The uncertain effect of menopause on blood pressure.

In affluent societies blood pressure increases with age from early life to the eighth decade with sex differences. Before middle age, lower blood pressure values are observed in women than in coeval men, whereas the reverse seems to occur thereafter. Menopause is considered the major determinant of blood pressure rise in women. If this hypothesis is well-founded, menopause can be regarded as one of the main cardiovascular risk factors, involving more than half of the human population, as well as the most ineluctable. In industrialized countries, age at menopause ranges between 50 and 52 years. The popular message is that fertile women are protected from cardiovascular risk by circulating estrogens, a privilege that is lost when postmenopausal women become not different from men from the point of view of risk factors and cardiovascular events. Nevertheless, the hypothesis that menopause or the estrogen decrease are per se associated to blood pressure increase is still under debate. Indeed, the epidemiological challenge is due to the coincidence between advancing menopause and aging, and also to the evidence that both menopause and blood pressure have common determinants such as body mass index, diet, smoking, and socio-economic class. The strongest doubt is whether menopause is a dependent or independent risk factor for high BP, i.e. whether its action on blood pressure-if any-is due directly to estrogen fall or to other indirect factors.