Dad's smoking linked to menopause in daughters

NEW YORK (Reuters Health) - When men smoke while their partners are pregnant, their daughters may end up hitting menopause about a year earlier, suggests a new study.

Previous research has found that a woman's own smoking habits, as well her partner's, may also precipitate the point at which she can no longer get pregnant.

Now, "it seems that the effect of paternal smoking on daughters' reproductive life span is stronger than that of (her) husband smoking," study researcher Dr. Misao Fukuda, of the M&K Health Institute in Ako, Japan, told Reuters Health in an email.

He said it's possible that lighting up around the time of conception could affect sperm cells or the embryo's development.

The researchers questioned more than 1,000 Japanese women who were visiting clinics for gynecologic exams and were past menopause. They asked the women how old they were when they got their periods and when they hit menopause, as well as whether they or their husbands smoked in between those dates.

The researchers also had women ask their parents about whether their mothers or fathers smoked while their mothers were pregnant.

About three-quarters of fathers had smoked while their daughters were in the womb, just as three-quarters of women said their husbands smoked before they hit menopause. Far fewer women in both generations -- between four and six percent -- had smoked themselves while pregnant or during the time they could have become pregnant.

Across all participants, women stopped getting their periods when they were 51 years old, on average.

Women who were smokers hit menopause an average of about 14 months earlier than women who didn't light up. When their husbands smoked, they hit menopause five months earlier -- but that didn't pass statistical tests to show a definitive effect.

Women whose dads smoked while they were in the womb stopped having their periods about 13 months earlier than those whose dads were nonsmokers, Fukuda and colleagues report in Fertility and Sterility. Whether her dad smoked did not influence when a woman had started her period, however.

Not enough mothers smoked for the researchers to determine how that influenced when their daughters hit puberty or menopause.

And the researchers couldn't be sure, based on this study, that the effect of a father's smoking happened before their daughters were born, and not when they were kids.

"The whole issue of teasing apart prenatal effects versus childhood (effects) is really hard to do," said Jennifer Ferris, who has studied the link between secondhand smoke and puberty at Columbia University but was not involved in the current study.

"Most of the time if the woman's smoking when she's pregnant or the father's smoking when she's pregnant, that child will also be exposed during childhood," she told Reuters Health.

In addition to the effect on sperm cells suggested by Fukuda, Ferris said that chemicals from cigarette smoke may alter glands in the brain that produce reproductive hormones.

She said that more research is needed to explain the link between secondhand smoke and reproduction.

Most women know now that it's dangerous to smoke during pregnancy, Ferris said. However, she added, "It would be nice to see more studies looking at paternal smoking because that still may be more common than women smoking during pregnancy."

SOURCE: http://bit.ly/lV2Hl5 Fertility and Sterility, online May 16, 2011.