Anthropometric Measurements and Epithelial Ovarian Cancer Risk in African–American and White women

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.

Obesity in children and adolescents and the risk of ovarian cancer: A systematic review and dose‒response meta-analysis

OBJECTIVE

The relationship between obesity in children and adolescents and the risk of ovarian cancer remains controversial. The aim of this meta-analysis was to explore the exact shape of this relationship.

METHODS

We conducted dose‒response meta-analyses of cohort and case‒control studies, including published studies derived from searches in the PubMed, Embase, Web of Science and Cochrane Library databases until October 2022. Pooled effect size estimates are expressed as relative risks (RRs) or odds ratios (ORs) with 95% confidence intervals (CIs) and were evaluated by fixed-effect models. A nonlinear dose‒response meta-analysis was performed by using a restricted cubic spline model.

RESULTS

After screening 4215 publications, 10 studies were included in the present meta-analysis. Overall analyses revealed statistically significant associations of obesity in children and adolescents with ovarian cancer (adjusted RR = 1.19, 95% CI: 1.11 to 1.28, P < 0.001). Moreover, the association was consistently significant in most subgroup analyses, for example, using geographic stratification, the results remained stable both in the Americas(RR = 1.11; 95% CI: 1.01 to 1.21; P = 0.022) and Europe (RR = 1.46; 95% CI: 1.21 to 1.77; P<0.001). For the dose‒response analyses, the risk of ovarian cancer increased with the degree of obesity, and the trend increased rapidly when body mass index (BMI) was over 25.95 kg/m2.

CONCLUSION

Our findings indicate that obesity in children and adolescents is a risk factor for ovarian cancer, and the risk increases with increasing BMI.

Genital Powder Use and Risk of Epithelial Ovarian Cancer in the Ovarian Cancer in Women of African Ancestry Consortium

BACKGROUND

Genital powder use is more common among African-American women; however, studies of genital powder use and ovarian cancer risk have been conducted predominantly in White populations, and histotype-specific analyses among African-American populations are limited.

METHODS

We used data from five studies in the Ovarian Cancer in Women of African Ancestry consortium. Participants included 620 African-American cases, 1,146 African-American controls, 2,800 White cases, and 6,735 White controls who answered questions on genital powder use prior to 2014. The association between genital powder use and ovarian cancer risk by race was estimated using logistic regression.

RESULTS

The prevalence of ever genital powder use for cases was 35.8% among African-American women and 29.5% among White women. Ever use of genital powder was associated with higher odds of ovarian cancer among African-American women [OR = 1.22; 95% confidence interval (CI) = 0.97-1.53] and White women (OR = 1.36; 95% CI = 1.19-1.57). In African-American women, the positive association with risk was more pronounced among high-grade serous tumors (OR = 1.31; 95% CI = 1.01-1.71) than with all other histotypes (OR = 1.05; 95% CI = 0.75-1.47). In White women, a significant association was observed irrespective of histotype (OR = 1.33; 95% CI = 1.12-1.56 and OR = 1.38; 95% CI = 1.15-1.66, respectively).

CONCLUSIONS

While genital powder use was more prevalent among African-American women, the associations between genital powder use and ovarian cancer risk were similar across race and did not materially vary by histotype.

IMPACT

This is one of the largest studies to date to compare the associations between genital powder use and ovarian cancer risk, overall and by histotype, between African-American and White women.

Invited Commentary: Relationship Between Ovulation and Markers of Systemic Inflammation Versus Markers of Localized Inflammation

In this issue of the American Journal of Epidemiology, Huang et al. (Am J Epidemiol. 2020;189(7):660-670) report an inverse relationship between lifetime ovulatory years (LOY) and circulating levels of C-reactive protein (CRP), counter to their hypothesis. CRP is a nonspecific systemic marker of chronic inflammation, and there is evidence that there are other drivers of systemic inflammation as measured by CRP. There also is a body of evidence supporting the possibility that ovulation may be responsible for a localized inflammatory response. Because ovarian cancer is the fifth most common cause of cancer death in women, preventive strategies are urgently needed. The findings of this report underscore the need for new research initiatives to determine the relationship between incessant ovulation and ovarian cancer risk in order to identify mechanisms of carcinogenesis.

