Invited commentary: Studying the epidemiology of uterine leiomyomata--past, present, and future.

Uterine leiomyomata have a substantial impact on women's reproductive health, but epidemiologists have focused relatively little energy on identifying risk factors for this condition. Only a handful of studies, most of which were not designed to address methodological challenges posed by these tumors, have been conducted. These studies focused almost exclusively on reproductive and hormonal characteristics as possible risk factors, but consistent relations have not emerged. Three new reports (from two studies) in this issue of the Journal target the paucity of information on uterine leiomyomata risk factors by testing novel hypotheses, by employing designs that incorporate subclinical tumors or account for variable management of clinically recognized disease, or by using a combination of these approaches. The success of these strategies and the contributions of the new findings are discussed. Recommendations are made for a program of research that eventually could improve our knowledge of uterine leiomyomata etiology and yield clues to the prevention of associated morbidity.