Relation of Anthropometric Measurements to Ovarian Cancer Risk in a Population-based Case–control Study (United States)

Trajectories of body fatness in adulthood and the risk of ovarian cancer

BACKGROUND

While excess body fatness in older adulthood has been linked to ovarian cancer, the influence of changes in body fatness over time is unclear. This study examined the association between adulthood trajectories of body mass index (BMI), a proxy for body fatness, and ovarian cancer.

METHODS

In a population-based case-control study (440 cases, 820 controls), we used a group-based trajectory approach to identify BMI trajectories from age 20-70. Using unconditional logistic regression, we estimated adjusted odds ratios (aOR) and 95 % confidence intervals (95 % CI) for the associations between the estimated trajectories and ovarian cancer.

RESULTS

We identified three distinct BMI trajectories: a normal-stable trajectory, a normal-to-overweight trajectory and an overweight-to-obese trajectory, which included 63.2 %, 31.0 % and 6.8 % of the population, respectively. Multivariable aORs suggested that participants with normal weight at the onset of adulthood who became overweight over their adulthood time did not differ in their risk of ovarian cancer compared to those who maintained a normal weight throughout adulthood (aOR (95 %CI): 0.89 (0.69-1.16)). Among those in the overweight-to-obese trajectory, the aOR (95 %CI) was 1.45 (0.87-2.43), and thus in the direction of an increased ovarian cancer risk compared to those who maintained a normal weight.

CONCLUSION

Our findings underscore the need for further research to clarify the role of body fatness across the lifetime in the etiology of ovarian cancer.

Management of obesity across women's life course: FIGO Best Practice Advice

Obesity is a chronic, progressive, relapsing, and treatable multifactorial, neurobehavioral disease. According to the World Health Organization, obesity affects 15% of women and has long-term effects on women's health. The focus of care in patients with obesity should be on optimizing health outcomes rather than on weight loss. Appropriate and common language, considering cultural sensitivity and trauma-informed care, is needed to discuss obesity. Pregnancy is a time of significant physiological change. Pre-, ante-, and postpartum clinical encounters provide opportunities for health optimization for parents with obesity in terms of, but not limited to, fertility and breastfeeding. Pre-existing conditions may also be identified and managed. Beyond pregnancy, women with obesity are at an increased risk for gastrointestinal and liver diseases, impaired kidney function, obstructive sleep apnea, and venous thromboembolism. Gynecological and reproductive health of women living with obesity cannot be dismissed, with accommodations needed for preventive health screenings and consideration of increased risk for gynecologic malignancies. Mental wellness, specifically depression, should be screened and managed appropriately. Obesity is a complex condition and is increasing in prevalence with failure of public health interventions to achieve significant decrease. Future research efforts should focus on interprofessional care and discovering effective interventions for health optimization.

Obesity and ovarian cancer risk: A systematic review

The association between obesity and ovarian cancer risk has been extensively investigated, but studies have yielded inconsistent findings. This review aims to summarise and discuss the evidence generated to date. Articles published in English prior to August 2016 were retrieved from PubMed. Keywords included obesity, overweight, body size, body mass index, waist-hip ratio, waist circumference, body weight, ovarian cancer, ovarian carcinoma, ovarian neoplasm, and ovarian tumour. Eligible studies compared two or more groups of women, with at least one group in the overweight or obese category and one comprising normal weight controls. Summary data in the form of relative risk, hazard ratio, or odds ratio for each comparison group from individual studies were collated and reviewed. Forty-three studies were included in the final analysis, with a total of 3,491,943 participants. All studies included body mass index as an exposure measure, and a majority relied on self-reported measures from participants; 14 studies found a statistically significant positive association between ovarian cancer risk and higher body mass index, 26 studies found no significant association, and 3 studies found a negative association between ovarian cancer risk and higher body mass index. This review concludes that there is limited, inconsistent evidence of a positive association between obesity and ovarian cancer risk.