Ovarian Cancer in Women of African Ancestry (OCWAA) consortium: a resource of harmonized data from eight epidemiologic studies of African American and white women

PURPOSE

Although the incidence rate of epithelial ovarian cancer (EOC) is somewhat lower in African American (AA) than white women, survival is worse. The Ovarian Cancer in Women of African Ancestry (OCWAA) consortium will overcome small, study-specific sample sizes to better understand racial differences in EOC risk and outcomes.

METHODS

We harmonized risk factors and prognostic characteristics from eight U.S.

STUDIES

the North Carolina Ovarian Cancer Study (NCOCS), the Los Angeles County Ovarian Cancer Study (LACOCS), the African American Cancer Epidemiology Study (AACES), the Cook County Case-Control Study (CCCCS), the Black Women's Health Study (BWHS), the Women's Health Initiative (WHI), the Multiethnic Cohort Study (MEC), and the Southern Community Cohort Study (SCCS).

RESULTS

Determinants of disparities for risk and survival in 1,146 AA EOC cases and 2,922 AA controls will be compared to 3,368 white EOC cases and 10,270 white controls. Analyses include estimation of population-attributable risk percent (PAR%) by race.

CONCLUSION

OCWAA is uniquely positioned to study the epidemiology of EOC in AA women compared with white women to address disparities. Studies of EOC have been underpowered to address factors that may explain AA-white differences in the incidence and survival. OCWAA promises to provide novel insight into disparities in ovarian cancer.

Tubal ligation and ovarian cancer risk in African American women

PURPOSE

Tubal ligation has been associated with reduced risk of epithelial ovarian cancer (EOC) in studies of primarily white women, but less is known about the association in African American (AA) women. We sought to evaluate the associations among 597 invasive ovarian cancer cases and 742 controls of AA descent recruited from the African American Cancer Epidemiology Study, a population-based case-control study in 11 geographical areas in the US.

METHODS

Multivariable logistic regression models were used to estimate odds ratios (OR) and 95% confidence intervals (CI) adjusted for potentially confounding factors.

RESULTS

An inverse association between tubal ligation and EOC was observed that was not statistically significant (OR 0.88, 95% CI 0.68-1.14). However, an inverse association with EOC risk was observed among women who had a tubal ligation at age 35 years or older (OR 0.64; 95% CI 0.41-0.98), but not among those who had a tubal ligation before age 35 (OR 0.98; 95% CI 0.74-1.29) (p for interaction = 0.08). The association also varied considerably by tumor subtype. A strong inverse association was observed for endometrioid tumors (OR 0.31, 95% CI 0.14-0.70), whereas associations with mucinous (OR 0.87, 95% CI 0.36-2.12) and serous (OR 0.94, 95% CI 0.71-1.24) tumors were weaker and not statistically significant. A statistically non-significant positive association for clear cell tumors (OR 1.84, 95% CI 0.58-5.82) was based on a low number of cases.

CONCLUSIONS

Our findings show that tubal ligation may confer a reduced risk for EOC among AA women that is comparable to the associations that have been previously observed in primarily white populations.

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.

Dietary Quality and Ovarian Cancer Risk in African-American Women

This study evaluated 3 index-based dietary patterns-Healthy Eating Index (HEI)-2005, HEI-2010, and Alternate Healthy Eating Index (AHEI)-2010-in relation to ovarian cancer risk in African-American women. The study was conducted among 415 ovarian cancer cases and 629 age- and site-matched controls of African-American descent recruited from the population-based African American Cancer Epidemiology Study. Multivariable unconditional logistic regression models were used to estimate odds ratios and 95% confidence intervals between quartiles of dietary quality indices and ovarian cancer risk, adjusting for potential confounders. We found that higher AHEI-2010 scores, but not HEI-2005 or HEI-2010 scores, were associated with lower risk of ovarian cancer (comparing the highest quartile (4th) vs. lowest (1st), odds ratio (OR) = 0.66, 95% confidence interval (CI): 0.45, 0.98; P for trend = 0.05). When stratified by menopausal status, no noteworthy associations were observed among premenopausal women. However, among postmenopausal women, greater adherence to HEI-2010 (quartile 4 vs. quartile 1, OR = 0.57, 95% CI: 0.36, 0.92; P for trend = 0.03) and AHEI-2010 (quartile 4 vs. quartile 1, OR = 0.49, 95% CI: 0.31, 0.78; P for trend = 0.01) were inversely associated with ovarian cancer. Our findings indicate that adherence to an overall healthy dietary pattern may reduce ovarian cancer risk in African-American women, and particularly among postmenopausal African-American women.

