Case-control study of lifetime total physical activity and endometrial cancer risk

Prospective cohort of pre- and post-diagnosis alcohol consumption and cigarette smoking on survival outcomes: an Alberta Endometrial Cancer Cohort Study

PURPOSE

To examine the independent and joint relationships between cigarette smoking and alcohol consumption with survival outcomes after endometrial cancer diagnosis.

METHODS

Pre- and post-diagnosis smoking and drinking histories were obtained from endometrial cancer survivors diagnosed between 2002 and 2006 during in-person interviews at-diagnosis and at ~ 3 years post-diagnosis. Participants were followed until death or January 2022. Multivariable-adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated with Cox proportional hazards regression for associations with disease-free survival (DFS) and overall survival (OS).

RESULTS

During a median 16.9 years of follow-up (IQR = 15.5-18.1 years), 152 of the 540 participants had a DFS event (recurrence: n = 73; deaths: n = 79) and 134 died overall. Most participants in this cohort were current drinkers (pre = 61.3%; post = 64.7%) while few were current cigarette smokers (pre = 12.8%; post = 11.5%). Pre-diagnosis alcohol consumption was not associated with survival, yet post-diagnosis alcohol intake ≥ 2 drinks/week was associated with worse OS compared with lifetime abstention (HR = 2.36, 95%CI = 1.00-5.54) as well as light intake (HR = 3.87, 95% CI = 1.67-8.96). Increased/consistently high alcohol intake patterns were associated with worse OS (HR = 2.91, 95% CI = 1.15-7.37) compared with patterns of decreased/ceased intake patterns after diagnosis. A harmful dose-response relationship per each additional pre-diagnosis smoking pack-year with OS was noted among ever smokers. In this cohort, smoking and alcohol individually were not associated with DFS and combined pre-diagnosis smoking and alcohol intakes were not associated with either outcome.

CONCLUSION

Endometrial cancer survivors with higher alcohol intakes after diagnosis had poorer OS compared with women who had limited exposure. Larger studies powered to investigate the individual and joint impacts of cigarette smoking and alcohol use patterns are warranted to provide additional clarity on these modifiable prognostic factors.

Prospective Cohort of Pre- and Post-Diagnosis Diet with Survival Outcomes: an Alberta Endometrial Cancer Cohort Study

BACKGROUND

The prognostic relationship between diet and endometrial cancer survival remains largely unknown. We sought to determine pre- and post-diagnosis dietary composition, glycemic load (GL), inflammatory potential (dietary inflammatory index) and quality [Canadian Healthy Eating Index (C-HEI) 2005] associations with disease-free (DFS) and overall survival (OS) among endometrial cancer survivors. In addition, we assessed associations between dietary changes with OS and explored obesity/physical activity effect modification.

METHODS

Survivors, diagnosed in Alberta, Canada between 2002 and 2006, completed past-year, food-frequency questionnaires at-diagnosis (n = 503) and 3-year follow-up (n = 395). Participants were followed to death or January 2022. Cox proportional regression estimated HR [95% confidence intervals (CI)] for dietary survival associations.

RESULTS

During 16.9 median years of follow-up, 138 participants had a DFS event and 120 died. Lower pre-diagnosis GL (HRT1vsT3, 0.49; 95% CI, 0.25-0.97) and greater post-diagnosis energy intakes (EI) from total- and monounsaturated-fat (HRT3vsT1, 0.48; 95% CI, 0.26-0.87) were associated with better OS. Higher pre-diagnosis C-HEI, less inflammatory diets and lower added sugar intakes were nonlinearly associated with better DFS. Consistently low pre- to post-diagnosis EI from carbohydrates and total-fats were associated with better (HR, 0.36; 95% CI, 0.18-0.72) and worse (HR, 2.26; 95% CI, 1.21-4.20) OS, respectively. Decreased pre- to post-diagnosis C-HEI was associated with worse OS. In stratified analysis, healthy diets were most beneficial for survivors with obesity and physical inactivity.

CONCLUSIONS

Adherence to higher quality dietary patterns were associated with better survival.

IMPACT

Our study provides novel evidence that both pre- and post-diagnosis diet are important prognostic factors for endometrial cancer survivors. Post-diagnosis survival associations with diet composition and quality highlight the potential for future interventions.

Quantifying the Effect of Physical Activity on Endometrial Cancer Risk

Endometrial cancer incidence is rising, with 435,000 global cases in 2019. An effective, low-cost primary prevention strategy is required to reduce disease burden. Obesity, insulin resistance, and inflammation contribute to endometrial carcinogenesis and physical activity targets these pathways. This study sought to quantify the amount of physical activity required to impact upon endometrial cancer risk. Physical activity data from 222,031 female participants with an intact uterus in the UK Biobank study were analyzed using a multivariable Cox proportional hazards model. A systematic review of the literature was performed, searching CENTRAL, Embase, and MEDLINE databases up to April 19, 2021. Studies including participants with and without endometrial cancer investigating the effect of physical activity measured in MET-hours/week (MET-h/week) on disease risk were included. Two reviewers independently selected studies, extracted data, and evaluated the risk of bias. Within the UK Biobank, each 1 MET-h/week increase in total physical activity was associated with a 0.2% [95% confidence interval (CI), 0.1-0.4; P = 0.020] reduction in endometrial cancer risk, equating to a 10.4% reduction if performing 50 MET-h/week or 7 hours of jogging per week. Eleven cohort and 12 case-control studies were identified in the systematic review, including 821,599 participants. One study reported a nonsignificant effect of 1 MET-h/week increases in physical activity on endometrial cancer risk (OR, 1.00; 95% CI, 0.99-1.00). Eight studies found significant reductions in disease risk of 15%-53%, but only in the most physically active individuals. Physical activity reduces endometrial cancer risk, but the effect size appears small. Regular vigorous activity should be encouraged to maximize the health benefit observed.

PREVENTION RELEVANCE

Effective, low-cost primary prevention strategies are urgently needed to tackle the rapid global increase in endometrial cancer. We sought to quantify the effect of physical activity on endometrial cancer risk, noting a linear inverse relationship influenced by body mass index. The most beneficial type and amount of activity remain unclear.

Associations of insulin resistance and inflammatory biomarkers with endometrial cancer survival: The Alberta endometrial cancer cohort study

Background

Metabolic dysfunction and inflammation have been associated with endometrial cancer risk; however, their influence on endometrial cancer survival is less understood.

Methods

A prospective cohort study of 540 endometrial cancer cases diagnosed between 2002 and 2006 in Alberta were followed for survival outcomes to 2019. Baseline blood samples collected either pre‐ or post‐hysterectomy were analyzed for glucose, insulin, adiponectin, leptin, tumor necrosis factor‐α, interleukin‐6, and C‐reactive protein. Covariates were obtained during in‐person interviews and via medical chart abstraction. Cox proportional hazard regression models were used to estimate multivariable‐adjusted hazard ratios (HR) and 95% confidence intervals (95% CI) for the association between each biomarker and disease‐free and overall survival.

Results

Blood samples were collected from 520 of the 540 participants (presurgical n = 235; postsurgical n = 285). During the median follow‐up of 14.3 years (range 0.4–16.5 years), there were 125 recurrences, progressions, and/or deaths with 106 overall deaths. None of the biomarkers were associated with disease‐free or overall survival in multivariable‐adjusted analyses. In an exploratory stratified analysis, the highest level of presurgical adiponectin, compared to the lowest level, was associated with improved disease‐free (HR = 0.42, 95% CI = 0.20–0.85) and overall (HR = 0.41, 95% CI = 0.18–0.92) survival, whereas no statistically significant associations were noted for postsurgical measures of adiponectin.