Obesity and Ovarian Cancer

Ovarian cancer is the most fatal gynecologic cancer and is an important source of cancer-related mortality, particularly in developed countries. Despite substantial research examining adiposity (primarily adult body mass index [BMI]), the overall evidence suggests only a weak positive association between adiposity and risk of ovarian cancer, with stronger associations observed for population-based case-control studies compared to prospective studies. Ovarian cancer is not one disease and emerging data suggest that higher BMI may only be associated with risk of certain histologic subtypes, including low-grade serous and invasive mucinous tumors. Interestingly, some larger studies and meta-analyses have reported a stronger relationship with premenopausal ovarian cancers, which are more likely to be of these subtypes. Relatively few studies have conducted detailed examinations of other adiposity-related factors such as measures of abdominal adiposity, early-life body size and weight change. While the underlying mechanisms that may relate adiposity to risk are unclear, increased inflammatory biomarkers have been associated with risk and hormonal factors, including androgen levels, may be important for the development of mucinous tumors. Future research should leverage the large sample sizes of consortia to evaluate associations by key tumor characteristics as well as consider patterns of weight change over the life course with both ovarian cancer risk and survival.

The association between overweight, obesity and ovarian cancer: a meta-analysis

OBJECTIVE

Epidemiological studies have reported an inconsistent association between obesity and ovarian cancer. To update the current knowledge of and further qualify the association between overweight, obesity and ovarian cancer risk, we conducted a meta-analysis of published observational studies.

METHODS

Using the PubMed, MEDLINE and EMBASE databases, we performed a literature search of all of the case-control and cohort studies published as original articles in English before March 2015. We included 26 observational studies, of which 13 were case-control studies (7782 cases and 21 854 controls) and 13 were cohort studies (5181 cases). Fixed- and random-effects models were used to compute summary estimates and the corresponding 95% confidence intervals. Subgroup analyses were also performed.

RESULTS

The pooled relative risk for overweight and obesity compared with normal weight (body mass index = 18.5-24.9 kg/m(2)) was 1.07 (95% confidence interval: 1.02-1.12) and 1.28 (95% confidence interval: 1.16-1.41), respectively. In subgroup analyses, we found that overweight/obesity increased the risk of ovarian cancer in most groups, except for the postmenopausal group (overweight: pooled relative risk = 0.97, 95% confidence interval: 0.76-1.24; obesity: pooled relative risk = 0.93, 95% confidence interval: 0.61-1.42). There was no evidence of publication bias.

CONCLUSIONS

Increased body weight was associated with an increased risk of ovarian cancer; in particular, severe obesity demonstrated a stronger risk effect. No statistically significant association was observed in the postmenopausal period, but was in the premenopausal period.

Body mass index effects on risk of ovarian cancer: a meta- analysis

OBJECTIVES

The association between body mass index (BMI) and ovarian cancer risk is unclear and requires further investigation. The present meta-analysis was conducted to assess the effect of overweight and obesity on ovarian cancer risk in the premenopausal and postmenopausal periods.

DATA SOURCES

Major electronic databases were searched until February 2014 including Medline and Scopus. Reference lists and relevant conference databases were searched and the authors were contacted for additional unpublished references.

REVIEW METHODS

All cohort and case-control studies addressing the effect of BMI on ovarian cancer were included, irrespective of publication date and language. The effect measure of choice was risk ratio (RR) for cohort studies and odds ratio (OR) for case-control studies. The results were reported using a random effects model with 95% confidence intervals (CIs).

RESULTS

Of 3,776 retrieved studies, 19 were ultimately analyzed including 10 cohort studies involving 29,237,219 person-years and 9 case-control studies involving 96,965 people. The results of both cohort and case-control studies showed being overweight and obesity increased the risk of ovarian cancer compared to women with normal weight during both premenopausal and postmenopausal periods: RR=1.08 (95%CI: 0.97, 1.19) and OR=1.26 (95%CI: 0.97, 1.63) for overweight and RR=1.27 (95%CI: 1.16, 1.38) and OR=1.26 (95%CI: 1.06, 1.50) for obesity.

