A prospective cohort study of cigarette smoking and the risk of endometrial cancer

Advance Rectal Cancer in a Young Patient: Should Screening Start Early?

Colorectal cancer is the third most common non-cutaneous malignancy in the United States, and the second most common cause of cancer-related deaths. Colorectal cancer is a broad term to include both colon and rectal cancer. Rectal cancer is commonly seen in age more the 50 years and often present with rectal bleeding. In this article, we will be discussing about a young female patient who presented with somatic pain as an initial symptom for metastatic rectal adenocarcinoma.

Exercise intervention as a protective modulator against metabolic disorders in cigarette smokers

[Purpose] assess the impact of exercise intensity on desire to smoke, serum cotinine, stress hormones, total antioxidant capacity, and oxidative free radicals as potential markers of cardiopulmonary metabolic disorders were measured.in cigarette smokers. [Subjects and Methods] The participants (150 randomly selected healthy men, aged 18–55 years) were classified into 4 smoking groups: control (non-smokers; N= 30); mild (N = 33); moderate (N = 42), and heavy (N = 45). The participants were assigned to either moderate (8 weeks) or short-term (20–45 min) exercise training. The desire to smoke, Mood and Physical Symptoms Scale, and Subjective Exercise Experiences Scale scores, cotinine, stress hormones (cortisol and testosterone), free radicals (malondialdehyde, nitric oxide), and total antioxidant capacity were evaluated. [Results] Significant increases in serum cotinine, cortisol, testosterone, nitric oxide, and malondialdehyde levels and a reduction in total antioxidant capacity activity were observed in all smoker groups; heavy smokers showed a higher change in metabolites. In all smoker groups, both short and moderate- intensity exercises significantly reduce cotinine, cortisol, testosterone, and malondialdehyde and increased nitric oxide levels and total antioxidant capacity activity; further, the desire to smoke, Mood and Physical Symptoms Scale, and Subjective Exercise Experiences Scale scores were reduced. This supports the ability of exercise to increase nitric oxide bioavailability, enhance of blood vessels function and ultimately decrease the incidence of cardiopulmonary disorders. [Conclusion] Exercise interventions with varying intensities may be used as nicotine replacement therapy or protective aids against smoking-related cardiopulmonary disorders.

Long-term impact of preeclampsia on maternal endometrial cancer risk

BACKGROUND

Endometrial cancer is mainly dependent on oestrogen exposure. Preeclampsia has shown to reduce oestrogen levels hence preeclampsia may affect later endometrial cancer risk.

METHODS

We conducted a case-control study of 523 Danish women with endometrial cancer and 52 299controls during 1978-2010. The association between preeclampsia and later endometrial cancer was evaluated overall and according to preeclampsia onset and type of endometrial cancer in conditional logistic regression models.

RESULTS

We observed no overall association between preeclampsia and endometrial cancer risk (OR=1.11 (95% CI 0.68-1.81)). This was true for all endometrial cancer subtypes. In an analysis of preeclampsia onset, however, we report a markedly increased risk of endometrial cancer following early-onset preeclampsia (OR=2.64 (95% CI 1.29-5.38)).

CONCLUSIONS

Although we report no obvious association between preeclampsia and endometrial cancer, studying the subset of early-onset preeclampsia may prove fruitful in further understanding the aetiology of endometrial cancer.

Endometrial cancer and oral contraceptives: an individual participant meta-analysis of 27 276 women with endometrial cancer from 36 epidemiological studies

BACKGROUND

Oral contraceptives are known to reduce the incidence rate of endometrial cancer, but it is uncertain how long this effect lasts after use ceases, or whether it is modified by other factors.

METHODS

Individual participant datasets were sought from principal investigators and provided centrally for 27 276 women with endometrial cancer (cases) and 115 743 without endometrial cancer (controls) from 36 epidemiological studies. The relative risks (RRs) of endometrial cancer associated with oral contraceptive use were estimated using logistic regression, stratified by study, age, parity, body-mass index, smoking, and use of menopausal hormone therapy.