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.

A prospective study of reproductive factors and exogenous hormone use in relation to ovarian cancer risk among Black women

PURPOSE

Extensive data in White women have linked oral contraceptive use, tubal ligation, and parity to reduced risk of ovarian cancer; results on postmenopausal female hormone use are mixed. Few studies, all of which are case-control studies, have been undertaken among Black women. The aim of the present study was to prospectively assess associations of reproductive factors and exogenous hormones with ovarian cancer among Black women.

METHODS

During follow-up from 1995 to 2013 in the Black Women's Health Study, a prospective cohort study, 115 incident cases of ovarian cancer were identified. Cox proportional hazards models were used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) for the relation of the factors of interest to risk of ovarian cancer, with control for covariates.

RESULT

Oral contraceptive use was inversely associated with ovarian cancer risk: The HR for ≥10 years of use relative to <1 year was 0.50 (95% CI 0.30-0.98). For postmenopausal female hormone use, the HRs for ever use of estrogen with progestin and of estrogen alone were 1.37 (0.73-2.55) and 1.66 (0.90-3.07), respectively. The HRs for parity and tubal ligation were below 1.0, but were not statistically significant.

CONCLUSION

Overall, the findings indicate that the relation of reproductive factors and exogenous hormone use to risk of ovarian cancer is similar among Black and White women. The results on estrogen-only supplements and estrogen with progestin supplements add to evidence from Whites, indicating that use of hormone supplements may be associated with increased risk of ovarian cancer.

Assessment of Multifactor Gene-Environment Interactions and Ovarian Cancer Risk: Candidate Genes, Obesity, and Hormone-Related Risk Factors

BACKGROUND

Many epithelial ovarian cancer (EOC) risk factors relate to hormone exposure and elevated estrogen levels are associated with obesity in postmenopausal women. Therefore, we hypothesized that gene-environment interactions related to hormone-related risk factors could differ between obese and non-obese women.

METHODS

We considered interactions between 11,441 SNPs within 80 candidate genes related to hormone biosynthesis and metabolism and insulin-like growth factors with six hormone-related factors (oral contraceptive use, parity, endometriosis, tubal ligation, hormone replacement therapy, and estrogen use) and assessed whether these interactions differed between obese and non-obese women. Interactions were assessed using logistic regression models and data from 14 case-control studies (6,247 cases; 10,379 controls). Histotype-specific analyses were also completed.

RESULTS

SNPs in the following candidate genes showed notable interaction: IGF1R (rs41497346, estrogen plus progesterone hormone therapy, histology = all, P = 4.9 × 10(-6)) and ESR1 (rs12661437, endometriosis, histology = all, P = 1.5 × 10(-5)). The most notable obesity-gene-hormone risk factor interaction was within INSR (rs113759408, parity, histology = endometrioid, P = 8.8 × 10(-6)).

CONCLUSIONS

We have demonstrated the feasibility of assessing multifactor interactions in large genetic epidemiology studies. Follow-up studies are necessary to assess the robustness of our findings for ESR1, CYP11A1, IGF1R, CYP11B1, INSR, and IGFBP2 Future work is needed to develop powerful statistical methods able to detect these complex interactions.

IMPACT

Assessment of multifactor interaction is feasible, and, here, suggests that the relationship between genetic variants within candidate genes and hormone-related risk factors may vary EOC susceptibility. Cancer Epidemiol Biomarkers Prev; 25(5); 780-90. ©2016 AACR.

