risk people's health develops over a period of years.

Enzyme Against Gum Disease

A new study suggests that gum disease may result from reduced levels of a key enzyme in cells, as well as indifferent dental hygiene.

The enzyme, known as cathepsin C, appears to trigger immunological reactions that destroy diseased cells and eliminate infections in the mouth.

The new research, published in the December issue of the journal Nature Genetics, suggests that even slightly reduced levels of cathepsin C as a result of a genetic mutation may reduce a person's ability to ward off periodontitis, infection below the gum line. Restoring the enzyme to normal levels could be a new approach to preventing and treating gum disease.