FINDINGS

The median age of cases was 63 years (IQR 57-68) and the median year of cancer diagnosis was 2001 (IQR 1994-2005). 9459 (35%) of 27 276 cases and 45 625 (39%) of 115 743 controls had ever used oral contraceptives, for median durations of 3·0 years (IQR 1-7) and 4·4 years (IQR 2-9), respectively. The longer that women had used oral contraceptives, the greater the reduction in risk of endometrial cancer; every 5 years of use was associated with a risk ratio of 0·76 (95% CI 0·73-0·78; p<0·0001). This reduction in risk persisted for more than 30 years after oral contraceptive use had ceased, with no apparent decrease between the RRs for use during the 1960s, 1970s, and 1980s, despite higher oestrogen doses in pills used in the early years. However, the reduction in risk associated with ever having used oral contraceptives differed by tumour type, being stronger for carcinomas (RR 0·69, 95% CI 0·66-0·71) than sarcomas (0·83, 0·67-1·04; case-case comparison: p=0·02). In high-income countries, 10 years use of oral contraceptives was estimated to reduce the absolute risk of endometrial cancer arising before age 75 years from 2·3 to 1·3 per 100 women.

INTERPRETATION

Use of oral contraceptives confers long-term protection against endometrial cancer. These results suggest that, in developed countries, about 400 000 cases of endometrial cancer before the age of 75 years have been prevented over the past 50 years (1965-2014) by oral contraceptives, including 200 000 in the past decade (2005-14).

FUNDING

Medical Research Council, Cancer Research UK.

Cigarette smoking, physical activity, and alcohol consumption as predictors of cancer incidence among women at high risk of breast cancer in the NSABP P-1 trial

BACKGROUND

NSABP P-1 provides an opportunity to examine the association of behavioral factors with prospectively monitored cancer incidence and interactions with tamoxifen.

METHODS

From 1992 to 1997, 13,388 women with estimated 5-year breast cancer risk greater than 1.66% or a history of lobular carcinoma in situ (87% younger than age 65; 67% postmenopausal) were randomly assigned to tamoxifen versus placebo. Invasive breast cancer, lung cancer, colon cancer, and endometrial cancer were analyzed with Cox regression. Predictors were baseline cigarette smoking, leisure-time physical activity, alcohol consumption, and established risk factors.

RESULTS

At median 7 years follow-up, we observed 395, 66, 35, and 74 breast cancer, lung cancer, colon cancer, and endometrial cancer, respectively. Women who had smoked were at increased risk of breast cancer (P = 0.007; HR = 1.3 for 15-35 years smoking, HR = 1.6 for ≥ 35 years), lung cancer (P < 0.001; HR = 3.9 for 15-35 years, HR = 18.4 for ≥ 35 years), and colon cancer (P < 0.001; HR = 5.1 for ≥ 35 years) versus never-smokers. Low activity predicted increased breast cancer risk only among women assigned to placebo (P = 0.021 activity main effect, P = 0.013 activity-treatment interaction; HR = 1.4 for the placebo group) and endometrial cancer among all women (P = 0.026, HR = 1.7). Moderate alcohol (>0-1 drink/day) was associated with decreased risk of colon cancer (P = 0.019; HR = 0.35) versus no alcohol. There were no other significant associations between these behaviors and cancer risk.

CONCLUSION

Among women with elevated risk of breast cancer, smoking has an even greater impact on breast cancer risk than observed in past studies in the general population.

IMPACT

Women who smoke or are inactive should be informed of the increased risk of multiple types of cancer.

Cigarette smoking and endometrial carcinoma risk: the role of effect modification and tumor heterogeneity

PURPOSE

The inverse relationship between cigarette smoking and endometrial carcinoma risk is well established. We examined effect modification of this relationship and associations with tumor characteristics in the National Institutes of Health-AARP Diet and Health Study.

METHODS

We examined the association between cigarette smoking and endometrial carcinoma risk among 110,304 women. During 1,029,041 person years of follow-up, we identified 1,476 incident endometrial carcinoma cases. Multivariable Cox proportional hazards regression models were used to estimate relative risks (RRs) and 95 % confidence intervals (CIs) for the association between smoking status, years since smoking cessation, and endometrial carcinoma risk overall and within strata of endometrial carcinoma risk factors. Effect modification was assessed using likelihood ratio test statistics. Smoking associations by histologic subtype/grade and stage at diagnosis were also evaluated.

