Secondhand Smoke May Increase Infertility Risk, Early Menopause
Women under 50 who smoke or who are exposed to secondhand smoke are at an increased risk of early menopause and infertility, according to a recent study.
Researchers examined information from the Women's Health Initiative Observational Study (WHI OS), which involved 93,000 women who took part in the research between 1993 and 1998. The study authors then analyzed data on natural menopause age, fertility issues and smoking habits.
Full data on tobacco exposure and fertility, including that of the partner, were available for 88,732 women. And 79,690 of the total sample of 93,676 had had a natural menopause, defined as not having had surgery to remove their ovaries and an absence of periods for 12 consecutive months.
During this time, researchers asked current and former smokers how many cigarettes they smoked daily, the age in which they started smoking and how many years they had been smoking.
Study results showed that tobacco exposure was linked to an increased risk of infertility and earlier menopause, even after accounting for external factors such as alcohol intake, body mass index (BMI) at 18 years, educational attainment, fitness level, use of oral contraceptives, exposure to insecticides and age of first menstrual period.
About 15.4 percent of women who smoked during the time period who also provided fertility information said they had difficulties conceiving throughout a period of 12 months or more. Furthermore, 45 percent said they went through menopause before age 50.
Women who smoked before 15 were also at an increased risk of going through menopause sooner, researchers say, at nearly 22 months in advance. The same was true of those who smoked at least 25 cigarettes per day--experiencing menopause at least 18 months early.
Women who were regularly exposed to second-hand smoke were also at risk even if they were not smokers themselves. These women either lived with a smoker as a child, lived with a partner who smoked or worked with a smoking colleague for a period of 10 years or more. These women had an 18 percent increased risk of developing fertility issues when compared to those not exposed to passive smoking.
"Smoking damages the genetic material in eggs and sperm, which means miscarriage and birth-defect rates are higher among patients who smoke. Due to the toxins from cigarettes, smokers are more likely to suffer from miscarriage than nonsmokers," said Cleveland Clinic's Dr. Daniel Neides.
The study is published (Dec. 14) in the journal Tobacco Control.
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