By Kathleen Doheny
Other research has linked smoking with higher rates of infertility and perhaps earlier menopause. However, "secondhand smoke is less researched," especially among never-smoking women, said study author Andrew Hyland, chair of health behavior at Roswell Park Cancer Institute, in Buffalo, N.Y.
In the study, Hyland and his colleagues evaluated women enrolled in the Women's Health Initiative, a large study launched in 1991 to look at a variety of health issues in more than 160,000 generally healthy, postmenopausal women.
Hyland's team looked at information about age of menopause and fertility, along with tobacco exposure, among some of the women enrolled in the study. The investigators evaluated information available on about 88,000 women to look at the fertility effects. They also looked at information on about 80,000 to examine onset of natural, or nonsurgical, menopause.
Both smoking and exposure to secondhand smoke were linked to fertility issues and early menopause (before the typical age of 50), the researchers found.
Compared with never smokers, current or former smokers were 14 percent more likely to be infertile and 26 percent more likely to have early menopause. Early menopause has been linked with a higher risk of death from all causes, Hyland pointed out.
Among never smokers, those exposed to the highest level of secondhand smoke (such as living with a smoker for 10 years or more) were 18 percent more likely to have fertility problems and early menopause, the study found.
Women who had ever smoked reached menopause about 22 months before those who never smoked or never were exposed to smoke. Those exposed to the highest level of passive smoke reached menopause 13 months earlier than those not exposed, the findings showed.
But the study cannot prove cause and effect, Hyland added. "This is an observational study looking at data already collected," he said. "It [the link] could be something associated with early development and exposure as a young child."
Smoke interacts with hormones and can have adverse effects as well, he added.
The study was published online Dec. 15 in the journal Tobacco Control.
The findings are a valuable reminder to avoid all smoke, said Patricia Folan, director of the Center for Tobacco Control at North Shore-LIJ Health System in Great Neck, N.Y.
"This study provides additional motivation and incentive for women of all ages to avoid smoking and exposure to secondhand smoke, as well as to quit smoking," she said. Both are associated with premature birth, low birth weight, infant death and certain birth defects, she added.
"This evidence, in addition to the data from the current study, offers health care providers, particularly ob-gyn practitioners, the information needed to counsel women about the hazards of smoking and secondhand smoke, and to encourage cessation," Folan said.