RESULTS

Reduced endometrial carcinoma risk was evident among former (RR 0.89, 95 % CI 0.80, 1.00) and current (RR 0.65, 95 % CI 0.55, 0.78) smokers compared with never smokers. Smoking cessation 1-4 years prior to baseline was significantly associated with endometrial carcinoma risk (RR 0.65, 95 % CI 0.48, 0.89), while cessation ≥ 10 years before baseline was not. The association between smoking and endometrial carcinoma risk was not significantly modified by any endometrial carcinoma risk factor, nor did we observe major differences in risk associations by tumor characteristics.

CONCLUSION

The cigarette smoking-endometrial carcinoma risk relationship was consistent within strata of important endometrial carcinoma risk factors and by clinically relevant tumor characteristics.

Cigarette smoking and endometrial cancer risk: the modifying effect of obesity

The objective of this study was to evaluate the association between cigarette smoking and endometrial cancer risk by investigating potential modifying effects of menopausal status, obesity, and exogenous hormones. We pooled data from three case-control studies with the same study design conducted in Italy and Switzerland between 1982 and 2006. Overall, 1446 incident endometrial cancers and 4076 hospital controls were enrolled. Odds ratios (OR) and 95% confidence intervals (CI) were estimated using logistic regression models, conditioned on study and centre, and adjusted for age, period of interview, age at menarche, parity, and body mass index. In comparison with never smokers, current smokers showed reduced endometrial cancer risk (OR: 0.80; 95% CI: 0.66-0.96), with a 28% decrease in risk for smoking ≥ 20 cigarettes/day. The association did not vary according to menopausal status, oral contraceptive use, or hormone replacement therapy. However, heterogeneity emerged according to body mass index among postmenopausal women, with obese women showing the greatest risk reduction for current smoking (OR: 0.47; 95% CI: 0.27-0.81). In postmenopausal women, obesity turned out to be an important modifier of the association between cigarette smoking and the risk of endometrial cancer. This finding calls for caution in interpreting the favorable effects of cigarette smoking, considering the toxic and carcinogenic effects of tobacco.

Relationships between psychological distress, coping styles, and HPA axis reactivity in healthy adults

Psychological distress and coping styles have been suggested to relate to altered function in the hypothalamic-pituitary-adrenal (HPA) axis, although there remains much to be understood about their relationships. High and low cortisol levels (or reactivity) both represent HPA axis dysfunction, with accumulated evidence suggesting that they are linked to different types of psychopathology. The dexamethasone (DEX)/corticotropin-releasing hormone (CRH) test has been extensively used to identify HPA axis abnormalities in various psychiatric conditions including mood disorders; however, the possible associations of psychological distress and coping styles with HPA axis function have not been well documented using this test. Here, we examined the relationships of HPA axis reactivity as measured by the DEX/CRH test with subjectively perceived psychological distress and coping styles, both of which were assessed with self-report questionnaires, in 121 healthy volunteers. Subjects were divided into three groups by the cortisol suppression pattern, namely the incomplete-suppressors (DST-Cortisol ≥ 5 μg/dL or DEX/CRH-Cortisol ≥ 5 μg/dL), moderate-suppressors (DST-Cortisol < 5 μg/dL and 1 μg/dL ≤ DEX/CRH -Cortisol < 5 μg/dL), and enhanced-suppressors (DST-Cortisol < 5 μg/dL and DEX/CRH-Cortisol < 1 μg/dL). The enhanced-suppressors showed significantly higher scores in obsessive-compulsive, interpersonal sensitivity and anxiety symptoms and significantly more frequent use of avoidant coping strategy, compared to the other two groups. These results point to the important role of enhanced suppression of cortisol, or blunted cortisol reactivity, in non-clinical psychopathology such as avoidant coping strategy and greater psychological distress.

Active and passive cigarette smoking and the risk of endometrial cancer in Poland

BACKGROUND

Epidemiological studies have consistently reported that active cigarette smoking is inversely associated with endometrial cancer risk. However, dose-response relationships with quantitative measures of active smoking or passive smoking remain less clear.

METHODS

Data on lifetime active and passive smoking were collected for 551 endometrial cancer cases and 1925 controls in a population-based case-control study conducted during 2001-2003 in Poland (Warsaw and Łódz).

