Being exposed to second-hand smoke causes the menopause to start up to two years earlier, a study has warned.
Smoking and living with heavy smokers brings on the change quicker before the age of 50 than non-smokers.
And one of the largest studies of its kind found an increased risk of infertility.
Current or former smoking was associated with a 14 per cent greater risk of infertility and a 26 per cent heightened risk of menopause before the age of 50.
The average age at the start of the menopause was significantly earlier among smokers than it was among those who have never smoked and who hadn’t been exposed to second-hand smoke.
Current or former smoking
Greater risk of infertility Raised risk of menopause before age 50
For heavy smokers, defined as over 30 a day, the menopause arrived almost 22 months earlier for those who said they had started smoking before their 15th birthday and 18 months earlier among those who smoked at least 25 cigarettes a day.
Women exposed to second-hand smoke at the highest level – 10 or more years of living with a smoker as a child, 20 or more years of living with a smoking partner who smoked at home, and 10 or more years working with a smoker – were 18 per cent more likely to have had infertility problems than women who had never been exposed to passive smoking.
The highest level of passive smoke exposure was associated with the arrival of menopause 13 months earlier than those never exposed to it.
Highest level of passive smoking versus never exposed to it
More likely to have had infertility problems Earlier arrival of menopause in months
Danielle Smith, of the Department of Health Behavior at Roswell Park Cancer Institute in the US, said: “Our study demonstrates significant associations between lifetime tobacco exposure – by active smoking of current and former smokers and by independently studied secondhand smoke exposure – and women’s health issues of infertility and menopause occurring before the age of 50 years.
“It is one of the first studies of this size and statistical power to investigate and quantify active and passive smoking and women’s health issues.
“It strengthens the current evidence that all women need to be protected from active and passive tobacco smoke.”
The study was based on lifetime smoking habits, fertility problems, and age at natural menopause of 93,676 women taking part in the Women’s Health Initiative Observational Study.
All had gone through the menopause and were aged between 50 and 79 when they were recruited to the study between 1993 and 1998.
Details of tobacco exposure and fertility including that of the partner were available for 88,732 women.
And 79,690 had had a natural menopause.
Although the clinical significance of earlier menopause was not clear other studies have linked earlier menopause to a heightened risk of death from any cause.
And there are plausible biological explanations for the results as the toxins found in tobacco smoke are known to have various deleterious effects on many aspects of reproduction and to disrupt hormone production and activity.
Ms Smith added: “Our findings support the association between active smoking and infertility.
“The suggestive dose-response relationship between heavier smoking and infertility found in our analysis are similar to measures of association found in another large prospective cohort study.
“Associations between secondhand smoke and infertility have been studied since the 1980’s with mixed results, perhaps due to small sample sizes and/or methodological limitations.
“Using data from a large prospective cohort, our study adds to the evidence base by demonstrating significant associations between the highest secondhand smoke exposure during reproductive life and delayed conception.”
The study was published in the journal Tobacco Control.