title: Sensitivity to change of the Beach Questionnaire to behaviour, attitudes and knowledge related to sun exposure: quasi-experimental before-after study.
abstract: BACKGROUND
  Health questionnaires must present accredited measurement properties such as validity, reliability and sensitivity to change, the latter being essential for interventions to be planned and for evaluating their effectiveness. The aim of this study was to evaluate the sensitivity to change of a Beach Questionnaire.
  
  
  METHODS
  Quasi-experimental before-after study carried out in 2011, for a study population of adolescents attending schools in the Costa del Sol. First, the questionnaire was administered to the adolescents, after which a multicomponent educational intervention was carried out; finally, three months later, the same questionnaire was re-administered to the same adolescents. Changes were assessed in the categories of each item, using the McNemar test, and the changes in the scores, standardised to a range of 0-100, using the Student t test for paired samples, and including the mean of the differences and the 95% confidence interval. The level of statistical significance was set at p < 0.05.
  
  
  RESULTS
  228 adolescents, aged 14-17 years, and 55.3% were girls. Statistically significant changes were observed in sunburn experiences, exposure to the sun at mid-day and attitudes to sun exposure and suncreams. For the seven items related to knowledge about sun exposure, a higher rate of correct answers was observed. The analysis of changes, within the standardised range, revealed a significant improvement in the scores for sun exposure habits (MD 4.33; CI 95% 2.2-6.5), attitudes to sun exposure (MD 2.22; CI 95% 1.2-3.2) and knowledge (MD 9.10; CI 95% 7.1-11.1), but not in those for sun-protection practices (MD 0.23; CI 95% -1.2-1.7).
  
  
  CONCLUSIONS
  The Beach Questionnaire on behaviour, attitudes and knowledge related to sun exposure is the first such instrument in Spanish language to provide sufficient sensitivity to change. It constitutes a useful tool for epidemiologic research into photoprotection and for skin cancer prevention programmes.
authors: Doctoral student at the University of Granada, Granada, Spain`. tfm_84@hotmail.com.|Dermatology Department, Costa del Sol Hospital, Marbella, Spain. tfm_84@hotmail.com.
authors: Teresa
authors: T
authors: Fernández-Morano
authors: Dermatology Department, Costa del Sol Hospital, Marbella, Spain. magdatm@hcs.es.|Red de Investigación en Servicios de Salud en Enfermedades Crónicas-Redissec, Granada, Spain. magdatm@hcs.es.
authors: Magdalena
authors: M
authors: de Troya-Martín
authors: Red de Investigación en Servicios de Salud en Enfermedades Crónicas-Redissec, Granada, Spain. frivas@hcs.es.|Research Department Costa del Sol Hospital, Marbella, Spain. frivas@hcs.es.
authors: Francisco
authors: F
authors: Rivas-Ruiz
authors: Dermatology Department, Costa del Sol Hospital, Marbella, Spain. nuriaderm1@gmail.com.
authors: Nuria
authors: N
authors: Blázquez-Sánchez
authors: School of Medicine, Granada University, Granada, Spain. abuendia@ugr.es.
authors: Agustín
authors: A
authors: Buendía-Eisman
mesh_terms: D000293:Adolescent; D000294:Adolescent Behavior; D065187:Controlled Before-After Studies; D005260:Female; D007722:Health Knowledge, Attitudes, Practice; D006801:Humans; D008297:Male; D011594:Psychometrics; D015203:Reproducibility of Results; D013030:Spain; D013471:Sunburn / Q000175:diagnosis* / Q000453:epidemiology* / Q000517:prevention & control; D013472:Sunlight / Q000009:adverse effects; D011795:Surveys and Questionnaires / Q000592:standards*
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