RESULTS

Compared with never active smokers, active current (Odds Ratio (OR)=0.51, 95% Confidence Interval (CI): 0.39, 0.68) and former smokers (OR=0.60, 95% CI: 0.45, 0.80) were at a statistically significantly decreased risk. We did not observe statistically significant inverse dose-response relationships with increasing exposure with duration and cumulative measures. However, there was some indication that the highest category of number of years (OR=0.35, 95% CI: 0.23-0.55), intensity (OR=0.41, 95% CI: 0.24-0.69), and dose (OR=0.38, 95% CI: 0.24-0.60) of smoking among current smokers had the greatest inverse association compared to never smokers. Our data did not support the presence of an inverse association with passive smoking among never active smokers (OR=0.92; 95% CI: 0.65, 1.29).

CONCLUSION

Our results support that long-term and heavy smoking among current smokers strongly influence endometrial cancer risk.

A population-based cohort study on sun habits and endometrial cancer

Background:

No large cohort study has examined the risk of endometrial cancer in relation to sun exposure.

Methods:

A population-based cohort study of 29 508 women who answered a questionnaire in 1990–92, of whom 24 098 responded to a follow-up enquiry in 2000–02. They were followed for an average of 15.5 years.

Results:

Among the 17 822 postmenopausal women included, 166 cases of endometrial cancer were diagnosed. We used a multivariate Cox regression analysis adjusting for age and other selected demographic variables to determine the risk of endometrial cancer. Women using sun beds >3 times per year reduced their hazard risk (HR) by 40% (0.6, 95% confidence interval (CI) 0.4–0.9) or by 50% when adjusting for body mass index or physical activity (HR 0.5, 95% CI 0.3–0.9), and those women who were sunbathing during summer reduced their risk by 20% (HR 0.8 95% CI 0.5–1.5) compared with women who did not expose themselves to the sun or to artificial sun (i.e., sun beds).

Conclusion:

Exposure to artificial sun by the use of sun beds >3 times per year was associated with a 40% reduction in the risk of endometrial cancer, probably by improving the vitamin D levels during winter.

Smoking, earlier menarche and low parity as independent risk factors for gynecologic cancers in Japanese: a case-control study

During recent decades, the incidence of gynecologic cancers, i.e., cancers of the cervix, endometrium and ovary, has increased in Japan. However, risk factors of gynecologic cancers have not been fully clarified in Japan. To investigate common and site-specific risk factors among gynecologic cancers, we conducted a hospital-based case-control study. The cases, i.e., 151 cervical, 103 endometrial and 141 ovarian cancer cases and the controls (n = 2016) were selected from female patients aged 30 and over, who were admitted to a single hospital in Miyagi Prefecture from 1997 to 2003. Information on reproductive factors, exogenous hormone use, and lifestyles including smoking was collected using a self-administered questionnaire. Smoking was significantly associated with an increased risk of cervical cancer. A dose-response relationship with the number of cigarettes per day was also observed (p for trend = 0.004). Older age at menarche was associated with a decreased risk of endometrial and ovarian cancers. For these cancers, the decreased risk was detected with increasing parity number (endometrium, p for trend = 0.0001; ovary, p = 0.0002). There was no significant association between exogenous hormone use and gynecologic cancer risk. The results indicate that smoking is a major risk factor of cervical cancer. In addition, hormonal factors, which are related to early onset of menarche and low parity, are common risk factors for endometrial and ovarian cancers. The increase in female smokers and the decrease in fertility rate may contribute to the increase in gynecologic cancer incidence in Japan.

Cigarette smoking and the risk of endometrial cancer: a meta-analysis

OBJECTIVE

Epidemiologic findings are inconsistent concerning the association of endometrial cancer risk with cigarette smoking. We conducted a meta-analysis of epidemiologic studies to examine this relation.

METHODS

A systematic literature search up to June of 2007 was performed in MEDLINE and EMBASE. Study-specific risk estimates were pooled using a random-effects model.

RESULTS

Ten prospective and 24 case-control studies were included in the analysis of the effect of ever smoking. Ever smoking was statistically significantly associated with a reduced risk of endometrial cancer among prospective studies (relative risk 0.81; 95% confidence interval [CI], 0.74-0.88) and case-control studies (odds ratio 0.72; 95% CI, 0.66-0.79). The inverse association was significant among current and former smokers. Six prospective and 6 case-control studies were included in the quantitative analysis. We noted that an increase in smoking of 20 cigarettes per day was statistically significantly associated with 16% and 27% reduced risks of endometrial cancer in prospective and case-control studies, respectively. We also found that cigarette smoking was significantly associated with a decreased risk of endometrial cancer among postmenopausal women (relative risk 0.71; 95% CI, 0.65-0.78) but not among premenopausal women. In addition, the risk reduction seemed to be stronger among hormone replacement therapy users than nonusers.

