SunSmart: evaluation of a pilot school-based sun protection intervention in Hispanic early adolescents.

The incidence of melanoma is rising among Hispanic populations in the United States. The purpose of this study is to evaluate the impact of a pilot sun safety educational intervention conducted from 2006 to 2012 on Hispanic early adolescents in a high ultraviolet environment. Nineteen schools with high Hispanic enrollment were recruited from urban neighborhoods in Los Angeles. The analytic sample was restricted to students identifying as Hispanic or Latino (n = 777). A mixed effects linear model was used to test mean changes from pre- to posttest on students' sun protection knowledge, attitudes and behaviors. Significant improvements were observed across several cognitive outcomes related to sun protection, including knowledge of and attitudes toward sun protection and self-efficacy to wear sunscreen. However, changes in sun protective behaviors were not achieved. Although some improvements were observed, future studies should identify the factors that motivate sun protection in this population and develop tailored prevention strategies, as improving the sun safe behaviors of Hispanic youths may aid in reducing the risk of melanoma in adulthood in this population.

Evidence of genetic susceptibility to infectious mononucleosis: a twin study.

Infectious mononucleosis is a clinical manifestation of primary Epstein-Barr virus infection. It is unknown whether genetic factors contribute to risk. To assess heritability, we compared disease concordance in monozygotic to dizygotic twin pairs from the population-based California Twin Program and assessed the risk to initially unaffected co-twins. One member of 611 and both members of 58 twin pairs reported a history of infectious mononucleosis. Pairwise concordance in monozygotic and dizygotic pairs was respectively 12·1% [standard error (s.e.)=1·9%] and 6·1% (s.e.=1·2%). The relative risk (hazard ratio) of monozygotic compared to dizygotic unaffected co-twins of cases was 1·9 [95% confidence interval (CI) 1·1-3·4, P=0·03], over the follow-up period. When the analysis was restricted to same-sex twin pairs, that estimate was 2·5 (95% CI 1·2-5·3, P=0·02). The results are compatible with a heritable contribution to the risk of infectious mononucleosis.

Development and representativeness of a large population-based cohort of native Californian twins.

We have established a large cohort of twins to facilitate studies of the role of genetics and environment in the development of disease. The cohort has been derived from all multiple births occurring in California between 1908-82 (256,616 in total). We report here on our efforts to contact these twins and their completion of a detailed 16 page risk factor questionnaire. Addresses of the individuals were obtained by linking the birth records with the California Department of Motor Vehicles (DMV) roster of licensees. To date this has been completed for twins born between 1908 and 1972 (200,589 individuals). The linkage has revealed 112,468 matches and, because of less complete DMV records in some years, was less successful in older females than in younger females and all males. Over 41,000 twins have participated by completing the questionnaire. Based on estimates of numbers of individuals receiving a questionnaire, we estimate our crude response rate to be between 42.2% and 49.6%, highest among females in their 40s (62.8%). We describe the representativeness of the twins in the original birth cohort, those identified by the linkage, and those completing the questionnaire. Compared to the 1990 resident population of California-born resident singletons, the respondents were of similar age, sex, race and residential distribution (for although we were able to locate fewer older females, they had a higher response rate), but were less likely to have been educated for more than 12 years. We provide a brief synopsis of studies nested within this cohort. We also elucidate our plans for expanding the cohort in the near future.

Childhood leukaemias in New Zealand: time trends and ethnic differences.

Registrations from the New Zealand Cancer Registry were used to examine time trends in the incidence of leukaemias among children aged 0-14. There was a statistically significant increase in the incidence of leukaemia among children aged 0-4 during 1953-57 to 1988-90. In this age group, the recorded incidence rate increased from 4.89 per 100,000 person-years in 1953-57 to 7.92 in 1988-90. During 1973-77 to 1988-90 (and probably in earlier years), the increase was due to an increase in acute lymphoblastic leukaemia (ALL). The trends were unlikely to be due to changes in diagnosis or case ascertainment. The childhood leukaemia trends might be related to trends in family size, maternal age, socioeconomic level or exposure to infections. However, there are uncertainties about the importance of these factors or about their trends. The incidence of acute non-lymphoblastic leukaemia (ANLL) decreased between 1968-72 and 1988-90. The time trends highlight the likely importance of environmental factors in the aetiology of childhood leukaemias in New Zealand. The risk of ALL was lower in the Maori than in the non-Maori population (relative risk Maori/non-Maori 0.74). The risk of ANLL was higher among Maori (relative risk 1.84).