Conclusions

Overall, there was no evidence of an association between biomarkers of insulin resistance and inflammation with mortality outcomes in endometrial cancer survivors. Future cohort studies with serial blood samples are needed to understand the impact of changes in insulin resistance and inflammatory markers on endometrial cancer survival.

Prospective Cohort Study of Pre- and Post-Diagnosis Obesity and Endometrial Cancer Survival

BACKGROUND

Disease-free and overall survival associations with anthropometric measures of obesity and changes in these exposures remain unknown among endometrial cancer survivors.

METHODS

Endometrial cancer survivors diagnosed between 2002-2006 completed direct anthropometric measurements and self-reported lifetime weight history during in-person interviews approximately 4 months after diagnosis (peri-diagnosis) and approximately 3 years after diagnosis (follow-up). Participants were followed until death or March 20, 2019. Cox proportional regression estimated multivariable-adjusted hazard ratios (HR) and 95% confidence intervals (CI) for body mass index (BMI), weight, waist circumference, and waist-hip ratio with disease-free survival (DFS) and overall survival (OS). Statistical tests were two-sided.

RESULTS

540 and 425 cancer survivors were assessed peri-diagnosis and follow-up, respectively. During the median 14.2 years of follow-up (range = 0.3-16.5 years), 132 participants had a recurrence and/or died (DFS) with 111 deaths overall (OS). Reduced DFS was noted with greater recalled weight one-year before-diagnosis (HR = 1.88, 95% CI = 1.15 to 3.07), BMI one-year before-diagnosis (HR = 1.88, 95% CI = 1.09 to 3.22), and measured peri-diagnosis BMI (HR = 2.04, 95% CI = 1.18 to 3.53). Measured peri-diagnosis waist circumference ≥88 cm was associated with decreased DFS (HR = 1.94, 95% CI = 1.24 to 3.03) and OS (HR = 1.90, 95% CI = 1.16 to 3.13). A two-fold decrease in DFS and OS was associated with ≥5% BMI or weight change from one-year before diagnosis to peri-diagnosis. No associations were observed for the assessment during follow-up.

CONCLUSION

One-year before- and peri-diagnosis anthropometric measures of obesity were associated with reduced survival among endometrial cancer survivors. Anthropometric changes from one-year before- to peri-diagnosis may provide an important indication of future survival in this population.

Transportation Physical Activity Earlier in Life and Areas of the Brain related to Dementia Later in Life

INTRODUCTION

Efforts to preserve brain function may be most effective when administered before there are changes in the brain, which may occur decades before the onset of Alzheimer's disease symptoms. White matter hyperintensities (WMH), a cardiovascular disease biomarker, are areas of hyperintense signals scattered in the white matter of the brain evident on magnetic resonance images. WMH increase with age and are associated with a higher risk of dementia. The purpose of this study was to determine if there was an association between different domains and intensities of physical activity earlier in life and lower risk of dementia later in life as indicated by less WMH.

METHODS

In this cross-sectional study, face-to-face interviews were conducted with the Lifetime Total Physical Activity Questionnaire. The metabolic equivalent of task (MET) hours/week/year of moderate (3.0-5.9 METs) and vigorous-intensity (≥6 METs) occupation, transportation, household and leisure-time physical activity was obtained across school-age (6-11), adolescence (12-18), young (19-39) and middle adulthood (40-64). WMH were calculated as the percent of intracranial volume in cognitively unimpaired middle (age 40-64) and older adults (age 65+). Simultaneous multiple linear regression determined associations between moderate and vigorous-intensity occupation, transportation, household and leisure-time physical activity across school-age, adolescence, young and middle adulthood with WMH.

RESULTS

Greater moderate-intensity transportation physical activity during young (b= -.09, p=.008) and middle adulthood (b= -.14, p=.013) was associated with lower WMH in middle and older adulthood, explaining 28% (p=.003) to 29% (p=.002) of the variance in WMH (n=54).

CONCLUSIONS

Changes to the physical environment that encourage walking, running or biking, such as sidewalks and bike paths, may be strategies to mitigate the age-related increases in WMH, areas of the brain associated with higher risk of dementia.

Physical Activity and Breast Cancer: A Case-Control Study in Southern Brazil

Physical inactivity is one of the greatest public health challenges in the 21st century. More than five million deaths a year are caused by lack of physical activity (PA) around the world. Despite its relevance to public health, about one-third of the world's adults do not meet current PA recommendations for health benefits. Thus, the aim of the present study was to investigate the association between lifetime PA and risk of breast cancer. A case-control study was conducted between November 2016 and June 2017. The cases were recruited from all cancer centers in the city of Pelotas in southern Brazil. Each case was age-matched (±5 years) with a neighborhood control enrolled based on nearby addresses of the cases. Overall, 230 cases and 231 controls were included. Lifetime leisure-time PA may decrease the odds of breast cancer (adjusted OR = 0.44; 95%CI 0.23-0.86) in the comparison between the most active with the least active quartile. PA was associated with a reduction in the odds of breast cancer. Future studies should aim at understanding the physiological pathways that could explain how an active lifestyle influences this disease, helping in the establishment of volume and intensities necessary to obtain the benefits.

Prospective Cohort Study of Pre- and Postdiagnosis Physical Activity and Endometrial Cancer Survival

PURPOSE

The aim of this study was to evaluate associations between pre- and postdiagnosis physical activity and survival in survivors of endometrial cancer by physical activity domain, intensity, dose (metabolic-equivalent task [MET]-hours/week/year), and change from pre- to postdiagnosis.

METHODS

We conducted a prospective cohort study in Alberta, Canada, of 425 women who were diagnosed with histologically confirmed invasive endometrial cancer between 2002 and 2006 and observed to 2019. The interviewer-administered Lifetime Total Physical Activity Questionnaire recorded prediagnosis (assessed at a median of 4.4 months after diagnosis) and postdiagnosis physical activity (assessed at a median of 3.4 years after diagnosis). Associations between physical activity and overall and disease-free survival were assessed using Cox proportional hazards models adjusted for age, stage, grade, treatments, body mass index, menopausal status, hormone therapy use, family history of cancer, and comorbidities.

RESULTS

After a median follow-up of 14.5 years, there were 60 deaths, including 18 endometrial cancer deaths, and 80 disease-free survival events. Higher prediagnosis recreational physical activity was statistically significantly associated with improved disease-free survival (> 14 v ≤ 8 MET-hours/week/year; hazard ratio [HR], 0.54; 95% CI, 0.30 to 0.96; P_trend = .04), but not overall survival (HR, 0.56; 95% CI, 0.29 to 1.07; P_trend = .06). Higher postdiagnosis recreational physical activity (> 13 v ≤ 5 MET-hours/week/year) was strongly associated with both improved disease-free survival (HR, 0.33; 95% CI, 0.17 to 0.64; P_trend = .001) and overall survival (HR, 0.33; 95% CI, 0.15 to 0.75; P_trend = .007). Participants who maintained high recreational physical activity levels from pre- to postdiagnosis also had improved disease-free survival (HR, 0.35; 95% CI, 0.18 to 0.69) and overall survival (HR, 0.43; 95% CI, 0.20 to 0.94) compared with those who maintained low physical activity levels.

CONCLUSION

Recreational physical activity, especially postdiagnosis, is associated with improved survival in survivors of endometrial cancer.

Associations of body mass index, weight change, physical activity and sedentary behavior with endometrial cancer risk among Japanese women: The Japan Collaborative Cohort Study

BACKGROUND

The impact of weight change, physical activity, and sedentary behavior on endometrial cancer risk among the Asian population is uncertain. We investigated the association of those factors with endometrial cancer risk among Japanese women with a low body mass index level.

