Scientists have given us many reasons not to smoke, but now, researchers from the University of Pennsylvania provide evidence that, in white women with specific genetic variations, smoking causes early signs of menopause - up to 9 years earlier than average.
Publishing their study in the journal Menopause, the researchers note that although prior research has shown that smoking accelerates menopause by 1-2 years, theirs is the first to suggest that genetics and smoking increases risks of early menopause.
The team did not find the same relationship between smoking, specific gene variants and earlier menopause in black women.
"It is possible that uniform relationships among white and African American women were not found due to other factors associated with race that modify the interaction between smoking and genes," says Dr. Samantha F. Butts, assistant professor of obstetrics and gynecology at Penn Medicine.
Although the symptoms of menopause, which include hot flashes and anxiety, can be uncomfortable, the researchers note that it also comes with increased risks of coronary artery disease, osteoporosis and death from all causes.
This is why women who enter menopause prematurely - before the average age of 50 - face added risks.
Smokers with genetic variant entered menopause 9 years early
For 14 years, the researchers followed over 400 women between the ages of 35 and 47, who took part in the Penn Ovarian Aging Study.
Researchers found that white women with a specific genetic variant who were heavy smokers entered menopause an average of 9 years earlier than their non-smoking counterparts.
The team found that women who carried variations of a gene called CYP3A4*1B and who did not smoke entered menopause an average of 13.91 years after entering the study.
However, light smokers and heavy smokers entered menopause an average of 11.36 years and 5.09 years after entering the study, respectively.
So, white females with the genetic variant who heavily smoked entered menopause about 9 years earlier than women with the genetic variants who did not smoke.
There was also a statistically significant difference in women who carried a gene called CYP1B1*3 and who smoked, though the researchers note this difference was not as strong as the findings for the other genetic variant.
Dr. Butts says their study could change the way the medical community thinks about reproductive risks and smoking in women:
"We already know that smoking causes early menopause in women of all races, but these new results show that if you are a white smoker with these specific genetic variants, your risk of entering menopause at any given time increases dramatically."
'Further investigation is needed'
The team notes that the two genes do not result in early menopause on their own, but rather, they increase risks of early menopause in white smokers. Of the white women in the study population, 62% had variations of the gene CYP3A4*1B.
Although the researchers did not investigate why there were no statistically significant relationships between smoking, the gene variants and early menopause in black women, Dr. Butts suggests this is an area future research should address:
"It is well known that race affects multiple features of menopause, and this could be another. Further investigation is needed to clarify this question."
Medical News Today recently reported on a study that suggested thirdhand smoke - the invisible remnant of tobacco smoke that remains on surfaces and even clings to dust - is linked to liver, lung and skin problems.