Kim N. Danforth

Breastfeeding and risk of ovarian cancer in two prospective cohorts.

ObjectiveTo describe the association between breastfeeding and ovarian cancer risk in two prospective cohorts.Materials & methodsWe pooled data from the Nurses’ Health Study and Nurses’ Health Study II. There were 391 cases of epithelial ovarian cancer diagnosed among 149,693 parous women with up to 16 years of follow-up. Data were analyzed using multivariate Cox proportional hazards models, controlling for age, parity, duration of oral contraceptive use, tubal ligation, and age at menarche.ResultsEver breastfeeding was associated with a non-significant reduction in ovarian cancer risk compared with never breastfeeding (RR = 0.86, 95% CI 0.70–1.06); the median duration of breastfeeding among women who breastfed was nine months. Breastfeeding of 18 or more months was associated with a significant decrease in ovarian cancer risk compared to never breastfeeding (RR = 0.66, 95% CI 0.46–0.96). For each month of breastfeeding the relative risk decreased by 2% (RR = 0.98 per month, 95% CI 0.97–1.00).ConclusionsThese data support a linear inverse association between breastfeeding and risk of epithelial ovarian cancer.

Body mass index, weight gain, and incident urinary incontinence in middle-aged women.

OBJECTIVE: To describe the relations between body mass index (BMI; kg/m2), weight gain, and incident urinary incontinence in middle-aged women. METHODS: This was a prospective study in the Nurses’ Health Study II. Participants reported their weight at age 18 years, and current weight and height in 1989; weight was updated on subsequent biennial questionnaires. From 2001–2003, incident cases with at least monthly incontinence were identified among 30,982 women aged 37 to 54 years who reported no incontinence in 2001. Information on incontinence type was collected from incident cases with at least weekly incontinence. Multivariable-adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for the associations between BMI in 2001, weight change from age 18 years to 2001, and incident incontinence were estimated using multivariable logistic regression models. RESULTS: Increasingly higher BMI was related to increasing odds of developing incontinence (P for trend<.001). Comparing women with BMI greater than or equal to 35 kg/m2 with lean women (BMI 21–22.9 kg/m2), the OR for at least monthly incontinence was 2.11 (95% CI 1.84–2.42). These increases were similar for all incontinence types. The odds of incontinence also increased with increasing adult weight gain (P for trend<.001); compared with women who maintained their weight within 2 kg, the OR for at least weekly incontinence was 1.44 (95% CI 1.05–1.97) among women who gained 5.1 to 10 kg and 4.04 (95% CI 2.93–5.56) among women who had gained more than 30 kg since early adulthood. We found no effect modification by initial weight in analyses of weight gain from age 18 years to 2001. CONCLUSION: Adiposity and weight gain seem to be strong independent risk factors for incontinence development in middle-aged women. LEVEL OF EVIDENCE: II

Circulating 25-Hydroxyvitamin D and Risk of Epithelial Ovarian CancerCohort Consortium Vitamin D Pooling Project of Rarer Cancers

A role for vitamin D in ovarian cancer etiology is supported by ecologic studies of sunlight exposure, experimental mechanism studies, and some studies of dietary vitamin D intake and genetic polymorphisms in the vitamin D receptor. However, few studies have examined the association of circulating 25-hydroxyvitamin D (25(OH)D), an integrated measure of vitamin D status, with ovarian cancer risk. A nested case-control study was conducted among 7 prospective studies to evaluate the circulating 25(OH)D concentration in relation to epithelial ovarian cancer risk. Logistic regression models were used to estimate odds ratios and 95% confidence intervals among 516 cases and 770 matched controls. Compared with 25(OH)D concentrations of 50–<75 nmol/L, no statistically significant associations were observed for <37.5 (odds ratio (OR) = 1.21, 95% confidence interval (CI): 0.87, 1.70), 37.5–<50 (OR = 1.03, 95% CI: 0.75, 1.41), or ≥75 (OR = 1.11, 95% CI: 0.79, 1.55) nmol/L. Analyses stratified by tumor subtype, age, body mass index, and other variables were generally null but suggested an inverse association between 25(OH)D and ovarian cancer risk among women with a body mass index of ≥25 kg/m2 (Pinteraction < 0.01). In conclusion, this large pooled analysis did not support an overall association between circulating 25(OH)D and ovarian cancer risk, except possibly among overweight women.