BACKGROUND This paper examines the effectiveness of the "Smoke-Free Class Competition" in delaying the onset of smoking in adolescence. Each participating class must decide if they want to be a "smoke-free class" for the 6-month period from fall to spring. Classes monitor their (non-)smoking behavior and report it to the teacher regularly. Classes in which pupils refrain from smoking for this p...

We examined trends in hookah use among New York City middle and high school students. We calculated prevalences, linear trends, and odds ratios of ever and current hookah use, by selected demographic variables, using 2008 through 2014 data from the New York State Youth Tobacco Survey. The prevalence of ever hookah use increased overall from 2008 through 2014 (8.9% to 13.0%, P = .01); current us...

AIMS The farming environment in childhood has been reported to decrease the risk of sensitisation to allergens. The purpose of the present study was to explore whether later exposure to a farming environment also could affect this sensitisation. METHODS A population based sample of 202 women who did not live on a farm and 231 who did. The subjects filled in a questionnaire and underwent skin ...

OBJECTIVE To describe the prevalences of asthma and rhinitis in adolescents (13-14 years of age) in the city of Fortaleza, Brazil, in 2010, comparing the results with those obtained in a prevalence survey conducted in 2006-2007. METHODS This was a cross-sectional study involving probabilistic samples of 3,015 and 3,020 adolescents in surveys conducted in 2006-2007 and 2010, respectively. The ...

BACKGROUND Local policy makers increasingly need information on health-related indicators at smaller geographic levels like districts or neighbourhoods. Although more large data sources have become available, direct estimates of the prevalence of a health-related indicator cannot be produced for neighbourhoods for which only small samples or no samples are available. Small area estimation provi...

Substantial development assistance has been directed towards reducing the high malaria burden in Malawi over the past decade. We assessed changes in transmission over this period of malaria control scale-up by compiling community Plasmodium falciparum rate (PfPR) data during 2000-2011 and used model-based geostatistical methods to predict mean PfPR2-10 in 2000, 2005, and 2010. In addition, we c...

Observers tend to miss a disproportionate number of targets in visual search tasks with rare targets. This 'prevalence effect' may have practical significance since many screening tasks (e.g., airport security, medical screening) are low prevalence searches. It may also shed light on the rules used to terminate search when a target is not found. Here, we use perceptually simple stimuli to explo...

The authors applied a time-series approach to assess the temporal trend of racial disparity in chlamydia prevalence between young, socioeconomically disadvantaged blacks and whites entering the US National Job Training Program. Racial disparity was defined as the arithmetic difference between age group-, specimen type-, and region of residence-standardized chlamydia prevalences in blacks and wh...

Myopia is of diverse aetiology. A small proportion of myopia is clearly familial, generally early in onset and of high level, with defined chromosomal localisations and in some cases, causal genetic mutations. However, in economically developed societies, most myopia appears during childhood, particularly during the school years. The chromosomal localisations characterised so far for high famil...

The success of introduced species is frequently explained by their escape from natural enemies in the introduced region. We tested the enemy release hypothesis with respect to two well studied blood parasite genera (Plasmodium and Haemoproteus) in native and six introduced populations of the common myna Acridotheres tristis. Not all comparisons of introduced populations to the native population...