Obesity, weight gain, and ovarian cancer risk in African American women

Although there is growing evidence that higher adiposity increases ovarian cancer risk, little is known about its impact in African American (AA) women, the racial/ethnic group with the highest prevalence of obesity. We evaluated the impact of body mass index (BMI) 1 year before diagnosis and weight gain since age 18 years on ovarian cancer risk in a population-based case-control study in AA women in 11 geographical areas in the US. Cases (n = 492) and age and site matched controls (n = 696) were identified through rapid case ascertainment and random-digit-dialing, respectively. Information was collected on demographic and lifestyle factors, including self-reported height, weight at age 18 and weight 1 year before diagnosis/interview. Multivariable logistic regression was used to compute odds ratios (OR) and 95% confidence intervals (CI), adjusting for potential covariates. Obese women had elevated ovarian cancer risk, particularly for BMI ≥ 40 kg/m(2) compared to BMI <25 (OR = 1.72, 95% CI: 1.12-2.66; p for trend: 0.03). There was also a strong association with weight gain since age 18 (OR: 1.52; 95% CI: 1.07-2.16; p for trend: 0.02) comparing the highest to lowest quartile. In stratified analyses by menopausal status, the association with BMI and weight gain was limited to postmenopausal women, with a 15% (95% CI: 1.05-1.23) increase in risk per 5 kg/m(2) of BMI and 6% (95% CI: 1.01-1.10) increase in risk per 5 kg of weight gain. Excluding hormone therapy users essentially did not change results. Obesity and excessive adult weight gain may increase ovarian cancer risk in post-menopausal AA women.

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.

Ovarian tumor-initiating cells display a flexible metabolism

An altered metabolism during ovarian cancer progression allows for increased macromolecular synthesis and unrestrained growth. However, the metabolic phenotype of cancer stem or tumor-initiating cells, small tumor cell populations that are able to recapitulate the original tumor, has not been well characterized. In the present study, we compared the metabolic phenotype of the stem cell enriched cell variant, MOSE-LFFLv (TIC), derived from mouse ovarian surface epithelial (MOSE) cells, to their parental (MOSE-L) and benign precursor (MOSE-E) cells. TICs exhibit a decrease in glucose and fatty acid oxidation with a concomitant increase in lactate secretion. In contrast to MOSE-L cells, TICs can increase their rate of glycolysis to overcome the inhibition of ATP synthase by oligomycin and can increase their oxygen consumption rate to maintain proton motive force when uncoupled, similar to the benign MOSE-E cells. TICs have an increased survival rate under limiting conditions as well as an increased survival rate when treated with AICAR, but exhibit a higher sensitivity to metformin than MOSE-E and MOSE-L cells. Together, our data show that TICs have a distinct metabolic profile that may render them flexible to adapt to the specific conditions of their microenvironment. By better understanding their metabolic phenotype and external environmental conditions that support their survival, treatment interventions can be designed to extend current therapy regimens to eradicate TICs.

Anthropometric measures and epithelial ovarian cancer risk among Chinese women: results from the Shanghai Women's Health Study

Background:

Studies of anthropometric measures and ovarian cancer risk have predominantly included women of European descent with mixed findings.

Methods:

Data from the prospective Shanghai Women's Health Study (SWHS) were used to evaluate associations between anthropometric measures and risk of epithelial ovarian cancer (EOC). Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated by Cox proportional hazards regression.

Results:

A total of 152 EOC cases occurred among 70 258 women. Increasing quartiles of weight, hip circumference, and weight gain during adulthood were associated with significantly increased EOC risks. Body mass index (BMI) was also associated; overweight (25⩽BMI<29.99) and obese women (BMI⩾30.0) had significantly increased risks (HR: 1.49, 95% CI: 1.05, 2.13, and HR: 2.42, 95% CI: 1.37, 4.28, respectively). No significant associations were observed for height, waist circumference, waist-to-hip ratio (WHR), and waist-to-height ratio (WHER).

Conclusion:

Results from this large prospective study of Chinese women support the hypothesis that general adiposity contributes to the aetiology of ovarian cancer.

Obesity and risk of ovarian cancer subtypes: evidence from the Ovarian Cancer Association Consortium

Whilst previous studies have reported that higher BMI increases a woman's risk of developing ovarian cancer, associations for the different histological subtypes have not been well defined. As the prevalence of obesity has increased dramatically, and classification of ovarian histology has improved in the last decade, we sought to examine the association in a pooled analysis of recent studies participating in the Ovarian Cancer Association Consortium. We evaluated the association between BMI (recent, maximum and in young adulthood) and ovarian cancer risk using original data from 15 case-control studies (13 548 cases and 17 913 controls). We combined study-specific adjusted odds ratios (ORs) using a random-effects model. We further examined the associations by histological subtype, menopausal status and post-menopausal hormone use. High BMI (all time-points) was associated with increased risk. This was most pronounced for borderline serous (recent BMI: pooled OR=1.24 per 5 kg/m(2); 95% CI 1.18-1.30), invasive endometrioid (1.17; 1.11-1.23) and invasive mucinous (1.19; 1.06-1.32) tumours. There was no association with serous invasive cancer overall (0.98; 0.94-1.02), but increased risks for low-grade serous invasive tumours (1.13, 1.03-1.25) and in pre-menopausal women (1.11; 1.04-1.18). Among post-menopausal women, the associations did not differ between hormone replacement therapy users and non-users. Whilst obesity appears to increase risk of the less common histological subtypes of ovarian cancer, it does not increase risk of high-grade invasive serous cancers, and reducing BMI is therefore unlikely to prevent the majority of ovarian cancer deaths. Other modifiable factors must be identified to control this disease.