METHODS

We performed a large-scale nationwide cohort study consisting of 33,801 female participants aged 40-79 years. The Cox proportional hazards model was used to calculate the hazard ratios (HRs) and 95% confidence intervals (CIs) of incident endometrial cancer.

RESULTS

The mean body mass index of participants was 22.8 kg/m². During a median follow-up of 14.8 years, 79 participants developed endometrial cancer. After adjustment for potential confounding factors, body mass index over 23.0 kg/m² was linearly associated with the risk of endometrial cancer. The HR (95%CI) per 5 kg/m² increase was 1.80(1.28-2.54). Weight increment ≥+5 kg since age 20 was associated with an increased risk of endometrial cancer compared to a weight change of -5 to <+5 kg (the multivariable HR (95% CI) was 1.96(1.12-3.40)). Compared with females who were mainly sitting at the worksite, those who were mainly standing and moving were at lower risk; the multivariable HRs (95% CIs) were 0.79(0.39-1.59) and 0.46(0.22-0.97), respectively, p for trend= 0.042. Hours of physical exercise, daily walking, and TV viewing were not associated with endometrial cancer risk.

CONCLUSIONS

Overweight and weight gain were positively associated with the risk of endometrial cancer, while worksite physical activity was inversely associated with the risk.

Influence of physical activity at a young age and lifetime physical activity on the risks of 3 obesity-related cancers: systematic review and meta-analysis of observational studies

CONTEXT

Excess weight has been linked to increased risks of 13 types of cancers. Physical activity is a non-nutritional modifiable lifestyle factor that is not only crucial for weight control but is also known to regulate hormones and metabolic pathways that may contribute to carcinogenesis. There is solid evidence that being physically active during middle and late adulthood lowers the risks of 3 obesity-related cancers, namely breast cancer, colon cancer, and endometrial cancer. However, the associations between physical activity at a young age (childhood, adolescence, and young adulthood; age 5 to ≤30 yr) and lifetime physical activity and the risks of breast cancer, colon cancer, and endometrial cancer are less defined.

OBJECTIVE

The present systematic review and meta-analysis of observational studies was performed in accordance with the MOOSE guidelines to determine whether physical activity at a young age and lifetime physical activity may lower the risks of breast cancer, colon cancer, and endometrial cancer.

DATA SOURCES

The PubMed and Web of Science databases were searched for relevant observational studies published from inception to July 2018.

STUDY SELECTION

Observational studies (prospective cohort, case-cohort, nested case-control, historical cohort, and case-control) were considered relevant if they investigated the association between physical activity at a young age or lifetime physical activity and the risks of developing selected cancers.

DATA EXTRACTION

A random-effects meta-analysis was performed to generate the summary relative risk (RR) with 95%CI for the highest vs the lowest category of physical activity of any type.

RESULTS

Eighty publications were included in the present meta-analysis. Higher physical activity at a young age was associated with lower risks of breast cancer (RR 0.81, 95%CI 0.76, 0.87) and colon cancer (RR 0.67, 95%CI 0.50, 0.88). Similarly, lifetime physical activity was inversely associated with the risks of breast cancer (RR 0.79, 95%CI 0.72, 0.86) and colon cancer (RR 0.75, 95%CI 0.69, 0.82). For breast cancer, menopausal status did not appear to modify the observed inverse association. The benefit with respect to endometrial cancer risk reduction was only observed with higher lifetime physical activity (RR 0.77, 95%CI 0.67, 0.88), not with higher physical activity at a young age (RR 0.89, 95%CI 0.73, 1.07).

CONCLUSIONS

Being physically active over a lifetime, starting from early childhood, may lower the risks of developing breast cancer, colon cancer, and endometrial cancer.

Physical Activity of ≥7.5 MET-h/Week Is Significantly Associated with a Decreased Risk of Cervical Neoplasia

Cervical cancer is one of the most prevalent malignant neoplasms worldwide. We investigated whether leisure-time physical activity is sufficient to decrease the cervical neoplasia risk and provide suggested guidance of metabolic equivalents of task–hours per week (MET-h/week) spent on leisure-time physical activity to prevent cervical neoplasia. Ultimately, 433 participants, including 126 participants with cervical intraepithelial neoplasia I or higher disease (≥CIN 1) and 307 healthy controls, were recruited. All participants completed a standardized questionnaire about leisure-time physical activity engagement (MET-h/week) and a general health questionnaire and had cervical specimens taken to detect human papillomavirus (HPV) infection. CIN 1 staging was identified from the specimens. Participants with physical activity of ≥3.75 MET-h/week had a significantly lower CIN risk compared to those with physical activity of <3.75 MET-h/week (p = 0.01). However, among participants with HPV infection or smokers, the minimal requirement of leisure-time physical actively to lessen the CIN risk was ≥7.5 MET-h/week. Lifetime leisure-time physical activity of ≥0.12 MET-h/week–year also significantly decreased the CIN risk, but women with HPV infection needed ≥13.2 MET-h/week–year to protect them from a CIN risk. We concluded that regular leisure-time physical activity of ≥7.5 MET-h/week and sustained lifetime leisure-time physical activity ≥13.2 MET-h/week–year are vital factors for protecting women against cervical neoplasia risk.

Prospective cohort study of metabolic syndrome and endometrial cancer survival

OBJECTIVE

Comorbidities are known to increase endometrial cancer risk, but the separate and combined impact of these risk factors on endometrial cancer survival remains unclear. This study aimed to determine the associations between metabolic syndrome and its components with disease-free survival, overall survival, endometrial cancer-specific survival and recurrence among endometrial cancer survivors.

METHODS

Cases from a population-based case-control study who were diagnosed with primary endometrial cancer between 2002 and 2006 in Alberta, Canada were followed until death or March 20, 2019. Baseline in-person interviews, direct anthropometric measurements and fasting blood samples were used to assess metabolic syndrome (presence of ≥3 of the following: waist circumference ≥ 88 cm, fasting blood glucose ≥100 mg/dL, triglycerides ≥150 mg/dL, high-density lipoprotein cholesterol <50 mg/dL and self-reported hypertension). Cox proportional hazards regression and Fine and Gray competing risk models were used to estimate multivariate-adjusted hazard ratios (95% CI) for these associations.

RESULTS

Among 540 endometrial cancer survivors, 325 had metabolic syndrome at diagnosis and 132 had a recurrence and/or died during the median 14.2 years of follow-up (range: 0.3-16.5 years). In multivariable analyses, being diagnosed with metabolic syndrome (HR = 1.98, 95% CI = 1.07-3.67) and having an elevated waist circumference (≥88 cm; HR = 2.12, 95% CI = 1.18-3.80; HR_{per 5 cm} = 1.21, 95% CI = 1.07-1.36) were associated with worse overall survival. Additionally, increasing waist circumference (per 5 cm) was also associated worse with disease-free survival (HR_{per 5 cm} = 1.11, 95% CI = 1.00-1.24).

CONCLUSION

The metabolic syndrome, in particular central adiposity, were associated with worse overall and disease-free survival in endometrial cancer survivors.

Case-control study of endogenous sex steroid hormones and risk of endometrial cancer

BACKGROUND

Epidemiologic evidence regarding the role of endogenous sex hormones in endometrial cancer etiology remains inconsistent. The objective of this study was to investigate if circulating levels of endogenous estrone, estradiol, sex hormone binding globulin (SHBG), testosterone, and androstenedione are associated with endometrial cancer risk.

METHODS

We conducted a population-based case-control study of 522 incident endometrial cancer cases and 976 population controls, in Alberta, Canada from 2002 to 2006. Study participants completed in-person interviews and provided fasting blood samples. Sex hormone levels were determined by enzyme-linked immunosorbent assays.

