Peer Pressure and Family Smoking Habits Influence Smoking Uptake in Teenage Boys Attending School: Multilevel Modeling of Survey Data

Introduction: Among young teens, about one in five smokes worldwide. Adolescents spend a considerable amount of their time in school, and the school environment is therefore important for child health practices and outcomes. Objectives: We aimed to investigate the impact on smoking behavior of the school environment and the personal characteristics of male teenage students attending schools in Pakistan, taking into account the survey sampling structure. Methods: A two-stage cluster sampling with stratification was employed, and we interviewed 772 male secondary school students. We adopted random effect and generalizing estimating equation models. Results: Peer pressure in particular had a strong influence on adolescents smoking;those whose friends smoked were up to 6 times more likely to smoke. Family smoking was also significantly associated with adolescents smoking, but those students whose mother was educated were 50% less likely to smoke. The fitted random effect model indicated that the between school variability was significant (p-value < 0.01), indicating differences in smoking habits between schools. A random coefficient model showed that variability among schools was not significantly different for public and private schools. Conclusion: Public health campaigns for smoking cessation should target not only the individual but also the families of adolescents attending schools.

Multilevel Modeling of Binary Outcomes with Three-Level Complex Health Survey Data

Complex survey designs often involve unequal selection probabilities of clus-ters or units within clusters. When estimating models for complex survey data, scaled weights are incorporated into the likelihood, producing a pseudo likeli-hood. In a 3-level weighted analysis for a binary outcome, we implemented two methods for scaling the sampling weights in the National Health Survey of Pa-kistan (NHSP). For NHSP with health care utilization as a binary outcome we found age, gender, household (HH) goods, urban/rural status, community de-velopment index, province and marital status as significant predictors of health care utilization (p-value < 0.05). The variance of the random intercepts using scaling method 1 is estimated as 0.0961 (standard error 0.0339) for PSU level, and 0.2726 (standard error 0.0995) for household level respectively. Both esti-mates are significantly different from zero (p-value < 0.05) and indicate consid-erable heterogeneity in health care utilization with respect to households and PSUs. The results of the NHSP data analysis showed that all three analyses, weighted (two scaling methods) and un-weighted, converged to almost identical results with few exceptions. This may have occurred because of the large num-ber of 3rd and 2nd level clusters and relatively small ICC. We performed a sim-ulation study to assess the effect of varying prevalence and intra-class correla-tion coefficients (ICCs) on bias of fixed effect parameters and variance components of a multilevel pseudo maximum likelihood (weighted) analysis. The simulation results showed that the performance of the scaled weighted estimators is satisfactory for both scaling methods. Incorporating simulation into the analysis of complex multilevel surveys allows the integrity of the results to be tested and is recommended as good practice.

Screening of Psychiatric Disorders among Hearing-Impaired Children and Adolescents Aged 4 - 16 Years Attending Special Education Institutions in Karachi

Aim: The aim of this study was to estimate the prevalence of psychiatric problems and to identify associated factors among hearing-impaired children and adolescents (aged 4 - 16 years) attending special education institutions in Karachi, Pakistan. Methods: A cross-sectional study, using stratified random sampling was conducted in two special education institutions in Karachi from September 2010 to July 2011 on 272 hearing-impaired children aged 4 - 16 years. Multi-informant rating (responding parent and teacher) was used to assess the prevalence of psychiatric problems on Strengths and Difficulties Questionnaire (SDQ). Kappa statistic was computed to assess agreement between parents/teachers ratings. Multivariable logistic regression analysis was conducted to identify the factors associated with psychiatric problems of children. Results: An overall parent-rated prevalence of psychiatric problems among hearing-impaired children was estimated as 18% and teacher-rated prevalence as 32.7%;poor inter-rater agreement was found between the two raters (Kappa statistic = 0.09). Multivariate model indicated protective effect of child’s age greater than 6 months at the time of diagnosis AOR: 0.49;95% CI (0.25, 0.96). Depression among responding parents AOR: 2.61;95% CI (1.34, 5.11) was identified as a risk factor. Children with good performance AOR: 3.09;95% CI (1.04, 9.25) and fair/poor performance AOR: 3.43;95% CI (1.17, 10.04) were more likely to have psychiatric problems compared to children with outstanding/excellent performance. Cronbach’s alpha of 0.71 on overall SDQ indicated an acceptable internal consistency. Conclusion: Awareness programs should be held for parents and teachers for better dealing with hearing-impaired children.

A Systematic Review of Observational Studies, Demonstrating Smoking among School Going Adolescents

Objective: To characterize the methods of design and analysis currently adopted in survey research of school-based observational studies for smoking, and to identify the common pitfalls made by researchers. Methods: The systematic review was conducted in 2009 and consisted of observational studies in school settings published between January 2005 and January 2009. Smoking status was the main outcome of interest. Following Cochrane style, five steps were followed: setting selection criteria for studies and conducting a literature search;review of abstracts;review of complete articles;data extraction and quality assessment of included studies;and, finally, synthesis of studies. Results: Of the 292 abstracts retrieved, 45 (15.4%) articles were selected for the final review. Inconsistencies were found in the definition of smoking behaviour which impeded generalisability. Individual-level factors had importance, but environmental level factors were also important in studying the aetiology of smoking. Results showed that studies inappropriately reported sample size estimation and important confounding factors. Hierarchical linear modelling, random effects modelling and structural equation modelling were employed in comparatively few studies. Conclusions: There were concerns regarding data analysis of complex surveys. Fifty five percent of reviewed studies ignored environmental effects which may have produced unreliable inferences. Multi-level analysis assisted in understanding school-level effects.