Weight gain during adulthood and body weight at age 20 are associated with the risk of endometrial cancer in Japanese women

Risk factors for endometrial cancer in Black women

PURPOSE

The incidence of endometrial cancer (EC) has been increasing faster among Black women than among other racial/ethnic groups in the United States. Although the mortality rate is nearly twice as high among Black than White women, there is a paucity of literature on risk factors for EC among Black women, particularly regarding menopausal hormone use and severe obesity.

METHODS

We pooled questionnaire data on 811 EC cases and 3,124 controls from eight studies with data on self-identified Black women (4 case-control and 4 cohort studies). We analyzed cohort studies as nested case-control studies with up to 4 controls selected per case. We used logistic regression to estimate multivariable-adjusted odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

We observed a positive association between BMI and EC incidence (P_trend < 0.0001) The OR comparing BMI ≥ 40 vs. < 25 kg/m² was 3.92 (95% CI 2.91, 5.27). Abdominal obesity among those with BMI < 30 kg/m² was not appreciably associated with EC risk (OR 1.21, 95% CI 0.74, 1.99). Associations of reproductive history with EC were similar to those observed in studies of White women. Long-term use of estrogen-only menopausal hormones was associated with an increased risk of EC (≥ 5 years vs. never use: OR 2.08, 95% CI: 1.06, 4.06).

CONCLUSIONS

Our results suggest that the associations of established risk factors with EC are similar between Black and White women. Other explanations, such as differences in the prevalence of known risk factors or previously unidentified risk factors likely underlie the recent increases in EC incidence among Black women.

Adult lifetime body mass index trajectories and endometrial cancer risk

OBJECTIVE

To identify body mass index (BMI) trajectories in adult life and to examine their association with endometrial cancer (EC) risk, also exploring whether relations differ by HRT use.

DESIGN

Pooled analysis of two case control studies.

SETTING

Italy and Switzerland.

POPULATION

A total of 458 EC cases and 782 controls.

METHODS

We performed a latent class growth model in order to identify homogenous BMI trajectories over 6 decades of age, with a polynomial function of age. Odds Ratios (ORs) and the corresponding 95% confidence intervals (CI) for EC risk were derived through a multiple logistic regression model, correcting for classification error.

MAIN OUTCOME MEASURES

The relation of BMI trajectories with endometrial cancer.

RESULTS

We identified 5 BMI trajectories. Compared with women in the 'Normal weight-stable' trajectory, a reduction by about 50% in the risk of EC emerged for those in the 'Underweight increasing to normal weight' (95% CI=0.28-0.99). The 'Normal weight increasing to overweight' and the 'Overweight-stable' trajectories were associated to, respectively, an excess of 3% (95% CI=0.66-1.60) and of 71% (95% CI= 1.12-2.59) in cancer risk. The OR associated to the trajectory 'Overweight increasing to obese' was 2.03 (95% CI= 1.31-3.13). Stronger effects emerged among HRT never users (OR= 2.19 for the 'Overweight-stable' trajectory and OR=2.49 for the 'Overweight increasing to obese' trajectory).

CONCLUSIONS

Our study suggests that longer exposure to overweight and obesity across lifetime is associated with an increased risk of endometrial cancer. Weight during adulthood also appears to play an important role.

Obesity increases endometrial cancer risk in Chinese women with postmenopausal bleeding

OBJECTIVE

We examined the relationship between body mass index (BMI) at referral and subsequent diagnosis of endometrial cancer in a cohort of Chinese women presenting with postmenopausal bleeding, to determine whether BMI of 25 kg/m2 would serve to delineate women at increased risk of endometrial cancer.

METHODS

This cohort included 4,164 Chinese women referred for postmenopausal bleeding from 2002 to 2013. For all women, a medical history was taken, and physical examination, BMI measurement, transvaginal pelvic ultrasonography, and endometrial sampling were performed. Additional investigations were performed as indicated clinically. The presence of risk factors for endometrial cancer and histological diagnoses were compared among groups defined by the standard Asian BMI cut-off values.

