RESUMEN
<p><b>OBJECTIVE</b>Hypothesis showed that women have higher risks of lung cancer than men when given similar levels of tobacco exposure, implying that sex-related hormones might have a role to play. The study is to identify the influence of female hormones on risk of lung cancer.</p><p><b>METHODS</b>We evaluated the association between lung cancer risk and menstrual/reproductive factors on a subset of self-responding females in a population based case-control study in Eastern Gansu, 1994 - 1998. The analysis included 109 lung cancer cases and 435 controls selected from the census list and matched to cases on age and prefecture.</p><p><b>RESULTS</b>Odds ratios were lower for later ages at menarche (trend, P = 0.015) and later ages at menopause (trend, P = 0.074).</p><p><b>CONCLUSION</b>Despite limitations, these findings suggested a possible role related to hormones in the etiology of lung cancer in females.</p>