CONCLUSION

Cigarette smoking was found to be significantly associated with a reduced risk of endometrial cancer, especially among postmenopausal women.

Alcohol consumption, cigarette smoking, and endometrial cancer risk: results from the Netherlands Cohort Study

Objective

To examine the association between alcohol consumption, cigarette smoking, and endometrial cancer.

Methods

In 1986, the Netherlands Cohort Study was initiated. A self-administered questionnaire on dietary habits and other cancer risk factors was completed by 62,573 women. Follow-up for cancer was established by record linkage to the Netherlands Cancer Registry.

Results

After 11.3-years of follow-up, 280 incident endometrial cancer cases were available for analyses. In multivariate analysis, the rate ratio (RR) for alcohol users versus non-users was 1.06 (95% Confidence Interval (95% CI) = 0.78–1.43). There were neither dose-dependent trends nor associations with different types of beverages. The RR for former and current smokers versus never-smokers was 0.83 (95% CI = 0.58–1.20) and 0.59 (95% CI = 0.40–0.88), respectively. These estimates did not change significantly when body mass index (BMI) and age at menopause were added to the models.

Conclusions

There is no association between alcohol consumption and endometrial cancer. Current smoking is associated with a reduced risk of endometrial cancer. This association is neither mediated by BMI nor by age at menopause.

Risk of endometrial cancer in relationship to cigarette smoking: Results from the EPIC study

Current epidemiologic evidence indicates that cigarette smoking reduces the risk of endometrial cancer. We examined data from the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort to analyze further aspects of the smoking-endometrial cancer relationship, such as possible modifying effects of menopausal status, HRT use, BMI and parity. In a total of 249,986 women with smoking exposure and menopausal status information, 619 incident endometrial cancer cases were identified during 1.56 million person-years of follow-up. Among postmenopausal women, the hazard ratio (HR) for current smokers versus never smokers was 0.70 (95% CI = 0.53-0.93), while it was 1.75 (95% CI = 1.13-2.70) among premenopausal women at recruitment. After adjustment for risk factors, the HR for postmenopausal women was slightly attenuated to 0.78 (95% CI = 0.59-1.03). No heterogeneity of effect was observed with HRT use or BMI. Among premenopausal women, current smokers of more than 15 cigarettes per day or who smoked for 30 years or more at the time of recruitment had a more than 2-fold increased risk of endometrial cancer compared to never smokers (HR = 2.54; 95% CI = 1.47-4.38 and HR = 2.23; 95% CI = 1.04-4.77, respectively). Past smoking was not associated with endometrial cancer risk, either among pre- or postmenopausal women. In this prospective study, we observed an increased risk of endometrial cancer with cigarette smoking in premenopausal women. The reduction of endometrial cancer risk observed among postmenopausal women does not have direct public health relevance since cigarette smoking is the main known risk factor for cancer.

Active and passive smoking and risk of ovarian cancer

It is unclear whether smoking is a risk factor for epithelial ovarian cancer, although some studies have suggested that it may be associated with an increased risk of mucinous tumors. This study investigated the effect of smoking and environmental tobacco smoke (ETS) on ovarian cancer risk among 434 women with primary epithelial ovarian, peritoneal, or fallopian cancers and 868 age- and region-matched hospital controls with nonneoplastic conditions. All participants completed a comprehensive epidemiologic questionnaire. Results indicate that decreased risk of ovarian cancer was associated with being a nonsmoker exposed to ETS (adjusted odds ratio [aOR] 0.68, 95% confidence interval [CI] 0.46-0.99), a former smoker (aOR 0.76, 95% CI 0.53-1.10), or a current smoker (aOR 0.53, 95% CI 0.32-0.88). A similar protective effect was noted for smokers with moderate or high exposure based on smoking intensity, duration, and cumulative exposure, as well as for never smokers exposed to ETS. Results did not differ substantially by histologic subtype. Although prevailing theories of ovarian cancer etiology implicate incessant ovulation, characteristics of the study population suggest that anovulation was not the protective mechanism in this study. Immunosuppression by nicotine or upregulation of enzymes that metabolize carcinogens may be responsible for the effects observed.

