Background: Environmental factors explain only a small part of the age variance at which menopause commences. The variation in natural menopause is a trait predominantly determined by interaction of multiple genes, whose identity and causative genetic variation remains to be determined. Menopause is a retrospective marker for the reproductive capacity of preceding years, since subfertility and infertility precede menopause at distinct time-intervals. In the present study we have investigated the contribution of genetic factors to menopausal age.
Methods: Data were collected from a random population sample of singleton and twin sisters participating in a prospective breast cancer screening project, who had subsequently experienced natural menopause. Heritability of menopausal age was estimated with analysis of variance, Mx modelling and Gibbs sampling.
Results: All produced almost identical heritability estimates of 0.85-0.87 for singleton sisters, suggesting a strong genetic contribution to menopausal age. Twin data were used to distinguish additive genetic from common environmental effects; a heritability of 0.71-0.72 was determined, which does not deviate significantly from the estimate for singleton sisters.
Conclusions: According to our findings, a woman with a family history of early menopause risks early menopause and consequently early reproductive failure herself.