RESULTS

Higher levels of androstenedione were associated with increased endometrial cancer risk (OR 1.44, 95% CI 1.04-2.02). Endometrial cancer risk in pre- and peri-menopausal women was reduced for the highest versus lowest quartiles of estrone (OR 0.44, 95% CI 0.22-0.88) and estradiol (OR 0.30, 95% CI 0.14-0.65), but in post-menopausal women, the endometrial cancer risk was increased for the highest versus lowest quartile of androstenedione (OR 1.82, 95% CI 1.25-2.65). In addition, endometrial cancer risk in normal/underweight women was decreased for the highest versus lowest quartile of serum SHBG (OR 0.39, 95% CI 0.19-0.84).

CONCLUSIONS

Overall, positive associations were found for androstenedione concentrations, while sub-group analyses revealed = inverse associations with estrogens and SHBG. Results of this study provide empirical evidence for the role of circulating sex hormones in endometrial cancer etiology and highlight the importance of modifiable factors that contribute to changes in sex hormone concentration levels.

Lifetime Physical Activity and White Matter Hyperintensities in Cognitively Intact Adults

BACKGROUND

White matter hyperintensities (WMHs) observed on magnetic resonance images are associated with depression and increase the risk of stroke, dementia, and death. The association between physical activity and WMHs has been inconsistently reported in the literature, perhaps because studies did not account for a lifetime of physical activity or depression.

OBJECTIVES

The aim of this study was to determine the extent to which a lifetime of leisure-time physical activity is associated with less WMHs while accounting for depression.

METHODS

Face-to-face interviews were conducted with the Lifetime Total Physical Activity Questionnaire, where the metabolic equivalent of task hours per week per year was calculated. Cognitively intact participants also underwent magnetic resonance imaging, where WMHs as a percentage of intracranial volume was obtained. Hierarchical multiple linear regression was performed to compare WMHs in a more active group with a group with no psychiatric history (n = 20, mean age = 62.2 years), with a less active group with no psychiatric history (n = 13, mean age = 64.0 years), and a less active group with history of late-onset depression (n = 14, mean age = 62.8 years).

RESULTS

There was not a statistically significant difference in WMHlg10 between the more and less active groups without a psychiatric history (b = .09, p > .05) or between the more active group without a psychiatric history and the less active group with a history of depression (b = .01, p > .05). The model was predictive of WMHlg10, explaining an adjusted 15% of the variance in WMHs (p = .041).

DISCUSSION

A lifetime of leisure-time physical activity was not associated with WMHs when accounting for depression.

Risk factors for endometrial carcinoma among postmenopausal women in Sri Lanka: a case control study

Background

Endometrial carcinoma burden is on the rise globally. The objective of this study was to determine the risk factors for endometrial carcinoma among postmenopausal women in Western province in Sri Lanka.

Methods

A case control study was conducted recruiting 83 incident cases of endometrial carcinoma and 332 unmatched hospital controls from all the secondary and tertiary care hospitals in the province using consecutive sampling technique. A case was defined as a postmenopausal woman who had been residing in the province for at least a period of 1 year, diagnosed to have endometrial carcinoma with histological confirmation within 3 months of the initiation of data collection of the study. Data were collected using validated interviewer administered questionnaire. Risk factor were identified through multiple logistic regression and results were expressed as adjusted odds ratios (AOR) and 95% confidence intervals (CI).

Results

The independent risk factors of endometrial carcinoma are having family history of any type of cancer among first degree relative (AOR = 12.6; 95% CI:5.14–30.9), generalized obesity (BMI ≥25 kg/m²) (AOR = 11.85; 95% CI:5.12–27.4), never conceived (AOR = 3.84; 95% CI:1.37–10.7), age at menarche ≤11 years (AOR = 4.07; 95% CI:1.16–14.2), age > 55 years (AOR = 4.69; 95% CI:2.16–10.2), monthly family income of ≤20,000 Rupees (AOR = 2.65; 95% CI:1.31–5.39), sub-optimal consumption of deep fried food (AOR = 0.17; 95% CI:0.06–0.46), and low level household activities (AOR = 2.82; 95% CI:1.34–5.92).

Conclusions

There were eight independent risk factors of endometrial carcinoma specific for Sri Lankan postmenopausal women identified. Some modifiable risk factors such as generalized obesity, sub-optimal dietary practices and low level physical activities need to be addressed at primary prevention level.

Adverse Effects of Prolonged Sitting Behavior on the General Health of Office Workers

BACKGROUND

Excessive sitting behavior is a risk factor for many adverse health outcomes. This study aimed to survey the prevalence of sitting behavior and its adverse effects among Iranian office workers.

METHODS

This cross-sectional study included 447 Iranian office workers. A two-part questionnaire was used as the data collection tool. The first part surveyed the demographic characteristics and general health of the respondents, while the second part contained the Nordic Musculoskeletal Questionnaire (NMQ) to assess symptoms. Statistical analyses were performed using the Statistical Package for the Social Sciences software using Mann-Whitney U and Chi-square tests and multiple logistic regression analysis.

RESULTS

The respondents spent an average of 6.29 hours of an 8-hour working shift in a sitting position. The results showed that 48.8% of the participants did not feel comfortable with their workstations and 73.6% felt exhausted during the workday. Additionally, 6.3% suffered from hypertension, and 11.2% of them reported hyperlipidemia. The results of the NMQ showed that neck (53.5%), lower back (53.2%) and shoulder (51.6%) symptoms were the most prevalent problem among office workers. Based upon a multiple logistic regression, only sex had a significant association with prolonged sitting behavior (odds ratio = 3.084). Our results indicated that long sitting times were associated with exhaustion during the working day, decreased job satisfaction, hypertension, and musculoskeletal disorder symptoms in the shoulders, lower back, thighs, and knees of office workers.

CONCLUSION

Sitting behavior had adverse effects on office workers. Active workstations are therefore recommended to improve working conditions.

Breastfeeding and Endometrial Cancer Risk: An Analysis From the Epidemiology of Endometrial Cancer Consortium

OBJECTIVE

To investigate the association between breastfeeding and endometrial cancer risk using pooled data from 17 studies participating in the Epidemiology of Endometrial Cancer Consortium.

METHODS

We conducted a meta-analysis with individual-level data from three cohort and 14 case-control studies. Study-specific odds ratios (ORs) and 95% confidence intervals (CIs) were estimated for the association between breastfeeding and risk of endometrial cancer using multivariable logistic regression and pooled using random-effects meta-analysis. We investigated between-study heterogeneity with I  and Q statistics and metaregression.

RESULTS

After excluding nulliparous women, the analyses included 8,981 women with endometrial cancer and 17,241 women in a control group. Ever breastfeeding was associated with an 11% reduction in risk of endometrial cancer (pooled OR 0.89, 95% CI 0.81-0.98). Longer average duration of breastfeeding per child was associated with lower risk of endometrial cancer, although there appeared to be some leveling of this effect beyond 6-9 months. The association with ever breastfeeding was not explained by greater parity and did not vary notably by body mass index or histologic subtype (grouped as endometrioid and mucinous compared with serous and clear cell).

CONCLUSION

Our findings suggest that reducing endometrial cancer risk can be added to the list of maternal benefits associated with breastfeeding. Ongoing promotion, support, and facilitation of this safe and beneficial behavior might therefore contribute to the prevention of this increasingly common cancer.

Odds ratio analysis in women with endometrial cancer

Introduction

Despite the progress in diagnosis and treatment of malignant tumours, the effects of treatment are insufficient. Reduction of the risk of cervical, ovarian, and endometrial cancer is possible by introducing preventative actions.

Aim of the study

The aim of the thesis is the analysis of selected risk factors that may affect the increase or decrease in the odds ratio of developing endometrial cancer.