RESULTS

Within the cohort, 868 (20.8%) were overweight (BMI 23-24.9 kg/m2) and 1,611 (38.7%) were obese (BMI ≥25 kg/m2), and 162 (3.9%) had endometrial cancer. The prevalence of endometrial cancer correlated with BMI category (P < 0.001). On multivariate analysis, BMI ≥25 kg/m2 was independently associated with 1.57 times risk of endometrial cancer (95% CI 1.13-2.20, P = 0.008) compared with BMI less than 25 kg/m2.

CONCLUSION

When managing postmenopausal bleeding in Chinese women, the Asian BMI standard for obesity at 25 kg/m2 identified 51% of endometrial cancers in this group and denoted a 57% increased risk of endometrial cancer. Thus obesity could be used to triage women presenting with postmenopausal bleeding for prioritized investigations.

Population-Based Screening for Endometrial Cancer: Human vs. Machine Intelligence

Incidence and mortality rates of endometrial cancer are increasing, leading to increased interest in endometrial cancer risk prediction and stratification to help in screening and prevention. Previous risk models have had moderate success with the area under the curve (AUC) ranging from 0.68 to 0.77. Here we demonstrate a population-based machine learning model for endometrial cancer screening that achieves a testing AUC of 0.96. We train seven machine learning algorithms based solely on personal health data, without any genomic, imaging, biomarkers, or invasive procedures. The data come from the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial (PLCO). We further compare our machine learning model with 15 gynecologic oncologists and primary care physicians in the stratification of endometrial cancer risk for 100 women. We find a random forest model that achieves a testing AUC of 0.96 and a neural network model that achieves a testing AUC of 0.91. We test both models in risk stratification against 15 practicing physicians. Our random forest model is 2.5 times better at identifying above-average risk women with a 2-fold reduction in the false positive rate. Our neural network model is 2 times better at identifying above-average risk women with a 3-fold reduction in the false positive rate. Our machine learning models provide a non-invasive and cost-effective way to identify high-risk sub-populations who may benefit from early screening of endometrial cancer, prior to disease onset. Through statistical biopsy of personal health data, we have identified a new and effective approach for early cancer detection and prevention for individual patients.

Association of BMI and height with the risk of endometrial cancer, overall and by histological subtype: a population-based prospective cohort study in Japan

Evidence on the association between BMI, height, and endometrial cancer risk, including by subtypes, among Asian populations remains limited. We evaluated the impact of BMI and height on the risk of endometrial cancer, overall and by histological subtype. We prospectively investigated 53 651 Japanese women aged 40-69 years. With an average follow-up duration of 18.6 years, 180 newly diagnosed endometrial cancers were reported, including 119 type 1 and 21 type 2. The association between BMI, height, and endometrial cancer risk was assessed using a Cox proportional hazards regression model with adjustment for potential confounders. Overweight and obesity were associated positively with the risk of endometrial cancer. Compared with BMI of 23.0-24.9 kg/m, hazard ratios (HRs) (95% confidence intervals) were 1.93 (1.17-3.16) for BMI of 27.0-29.9 kg/m and 2.37 (1.20-4.66) for BMI of at least 30.0 kg/m. On analysis by histological subtype, with each increase in BMI of 5 U, the estimated HR of type 1 endometrial cancer increased (HR=1.54, 95% confidence interval: 1.21-1.98), but HR of type 2 endometrial cancer was unaffected. There was no statistically significant association between height and endometrial cancer risk. In conclusion, the risk of endometrial cancer was elevated in women with a BMI of at least 27.0 kg/m. By histological subtype, BMI was associated with type 1, but not type 2 endometrial cancer risk among a population with a relatively low BMI compared with western populations.

Biological Mechanisms for the Effect of Obesity on Cancer Risk: Experimental Evidence

Multiple epidemiological studies demonstrated that overweight and obesity significantly increase the risk of several types of cancer. As the prevalence of obesity is dramatically rising, it is expected that it will represent one of the major lifestyle-associated risk factors for cancer development in the near future. Numerous recent studies expanded knowledge about key players and pathways, which are deregulated in the obese state and potentially promote cancer initiation, progression and aggressiveness via remote and local effects. These players include (but are not limited to) insulin/IGF, adipokines and inflammatory signaling molecules as well as metabolites. Nevertheless, the detailed mechanisms linking obesity and malignant transformation at the systemic, cellular and molecular level still demand further investigation. Additionally, dysfunctional molecular metabolic pathways appear to be specific for distinct cancer entities, thereby yet precluding definition of a common principle. This chapter will present an overview of the current knowledge of molecular nodes linking obesity and cancer and will briefly touch upon potential therapy options addressing metabolic cancer etiologies.

