The impact of family history on ovarian cancer risk. The Utah Population Database
R. A. Kerber and M. L. Slattery
Department of Family and Preventive Medicine, University of Utah School of Medicine, Salt Lake City, USA.
OBJECTIVE: To estimate the relative risks and population attributable risks
of ovarian cancer associated with family histories of cancer at several
sites. METHODS: A matched case-control analytic study (662 cases, 2647
controls), employing the Utah Population Database, a genealogy of
approximately 1 million individuals linked to cancer incidence data from
the Utah Cancer Registry. Family history was assessed using kinship order
and a kinship-weighted familial standardized incidence ratio statistic.
RESULTS: Family histories of ovarian, uterine, breast, and pancreatic
cancer were significantly associated with increased risk of ovarian cancer.
The relative risk of ovarian cancer was 4.31 (95% confidence interval [CI],
2.35 to 7.90) for women with a first-degree relative with ovarian cancer,
2.12 (95% CI, 1.19 to 3.78) for women with an affected second-degree
relative, and 1.48 (95% CI, 0.98 to 2.24) for women with an affected
third-degree relative. The odds ratio (OR) was 2.06 (95% CI, 1.44 to 2.93)
for those with the highest familial standardized incidence ratio. No age
differences were observed between cases with and without a family history
of ovarian cancer. There was substantial heterogeneity of family history
effects by cell type. Increased parity was not protective among women with
a strong family history of cancer at the sites studied (OR, 1.11; 95% CI,
0.38 to 3.26), although it was protective among women without a family
history of these cancers (OR, 0.29; 95% CI, 0.11 to 0.62). CONCLUSIONS: The
risk of ovarian cancer was substantially increased among women with family
histories of ovarian, uterine, pancreatic, and, to a lesser degree, breast
cancer. Among women with family histories of any of these cancers, the risk
of ovarian cancer is not diminished by high parity.
