The relationship between physical activity and the risk of ovarian cancer w
as analyzed using data from a case-control study conducted between 1992 and
1999 in Italy. Cases were 1,031 women with incident, histologically confir
med, invasive epithelial ovarian cancer and controls were 2,411 women admit
ted to hospital for acute non-neoplastic, non-hormonal conditions. Compared
to women with the lowest level of occupational physical activity, the ORs
of ovarian cancer obtained adjusting for center, year of interview and age
for women with the highest level of physical activity were 0.70, 0.52 and 0
.64 (all statistically significant) respectively, at ages 15-19, 30-39 and
50-59 years, with significant trends in risk for the 2 youngest age groups.
The corresponding ORs became 0.89, 0.67 and 0.76 after further allowance f
or several co-variates of ovarian cancer, including education, which was po
sitively associated with cancer risk. No significant association was found
with leisure-time physical activity though the risk was below unity in wome
n with the highest level of activity. The multivariate OR was 0.44 for wome
n with the highest level of combined occupational plus leisure-time physica
l activity. The inverse relationship between occupational physical activity
and ovarian cancer risk was not heterogeneous across strata of selected co
-variates. (C) 2001 Wiley-Liss, Inc.