CONCLUSIONS

There is sufficient evidence that an increase in BMI can increase the risk of ovarian cancer regardless of the menopausal status, mimicking a dose-response relationship although the association is not very strong.

Collaborative Group on Epidemiological Studies of Ovarian Cancer. Ovarian cancer and smoking: individual participant meta-analysis including 28,114 women with ovarian cancer from 51 epidemiological studies

Background

Smoking has been linked to mucinous ovarian cancer, but its effects on other ovarian cancer subtypes and on overall ovarian cancer risk are unclear, and the findings from most studies with relevant data are unpublished. To assess these associations, we review the published and unpublished evidence.

Methods

Eligible epidemiological studies were identified by electronic searches, review articles, and discussions with colleagues. Individual participant data for 28 114 women with and 94 942 without ovarian cancer from 51 epidemiological studies were analysed centrally, yielding adjusted relative risks (RRs) of ovarian cancer in smokers compared with never smokers.

Findings

After exclusion of studies with hospital controls, in which smoking could have affected recruitment, overall ovarian cancer incidence was only slightly increased in current smokers compared with women who had never smoked (RR 1·06, 95% CI 1·01–1·11, p=0·01). Of 17 641 epithelial cancers with specified histology, 2314 (13%) were mucinous, 2360 (13%) endometrioid, 969 (5%) clear-cell, and 9086 (52%) serous. Smoking-related risks varied substantially across these subtypes (p_{heterogeneity}<0·0001). For mucinous cancers, incidence was increased in current versus never smokers (1·79, 95% CI 1·60–2·00, p<0·0001), but the increase was mainly in borderline malignant rather than in fully malignant tumours (2·25, 95% CI 1·91–2·65 vs 1·49, 1·28–1·73; p_{heterogeneity}=0·01; almost half the mucinous tumours were only borderline malignant). Both endometrioid (0·81, 95% CI 0·72–0·92, p=0·001) and clear-cell ovarian cancer risks (0·80, 95% CI 0·65–0·97, p=0·03) were reduced in current smokers, and there was no significant association for serous ovarian cancers (0·99, 95% CI 0·93–1·06, p=0·8). These associations did not vary significantly by 13 sociodemographic and personal characteristics of women including their body-mass index, parity, and use of alcohol, oral contraceptives, and menopausal hormone therapy.

Interpretation

The excess of mucinous ovarian cancers in smokers, which is mainly of tumours of borderline malignancy, is roughly counterbalanced by the deficit of endometrioid and clear-cell ovarian cancers. The substantial variation in smoking-related risks by tumour subtype is important for understanding ovarian carcinogenesis.

Funding

Cancer Research UK and MRC.

Collaborative Group on Epidemiological Studies of Ovarian Cancer. Ovarian cancer and body size: individual participant meta-analysis including 25,157 women with ovarian cancer from 47 epidemiological studies

BACKGROUND

Only about half the studies that have collected information on the relevance of women's height and body mass index to their risk of developing ovarian cancer have published their results, and findings are inconsistent. Here, we bring together the worldwide evidence, published and unpublished, and describe these relationships.

METHODS AND FINDINGS

Individual data on 25,157 women with ovarian cancer and 81,311 women without ovarian cancer from 47 epidemiological studies were collected, checked, and analysed centrally. Adjusted relative risks of ovarian cancer were calculated, by height and by body mass index. Ovarian cancer risk increased significantly with height and with body mass index, except in studies using hospital controls. For other study designs, the relative risk of ovarian cancer per 5 cm increase in height was 1.07 (95% confidence interval [CI], 1.05-1.09; p<0.001); this relationship did not vary significantly by women's age, year of birth, education, age at menarche, parity, menopausal status, smoking, alcohol consumption, having had a hysterectomy, having first degree relatives with ovarian or breast cancer, use of oral contraceptives, or use of menopausal hormone therapy. For body mass index, there was significant heterogeneity (p<0.001) in the findings between ever-users and never-users of menopausal hormone therapy, but not by the 11 other factors listed above. The relative risk for ovarian cancer per 5 kg/m(2) increase in body mass index was 1.10 (95% CI, 1.07-1.13; p<0.001) in never-users and 0.95 (95% CI, 0.92-0.99; p=0.02) in ever-users of hormone therapy.