Material and methods

The study was conducted among patients of the Gynaecology and Obstetrics Hospital of Poznań University of Medical Sciences in the years 2011-2013.

The research included a total of 548 female respondents aged between 40 and 84 years. Women responded to questions assessing elements of lifestyle such as consumption of alcohol, smoking, and eating certain groups of foods.

Results

The respondents consuming fruits and vegetables several times a week have a reduced risk of odds ratio and the OR is 0.85; 95% CI: 0.18-4.09, compared to the women who rarely consume vegetables and fruits. Consumption of whole-wheat bread several times a week reduces the risk of developing the cancer, OR = 0.59; 95% CI: 0.14-2.47, compared to women not consuming wholegrain bread at all. Respondents who consumed red meat, such as veal, pork, and lamb in the amount of 101-200 g per day have an increased risk of developing the disease: OR = 2.16; 95% CI: 1.09-4.28, compared to women not consuming red meat at all.

Conclusions

A diet rich in fruit and vegetables, onions, garlic, whole grains, and beans should be introduced in order to reduce the risk of endometrial cancer. The consumption of red meat and white pasta should be reduced or even eliminated.

Cancer Prevention: Obstacles, Challenges and the Road Ahead

Approaches to reduce the global burden of cancer include two major strategies: screening and early detection and active preventive intervention. The latter is the topic of this Commentary and spans a broad range of activities. The genetic heterogeneity and complexity of advanced cancers strongly support the rationale for early interruption of the carcinogenic process and an enhanced focus on prevention as a priority strategy to reduce the burden of cancer; however, the focus of cancer prevention management should be on individuals at high risk and on primary localized disease in which screening and detection should also play a vital role. The timing and dose of (chemo-)preventive intervention also affects response. The intervention may be ineffective if the target population is very high risk or already presenting with preneoplastic lesions with cellular changes that cannot be reversed. The field needs to move beyond general concepts of carcinogenesis to targeted organ site prevention approaches in patients at high risk, as is currently being done for breast and colorectal cancers. Establishing the benefit of new cancer preventive interventions will take years and possibly decades, depending on the outcome being evaluated. We also propose that comparative effectiveness research designs and the value of information obtained from large-scale prevention studies are necessary in order for preventive interventions to become a routine part of cancer management.

Body Mass Index Genetic Risk Score and Endometrial Cancer Risk

Genome-wide association studies (GWAS) have identified common variants that predispose individuals to a higher body mass index (BMI), an independent risk factor for endometrial cancer. Composite genotype risk scores (GRS) based on the joint effect of published BMI risk loci were used to explore whether endometrial cancer shares a genetic background with obesity. Genotype and risk factor data were available on 3,376 endometrial cancer case and 3,867 control participants of European ancestry from the Epidemiology of Endometrial Cancer Consortium GWAS. A BMI GRS was calculated by summing the number of BMI risk alleles at 97 independent loci. For exploratory analyses, additional GRSs were based on subsets of risk loci within putative etiologic BMI pathways. The BMI GRS was statistically significantly associated with endometrial cancer risk (P = 0.002). For every 10 BMI risk alleles a woman had a 13% increased endometrial cancer risk (95% CI: 4%, 22%). However, after adjusting for BMI, the BMI GRS was no longer associated with risk (per 10 BMI risk alleles OR = 0.99, 95% CI: 0.91, 1.07; P = 0.78). Heterogeneity by BMI did not reach statistical significance (P = 0.06), and no effect modification was noted by age, GWAS Stage, study design or between studies (P≥0.58). In exploratory analyses, the GRS defined by variants at loci containing monogenic obesity syndrome genes was associated with reduced endometrial cancer risk independent of BMI (per BMI risk allele OR = 0.92, 95% CI: 0.88, 0.96; P = 2.1 x 10⁻⁵). Possessing a large number of BMI risk alleles does not increase endometrial cancer risk above that conferred by excess body weight among women of European descent. Thus, the GRS based on all current established BMI loci does not provide added value independent of BMI. Future studies are required to validate the unexpected observed relation between monogenic obesity syndrome genetic variants and endometrial cancer risk.

The Breast Cancer to Bone (B2B) Metastases Research Program: a multi-disciplinary investigation of bone metastases from breast cancer

Background

Bone is the most common site of breast cancer distant metastasis, affecting 50–70 % of patients who develop metastatic disease. Despite decades of informative research, the effective prevention, prediction and treatment of these lesions remains elusive. The Breast Cancer to Bone (B2B) Metastases Research Program consists of a prospective cohort of incident breast cancer patients and four sub-projects that are investigating priority areas in breast cancer bone metastases. These include the impact of lifestyle factors and inflammation on risk of bone metastases, the gene expression features of the primary tumour, the potential role for metabolomics in early detection of bone metastatic disease and the signalling pathways that drive the metastatic lesions in the bone.

Methods/Design

The B2B Research Program is enrolling a prospective cohort of 600 newly diagnosed, incident, stage I-IIIc breast cancer survivors in Alberta, Canada over a five year period. At baseline, pre-treatment/surgery blood samples are collected and detailed epidemiologic data is collected by in-person interview and self-administered questionnaires. Additional self-administered questionnaires and blood samples are completed at specified follow-up intervals (24, 48 and 72 months). Vital status is obtained prior to each follow-up through record linkages with the Alberta Cancer Registry. Recurrences are identified through medical chart abstractions. Each of the four projects applies specific methods and analyses to assess the impact of serum vitamin D and cytokine concentrations, tumour transcript and protein expression, serum metabolomic profiles and in vitro cell signalling on breast cancer bone metastases.

Discussion

The B2B Research Program will address key issues in breast cancer bone metastases including the association between lifestyle factors (particularly a comprehensive assessment of vitamin D status) inflammation and bone metastases, the significance or primary tumour gene expression in tissue tropism, the potential of metabolomic profiles for risk assessment and early detection and the signalling pathways controlling the metastatic tumour microenvironment. There is substantial synergy between the four projects and it is hoped that this integrated program of research will advance our understanding of key aspects of bone metastases from breast cancer to improve the prevention, prediction, detection, and treatment of these lesions.

A systematic review and meta-analysis of physical activity and endometrial cancer risk

Physical activity is related to decreased endometrial cancer risk. However, a comprehensive investigation of activity domains, intensities, time periods in life, and potential interaction with body mass index is unavailable. We performed a meta-analysis of physical activity and endometrial cancer studies published through October 2014. We identified 33 eligible studies comprising 19,558 endometrial cancer cases. High versus low physical activity was related to reduced endometrial cancer risk [relative risk (RR) = 0.80; 95% confidence interval (CI) 0.75-0.85]. The corresponding RRs for recreational activity, occupational activity, household activity, and walking were 0.84 (95% CI 0.78-0.91), 0.81 (95% CI 0.75-0.87), 0.70 (95% CI 0.47-1.02), and 0.82 (95% CI 0.69-0.97), respectively (Pdifference). Walking/biking for transportation, walking for recreation, and walking without specification revealed summary RRs of 0.70 (95% CI 0.58-0.85), 0.94 (95% CI 0.76-1.17), and 0.88 (95% CI 0.52-1.50), respectively (Pdifference). Inverse associations were noted for light (RR 0.65; 95% CI 0.49-0.86), moderate to vigorous (RR 0.83; 95 % CI 0.71-0.96), and vigorous activity (RR 0.80; 95% CI 0.72-0.90; (Pdifference). A statistically significant inverse relation was found for postmenopausal (RR 0.81; 95% CI 0.67-0.97), but not premenopausal women (RR 0.74; 95% CI 0.49-1.13; (Pdifference). Physical activity performed during childhood/adolescence, young adulthood/midlife, and older age yielded RRs of 0.94 (95% CI 0.82-1.08), 0.77 (95% CI 0.58-1.01), and 0.69 (95% CI 0.37-1.28), respectively (Pdifference). An inverse relation was evident in overweight/obese (RR 0.69; 95% CI 0.52-0.91), but not normal weight women (RR 0.97; 95% CI 0.84-1.13; (Pdifference). In conclusion, recreational physical activity, occupational physical activity, and walking/biking for transportation are related to decreased endometrial cancer risk. Inverse associations are evident for physical activity of light, moderate to vigorous, and vigorous intensities. The inverse relation with physical activity is limited to women who are overweight or obese.

