Body Size and Risk of Epithelial Ovarian Cancer (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.

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.

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.

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.

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.

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.

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 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.

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.

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.

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 and cancer risk in a cohort of more than 65,000 adults in Austria

BACKGROUND

To investigate relations between weight loss or weight gain and the incidence of cancer.

PATIENTS AND METHODS

Weight change was assessed in a population-based cohort of >65 000 Austrian adults (28 711 men and 36 938 women) for a period of 7 years, after which participants were followed for incident cancers over 8 years on average. Incident cancers (other than nonmelanoma skin cancers) were ascertained by a population-based cancer registry (n = 3128). Cox proportional hazards models were used to estimate hazard rate ratios (HRs) stratified by age and adjusted for smoking, occupational group, blood glucose and body mass index at baseline.

RESULTS

In both men and women, neither weight loss nor weight gain was clearly associated with the incidence of all cancers combined. Weight loss (>0.10 kg/m(2)/year) was inversely associated with colon cancer in men [HR 0.50; 95% confidence interval (CI) 0.29-0.87], while high weight gain (> or =0.50 kg/m(2)/year) was inversely associated with prostate cancer (HR 0.43; 95% CI 0.24-0.76). Among women, high weight gain was positively associated with ovarian cancer (HR 2.48; 95% CI 1.05-5.85).

CONCLUSION

These findings indicate that recent weight change may influence the incidence of several types of cancer.

An analysis of ovarian cancer in the Million Women Study

In a reanalysis of the Million Women Study (MWS), their authors concluded that prolonged use of hormone replacement therapy (HRT) in postmenopausal women increases the risk of ovarian cancer. Although statistically significant their results are clinically irrelevant, since the attributable risk over 5 years is only 4 per 10 000 HRT users, a figure that is not confirmed by other large studies. This risk is much lower than those associated with obesity, lack of physical exercise, smoking and nulliparity, all of which are preventable. Therefore HRT should continue to be prescribed for symptom relief and improvement of quality of life because the benefits far outweigh the very low potential risks.