CONCLUSIONS

Ovarian cancer is associated with height and, among never-users of hormone therapy, with body mass index. In high-income countries, both height and body mass index have been increasing in birth cohorts now developing the disease. If all other relevant factors had remained constant, then these increases in height and weight would be associated with a 3% increase in ovarian cancer incidence per decade. Please see later in the article for the Editors' Summary.

Body size and the risk of ovarian cancer by hormone therapy use in the California Teachers Study cohort

OBJECTIVE

To investigate whether obesity and hormone therapy (HT) are associated with ovarian cancer risk among women in the California Teachers Study cohort.

METHODS

Of 56,091 women age ≥ 45 years, 277 developed epithelial ovarian cancer between 1995 and 2007. Multivariate Cox regression was performed.

RESULTS

Among women who never used HT, greater adult weight gain, waist circumference and waist-to-height ratio, but not adult BMI, increased risk of ovarian cancer. Compared to women who never used HT and had a stable adult weight, risk of ovarian cancer was increased in women who gained ≥ 40 lb (relative risk (RR) 1.8, 95% confidence interval (CI): 1.0-3.0) or used HT for >5 years (RR 2.3 95% CI: 1.3-4.1). Having both exposures (RR 1.9, 95% CI: 0.99-3.5), however, did not increase risk more than having either alone. Results were similar for waist circumference and weight-to-height ratio; however, differences across HT groups were not statistically significant.

CONCLUSIONS

This study suggests that abdominal adiposity and weight gain, but not overall obesity, increase ovarian cancer risk and that there may be a threshold level beyond which additional hormones, whether exogenous or endogenous, do not result in additional elevation in risk. However, large pooled analyses are needed to confirm these findings.

Anthropometric measures and risk of epithelial ovarian cancer: results from the nurses' health study

Epidemiologic evaluations of the relationship between anthropometry and ovarian cancer risk have not been conclusive. Using data collected from two large cohorts, the Nurses' Health Study (NHS) and NHSII, we prospectively evaluated the association between waist and hip circumference, the waist-to-hip ratio (WHR), and BMI with risk of epithelial ovarian cancer. Women completed biennial questionnaires assessing ovarian cancer risk factors beginning in 1976 (NHS) and 1989 (NHSII). For the WHR and BMI analyses, 333 and 862 confirmed cases were identified, respectively, through 1 June 2006 (NHS) and 1 June 2005 (NHSII). WHR and waist circumference were not associated with risk (P-trend = 0.63 and 0.65, respectively). There was evidence for a decreased risk with increasing hip circumference among postmenopausal women (P-trend = 0.03), but a suggestive positive association among premenopausal women (P-trend = 0.04) (P-interaction = 0.01). The hazard ratios (HRs) comparing the highest vs. lowest quintile of hip circumference among pre- and postmenopausal women were 1.54 (95% confidence interval (CI) = 0.45-5.23) and 0.66 (95%CI = 0.37-1.16), respectively. BMI was not clearly associated with risk in pre- or postmenopausal women. Results from this large prospective study suggest that hip circumference could be a possible risk factor for premenopausal ovarian cancer, but may reduce risk of postmenopausal ovarian cancer. The differential effect of hip circumference based on menopausal status requires further confirmation.