Intrauterine devices and endometrial cancer risk: a pooled analysis of the Epidemiology of Endometrial Cancer Consortium

Intrauterine devices (IUDs), long-acting and reversible contraceptives, induce a number of immunological and biochemical changes in the uterine environment that could affect endometrial cancer (EC) risk. We addressed this relationship through a pooled analysis of data collected in the Epidemiology of Endometrial Cancer Consortium. We combined individual-level data from 4 cohort and 14 case-control studies, in total 8,801 EC cases and 15,357 controls. Using multivariable logistic regression, we estimated pooled odds ratios (pooled-ORs) and 95% confidence intervals (CIs) for EC risk associated with ever use, type of device, ages at first and last use, duration of use and time since last use, stratified by study and adjusted for confounders. Ever use of IUDs was inversely related to EC risk (pooled-OR = 0.81, 95% CI = 0.74-0.90). Compared with never use, reduced risk of EC was observed for inert IUDs (pooled-OR = 0.69, 95% CI = 0.58-0.82), older age at first use (≥ 35 years pooled-OR = 0.53, 95% CI = 0.43-0.67), older age at last use (≥ 45 years pooled-OR = 0.60, 95% CI = 0.50-0.72), longer duration of use (≥ 10 years pooled-OR = 0.61, 95% CI = 0.52-0.71) and recent use (within 1 year of study entry pooled-OR = 0.39, 95% CI = 0.30-0.49). Future studies are needed to assess the respective roles of detection biases and biologic effects related to foreign body responses in the endometrium, heavier bleeding (and increased clearance of carcinogenic cells) and localized hormonal changes.

Television viewing and time spent sedentary in relation to cancer risk: a meta-analysis

BACKGROUND

Sedentary behavior is emerging as an independent risk factor for chronic disease and mortality. However, the evidence relating television (TV) viewing and other sedentary behaviors to cancer risk has not been quantitatively summarized.

METHODS

We performed a comprehensive electronic literature search in Cochrane, EMBASE, Medline, and SciSearch databases through February 2014 for published articles investigating sedentary behavior in relation to cancer incidence. Because randomized controlled trials are difficult to perform on this topic, we focused on observational studies that met uniform inclusion criteria. Data were extracted independently by both authors and summarized using random-effects meta-analysis and meta-regression. All statistical tests were two-sided.

RESULTS

Data from 43 observational studies including a total of 68936 cancer cases were analyzed. Comparing the highest vs lowest levels of sedentary time, the relative risks (RRs) for colon cancer were 1.54 (95% confidence interval [CI] = 1.19 to 1.98) for TV viewing time, 1.24 (95% CI = 1.09 to 1.41) for occupational sitting time, and 1.24 (95% CI = 1.03 to 1.50) for total sitting time. For endometrial cancer, the relative risks were 1.66 (95% CI = 1.21 to 2.28) for TV viewing time and 1.32 (95% CI = 1.08 to 1.61) for total sitting time. A positive association with overall sedentary behavior was also noted for lung cancer (RR = 1.21; 95% CI = 1.03 to 1.43). Sedentary behavior was unrelated to cancers of the breast, rectum, ovaries, prostate, stomach, esophagus, testes, renal cell, and non-Hodgkin lymphoma.

CONCLUSIONS

Prolonged TV viewing and time spent in other sedentary pursuits is associated with increased risks of certain types of cancer.

Exome-wide association study of endometrial cancer in a multiethnic population

Endometrial cancer (EC) contributes substantially to total burden of cancer morbidity and mortality in the United States. Family history is a known risk factor for EC, thus genetic factors may play a role in EC pathogenesis. Three previous genome-wide association studies (GWAS) have found only one locus associated with EC, suggesting that common variants with large effects may not contribute greatly to EC risk. Alternatively, we hypothesize that rare variants may contribute to EC risk. We conducted an exome-wide association study (EXWAS) of EC using the Infinium HumanExome BeadChip in order to identify rare variants associated with EC risk. We successfully genotyped 177,139 variants in a multiethnic population of 1,055 cases and 1,778 controls from four studies that were part of the Epidemiology of Endometrial Cancer Consortium (E2C2). No variants reached global significance in the study, suggesting that more power is needed to detect modest associations between rare genetic variants and risk of EC.

Are sitting occupations associated with increased all-cause, cancer, and cardiovascular disease mortality risk? A pooled analysis of seven British population cohorts

Background

There is mounting evidence for associations between sedentary behaviours and adverse health outcomes, although the data on occupational sitting and mortality risk remain equivocal. The aim of this study was to determine the association between occupational sitting and cardiovascular, cancer and all-cause mortality in a pooled sample of seven British general population cohorts.

Methods

The sample comprised 5380 women and 5788 men in employment who were drawn from five Health Survey for England and two Scottish Health Survey cohorts. Participants were classified as reporting standing, walking or sitting in their work time and followed up over 12.9 years for mortality. Data were modelled using Cox proportional hazard regression adjusted for age, waist circumference, self-reported general health, frequency of alcohol intake, cigarette smoking, non-occupational physical activity, prevalent cardiovascular disease and cancer at baseline, psychological health, social class, and education.

Results

In total there were 754 all-cause deaths. In women, a standing/walking occupation was associated with lower risk of all-cause (fully adjusted hazard ratio [HR] = 0.68, 95% CI 0.52–0.89) and cancer (HR = 0.60, 95% CI 0.43–0.85) mortality, compared to sitting occupations. There were no associations in men. In analyses with combined occupational type and leisure-time physical activity, the risk of all-cause mortality was lowest in participants with non-sitting occupations and high leisure-time activity.

Conclusions

Sitting occupations are linked to increased risk for all-cause and cancer mortality in women only, but no such associations exist for cardiovascular mortality in men or women.

Case-control study of lifetime alcohol consumption and endometrial cancer risk

Purpose

Alcohol consumption is hypothesized to increase the risk of endometrial cancer by increasing circulating estrogen levels. This study sought to investigate the association between lifetime alcohol consumption and endometrial cancer risk.

Methods

We recruited 514 incident endometrial cancer cases and 962 frequency age-matched controls in this population-based case–control study in Alberta, Canada, from 2002 to 2006. Participants completed in-person interviews querying lifetime alcohol consumption and other relevant health and lifestyle factors. Participants reported the usual number of drinks of beer, wine, and liquor consumed; this information was compiled for each drinking pattern reported over the lifetime to estimate average lifetime exposure to alcohol.

Results

Lifetime average alcohol consumption was relatively low (median intake: 3.9 g/day for cases, 4.9 g/day for controls). Compared with lifetime abstainers, women consuming >2.68 and ≤8.04 g/day alcohol and >8.04 g/day alcohol on average over the lifetime showed 38 and 35 % lower risks of endometrial cancer, respectively (p trend = 0.023). In addition, average lifetime consumption of all types of alcohol was associated with decreased risks. There was no evidence for effect modification by body mass index, physical activity, menopausal status, and hormone replacement therapy use combined and effects did not differ by type of endometrial cancer (type I or II).

