Hormone studies may prove a point

Re: “Numbers Can Lie” [Sept. 17]: The story says that randomized trials have refuted the findings of the Nurses’ Health Study that post-menopausal hormone therapy can reduce risk of heart disease. The truth is a bit more complicated.

Upon closer inspection, when like was compared with like (women of similar ages), the results were entirely consistent: Epidemiological studies and randomized trials of older women both have seen no cardiovascular benefit from this therapy, whereas in younger women, statistically significant reductions in heart disease are observed.

A recent editorial on this topic in the New England Journal of Medicine concluded that the trial results among older women were inappropriately generalized to women starting hormones at menopause.

Unfortunately, Times readers get [reporter Andreas] von Bubnoff’s version rather than that of the world’s leading medical journal.

The data for vitamin E are less clear, but recent randomized trials found significant reductions in vascular clots and a significant 24% reduction in cardiovascular mortality.

Of course, the road to truth on issues of health is difficult, and absolute certainty is rare, partly due to the complexity of living systems and variability among individuals. Despite epidemiology’s inherent limitations, it has an important record of success. Such studies have identified ways to substantially reduce heart disease, stroke, cancer, diabetes and other conditions.

Dr. Meir Stampfer

Stampfer is professor of epidemiology and nutrition at Harvard School of Public Health.