Gynecologic and Obstetric Consequences of Obesity in Adolescent Girls

In the past few decades, there has been an overwhelming increase in childhood and adolescent obesity worldwide. Besides the well recognized cardiometabolic complications and other physical conditions associated with obesity, during adolescence, it causes psychological and social distress in a period of life that is already sensitive for a girl. This in turn increases their risk of low self-esteem and depression. Furthermore, obesity diminishes health-related quality of life and years of life. Overweight and obese teenagers are more likely to have gynecologic and obstetric complications, during adolescence and also later in life. Consequences of obese and overweight childhood and adolescence include sexual maturation and reproductive dysfunction, alterations in menstruation, dysmenorrhea, risky sexual behavior, and inefficient use of contraception, polycystic ovary syndrome, bone density abnormalities, macromastia, and an increased risk of breast and endometrial cancer. Obese adolescents are at greater risk of pregnancy and perinatal complications, such as preeclampsia, gestational hypertension and preeclampsia, gestational diabetes mellitus, primary cesarean delivery, and induction of labor, to mention a few. Evidence shows that infants born to obese teenagers are also more likely to have complications including preterm or post-term delivery, small-for-gestational age newborns, macrosomia, meconium aspiration, respiratory distress, and even stillbirth, among others. This comprehensive review focuses on the gynecological and obstetric consequences of obesity in adolescent girls.

Body Size, Metabolic Factors, and Risk of Endometrial Cancer in Black Women

Total and abdominal obesity, as well as metabolic factors such as type 2 diabetes, have been associated with a higher risk of endometrial cancer in white women. It remains unclear to what extent these factors influence the risk of endometrial cancer in black women. We followed 47,557 participants from the Black Women's Health Study for incident endometrial cancer from 1995 through 2013 (n = 274). We used Cox regression models to estimate incidence rate ratios and 95% confidence intervals while accounting for potential confounders. Incidence rate ratios for body mass indices (weight (kg)/height (m)(2)) of 25.0-29.9, 30.0-34.9, 35.0-39.9, and ≥40.0 versus those <25.0 were 1.00 (95% confidence interval (CI): 0.67, 1.48), 1.49 (95% CI: 0.97, 2.30), 2.16 (95% CI: 1.34, 3.49), and 3.60 (95% CI: 2.24, 5.78), respectively (Ptrend <0.0001). A high weight-to-height ratio was also associated with a higher risk (for the highest quartile vs. the lowest, incidence rate ratio = 2.83, 95% CI: 1.77, 4.53), as was type 2 diabetes mellitus (incidence rate ratio = 1.52, 95% CI: 1.04, 2.21). Positive associations with measures of central adiposity (waist circumference, waist-to-hip ratio, and waist-to-height ratio) and hypertension were attenuated after we controlled for body mass index. Total adiposity was an independent risk factor for endometrial cancer among black women and appeared to explain most of the associations seen with other adiposity measures and metabolic factors.

Obesity and Endometrial Cancer

Endometrial cancer is the sixth most common cancer in women worldwide and the most common gynecologic malignancy in the developed world. This chapter explores the current epidemiologic evidence on the association between obesity and endometrial cancer risk and mortality. Using body mass index (BMI) as a measure of obesity, we found that obesity (defined as BMI > 30 and < 35 kg/m²) was associated with a 2.6-fold increase in endometrial cancer risk, while severe obesity (BMI > 35 kg/m²) was associated with a 4.7-fold increase compared to normal-weight women (BMI < 25 kg/m²). Increased central adiposity also increased endometrial cancer risk by 1.5- to twofold. Among both healthy and endometrial cancer patient populations, obesity was associated with a roughly twofold increase in endometrial cancer-specific mortality. This risk reduction was also observed for obesity and all-cause mortality among endometrial cancer patients. In the few studies that assessed risk associated with weight change, an increased endometrial cancer risk with weight gain and weight cycling was observed, whereas some evidence for a protective effect of weight loss was found. Furthermore, early-life obesity was associated with a moderately increased risk of endometrial cancer later in life. There are several mechanisms whereby obesity is hypothesized to increase endometrial cancer risk, including increased endogenous sex steroid hormones, insulin resistance, chronic inflammation and adipokines. Further research should focus on histological subtypes or molecular phenotypes of endometrial tumors and population subgroups that could be at an increased risk of obesity-associated endometrial cancer. Additionally, studies on weight gain, loss or cycling and weight loss interventions can provide mechanistic insight into the obesity-endometrial cancer association. Sufficient evidence exists to recommend avoiding obesity to reduce endometrial cancer risk.

