"It is well known that oxidative stress plays a role in atherosclerosis, cancer and other chronic conditions," said Holger Schunemann, research assistant professor and lead author on the study. "Our results suggest that free-radical damage also is associated with narrowing of the pulmonary airways."

The study is one of the first investigations of the relationship between lung function, oxidative stress caused by free oxygen molecules, also known as free radicals, and blood levels of antioxidants, substances that can help prevent free-radical damage.

Researchers assessed lung function in 132 non-smoking subjects between the ages of 37 and 73 years, by measuring the volume of air participants could force from their lungs during a one-second exhale. They collected blood samples from all participants and measured levels of thiobarbituric acid-reactive substances, or TBARS, a marker of oxidative stress, and levels of several compounds thought to protect against oxidative stress. Results showed that oxidative stress was associated with obstruction of the pulmonary airways.

"We know that obstruction of the pulmonary airways, as revealed by test of lung capacity, is a strong predictor of cardiovascular disease and all-cause mortality," said Schunemann. "These findings suggest a possible role of oxidants and antioxidants in determining lung function, and that these substances could represent, in part, the physiological link between impaired expiratory lung function and increased risk of death from chronic diseases, such as heart disease and lung cancer."

Women with depressive symptoms risk developing alcohol problems

Beth Moscato, research assistant professor in the Department of Social and Preventive Medicine and lead author of the study, hypothesized that depressive symptoms predicted subsequent alcohol problems in women, but that the inverse was true for men, i.e., that alcohol problems predicted depression.

To test the hypothesis, Moscato and colleagues studied a group of 1,306 adults from Erie County for seven years. Participants were at least 19 years old when the study began in 1986. Follow-up interviews were completed in 1989 and 1993.

Participants supplied information on alcohol use, alcohol-related problems and depressive symptoms, as well as socio-demographic information.

Results showed that women initially classified as having depressive symptoms were three times more likely to have alcohol problems after three years and 2 1/2 times more likely after four years than women who did not report depressive symptoms. No relationship was found at seven years. Alcohol problems did not predict subsequent depressive symptoms in men.

"These findings should be a flag to health practitioners," Moscato said. "If a woman has a high level of depressive symptoms, the practitioner should also evaluate drinking problems over time."

Breast-feeding for 20 months may lower risk of developing breast cancer

Results of their case-control study involving 1,313 women showed that premenopausal women had a 50 percent lower risk of breast cancer if they had breast-fed for at least 20 months, compared to women who had at least one baby and had not breast-fed. There was no effect of breast-feeding on the risk of breast cancer for women who were postmenopausal at the time of the study.

"This is one of a number of studies now that show a decreased risk of breast cancer with breast-feeding," said Jo L. Freudenheim, associate professor of social and preventive medicine and primary researcher on the study. "There is some question, however, about whether this is related to how long a woman breast-feeds, to inherent breast problems in women who don't succeed in breast-feeding when they try, to treatments to stop milk production or just to cessation of menstruation.This study shows that breast-feeding is protective, but the effect appears only if women breast-feed over a longer period of time," Freudenheim said. Breast-feeding time was measured in cumulative months during a lifetime.