Search

Breast cancer is one of the most commonly diagnosed invasive cancers. Established risk factors account for only a small proportion of cases. Previous studies have found reductions in sleep duration and quality in the general population over time. There is evidence to suggest a link between poor sleep and an increased risk of breast cancer. In this study, we investigated the relationship between breast cancer and sleep duration and quality in Western Australian women. Data were obtained from a population-based case-control study conducted from 2009 to 2011. Participants completed a self-administered questionnaire that included questions on sleep. Odds ratios and 95% confidence intervals were calculated using unconditional logistic regression. Sensitivity analysis for potential selection and misclassification bias was also conducted. We found no association between self-reported sleep duration on workdays and risk of breast cancer (for <6 hours, odds ratio (OR) = 1.05 (95% CI: 0.82, 1.33); for 6-7 hours, OR = 0.96 (95% CI: 0.80, 1.16); and for >8 hours, OR = 1.10 (95% CI: 0.87, 1.39), compared with the reference category of 7-8 hours' sleep). In addition, we found no association between sleep duration on nonworkdays, subjective sleep quality, or combined duration and quality and risk of breast cancer. This study does not provide evidence to support an association between self-reported sleep duration or quality and the risk of breast cancer.

Background: Merkel cell carcinoma (MCC) is an uncommon but aggressive cutaneous skin cancer. Even with the appropriate treatment, MCC is prone to recurrence, and metastases are common. Exposure to ultraviolet radiation has been suggested as contributing towards the development of MCC. MCC has not been extensively investigated in Australia, even though Australia has the highest incidence of sun-related cancers in the world., Objectives: To describe the demographics and determine trends of incidence and survival of MCC cases in Western Australia (WA)., Methods: All reported invasive cases of MCC incident between 1 January 1993 and 31 December 2007 were extracted from the WA Cancer Registry. Age-adjusted incidence rates for MCC were calculated using direct standardization to the U.S. standard 2000 population. Cause-specific survival was investigated using Kaplan-Meier and Cox proportional hazards analysis. results: Two hundred and fifteen cases were confirmed by pathological review as being definite cases of MCC. Patients were mainly males (65%) and elderly (median age 77 years). Standardized age-adjusted incidence rates were higher in men (1·0/100,000) than in women (0·63/100,000) and higher in older ages (15·5/100,000 in the 85+year age group) than younger ages (0·1/100,000 in the 30-34 year age group). Five-year cause-specific survival was 64%., Conclusions: Incidence of MCC in WA is the highest reported in the literature. In addition, MCC has worse survival than melanoma. The high rates and demographic and anatomical distribution are consistent with sun exposure playing a causal role., (© 2011 The Authors. BJD © 2011 British Association of Dermatologists.)