Parity and endometrial cancer risk: a meta-analysis of epidemiological studies

The association between parity and endometrial cancer risk is inconsistent from observational studies. We aimed to quantitatively assess the relationship by summarizing all relevant epidemiological studies. PubMed (MEDLINE), Embase and Scopus were searched up to February 2015 for eligible case–control studies and prospective studies. Random-effects model was used to pool risk estimations. Ten prospective studies, 35 case-control studies and 1 pooled analysis of 10 cohort and 14 case-control studies including 69681 patients were identified. Pooled analysis revealed that there was a significant inverse association between parity and risk of endometrial cancer (relative risk (RR) for parous versus nulliparous: 0.69, 95% confidence interval (CI) 0.65–0.74; I² = 76.9%). By evaluating the number of parity, we identified that parity number of 1, 2 or 3 versus nulliparous demonstrated significant negative association (RR = 0.73, 95% CI 0.64–0.84, I² = 88.3%; RR = 0.62, 95% CI 0.53–0.74, I² = 92.1%; and RR = 0.68, 95% CI 0.65–0.70, I² = 20.0% respectively). The dose-response analysis suggested a nonlinear relationship between the number of parity and endometrial cancer risk. The RR decreased when the number of parity increased. This meta-analysis suggests that parity may be associated with a decreased risk of endometrial cancer. Further studies are warranted to replicate our findings.

Overweight, obesity and endometrial cancer risk: results from a systematic review and meta-analysis

AIM

Findings from recent studies suggest that obesity may be associated with an increased risk of endometrial cancer, but several earlier studies were less conclusive. Here we strive to estimate this relationship in a meta-analysis of published data.

METHODS

We searched Pubmed and Embase for studies on body mass index and the risk of endometrial cancer, published from 1989 to 2011. Data were independently extracted and analyzed using random or fixed effects meta-analysis depending on the degree of heterogeneity.

RESULTS

Seven cohort studies and 11 case-control studies were included in the meta-analysis. Overall, the conditions of excess body weight ([EBW] defined as body mass index [BMI] ≥25 kg/m²), obesity (BMI ≥30 kg/m²) and overweight (25< BMI <30 kg/m²) were associated with an increased risk of endometrial cancer (relative risk [RR] for EBW=1.62, 95% confidence interval [CI], 1.39-1.89; for obesity RR=2.54, 95% CI, 2.11-3.06; for overweight RR=1.32, 95% CI, 1.16-1.50). Subgroup analyses showed that the positive associations were independent of study design, geographic locations, self-reported BMI, alcohol use, smoking habit, history of diabetes, hormone therapy, age at menarche, age at menopause, parity, and age at first full term pregnancy. However, there was no statistically significant association between EBW and endometrial cancer risk for measured BMI (for EBW RR=1.29, 95% CI, 0.66-2.53).

CONCLUSIONS

The findings from this meta-analysis strongly support that the conditions of EBW, overweight, and obesity are all associated with an increased risk of endometrial cancer. Also, the strength of the association increases with increasing BMI.

Obesity and the Endometrium: Adipocyte-Secreted Proinflammatory TNF α Cytokine Enhances the Proliferation of Human Endometrial Glandular Cells