Anthropometric measures and epithelial ovarian cancer risk in the European Prospective Investigation into Cancer and Nutrition

We examined the associations of measured anthropometric factors, including general and central adiposity and height, with ovarian cancer risk. We also investigated these associations by menopausal status and for specific histological subtypes. Among 226,798 women in the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort, there were 611 incident cases of primary, malignant, epithelial ovarian cancer diagnosed during a mean 8.9 years of follow-up. Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs), adjusted for potential confounders. Compared to women with body mass index (BMI) < 25 kg/m2, obesity (BMI > or = 30 kg/m2) was associated with excess ovarian cancer risk for all women combined (HR = 1.33, 95% CI = 1.05-1.68; p(trend) = 0.02) and postmenopausal women (HR = 1.59, 95% CI = 1.20-2.10; p(trend) = 0.001), but the association was weaker for premenopausal women (HR = 1.16, 95% CI = 0.65-2.06; p(trend) = 0.65). Neither height or weight gain, nor BMI-adjusted measures of fat distribution assessed by waist circumference, waist-hip ratio (WHR) or hip circumference were associated with overall risk. WHR was related to increased risk of mucinous tumors (BMI-adjusted HR per 0.05 unit increment = 1.17, 95% CI = 1.00-1.38). For all women combined, no other significant associations with risk were observed for specific histological subtypes. This large, prospective study provides evidence that obesity is an important modifiable risk factor for epithelial ovarian cancer, particularly among postmenopausal women.

Body mass index and risk of ovarian cancer

BACKGROUND

Convincing epidemiologic evidence links excess body mass to increased risks of endometrial and postmenopausal breast cancers, but the relation between body mass index (BMI) and ovarian cancer risk remains inconclusive. Potential similarities regarding a hormonal mechanism in the etiology of female cancers highlight the importance of investigating associations according to menopausal hormone therapy (MHT) use. However, to the authors' knowledge, data addressing whether the relation between BMI and ovarian cancer differs by MHT use are very sparse.

METHODS

The authors prospectively investigated the association between BMI and ovarian cancer among 94,525 US women who were followed between 1996 through 1997 to December 31, 2003. During 7 years of follow-up, 303 epithelial ovarian cancer cases were documented.

RESULTS

Compared with normal weight women (BMI of 18.5-24.9 kg/m(2)), the multivariate relative risk (MVRR) of ovarian cancer for obese women (BMI of >or=30 kg/m(2)) in the cohort as a whole was 1.26 (95% confidence interval [95% CI], 0.94-1.68). Among women who never used MHT, the MVRR for obese versus normal weight women was 1.83 (95% CI, 1.18-2.84). In contrast, no relation between BMI and ovarian cancer was apparent among women who ever used MHT (MVRR = 0.96; 95% CI, 0.65-1.43; P interaction = 0.02). Exploratory analyses also suggested a positive association between BMI and ovarian cancer among women without a family history of ovarian cancer (MVRR comparing obese vs normal weight women = 1.36; 95% CI, 1.00-1.86), but no relation with BMI was apparent among women with a positive family history of ovarian cancer (MVRR = 0.74; 95% CI, 0.34-1.62 [P interaction = .02]).

CONCLUSIONS

Based on the results of the current study, the authors suspect that obesity is associated with enhanced ovarian cancer risk through a hormonal mechanism.

Energy intake, physical activity, energy balance, and cancer: epidemiologic evidence

Energy intake, physical activity, and obesity are modifiable lifestyle factors. This chapter reviews and summarizes the epidemiologic evidence on the relation of energy intake, physical activity, and obesity to cancer. High energy intake may increase the risk of cancers of colon-rectum, prostate (especially advanced prostate cancer), and breast. However, because physical activity, body size, and metabolic efficiency are highly related to total energy intake and expenditure, it is difficult to assess the independent effect of energy intake on cancer risk. There are sufficient evidences to support a role of physical activity in preventing cancers of the colon and breast, whereas the association is stronger in men than in women for colon cancer and in postmenopausal than in premenopausal women for breast cancer. The evidence also suggests that physical activity likely reduces the risk of cancers of endometrium, lung, and prostate (to a lesser extent). On the other hand, there is little or no evidence that the risk of rectal cancer is related to physical activity, whereas the results have been inconsistent regarding the association between physical activity and the risks of cancers of pancreas, ovary and kidney. Epidemiologic studies provide sufficient evidence that obesity is a risk factor for both cancer incidence and mortality. The evidence supports strong links of obesity with the risk of cancers of the colon, rectum, breast (in postmenopausal women), endometrium, kidney (renal cell), and adenocarcinoma of the esophagus. Epidemiologic evidence also indicates that obesity is probably related to cancers of the pancreas, liver, and gallbladder, and aggressive prostate cancer, while it seems that obesity is not associated with lung cancer. The role of obesity in other cancer risks is unclear.