Conditions associated with antibodies against the tumor-associated antigen MUC1 and their relationship to risk for ovarian cancer

Many cancers, including ovarian, overexpress epithelial mucin (MUC1) and promote anti-MUC1 antibodies that may correlate with more favorable prognosis. By extension, risk for ovarian cancer might be reduced by preexisting MUC1-specific immunity. We measured anti-MUC1 antibodies in 705 control women, identified events predicting antibodies, and estimated ovarian cancer risk by comparing profiles of events generating antibodies in controls with those in 668 ovarian cancer cases. Factors predicting antibodies included oral contraceptive use, breast mastitis, bone fracture or osteoporosis, pelvic surgeries, nonuse of talc in genital hygiene, and to a lesser extent intrauterine device use and current smoking. There was a significant increase in the likelihood of having anti-MUC1 antibodies from 24.2% in women with 0 or 1 condition, to 51.4% in those with five or more conditions. By the same index of events, the risk for ovarian cancer was inversely associated with number of conditions predisposing to anti-MUC1 antibodies. Compared with having experienced 0 or 1 event, the adjusted risk for ovarian cancer decreased progressively with relative risks (and 95% confidence limits) of 0.69 (0.52-0.92), 0.64 (0.47-0.88), 0.49 (0.34-0.72), and 0.31 (0.16-0.61), respectively for women with two, three, four, and five or more events related to the presence of antibodies (P(trend) < 0.0001.) We conclude that several traditional and new risk factors for ovarian cancer may be explained by their ability to induce MUC1 immunity through exposure of MUC1 to immune recognition in the context of inflammatory or hormonal processes in various MUC1-positive tissues.

Endometrial Carcinoma Risks among Menopausal Estrogen plus Progestin and Unopposed Estrogen Users in a Cohort of Postmenopausal Women

BACKGROUND

Because unopposed estrogen substantially increases endometrial carcinoma risk, estrogen plus progestin is one menopausal hormone therapy formulation for women who have not had a hysterectomy. However, endometrial carcinoma risks among estrogen plus progestin users and among former unopposed estrogen users are not firmly established.

METHODS

We evaluated endometrial carcinoma risks associated with estrogen plus progestin and unopposed estrogen therapies in 30,379 postmenopausal Breast Cancer Detection Demonstration Project follow-up study participants. We ascertained hormone therapy use and other risk factors during telephone interviews and mailed questionnaires between 1979 and 1998. We identified 541 endometrial carcinomas via self-report, medical records, the National Death Index, and state cancer registries. Poisson regression generated time-dependent rate ratios (RR) and 95% confidence intervals (95% CI).

RESULTS

Endometrial carcinoma was significantly associated with estrogen plus progestin only use (n = 68 cancers; RR, 2.6; 95% CI, 1.9-3.5), including both sequential (progestin <15 days per cycle; n = 32 cancers; RR, 3.0; 95% CI, 2.0-4.6) and continuous (progestin at least 15 days per cycle; n = 15 cancers; RR, 2.3; 95% CI, 1.3-4.0) regimens. The RR increased by 0.38 (95% CI, 0.20-0.64) per year of estrogen plus progestin use, and RRs increased with increasing duration of use for both regimens. The strong association with unopposed estrogen use declined after cessation but remained significantly elevated > or =10 years after last use (RR, 1.5; 95% CI, 1.0-2.1).

CONCLUSIONS

Both estrogen plus progestin regimens significantly increased endometrial carcinoma risk in this study. Risks among unopposed estrogen users remained elevated long after last use. The prospect that all estrogen plus progestin regimens increase endometrial carcinoma risk deserves continued research.

