Both active and passive smoking have been linked to infertility and earlier menopause in a new large-scale study from the US.
Smoking a lot or being exposed to high levels of second-hand smoke could bring on the menopause one to two years sooner, suggest the findings published by in the journal Tobacco Control.
“It strengthens current evidence that all women need to be protected from active and passive tobacco smoke”
Researchers analysed information on smoking habits, fertility and menopause provided by more than 93,000 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 recruited to the study between 1993 and 1998.
The analysis found exposure to tobacco was linked to an increased risk of infertility and earlier menopause.
Women who smoked or used to smoke had a 14%greater risk of infertility, compared to those who had never smoked, the researchers discovered.
Meanwhile, smokers or former smokers had a 26% increased risk of going through the menopause before the age of 50.
In addition, the average age at the start of the menopause was significantly lower among smokers than for those who had never smoker or been exposed to second-hand smoke.
The team found the menopause arrived almost 22 months earlier among smokers who said they started smoking before they were 15, and 18 months earlier among those who smoked at least 25 cigarettes a day.
Passive smoking was also linked to fertility problems and earlier menopause.
Women who had never smoked but had been exposed to high levels of second-hand smoke were 18% more likely to have had fertility problems than women never exposed to passive smoking.
This applied to women who had spent 10 more years living with a smoker as a child, 20 or more years living with a partner who smoked at home or 10 or more years working people colleagues who smoked.
The researchers said the observational nature of the study meant they could not draw firm conclusion about cause and effect, but there were plausible biological explanations for the results.
For example, they noted that the toxins in tobacco smoke were known to have various negative effects on aspects of reproduction and to disrupt hormone production and activity.
“This 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,” said the researchers. “It strengthens current evidence that all women need to be protected from active and passive tobacco smoke.”