Age Of Onset Primarily Dictated By Genes.(Brief Article)

2001 SEP 13 - (NewsRx.com & NewsRx.net) -- The age at which a woman reaches menopause is 85% genetically determined, according to new research published in the August 30, 2001, issue of Human Reproduction.

A woman with a family history of early menopause is herself likely to have an early menopause and consequently early reproductive failure, concludes the team of researchers who have carried out the world's first study in non-twin sisters of the genetic factors involved in natural menopause.

As the age of menopause is a retrospective marker for a woman's reproductive capacity in the years beforehand, the researchers believe that finding that heritability plays such a major role in determining the menopause has important implications for women when childbirth is being delayed well beyond the age of 30. It was this social phenomenon that prompted them to undertake the project.

The team, from centers in Utrecht and Wageningen, the Netherlands, collected data from 243 non-twin sisters in 118 families among a random population sample participating in a breast cancer screening project that had begun in the 1970s. They also collected data from 22 nonidentical and 37 identical twins. In the breast cancer screening study all the women had agreed to provide extensive information about their health, their families, and reproductive history for compilation on a database designed for research purposes.

Using three different analytical models the researchers established nearly identical results: for non-twin sisters the age at which they reached menopause was 85%-87% determined by genetic factors. In twins it was 70%-71%, a figure which was not statistically significantly different from that of the non-twin sisters ("The role of genetic factors in age at natural menopause," Human Reprod, 2001;16(9):2014-2018).

Research leader, Dr. Jan-Peter de Bruin, from the Department of Obstetrics and Gynecology at the University Medical Centre in Utrecht, said that the project was undertaken because the researchers saw a serious social problem emerging with women delaying the age at which they have their first child.

"The increasing age at which women become pregnant with their first child is one of the most remarkable demographic changes in the last 30 to 40 years. More and more women will face involuntary childlessness if this trend keeps going," he said. "A woman with one or more first degree relatives with a history of early menopause is liable to experience earlier menopause herself. Further, this same woman is also expected to start becoming less fertile and to be completely infertile at an earlier age, thus being at greatly increased risk of remaining childless if she delays childbearing."