Body size and risk of epithelial ovarian and related cancers: a population-based case-control study

Different subtypes of ovarian cancer appear to have different causes; however, the association between body mass index (BMI) and the different subtypes is unclear. We examined the associations between body-mass index (BMI) and weight gain and risk of the different histological subtypes of epithelial ovarian cancer in a case-control study in Australia. Cases aged 18-79 with a new diagnosis of invasive epithelial ovarian cancer (n = 1,269) or borderline tumor (n = 311) were identified through a network of clinics and cancer registries throughout Australia. Controls (n = 1,509) were selected from the Electoral Roll. Height and weight (1 year previously, at age 20 and maximum weight) and other risk factor information were ascertained via a self-administered questionnaire. Obesity was positively associated with clear cell tumors (Odds Ratio 2.3; 95% confidence interval 1.2-4.2) but not invasive endometrioid or mucinous tumors. Although there was no association with invasive serous tumors overall (0.9; 0.7-1.2), we did see an increased risk of serous peritoneal tumors (2.9; 1.7-4.9), but not of serous tumors of the ovary and fallopian tube. Of the borderline subtypes, obesity was positively associated with serous (1.8; 1.1-2.8) but not mucinous tumors (1.1; 0.7-1.7). Overweight was not associated with any subtype overall. There was no association with BMI at age 20, or weight gain for any of the histological subtypes. These results add to the current evidence that obesity increases a woman's risk of developing distinct histological subtypes of ovarian cancer.

Inverse association of NSAID use and ovarian cancer in relation to oral contraceptive use and parity

We examined the association between non-steroidal anti-inflammatory drug (NSAID) use and ovarian cancer by potential effect modifiers, parity and oral contraceptive use, in a population-based case-control study conducted in Wisconsin and Massachusetts. Women reported prior use of NSAIDs and information on risk factors in a telephone interview. A total of 487 invasive ovarian cancer cases and 2653 control women aged 20-74 years were included in the analysis. After adjustment for age, state of residence and other covariates, ever use of NSAIDs was inversely associated with ovarian cancer in never users of oral contraceptives (odds ratio (OR)=0.58, 95% confidence interval (CI) 0.42-0.80) but not for ever users (OR=0.98, 95% CI 0.71-1.35) (P-interaction=0.03). A reduced risk with NSAID use was also noted in nulliparous women (OR=0.47, 95% CI 0.27-0.82) but not among parous women (OR=0.81, 95% CI 0.64-1.04) (P-interaction=0.05). These results suggest that use of NSAIDs were beneficial to women at greatest risk for ovarian cancer.

Height, body mass index, and ovarian cancer: a pooled analysis of 12 cohort studies

BACKGROUND

Although many studies have investigated the association between anthropometry and ovarian cancer risk, results have been inconsistent.

METHODS

The associations of height, body mass index (BMI), and ovarian cancer risk were examined in a pooled analysis of primary data from 12 prospective cohort studies from North America and Europe. The study population consisted of 531,583 women among whom 2,036 epithelial ovarian cancer cases were identified. To summarize associations, study-specific relative risks (RR) were estimated using the Cox proportional hazards model and then combined using a random-effects model.