Obesity, a state of chronic inflammation, is associated with poor fertility and low implantation rates and is a well-documented risk factor for endometrial cancer. Adipokines, such as tumor necrosis factor alpha, play an important role in initiation of endometrial cancer. The aim of this study is to evaluate in vitro effects of human adipocyte cells (SW872) on growth of endometrial glandular epithelial cells (EGE). Methods. We measured cell proliferation and expression of cell-growth proteins—proliferating cell nuclear antigen, cyclin D1, cyclin-dependent kinase-1, and apoptotic markers (BCL-2 and BAK) in human EGE cells cocultured with SW872 cells. EGE cells were also evaluated in SW872-conditioned media neutralized with anti-TNFα antibody. Results. A significant increase in EGE cell proliferation was observed in both SW872-conditioned media and in coculture (P < 0.05). We observed an upregulation of proliferation markers PCNA, cyclin D1, CDK-1, and BCL-2 and decrease in BAK (P < 0.05). Neutralization of SW872-conditioned media using anti-TNFα antibodies reversed EGE cell proliferation as indicated by BCL-2 expression. Conclusions. Adipocytes have potent proliferative paracrine effect on EGE cells which may be, in part, mediated via TNFα. Further understanding of the role of obesity in endometrial carcinogenesis should lead to better preventative and therapeutic strategies.

Anthropometric measures and the risk of endometrial cancer, overall and by tumor microsatellite status and histological subtype

Obesity is an established risk factor for endometrial cancer, but this association is not well understood for subtypes of endometrial cancer. We evaluated the association of recent and adult-life obesity with subtypes of endometrial cancer based on microsatellite status (microsatellite-stable (MSS) vs. microsatellite-instable (MSI)) and histology (type I vs. type II). Analyses were based on a population-based case-control study (524 cases and 1,032 controls) conducted in Alberta, Canada (2002-2006) and included the following groupings of subtypes: MSS = 337 and MSI = 130; type I = 458 and type II = 66. Logistic and polytomous logistic regression were used to estimate odds ratios and 95% confidence intervals for overall endometrial cancer and subtypes of endometrial cancer, respectively. The risks of all subtypes of endometrial cancer, except type II, increased with an increase in all of the anthropometric characteristics examined. The risks for MSI tumors were suggestively stronger than those for MSS tumors; the risk with high (≥30) body mass index (weight (kg)/height (m)(2)) was significantly stronger for MSI tumors (odds ratio = 4.96, 95% confidence interval: 2.76, 8.91) than for MSS tumors (odds ratio = 2.33, 95% confidence interval: 1.66, 3.28) (P-heterogeneity = 0.02). Obesity is associated with most subtypes of endometrial cancer, and further studies are warranted to elucidate the biological mechanisms underlying the stronger risk for the MSI subtype with a high body mass index.

Obesity as a major risk factor for cancer

The number of cancer cases caused by being obese is estimated to be 20% with the increased risk of malignancies being influenced by diet, weight change, and body fat distribution together with physical activity. Reports from the International Agency for Research into Cancer and the World Cancer Research Fund (WCRF) have shown that the strongest evidence exists for an association of obesity with the following cancer types: endometrial, esophageal adenocarcinoma, colorectal, postmenopausal breast, prostate, and renal, whereas the less common malignancies are leukemia, non-Hodgkin's lymphoma, multiple myeloma, malignant melanoma, and thyroid tumours. To be able to develop novel methods in prevention and treatment, we first must understand the underlying processes which link cancer to obesity. Four main systems have been identified as potential producers of cancer in obesity: insulin, insulin-like growth factor-I, sex steroids, and adipokines. Various novel candidate mechanisms have been proposed: chronic inflammation, oxidative stress, crosstalk between tumour cells and surrounding adipocytes, migrating adipose stromal cells, obesity-induced hypoxia, shared genetic susceptibility, and the functional defeat of immune function. Herein, we review the major pathogenic links between obesity and susceptibility to cancer.

Working conditions and major weight gain-a prospective cohort study

The objective of this study was to examine the associations of working conditions with major weight gain. Three different groups of work-related factors were examined: (i) work arrangements, (ii) physical working conditions, and (iii) psychosocial working conditions. The data are based on the Helsinki Health Study (HHS) questionnaire surveys. A baseline mail survey was made among middle-aged employees of the City of Helsinki in 2000-2002. A follow-up survey was made in 2007. Regression analyses with odds ratios and 95% confidence intervals were calculated. During the 5- to 7-year follow-up, 26% of women and 24% of men gained in weight 5 kg or more. Working conditions were mostly unassociated with weight gain. However, nighttime shift work, physical threat at work, and hazardous exposures at work were moderately associated with weight gain. More attention should be devoted to the prevention of weight gain in general and among risk groups in particular.