Conclusion

This study provides epidemiologic evidence for an inverse association between relatively modest lifetime average alcohol consumption (approximately 1/4 to 1/2 drink/day) and endometrial cancer risk. The direction of this relation is consistent with previous studies that examined similar levels of alcohol intake.

Endometrial cancer and a family history of cancer

OBJECTIVE

Lynch Syndrome (LS), an inherited genetic syndrome, predisposes to cancers such as colorectal and endometrial. However, the risk for endometrial cancer (EC) in women not affected by LS, but with a family history of cancer, is currently unknown. We examined the association between a family history of cancer and the risk for EC in non-LS patients.

METHODS

This population-based case-control study included 519 EC cases and 1015 age-matched controls and took place in Alberta, Canada between 2002 and 2006. Information about risk factors, including family history of cancer in first and second degree relatives, was ascertained via in-person interviews. Microsatellite instability (MSI) status of tumor tissue was assessed to determine involvement of DNA mismatch repair (MMR) genes.

RESULTS

A first or second degree family history of uterine cancer was modestly associated with the risk for overall EC [odds ratio (OR), 1.3; 95% confidence interval (CI), 0.9, 1.9], and the risks were similar for MSI+cancer (OR=1.5, 95%CI=0.7, 3.3) and MSI- cancer (OR=1.3, 95%CI=0.8, 2.4). Although consistent, these associations were modest and not significant. In contrast, the risk for MSI+cancer was elevated with a reported family history of colorectal cancer (OR=1.4, 95%CI=1.0, 2.2), but not for MSI- cancer.

CONCLUSIONS

A family history of uterine cancer may be modestly associated with EC risk in non-LS patients regardless of MSI status, suggesting that risk was not related to inherited defects in the MMR gene pathway. These results provide preliminary support for an EC-specific genetic syndrome.

Invited commentary: are dietary intakes and other exposures in childhood and adolescence important for adult cancers?

In this issue of the Journal, Nimptsch et al. (Am J Epidemiol. 2013;178(2):172-183) report significant associations between female adolescents' poultry consumption in high school and subsequent reduced risk of colorectal adenomas in adulthood. Consumption of red meat or fish was not related to risk, but replacement with poultry reduced the risk of later adenomas. Most epidemiologic studies of adult diseases lack exposure data from the distant past. By focusing on a cancer precursor lesion and using a variety of methods to assess data quality, the investigators address concerns about the quality of distant recall. These findings add to the growing evidence that links childhood and adolescent lifestyle and environmental exposures with subsequent risk of cancers arising in adulthood. Highlights of the literature on this topic and methodological challenges are summarized. Future studies would benefit from incorporating measures of lifestyle, diet, environmental exposures, and other risk factors from early in life and from validation and other data quality checks of such measurements. Sources of historical data on children's and adolescents' exposures should be sought and evaluated in conjunction with subsequent exposures in relationship to adult-onset cancers.

Contemporary clinical management of endometrial cancer

Although the contemporary management of endometrial cancer is straightforward in many ways, novel data has emerged over the past decade that has altered the clinical standards of care while generating new controversies that will require further investigation. Fortunately most cases are diagnosed at early stages, but high-risk histologies and poorly differentiated tumors have high metastatic potential with a significantly worse prognosis. Initial management typically requires surgery, but the role and extent of lymphadenectomy are debated especially with well-differentiated tumors. With the changes in surgical staging, prognosis correlates more closely with stage, and the importance of cytology has been questioned and is under evaluation. The roles of radiation in intermediate-risk patients and chemotherapy in high-risk patients are emerging. The therapeutic index of brachytherapy needs to be considered, and the best sequencing of combined modalities needs to balance efficacy and toxicities. Additionally novel targeted therapies show promise, and further studies are needed to determine the appropriate use of these new agents. Management of endometrial cancer will continue to evolve as clinical trials continue to answer unsolved clinical questions.

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.

Hormonal and reproductive risk factors for sporadic microsatellite stable and unstable endometrial tumors

Hormonal and reproductive factors modulate bioavailable estrogen to influence endometrial cancer risk. Estrogen affects the microsatellite status of tumors, but the relation between these estrogen-related factors and microsatellite instability (MSI) status of endometrial tumors is not known. We evaluated associations between hormonal and reproductive factors and risks of microsatellite stable (MSS) and MSI endometrial cancer among postmenopausal women (MSS cases = 258, MSI cases = 103, and controls = 742) in a population-based case-control study in Alberta, Canada (2002-2006). Polytomous logistic regression was used to estimate ORs and 95% confidence intervals (95% CI). We observed a significant trend in risk reduction for MSI (Ptrend = 0.005) but not MSS (Ptrend = 0.23) cancer with oral contraceptive use; with 5-year use or more, the risk reduction was stronger for MSI (OR = 0.42; 95% CI, 0.23-0.77) than for MSS cancer (OR = 0.80; 95% CI, 0.54-1.17; Pheterogeneity = 0.05). For more recent use (<30 years), the risk reduction was stronger for MSI (OR = 0.36; 95% CI, 0.19-0.69) than for MSS cancer (OR = 0.77; 95% CI, 0.51-1.15; Pheterogeneity = 0.032). No differential risk associations were observed for menopausal hormone use, parity and age at menarche, menopause or first pregnancy. We found limited evidence for statistical heterogeneity of associations of endometrial cancer risk with hormonal and reproductive factors by MSI status, except with oral contraceptive use. This finding suggests a potential role for the MMR system in the reduction of endometrial cancer risk associated with oral contraceptive use, although the exact mechanism is unclear. This study shows for the first time that oral contraceptive use is associated with a reduced risk for MSI but not for MSS endometrial cancer.

Metformin and the risk of endometrial cancer: a case-control analysis

OBJECTIVE

To explore the risk of endometrial cancer in relation to metformin and other antidiabetic drugs.

METHODS

We conducted a case-control analysis to explore the association between use of metformin and other antidiabetic drugs and the risk of endometrial cancer using the UK-based General Practice Research Database (GPRD). Cases were women with an incident diagnosis of endometrial cancer, and up to 6 controls per case were matched in age, sex, calendar time, general practice, and number of years of active history in the GPRD prior to the index date. Odds ratios (ORs) with 95% confidence intervals (95% CI) were calculated and results were adjusted by multivariate logistic regression analyses for BMI, smoking, a recorded diagnosis of diabetes mellitus, and diabetes duration.

RESULTS

A total of 2554 cases with incident endometrial cancer and 15,324 matched controls were identified. Ever use of metformin compared to never use of metformin was not associated with an altered risk of endometrial cancer (adj. OR 0.86, 95% CI 0.63-1.18). Stratified by exposure duration, neither long-term (≥25 prescriptions) use of metformin (adj. OR 0.79, 95% CI 0.54-1.17), nor long-term use of sulfonylureas (adj. OR 0.96, 95% CI 0.65-1.44), thiazolidinediones (≥15 prescriptions; adj. OR 1.22, 95% CI 0.67-2.21), or insulin (adj. OR 1.05 (0.79-1.82) was associated with the risk of endometrial cancer.

CONCLUSION

Use of metformin and other antidiabetic drugs were not associated with an altered risk of endometrial cancer.