Is body size associated with ovarian cancer in southern Chinese women?

PURPOSE

To investigate the association between risk of ovarian cancer and body size among southern Chinese women.

METHODS

A hospital-based case-control study was undertaken in Guangzhou, Guangdong Province, from 2006 to 2008. Participants were 500 incident ovarian cancer patients and 500 controls, with a mean age of 59 years. Information on adult height and weight was obtained via face-to-face interview using a structured questionnaire. Logistic regression analyses were performed to assess the association between anthropometric factors and the ovarian cancer risk.

RESULTS

Compared with women having body weight ≤50 kg and body mass index (BMI) <18.5 kg/m(2), the adjusted odds ratios (ORs) of ovarian cancer were 1.84 (95 % confidence interval (CI) 1.34-2.54) and 1.77 (95 % CI 1.04-3.02) in those women who had body weight >55 kg and BMI ≥23 kg/m(2), respectively. Significant dose-response relationships were also observed for both weight and BMI (p < 0.01). Body height was not significantly associated with ovarian cancer risk.

CONCLUSION

Body weight and BMI were associated with increased risk of ovarian cancer in southern Chinese women.

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.

Anthropometric measures and risk of ovarian cancer among BRCA1 and BRCA2 mutation carriers

Studies conducted among women in the general population suggest that various anthropometric measures, including height and weight, may be associated with the risk of developing ovarian cancer. Whether such an association exists among women who carry a BRCA1 or BRCA2 mutation has not been evaluated. Thus, we investigated the association between height, weight, changes in body weight, and BMI, and the risk of developing ovarian cancer among 938 women carrying a BRCA1 or BRCA2 mutation. A matched case-control study was conducted in 469 pairs of women carrying a deleterious mutation in either BRCA1 (n = 403 pairs) or BRCA2 (n = 66 pairs). Information about height and weight at ages 18, 30, and 40 was collected from a questionnaire routinely administered to women during the course of genetic counseling. Conditional logistic regression was used to estimate the association between these body size measures and the risk of ovarian cancer. Height, weight, and BMI were not associated with the risk of ovarian cancer (P-trend ≥ 0.15). Also, there was no association between changes in body weight between ages 18-30, or ages 30-40, or ages 18-40 and the risk of ovarian cancer (P-trend ≥ 0.28). The results from this study suggest that height, weight, or weight gain do not influence the risk of ovarian cancer among carriers of a BRCA1 or BRCA2 mutation.

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.

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.

Ovarian cancer risk factors in African-American and white women

Ovarian cancer is the most lethal gynecologic malignancy in both African-American and white women. Although prevalences of many ovarian cancer risk factors differ markedly between African Americans and whites, there has been little research on how the relative contributions of risk factors may vary between racial/ethnic groups. Using data from a North Carolina case-control study (1999-2008), the authors conducted unconditional logistic regression analyses to calculate odds ratios and 95% confidence intervals for ovarian cancer risk factors in African-American (143 cases, 189 controls) and white (943 cases, 868 controls) women and to test for interactions by race/ethnicity. They also calculated attributable fractions within each racial/ethnic group for the modifiable factors of pregnancy, oral contraceptive use, tubal ligation, and body mass index. Many risk factors showed similar relations across racial/ethnic groups, but tubal ligation and family history of breast or ovarian cancer showed stronger associations among African Americans. Younger age at menarche was associated with risk only in white women. Attributable fractions associated with tubal ligation, oral contraceptive use, and obesity were markedly higher for African Americans. The relative importance of ovarian cancer risk factors may differ for African-American women, but conclusions were limited by the small sample. There is a clear need for further research on etiologic factors for ovarian cancer in African-American women.

