Study Reveals Genetic Impact of Risk of Early Menopause for Smokers

Researchers from the Perelman School of Medicine at the University of Pennsylvania report evidence that smoking can cause earlier signs of menopause. This relates specifically to white women who have certain genetic variations and who were heavy smokers. Their study was published online in the journal Menopause.

This isn’t the first study that showed that smoking has an effect on menopause. Previous studies found that smoking can hasten menopause by about one or two years – no matter what the race or genetic background of the woman. The new study is unique because it found a higher risk of menopause in some white women who smoke.

The study did not find any statistically significant relationships between smoking, early menopause, and specific gene variants with African American women. The study did not examine why there wasn’t any statistically significant correlations in that group. There is no indication that the study involved women who were of other races.

The study enrolled more than 400 women. They ranged in age from 35 to 47. The women were part of the Penn Ovarian Aging Study. A total of 7% of the women in the study carried a variation in the CYP3A4*1B gene. 62% of the women in the study carried a variation of the CYP1B1*3 gene. The study included women who were heavy smokers, who were light smokers, and who were nonsmokers.

On average, women typically enter menopause around age 50. There are many symptoms of menopause that people tend to recognize. This includes hot flashes, insomnia, and changes in mood. Menopause also is associated with risks of certain diseases, such as coronary artery disease and osteoporosis.

The average time-to-menopause after entering the study was noted. White women who carried a variation in the CYP3A4*1B gene, and who were heavy smokers, entered menopause 5.09 years after entering the study. Those who carried a variation in that gene, and who were light smokers, entered menopause at 11.36 years. The group who carried a variation in that gene, and who were nonsmokers, didn’t enter menopause until 13.91 years after the study began.

Overall, this meant that the average time-to-menopause for heavily smoking white females who had a variation in the CYP3A4*1B gene was about 9 years earlier than in the women who carried a variation in that gene and who were nonsmokers. This study shed some light on how we should think about the reproductive risks of women who smoke. White women who have carry a variation on the CYP3A4*1B gene may want to limit the amount that they smoke, or avoid doing so altogether.

What about the group that carried a variation on the CYP1B1*3 gene? The average time to menopause for white women who were heavy smokers was 10.41 years. The average time to menopause for light smokers was 10.42 years. The average time to menopause for nonsmokers was 11.08 years. This is an increased risk, but not as high as for the group with the variations on the CYP3A4*1B gene.

Image by Iqbal Osman on Flickr.

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