algorithm of smoking stages assessment in adolescents: a validation study using the latent class analysis model

Not withstanding the importance of smoking stages evaluation in adolescents, there is not an appropriate instrument for its measurement. This study aims to introduce an appropriate instrument for measurement of smoking stages in adolescents and to examine its validity using latent class analysis [LCA] model. We designed an algorithm to measure the smoking stages. The relevancy and clarity of the algorithm was examined by experts and lay experts. We assessed the reliability of our algorithm using test retest method. Moreover, using the LCA, we studied the validity of the stages measured by the designed algorithm in 4903 students [ages 14-19], who were randomly selected from grade 10 high school students in Tabriz [North West of Iran]. The algorithm content validity indicates high relevancy and clarity percentages. Intra-class correlation of 0.929 was found in the assessment of the reliability of smoking stages [9 stages] in 154 students within a two week interval. The LCA model revealed nine interpretable classes [G[2] = 0.051, df = 1, P = 0.821] for the measurement of smoking stages. Examination of the smoking cessation stages in a sample of 218 students in the cessation stage demonstrated that the results for five classes could be interpreted [G[2] = 0.001, df = 1, P = 0.975]. The results suggested that this algorithm is clear, valid, and reliable.

[ incidence rate of the delibeate self-injury in male high school pupils, Tabriz- Iran]

Self-injury [SI], also called self-mutilation or cutting, is highly stigmatized emotional disorder. The aim of this study was to estimate the incidence rate of self-injury among male pupils in Tabriz - North West in Iran and to evaluate the associated risk factors. In this longitudinal study of all the pupils high school in Tabriz, 1772 [13.7%] were randomly sampled, and assessed in this and subsequent year. A self-administered questionnaire with 48 questions was distributed to high school in February and March 2005. After one year [February and March 2006], another questionnaire with 10-items was distributed to those students to determine the incidence rate of self-injury. The influence of different factors on self-injury was evaluated with a logistic regression model. The mean age of the subjects was 16.3 +/- 0.87 [min 15, max 19] years. At the end of follow-up, 4.8% of pupils reported incidence of self-injury. Most type of incidenced self-injury were cutting and burning. The results of logistic regression model indicate that transition in smoking stages [OR=2.81], incidence of alcohol drinking [OR=2.27] and having smoker friend [OR=1.78] were factors associated with incidence of self-injury. This study showed that incidence rate of self-injury in this group of adolescents was 4.8% in one year, which related to age, alcohol and ciggaret smoking