Smoking and the risk of endometrial cancer: results from the Nurses' Health Study

An inverse association between smoking and endometrial cancer has generally been observed, primarily among current smokers. To assess this association, we analyzed data from the prospective Nurses' Health Study. From 1976 to 2000, 702 cases of invasive endometrial cancer were identified during 1.8 million person-years of follow-up. Smoking status was assessed in 1976 and updated every 2 years. Cox proportional hazards models were used to calculate multivariate relative risks (RRs), controlling for endometrial cancer risk factors. Compared to never smokers, the multivariate RR of endometrial cancer was significantly lower among both current smokers (RR = 0.63; 95% CI = 0.50-0.79) and past smokers (RR = 0.73; 95% CI = 0.62-0.87). When additionally adjusting for body mass index (BMI), the RR for current smokers was attenuated (RR = 0.72; 95% CI = 0.57-0.90), but the RR for past smokers did not change. Risk was lower among women who smoked 35 or more cigarettes a day (RR = 0.60; 95% CI = 0.39-0.91) and among those who smoked for 40 or more years (RR = 0.63; 95% CI = 0.45-0.87). Tests for trend, which excluded never smokers, were not statistically significant for any of the smoking variables analyzed. These data indicate that both current and past smoking are associated with a lower risk of endometrial cancer. The findings provide insight into disease etiology and suggest that the influence of smoking on endometrial cancer risk occurs even in early adulthood, is long-lasting, and may not be attributed solely to short-term hormonal modulation.

Smoking and hormones in health and endocrine disorders

Smoking has multiple effects on hormone secretion, some of which are associated with important clinical implications. These effects are mainly mediated by the pharmacological action of nicotine and also by toxins such as thiocyanate. Smoking affects pituitary, thyroid, adrenal, testicular and ovarian function, calcium metabolism and the action of insulin. The major salient clinical effects are the increased risk and severity of Graves' hyperthyroidism and opthalmopathy, osteoporosis and reduced fertility. Smoking also contributes to the development of insulin resistance and hence type 2 diabetes mellitus. An important concern is also the effect of smoking on the foetus and young children. Passive transfer of thiocyanate can cause disturbance of thyroid size and function. Furthermore, maternal smoking causes increased catecholamine production, which may contribute to under perfusion of the foetoplacental unit.

Histologic types of epithelial ovarian cancer: have they different risk factors?

OBJECTIVES

The histologic types of epithelial ovarian cancer differ in clinical behavior, descriptive epidemiology, and genetic origins. The goals of the current study were to characterize further the relation of histologic-specific ovarian cancer risks to reproductive and lifestyle attributes.

METHODS

The authors conducted a pooled analysis of 10 case-control studies of ovarian cancer in US White women, involving 1834 patients with invasive epithelial ovarian cancer (1067 serous, 254 mucinous, 373 endometrioid, and 140 clear cell) and 7484 control women.

RESULTS

Risks of all four histological types were inversely associated with parity and oral contraceptive use, but the histologic types showed different associations with nonreproductive factors. Unique associations include an inverse relation of serous cancer risk to body mass index, a positive relation of mucinous cancer risk to cigarette smoking, and a weakly positive relation of endometrioid cancer risk to body mass index. Risk of all histologic types was unassociated with age at menarche, age at menopause, a history of infertility, noncontraceptive estrogen use, and alcohol consumption.

CONCLUSIONS

The most important modifiers of ovarian cancer risk (parity and oral contraceptive use) showed similar associations across the histologies. Nevertheless, the unique associations seen for other modifiers support the conjecture that the histologic types of epithelial ovarian cancer have different etiologies, which should be addressed in future investigations of the molecular basis of ovarian cancers and their responses to therapies.

Factors affecting menstrual cycle characteristics

This 1989-1991 study in California and Utah used daily urinary metabolites of estrogen and progesterone and computer algorithms to assess ovulatory status and day of ovulation. The authors examined the associations of risk factors with menstrual cycle characteristics for 309 working women aged 20-44 years who collected a median of five cycles each of daily urine samples. Linear mixed models were used to assess continuous menstrual outcomes. Compared with women less than age 35 years, women aged 35 years or older had a significantly decreased (-0.94 days, 95% confidence interval: -1.83, -0.05) adjusted mean cycle length. Age modified the effects of smoking, physical activity, ethnicity, and alcohol consumption on mean follicular phase length. Asian women had a significantly longer (1.65 days, 95% confidence interval: 0.54, 2.76) adjusted mean cycle length compared with Caucasian women. Compared with women who did not consume alcoholic drinks, women who did had a significantly shorter (-1.26 days, 95% confidence interval: -2.21, -0.31) adjusted mean cycle length. Mean cycle and phase lengths were significantly associated with length of the prior luteal phase. These results indicate that potentially modifiable risk factors, as well as immutable host factors, are associated with menstrual cycle characteristics that may in turn be related to subsequent disease risk.

