Weight, height, and body mass index and ovarian cancer risk in a prospective study

Published studies showed positive, inverse, and null associations between ovarian cancer and increasing body size. We assessed weight, height, and body mass index as risk factors for ovarian cancer. The Breast Cancer Detection Demonstration Project (BCDDP) Follow-up Study conducted telephone and mail interviews from 1979 to 1998. We measured height and weight at the original BCDDP annual screening visits (1973–1979) and collected self-reported updates during follow-up. For analysis, we used the measurements taken at the last visit before the start of the Follow-up Study. We identified ovarian cancers via self-report, medical record review, and linkage to National Death Index and state cancer registries. Poisson regression generated adjusted rate ratios (RRs) and 95% confidence intervals (CIs). A total of 350 ovarian cancers occurred among 46,026 women. Measured weight (≥161 lb [73 kg] vs. ≥120 lb [54.4 kg], RR = 1.1, 95% CI = 0.8–1.6) and measured height (≥66 in [167.6 cm] vs. <62 in [157.5 cm], RR = 0.9, 95% CI = 0.7–1.3) were not associated with ovarian cancer. Compared with body mass index (BMI; kg/m2) in the normal range (18.5–24.9), RRs for underweight (<18.5), overweight (25–29.9), and class I obesity (30–34.9) were all close to the null. The RR for class II obesity (≥35) was elevated, although not significantly (1.6, 95% CI = 0.9–2.9). This RR was slightly higher for parous women, women with a natural menopause, and women who never used menopausal estrogen therapy, but none of these interactions were statistically significant. The RR for obesity was higher for cancers of endometrioid histology than for other types. In this large cohort of predominantly postmenopausal women, increasing height, weight, and BMI did not significantly increase ovarian cancer risk. The prospects of positive or stronger associations within other risk factor strata or limited to certain histologic types may warrant continued study.