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.

Weight, dietary behavior, and physical activity in childhood and adolescence: implications for adult cancer risk

Lifestyle factors related to energy balance, including weight, dietary behavior and physical activity, are associated with cancer risk. The period of childhood and growth into adolescence and early adulthood may re-present a 'cumulative risk' for later adult-onset cancers. We review a number of epidemiologic studies that have examined associations among childhood and adolescent body size, diet, and physical activity with adult cancer risk. These studies suggest that unhealthy behaviors that develop early in life and persist over time may increase the risk of some cancer types, such as premenopausal breast, ovarian, endometrial, colon and renal cancer, adversely affect cancer-related morbidities, and increase mortality. Continued research is needed to further determine and refine how timing and degree of such exposures in early childhood and adolescence relate to adult cancer risk. Presently, sufficient evidence suggests a continued need for stronger primary prevention in cancer and obesity research via modified lifestyle behaviors earlier in the developmental spectrum, i.e. during childhood and adolescence.

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.

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.

Weight change during chemotherapy as a potential prognostic factor for stage III epithelial ovarian carcinoma: a Gynecologic Oncology Group study

OBJECTIVE

Platinum/Paclitaxel-based chemotherapy is a current treatment for advanced epithelial ovarian cancer. We sought to explore the association between weight change during treatment and survival, as well as the association between pre-chemotherapy body mass index (BMI) and survival.

METHODS

A retrospective data review was conducted of 792 advanced ovarian cancer patients who participated in a phase III randomized trial of cisplatin/paclitaxel versus carboplatin/paclitaxel. Pre-chemotherapy BMI was calculated following surgery. Weight change was defined as the ratio of body weight at completion of protocol therapy to pre-chemotherapy body weight. Progression-free survival (PFS) and overall survival (OS), classified by BMI or relative weight change, were estimated by Kaplan-Meier, and associations were assessed using a Cox model controlled for known prognostic variables (age, race, performance status, histology, tumor grade, tumor residual and treatment group).

RESULTS

There was no association between pre-chemotherapy BMI and survival. There was a significant relationship between median OS and weight change as follows: >5% decrease=48.0 months; 0-5% decrease=49.3 months; 0-5% increase=61.1 months; and >5% increase=68.2 months. Adjusted for covariates, the relative risk of death increased by 7% for each 5% decrease in body weight (HR=0.93, 95% CI=0.88-0.99; p=0.013).

CONCLUSIONS

Change of body weight during primary chemotherapy was a strong prognostic factor for overall survival. Loss of body weight during primary therapy is an indicator for poor OS; weight gain is an indicator for improved survival. This study supports the development of strategies to minimize weight loss that can be assessed in a prospective, randomized study to improve patient outcomes.

Trinucleotide repeat polymorphisms in the androgen receptor gene and risk of ovarian cancer

INTRODUCTION

Androgens may play a role in the development of ovarian cancers. Two trinucleotide repeat polymorphisms have been described in exon 1 of the androgen receptor (AR) gene that may affect its function. Previous studies of ovarian cancer and AR repeat polymorphisms have been inconsistent.

METHODS

We analyzed CAG and GGC repeat length polymorphisms in the AR gene using data from a population-based case-control study of ovarian cancer that included 594 cases and 681 controls. Repeat lengths were determined by fluorescent DNA fragment analysis using ABI GeneScan software. Change point models were used to determine appropriate repeat length cutoff points by race (African American versus Caucasian) for both the shorter and longer CAG and GGC repeats.

RESULTS

No relationship was observed between CAG repeat length and ovarian cancer among Caucasians. Among African Americans, having a short repeat length on either allele was associated with a 2-fold increase in ovarian cancer risk (age-adjusted odds ratio, 2.2; 95% confidence interval, 1.1-4.1). Having short CAG repeat lengths for both alleles was associated with a 5-fold increased risk for developing ovarian cancer (age-adjusted odds ratio, 5.4; 95% confidence interval, 1.4-1.7). No relationship with the GGC repeat length polymorphisms was observed.

CONCLUSION

These results suggest that having a short CAG repeat length in AR increases ovarian cancer risk in African Americans. The failure to observe this relationship in Caucasians may be due to the rarity of such short CAG alleles in this population or could reflect racial differences in disease etiology.

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.