Metabolic abnormalities (hypertension, hyperglycemia and overweight), lifestyle (high energy intake and physical inactivity) and endometrial cancer risk in a Norwegian cohort

Since high energy intake, inactivity, hypertension and diabetes are linked to obesity and an unfavorable hormonal profile, we wanted to test whether energy intake, physical activity, blood pressure and serum glucose are related to the risk of endometrial cancer independent of the body mass index (BMI). A cohort of 24,460 women, aged 20-49 years, attended a Norwegian health screening twice during 1974-1981; they answered questions about diet, physical activity and chronic diseases, and their height, weight, blood pressure and non-fasting serum glucose were measured. By the end of 1996, during 15.7 years of follow-up, 130 cases of endometrial carcinomas were identified. The relative risks (RRs) for endometrial cancer were estimated in proportional hazards models including potentially confounding factors. Obese women (BMI > or = 30 kg/m(2)) were at 2.6 times increased risk of endometrial cancer compared to normal weight women (BMI < 25 kg/m(2)) (RR = 2.57, 95%CI = 1.61-4.10). Among overweight women (BMI > or = 25 kg/m(2)), non-fasting serum glucose in the upper quartile vs. in the lower quartile was associated with a 2.4 times increase in risk (RR = 2.41, 95%CI = 1.08-5.37), whereas among obese women, blood pressure above 140/90 mmHg vs. below 140/90 mmHg in both surveys was associated with a 3.5 times increase in risk (RR = 3.47, 95%CI = 1.24-9.70). Especially in women younger than 50 years, high energy intake (5,044-6,401 kJ/day) conferred higher risk compared to low energy intake (< 4266 kJ/day) (RR = 3.40, 95%CI = 1.52-7.60). Increasing recreational activity tended to be protective. Among obese women with non-sedentary jobs at both screenings, RR declined to 0.18 (95%CI = 0.05-0.62) as the level of sustained occupational activity increased (p(trend) = 0.03). Our results suggest that inactivity and high energy intake are major risk factors for endometrial cancer independent of BMI, and that hypertension and relative hyperglycemia are significant markers of risk, especially among the heaviest women.

Trends in incidence rates for obesity-associated cancers in the US

The purpose of this study was to assess the possible impact of rising prevalence of obesity in US adults (since the late 1970s) on incidence rates (1973-1999) for cancers strongly associated with obesity, and to estimate the number of incident cancers (in 2002) potentially attributable to obesity. Data from a group of high-quality population-based cancer registries, regarded as generally representative of the unknown cancer rates in the entire US, were used to obtain average annual age-standardized incidence rates (ASIRs) per 100,000 from 1973 to 1975 through 1997-1999 for selected obesity-related cancers. Temporal increases in ASIRs were evident during the entire period for kidney and adenocarcinomas of the esophagus and gastric cardia, while during the 1990's the decline in ASIRs for adenocarcinoma of the uterine corpus was reversed and the ASIRs for breast cancer continued to increase for age 50+ years, suggesting a potential impact of rising obesity prevalence rates. An estimated 41,383 new cancers (about 3.2% of all cancers) diagnosed in the US in 2002 may be potentially attributable to obesity. Further analytic epidemiologic studies are needed to assess the risks of other cancers in relation to both obesity and body fat distribution.

Cigarette smoking and the risk of endometrial cancer

Epidemiological studies have shown that cigarette smoking is associated with a reduced risk of endometrial cancer, in contrast to the increased risks observed with many other non-respiratory-tract cancers, including those of the bladder, pancreas, and cervix uteri. Some studies of endometrial cancer suggest that the inverse association with smoking is limited to certain groups of women, such as those who are postmenopausal or those taking hormone-replacement therapy. The biological mechanisms that might underlie this association remain unclear, although several have been proposed, including an antioestrogenic effect of cigarette smoking on circulating oestrogen concentrations, a reduction in relative bodyweight, and an earlier age at menopause. We have examined the evidence for an association between cigarette smoking and risk of endometrial cancer, including studies related to the proposed biological mechanisms.