A large study linked passive and active smoking to early menopause and fertility problems in women below 50 years old. High tobacco exposure was associated with early menopause up to two years in advance. The findings were directly compared to lifetime non-smoking women not exposed to passive smoking.
The study involved over 93,000 women who took part in the Women's Health Initiative Observational Study (WHI OS) between 1993 and 1998. The researchers analyzed data on natural menopause age, fertility issues and smoking habits.
The 88,732 women provided data on fertility problems and tobacco exposure, including their partners' data. Aged 50 and 79, all the participants already went through menopause. About 79,690 women out of 93,676 went through a natural menopause.
Among the smoking women who provided fertility data, 15.4 percent said they had troubles conceiving within a period of 12 months or more. About 45 percent said they went through menopause before reaching the age of 50.
Past and currents smokers carry a 14 percent increased risk of developing fertility problems and 26 percent increased risk of experiencing early menopause before age 50.
Women who started smoking before age 15 reported earlier menopause nearly 22 months in advance. Women who go through 25 cigarettes daily got their menopause at least 18 months early.
The research team also analyzed women who never smoked but were exposed to second hand tobacco smoke. These women either lived with a smoker during their childhood years (10 years or more), lived with a smoking partner at home (20 years or more) or worked with a smoking colleague (10 years or more).
Findings showed these women carry an 18 percent increased risk of developing fertility issues compared to women never exposed to passive smoking. Women bared to the highest rate of passive smoking reported an earlier menopause by 13 months.
The findings were universal after considering external factors such as alcohol intake, body mass index at 18 years of age, fitness level, educational attainment, exposure to insecticides, usage of oral contraceptives and age of first menstrual period. The research was published in the Tobacco Control journal on Dec. 14.
The research team stressed the observation status of the study, which means no stable conclusions can be created with regard to the cause and effect. However, the findings support the claims of past smaller studies.
The harmful effects of tobacco smoke toxins are widespread. These toxins can affect the reproduction aspects and interfere with the hormone activities.
"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.
Photo: Javier Ignacio Acuña Ditzel | Flickr