The association between anthropometric factors and ovarian cancer risk was investigated using data from 762 cases and 1348 controls participating in a population-based case-control study in the Delaware Valley from 1994–1998. Because factors such as oral contraceptive (OC), hormone therapy (HT), and parity may affect weight and hormone levels, the associations were examined in women with and without these characteristics.
Unconditional logistic regression was used to calculate odds ratios and 95% confidence intervals while controlling for age, race, parity, family history of ovarian cancer, tubal ligation, and OC use.
Compared with controls, cases were taller and heavier in recent years and at age 18. Results did not differ by OC or HT use. However, anthropometric associations differed significantly based on parity, as increasing anthropometric measures were associated with increased ovarian cancer risk among nulliparous women only. Adjusted OR for recent body mass index (BMI) quartile 4 compared with quartile 1 for nulliparous women was 2.53 (95% confidence interval [CI]: 1.39, 4.61) compared with 0.96 (95% CI: 0.70, 1.31) for parous women. Additionally, adult weight gain was significant only for nulliparous women. Adjusted OR for weight change (recent to age 18) quartile 4 compared with quartile 1 for nulliparous women was 3.73 (95% CI: 1.88, 7.42) versus 1.09 (95% CI: 0.78, 1.51) for parous women.
BMI and weight in women's adult lifetime may be positively associated with ovarian cancer risk. Observations were most apparent for nulliparous women, possibly reflecting an interaction between local inflammation caused by incessant ovulation and increased estrogen exposure on ovarian epithelium. Cancer 2006. © 2006 American Cancer Society.