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

Primary and secondary prevention in the reduction of cancer morbidity and mortality

Overall, cancer is a highly preventable disease. Indeed, modifiable external factors, discovered by epidemiological studies during the last 50 years, account for a majority of all cancer deaths. In this review, we discuss briefly these factors and their contribution to the current burden of cancer with an emphasis on the developed countries. Needless to say, tobacco smoking remains the largest contributor to the cancer landscape, whilst the contribution of poor diet and obesity may be equally important, but much more difficult to quantify. Our main goal was to assess what prevention of cancer has accomplished and might accomplish in the next two decades. Based on (necessarily crude) estimates, age-adjusted mortality rates from cancer in year 2000 had been reduced by approximately 13% due to primary prevention and an additional 6% due to the combined effect of early diagnosis and screening (secondary prevention). According to a realistic goal for the year 2020, a further 29% reduction might be achieved by primary, and 4% by secondary prevention. The main contribution to such accomplishments would be a reduction in tobacco smoking, improvements in diet - including reduced alcohol intake - and arrest of the obesity epidemic, in part through increased physical exercise. Rather than being granted, these goals require great effort and major commitment from all those who share responsibility for public health. © 2001 Elsevier Science Ltd. All rights reserved

Epidemiologic studies of styrene and cancer: A review of the literature

Objective: To review the epidemiologic literature on styrene and cancer. Methods: We reviewed studies of workers exposed to styrene in manufacturing and polymerization, in the reinforced plastics industry, and in styrene-butadiene rubber production. We also reviewed studies of workers monitored for styrene exposure, studies of environmental exposure, community-based case-control studies of lymphoma and leukemia, and studies of DNA adducts. Studies of workers in the reinforced plastics industry were considered more informative because of higher worker exposure and less confounding by other carcinogens. Results: We found no consistent increased risk of any cancer among workers exposed to styrene. A study of reinforced plastic workers reported an association between average estimated styrene exposure and non-Hodgkin lymphoma (NHL, P = 0.05) but no trend with increasing duration of exposure. Other studies of styrene exposure and NHL found no increased risk. In two US studies of reinforced plastic workers, esophageal cancer mortality was increased, but these findings were generated in a background of multiple comparisons. Results for other cancers were unremarkable. Conclusions: The available epidemiologic evidence does not support a causal relationship between styrene exposure and any type of human cancer. \ua9 2009 by American College of Occupational and Environmental Medicine

Insulin resistance in relation to melanoma risk

Obesity, deregulation of adipocytokines, and insulin resistance are interrelated and have been implicated in carcinogenesis. In search of novel risk factors for melanoma, we explored the association of this disease with insulin resistance in a small size, case-control study. Homeostasis Model Assessment for Insulin Resistance (HOMA-IR), serum leptin, and adiponectin levels were determined in 55 patients with incident melanoma and 165 age-matched and sex-matched controls. Odds ratios were derived after adjusting for skin type, medical history, sociodemographic, lifestyle, and anthropometric parameters. Among the controls, HOMA-IR correlated positively with BMI (r=0.34; P=0.0001), waist-to-hip ratio (r=0.20; P=0.01) and negatively with serum adiponectin (r=-0.21; P=0.006), whereas the correlation with leptin was essentially null (r=0.09; P=0.27). The mean HOMA-IR was approximately 1.5 times higher in cases than in controls (P=0.05). The established positive association of melanoma with skin type was evident in multiple logistic regression models and so was the association with increasing HOMA-IR quintile (odds ratio for the fifth quintile=3.68; 95% confidence intervals 1.15-11.79, P=0.02). The latter persisted after adjustment for anthropometric variables and adiponectin but was attenuated when leptin was introduced in the model. These findings point to insulin resistance as a potentially independent risk factor for melanoma and need to be confirmed by future larger studies, ideally allowing the control of the directionality of the association. © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins

Insulin-like growth factor levels in cord blood, birth weight and breast cancer risk

Breast cancer incidence and birth weight are higher among Caucasian than Asian women, and birth size has been positively associated with breast cancer risk. Pregnancy hormone levels, however, have been generally lower in Caucasian than Asian women. We studied components of the insulin-like growth factor (IGF) system in cord blood from 92 singleton babies born in Boston, USA, and 110 born in Shanghai, China, in 1994-1995. Cord blood IGF-1 was significantly higher among Caucasian compared with Chinese babies (P10 6). The opposite was noted for IGF-2 (P10 4). IGF-1 was significantly positively associated with birth weight and birth length in Boston, but not Shanghai. In contrast, stronger positive, though statistically non-significant, associations of IGF-2 with birth size were only evident in Shanghai. The associations of birth weight and birth length were positive and significant in taller women (for IGF-1 in Boston P0.003 and 0.03, respectively; for IGF-2 in Shanghai P0.05 and 0.04, respectively), among whom maternal anthropometry does not exercise strong constraints in foetal growth. The documentation of higher cord blood levels of IGF-1, a principal growth hormone that does not cross the placenta, among Caucasian than in Asian newborns is concordant with breast cancer incidence in these populations. © 2009 Cancer Research UK