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Background:Marked influxes of people into rural areas, termed rural population mixing (PM), have been associated with excesses of childhood leukaemia (CL), consistent with mini-epidemics of a mainly immunising, subclinical infection to which CL is a rare response. For such situations of rural PM would promote contacts between infected and susceptible individuals, the latter tending to have a higher than average prevalence in rural or isolated areas. Confusion has arisen from some workers applying the term PM to non-rural situations lacking known recent change.Methods:Available PM studies using the original definition of influxes were examined, a meta-analysis carried out of studies of CL in relation to exposure to high levels of rural PM, and also a detailed analysis by age group.Results:The meta-analysis of 17 studies shows a significant CL excess in association with rural PM: overall relative risk (RR) at ages 0-14: 1.57; 95% confidence interval 1.44-1.72; at 0-4 years 1.72 (1.54-1.91). This contrasts with the absence of an excess of CL in similarly exposed urban areas (RR 1.00; 0.93-1.07), pointing to a high level of immunity there. The mixed results of studies using other definitions of PM were summarised. The excess associated with rural PM below age 2 years (RR 1.51; 1.17, 1.92) was not appreciably different from that at later childhood ages.Conclusion:Much of the inconsistency among studies ostensibly about CL and PM reflects the use of definitions other than that originally proposed. The broad similarity of the CL excess below age 2 with that at older childhood ages is inconsistent with the Greaves' delayed infection hypothesis, since any infection underlying the former is difficult to consider as delayed. [ABSTRACT FROM AUTHOR]

Background: Endometrial cancer is the most common gynaecological cancer in the western world, the incidence increasing in the United Kingdom by over 40% since 1993. Two types of endometrial cancer exist - oestrogen-dependent type 1 with good prognosis and non-oestrogen-dependent type 2 with poor prognosis. The histopathological distribution of the increase in endometrial cancer is unknown. This study investigates the observed incidence trends of the two types, the age, stage, and socioeconomic distribution of this increase and survival outcome.Methods: Data were analysed from 6867 women with endometrial cancer registered between 1994 and 2006, at a UK population-based cancer registry.Results: Increased endometrial cancer incidence is confined to type 1 cancers with a significant increase in age standardised incidence rate (ASR) from 12.0 per 100,000 (confidence interval (CI) 10.7-13.2) in 1994 to 16.3 per 100,000 (CI 14.9-17.7), P<0.001 in 2006, while ASR of type 2 cancer changed from 2.5 per 100,000 (CI 2.0-3.1) in 1994 to 2.2 per 100,000 (CI 1.7-2.7) in 2006, which was not statistically significant P>0.05. Increase in type 1 cancer is most marked in age groups 60-69 years (P<0.001) and 70-79 years (P<0.001) and distributed equally among socioeconomic quintiles. While outcome for type 1 cancer has improved, 1-year survival in type 2 cancer is unchanged from 73.1% in 1994 to 74.3%, P=0.089 and 5-year survival decreased from 55.1% to 40.9%, P=0.001.Conclusion: Increased incidence in endometrial cancer is confined to type 1 cancers, seen most in the 60-79 age groups and across all socioeconomic quintiles. Survival in type 2 cancer has decreased significantly. Urgent research is needed to investigate prevention strategies in type 1 and improve therapy in type 2 cancers. [ABSTRACT FROM AUTHOR]