RESULTS

Women with height > or =1.70 m had a pooled multivariate RR of 1.38 [95% confidence interval (95% CI), 1.16-1.65] compared with those with height <1.60 m. For the same comparison, multivariate RRs were 1.79 (95% CI, 1.07-3.00) for premenopausal and 1.25 (95% CI, 1.04-1.49) for postmenopausal ovarian cancer (P(interaction) = 0.14). The multivariate RR for women with a BMI > or =30 kg/m(2) was 1.03 (95% CI, 0.86-1.22) compared with women with a BMI from 18.5 to 23 kg/m(2). For the same comparison, multivariate RRs were 1.72 (95% CI, 1.02-2.89) for premenopausal and 1.07 (95% CI, 0.87-1.33) for postmenopausal women (P(interaction) = 0.07). There was no statistically significant heterogeneity between studies with respect to height or BMI. BMI in early adulthood was not associated with ovarian cancer risk.

CONCLUSION

Height was associated with an increased ovarian cancer risk, especially in premenopausal women. BMI was not associated with ovarian cancer risk in postmenopausal women but was positively associated with risk in premenopausal women.

Obesity and the risk of epithelial ovarian cancer: a systematic review and meta-analysis

Obesity is a risk factor for several hormone-related cancers but evidence for an effect on risk of epithelial ovarian cancer remains inconclusive. Many studies evaluating this association have had insufficient statistical power to detect modest effects, particularly for histological subtypes of ovarian cancer. We have therefore assembled the published evidence on obesity and ovarian cancer in a systematic literature review and meta-analysis. We identified eligible studies using Medline and manual review of retrieved references, and included all population-based studies that assessed the association between overweight, body mass index (BMI25-29.9) and obesity (BMI30) and histologically confirmed ovarian cancer. Meta-analysis was restricted to those studies that expressed effect as an odds ratio (OR), risk ratio, or standardised incidence ratio and 95% confidence interval (CI). We identified 28 eligible studies, of which 16 on adult obesity and 9 on obesity in early adulthood were suitable for meta-analysis. Overall, 24 of 28 studies reported a positive association between obesity and ovarian cancer, and in 10 this reached statistical significance. The pooled effect estimate for adult obesity was 1.3 (95%CI1.1-1.5) with a smaller increased risk for overweight (OR1.2;95%CI1.0-1.3). The pooled OR was stronger among case-control studies (OR=1.5) than cohort studies (OR=1.1). Overweight/obesity in early adulthood was also associated with an increased risk of ovarian cancer. There was no evidence that the association varied for the different histological subtypes of ovarian cancer. Ovarian cancer should be added to the list of cancers likely to be related to obesity.

Risk of ovarian cancer associated with BMI varies by menopausal status

Obesity has been linked to increased risk of several malignancies, but the role of obesity in the etiology of ovarian cancer remains unclear. Therefore, a hospital-based case-control study was conducted to investigate the association between body size and risk of ovarian cancer. Participants included 427 women with primary, incident ovarian cancer and 854 cancer-free controls. All participants received medical services at Roswell Park Cancer Institute in Buffalo, NY between 1982 and 1998 and completed a comprehensive epidemiological questionnaire. The instrument included questions regarding height and usual wt prior to survey. Participants were classified as underweight/normal (BMI < or = 24.9 kg/m2), overweight (BMI 25.0-29.9 kg/m2), or obese (BMI > or = 30.0 kg/m2). Compared with underweight/normal participants, being overweight (adjusted odds ratio [OR] = 1.02; 95% CI 0.77-1.36) or obese (adjusted OR = 1.17; 95% CI 0.84-1.65) was not significantly associated with an elevated risk of ovarian cancer. After stratification by menopausal status, BMI showed no significant association to ovarian cancer risk among postmenopausal women (> or = 50 y old). However, among premenopausal women (<50 y old), those classified as obese had a significantly increased risk (adjusted OR = 2.19; 95% CI 1.19-4.04) compared with women classified as normal/underweight. These findings suggest a potential influence of menopausal status on the total endogenous hormonal environment, including estrogens, androgens, and insulin-like growth factors, when considering the association between body size and ovarian cancer risk. In light of the fact that obesity is a modifiable risk factor, further investigation on this topic is warranted.