Endogenous androgens and risk of epithelial ovarian cancer: results from the European Prospective Investigation into Cancer and Nutrition (EPIC)

Few epidemiologic studies have examined the hypothesis that circulating androgens are involved in the development of ovarian cancer. We investigated the association between prediagnostic serum levels of androgens and sex hormone-binding globulin (SHBG) and ovarian cancer risk in a case-control study nested within the European Prospective Investigation into Cancer and Nutrition cohort. One hundred and ninety-two ovarian cancer cases and 346 matched controls not using exogenous hormones at baseline blood donation were eligible for the study. Serum levels of testosterone, androstenedione, dehydroepiandrosterone sulfate, and SHBG were measured by direct immunoassays. Free testosterone (fT) was calculated according to mass action laws. Multivariate conditional logistic regression was used to estimate odds ratios adjusted for possible confounders. Overall, there was no association between serum concentrations of androgens or SHBG and ovarian cancer risk. In postmenopausal women, fT concentrations were inversely related to risk [highest versus lowest tertile odds ratio 0.45 (0.24-0.86); P(trend) = 0.01]. Among women diagnosed before the age of 55 years, there was a negative association with SHBG and a positive association with fT and ovarian cancer risk, although these associations were not statistically significant. The present study suggests that circulating androgens and SHBG levels are not strongly associated with ovarian cancer risk, although levels of fT may be associated with an increased risk among women diagnosed at relatively young age. The heterogeneity of results on the associations of fT with ovarian cancer risk in postmenopausal women deserves further investigation.

Weight, Height, and Body Mass Index and Risk for Ovarian Cancer in a Cohort Study

PURPOSE

Reported associations between ovarian cancer and body size are inconsistent. We assessed ovarian cancer and anthropometry in the Breast Cancer Detection Demonstration Project Follow-Up Study.

METHODS

The 46,026 participants completed a baseline interview and mailed questionnaires between 1979 and 1998. By using multiple sources, we identified 346 incident ovarian cancers during follow-up. We calculated rate ratios (RRs) and 95% confidence intervals (CIs) to estimate relative risks for developing ovarian cancer associated with height and weight (measured 1973 to 1980) and self-reported current and usual adult weight (collected during follow-up).

RESULTS

Neither taller height (> or =66 versus <62 inches; RR, 0.90; 95% CI, 0.64-1.26) nor greater weight (> or =161 versus < or =120 lbs; RR, 1.09; 95% CI, 0.77-1.55) was associated with ovarian cancer. Compared with normal weight (body mass index [BMI], 18.5 to 24.9 kg/m(2)), overweight (BMI, 25 to 29.9 kg/m(2); RR, 1.00; 95% CI, 0.78-1.29) and obesity (BMI, 30 to 34.9 kg/m(2); RR, 0.94; 95% CI, 0.59-1.48) were not associated with ovarian cancer. Severe obesity (BMI > or = 35 kg/m(2)) produced a nonsignificantly elevated RR (1.55; 95% CI, 0.84-2.84). Associations with histologic types and statistical interactions with menopausal status and hormone therapy use were null.

CONCLUSIONS

Based on height and weight measured before baseline, overweight and obesity were not significantly associated with ovarian cancer in this cohort.

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.

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

OBJECTIVE

To examine the relationship between anthropometric measures and ovarian cancer by menopausal status.

METHODS

We analyzed data from a population-based case-control study comprised of 700 incident cases of epithelial ovarian cancer and 5,943 population controls from Massachusetts and Wisconsin enrolled between 1993 and 2001. In a telephone interview, information was gathered on established ovarian cancer risk factors, as well as adult height and age-specific body weight. Logistic regression was used to estimate multivariate-adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for body mass index (BMI) throughout life.

RESULTS

Recent BMI had no significant association with ovarian cancer risk (P-trend 0.14 for continuous BMI), after adjustment for age and other ovarian cancer risk factors. However, a non-significant positive association (overall P-trend 0.08) was observed for BMI at age 20; the risk estimate comparing a body mass of >25 kg/m2 to the lowest quintile (<or=18.88 kg/m2) was moderately but non-significantly elevated (OR 1.46; 95% CI 0.92, 2.31).

CONCLUSION

Results of this study suggest that maintenance of a lean body mass, particularly in early adult life, may decrease ovarian cancer risk.