Case-control study of markers of insulin resistance and endometrial cancer risk

Markers of insulin resistance such as the adiponectin:leptin ratio (A:L) and the homeostasis model assessment ratio (HOMA-IR) are associated with obesity and hyperinsulinemia, both established risk factors for endometrial cancer, and may therefore be informative regarding endometrial cancer risk. This study investigated the association between endometrial cancer risk and markers of insulin resistance, namely adiponectin, leptin, the A:L ratio, insulin, fasting glucose, and the HOMA-IR. We analyzed data from 541 incident endometrial cancer cases and 961 frequency age-matched controls in a population-based case-control study in Alberta, Canada from 2002 to 2006. Participants completed interview-administered questionnaires were assessed for anthropometric measures, and provided 8-h fasting blood samples either pre- or postoperatively. Blood was analyzed for concentrations of leptin, adiponectin, and insulin by immunoassay, and fasting plasma glucose levels were determined by fluorimetric quantitative determination. Compared with the lowest quartile, the highest quartile of insulin and HOMA-IR was associated with 64% (95% confidence intervals (CI): 1.12-2.40) and 72% (95% CI: 1.17-2.53) increased risks of endometrial cancer, respectively, and the highest quartile of adiponectin was associated with a 45% (95% CI: 0.37-0.80) decreased risk after multivariable adjustments. Null associations were observed between fasting glucose, leptin and A:L, and endometrial cancer risk. This population-based study provides evidence for a role of insulin resistance in endometrial cancer etiology and may provide one possible pathway whereby obesity increases the risk of this common cancer. Interventions aimed at decreasing both obesity and insulin resistance may decrease endometrial cancer risk.

Epidemiology of pancreatic cancer and the role of family history

Pancreatic cancer is a lethal disease for which only a small number of risk factors have been identified. In addition to older age, male gender, and black race, risk factors include smoking, obesity, long-standing diabetes and pancreatitis, and heavy alcohol use; allergies such as hay fever are related to lowered risk. Several genetic syndromes increase risk of pancreatic cancer. Work on more common genetic variants promises to reveal more potentially important genetic associations.

The epidemiology of endometrial and ovarian cancer

This review highlights similarities in the epidemiology of endometrial and ovarian cancer, including highly correlated incidence rates and similar risk factor profiles. Factors that decrease risk for both cancers include a late menarche, early age at first birth, giving birth and breastfeeding, and use of oral contraceptives. Short or irregular cycles and late menopause are associated with increased risk for both. Other risk factors that appear to operate in a similar direction include decreased risk associated with IUD use or a tubal ligation, and increased risk associated with obesity, lack of exercise, and use of talc powders in genital hygiene. Estrogen excess is proposed as the underlying mechanism for most endometrial cancers, whereas incessant ovulation has been suggested as the explanation for ovarian cancer. However, an increased number of estimated ovulatory cycles correlates directly with risk for both endometrial and ovarian cancer, suggesting that reproductive tissue turnover with an accumulation of PTEN or p53 mutations represents a possible common mechanism. An immune-based explanation involving mucin proteins represents another common mechanism that could explain additional risk factors. Maintenance of ideal weight, breastfeeding children, use of oral contraceptives, and avoidance of talc powders in genital hygiene are measures that could lower the risk for both types of cancer. Careful selection of patients for prophylactic oophorectomy for those women who are coming to hysterectomy for benign disease is an additional measure to consider for ovarian cancer.

Case-control study of the metabolic syndrome and metabolic risk factors for endometrial cancer

BACKGROUND

Metabolic syndrome may predict endometrial cancer risk better than diabetes, hypertension, dyslipidemia, dysglycemia, or weight alone, but few studies have examined this issue.

METHODS

We conducted a population-based case-control study in Alberta, Canada (2002-2006) that included 515 incident endometrial cancer cases and 962 frequency age-matched controls. Data were collected through in-person interviews, anthropometric measurements, and 8-hour fasting bloods drawn either pre- or postsurgery. Bloods were analyzed using quantitative colorimetric or absorbance-based assays (ELISA), specific to metabolic syndrome markers. Metabolic syndrome was defined using harmonized guidelines requiring presence of ≥ 3 of the following risk factors: waist circumference ≥ 88 cm, triglycerides ≥ 150 mg/dL, high-density lipoprotein cholesterol <50 mg/dL, treatment of previously diagnosed hypertension, and fasting blood glucose ≥ 100 mg/dL. OR and 95% CIs for endometrial cancer risk with presence of metabolic syndrome and individual metabolic syndrome components were estimated using logistic regression analysis.

RESULTS

Metabolic syndrome was significantly more prevalent among cases (62%) than controls (38%). A statistically significant increased risk for endometrial cancer was observed for metabolic syndrome (OR = 1.53; 95% CI: 1.17-2.00), as well as for some of the individual components of metabolic syndrome including waist circumference ≥ 88 cm (OR = 1.57; 95% CI: 1.18-2.08), hypertension (OR = 1.57; 95% CI: 1.18-2.09), and fasting blood glucose ≥ 100 mg/dL (OR = 1.31; 95% CI: 1.03-1.67). Some evidence for effect modification by menopausal status and body mass index was also found.

CONCLUSION

Metabolic syndrome is clearly associated with increased endometrial cancer risk.

IMPACT

Targeting the entire metabolic syndrome may optimize endometrial cancer risk reduction.

Risk of endometrial cancer in relation to individual nutrients from diet and supplements

OBJECTIVE

Intake of nutrients may influence the risk of endometrial cancer (EC). We aimed to estimate the association of intake of individual nutrients from food and from food plus supplements with EC occurrence.

DESIGN

A population-based case-control study conducted in Canada (2002-2006).

SETTING

Nutrient intakes from food and supplements were assessed using an FFQ. Logistic regression was used to estimate EC risk within quartile levels of nutrient intakes.

SUBJECTS

Incident EC cases (n 506) were identified from the Alberta Cancer Registry, and population controls were frequency- and age-matched to cases (n 981).

RESULTS

There existed little evidence of an association with EC for the majority of macronutrients and micronutrients examined. We observed a statistically significant increased risk associated with the highest, compared with the lowest, quartile of intake of dietary cholesterol (multivariable-adjusted OR = 1·51, 95 % CI 1·08, 2·11; P for trend = 0·02). Age-adjusted risk at the highest level of intake was significantly reduced for Ca from food sources (OR = 0·73, 95 % CI 0·54, 0·99) but was attenuated in the multivariable model (OR = 0·82, 95 % CI 0·59, 1·13). When intake from supplements was included in Ca intake, risk was significantly reduced by 28 % with higher Ca (multivariable-adjusted OR = 0·72, 95 % CI 0·51, 0·99, P for trend = 0·04). We also observed unexpected increased risks at limited levels of intakes of dietary soluble fibre, vitamin C, thiamin, vitamin B6 and lutein/zeaxanthin, with no evidence for linear trend.

CONCLUSIONS

The results of our study suggest a positive association between dietary cholesterol and EC risk and an inverse association with Ca intake from food sources and from food plus supplements.

Case-control study of dietary patterns and endometrial cancer risk

Dietary patterns, rather than intakes of specific foods or nutrients, may influence risk of endometrial cancer (EC). This population-based case-control study in Canada (2002-2006) included incident EC cases (n = 506) from the Alberta Cancer Registry and controls frequency age-matched to cases (n = 981). Past-year dietary patterns were defined using factor analysis of food frequency questionnaire data. Logistic regression was used to estimate EC risk within quartiles of dietary patterns. Three patterns (sweets, meat, plants) explained 23% of the variance in the dietary data. In multivariable models, EC risk was significantly reduced by 30% for women in the highest quartile of the healthier plants pattern (OR = 0.70, 95% CI 0.50-0.98, P trend = 0.02). When stratified by body mass index (BMI; kg/m(2)), risk was further reduced among overweight or obese women with a BMI ≥25 (OR = 0.57, 95% CI 0.39-0.83; P trend = 0.004). EC was not associated with the less healthy sweets and meat patterns. However, risk was modestly, but not significantly, elevated for higher intakes of the meat pattern among overweight or obese women. A mostly plant-based dietary pattern may reduce EC risk. Recommendations for risk reduction should focus on maintaining a healthy weight and the role of diet should be studied further.