With all the known health dangers of smoking tobacco, researchers have just added some more to the list. New research has linked smoking and exposure to secondhand smoke with a greater chance of infertility and early menopause.
The research, published in the journal Tobacco Control, comes from Andrew Hyland and colleagues from the Roswell Park Cancer Institute in Buffalo, New York. They studied 93,676 women aged 50 to 79 who took part in the Women’s Health Initiative Observational Study (WHI OS) between 1993 and 1998. They looked at data on smoking and exposure to cigarette smoke as well as other health information. 88,372 women were able to provide fertility information and 79,690 women had undergone natural menopause during the study. Natural menopause, which is defined as no menstruation for twelve consecutive months, is contrasted with surgery that causes menopause when the ovaries are removed.
Although other researchers had linked using tobacco with infertility and earlier menopause, these researchers wanted to know if the same held true for secondhand smoke exposure. The scientists surveyed smokers and former smokers about the age they began smoking, how many years they smoked, and how many cigarettes they smoked per day. They surveyed non-smokers about if they lived with a smoker as a child or adult, how long they were exposed, and whether they were exposed to tobacco smoke at work.
The researchers found that 13,621 of the women, about 15.4 percent, experienced infertility. Infertility involved trying unsuccessfully to conceive for at least twelve months when the issue was not known to be with the male partner. About 45 percent of the 79,690 women with natural menopause experienced it before the age of 50, contrasted to the average age of menopause, which is 51.
Not surprisingly considering past research, the researchers in this study found that current and former smokers had a 14 percent greater change of infertility and a 26 percent greater chance of having early menopause. Women who began smoking before the age of 15 and who used the most tobacco went through menopause 22 months earlier than those not exposed to tobacco, on average, and women smoking at least 25 cigarettes a day went through menopause 18 months earlier. This data seems to show that more smoking is linked to a greater risk of infertility and early menopause.
However, the smokers were not the only ones at risk for infertility and early menopause. When researchers looked at the non-smokers who had the most exposure to secondhand smoke, such as exposure in the home during childhood, living with a smoking partner for twenty years, or working with smoking co-workers for ten years, they found a similar outcome. This group experienced menopause about 13 months earlier, on average, than those not exposed to much tobacco smoke.
The links between tobacco smoke exposure, infertility, and early menopause remained even as researchers looked at use of oral contraceptives, age of puberty, level of physical activity, body mass index (BMI) at age 18, and insecticide exposure. Although the researchers could not rule out male partners being the cause of infertility in all cases, they had no reason to believe the statistics would be different between groups for that reason.
The current study did not look at how tobacco smoke exposure affects fertility and menopause. However, other studies have examined toxins in tobacco smoke and how they interfere with hormones and reproduction. Many studies have already established links between smoking and heart disease, stroke, lung cancer, and various other health issues.
Infertility and early menopause do have implications for women hoping to conceive a child. However, the health effects may go beyond just reproduction. Other studies had suggested a link between earlier menopause and a general decrease in lifespan, not good news for those with high tobacco smoke exposure. It seems that quitting smoking and limiting exposure to secondhand smoke could help women improve their reproductive and general health.