Journal of North Khorasan

Abstract Background & Objectives: In medical researchers, there are lots of correlated data which cannot be analyzed using the usual classical statistical methods because the assumption of independency between observations is not met. Data from cluster sampling, longitudinal studies, observations on paired organs and matched studies are examples of such data. Materials & Methods: Two statistical methods that can be used to correctly handle these kinds of data are marginal and mixed models. These models are different in considering correlation between subjects and Interpretation of the regression coefficients. These models were compared in this paper. Results: The regression coefficients in marginal models with non-identity link functions show the change in population whereas in mixed models they represent changes within a subject or a cluster. Conclusion: In result, in nonlinear models, application of these two kinds of models depends on the areas of their usage. While the marginal models are more attractive to the Health policy makers who are considering the potential effects of a variable on the population as a whole, the mixed model will be of most interest to a physician in a physician/patients context.

Abstract Background & Objectives: This study was performed to surveillance visible goiter. Iodine deficiency disorders (IDD) are among the most important health-nutrition problems. In the most area where exposed with iodine deficiency the only visible Complication is goiter. Material & Method: This study was performed with the data of the national study of health survey (1999) in Iran. In this survey 53633 people were selected and examined thyroid gland. In order to study risk factors of visible goiter Chi-square test and multiple mixed logistic regressions have been used. Result: Based on this study it has been shown that 32.1 percent of people have a kind of goiter. And 4.5 percent of people had visible goiter. Frequency of goiter was significantly different in the age categories, different sex and in rural and urban (p-value<0.001). The 6.1 percent of females have goiter and odds ratio of the goiter for women was 2.29 higher than males (CI95%=(2.09,2.50)). Also 5.4 percent of rural people have goiter and adjusted odds ratio of the goiter for rural people was 1.39 higher than urban people (CI95%=(1.28,1.50)). In this study 6 percent of 13 to 18 years old people have goiter which was the most prevalence of goiter among the age categories. Conclusion: Consider the result of this study, there should be more consideration on the nutrition of 13 to 18 age category, female and rural to prevent the goiter

Abstract Background and Objectives: The aim of the study was first to translate the Kidney Disease Quality of Life Short Form KDQOL-SF (version 1.3 (Questionnaire into Iranian and then to assess it in terms of validity and reliability on Iranian patients. Material & Methods: The questionnaire was first translated into Farsi by two independent translators, and then subsequently translated back into English. An initial test-retest reliability evaluation was performed on a sample of 20 patients from the total group (212 patients with end stage renal disease), over a ten day interval. Afterwards, reliability was estimated by internal consistency and validity was assessed using known group comparison and construct validity on the patient group as a whole. Finally, the factor structure of the questionnaire was extracted by performing exploratory factor analysis (EFA (. Results: All of the scales in the questionnaire showed good test–retest reliability(all above 0.7(. All of the items met the minimal criteria (i.e. 0.7 (for internal consistency and Cronbach's α ranged from 0.73 to 0.93. To test construct validity, we examined correlations of the kidney disease targeted scales and overall health rating scale. The majority of items correlated significantly with the overall health rating. Furthermore, results from a discriminate validity evaluation showed that the questionnaire could be used to discriminate between subgroups of the patients. Finally, a principal component analysis of the disease specific scales indicated that this part of the questionnaire could be summarized into a two-factor structure (disease burden and patient satisfaction (that jointly accounted for 63 % of the variance. Conclusion: The Iranian version of the KDQOL-SF questionnaire is both highly reliable and valid for use with Iranian ESRD patients.

Abstract Background & Objectives: Considering the high application of diagnostic tests in medical practice, understanding the concept of diagnostic test evaluation indices is highly important. Ability of test in distinguishing healthy subjects from patients is evaluated by sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV). Although their understanding is relatively straightforward, they are often used mistakenly or interchangeably. We have tried to present these concepts utilizing the diagrams to make it easier to understand and remember. Materials & Methods: we used diagrams to illustrate the concept of diagnostic indexes. Then we showed the effect of change of prevalence of disease in these indexes. Results: Sensitivity and specificity are not sensitive to the prevalence of disease in the population. On the other hand positive predicted value increase when the prevalence of disease increase and negative predictive value increase when the prevalence of disease decreases. Conclusion: Although it has been shown that sensitivity and specificity are essential in evaluation of accuracy in diagnostic tests, their ability to discover the degree of confidence is limited, so the predictive values is used to indicate the posterior probability of disease after observing the test results. It should be considered that predictive values are dependent upon the prevalence of disease in population and should not be generalized for different populations with different prevalence of diseases.

Abstract Background & objective: Physical inactivity is prevalent among adolescents around the worlds. This study tested the ability of the theory of planned behavior )TPB( to predict Physical Activity )PA( among adolescents in a 4-weeks longitudinal study. Materials & Methods: 623 adolescents were randomly selected from eight high schools in Qazvin. TPB measures, and a revised International Physical Activity Questionnaire were measured at baseline and 1-month follow-up. Hierarchical regression analyses were conducted regressing Physical Activity at Time 2 onto TPB. Results: the mean age of the adolescents was 15.5 years and the most of them were girls( 51.2 %(. Past behavior accounted for a significant 57% of the variance in Physical Activity in Step 1of analysis. In Step 2, TPB accounted for an additional 7% with attitude, subjective norms and perceived behavior control as a significant predictor. The analysis resulted in a significant amount of incremental variance accounted for by the intention ( Step 3(. Conclusion: The results of this study demonstrated the theory of planned behavior successfully predicted the most of physical activity's variance among adolescents. Our results suggest that theory-based interventions should be based on the TPB with a targeting on PBC

Abstract Background and Objectives: dental Caries prevalence is high among Iranian students. Studies have shown that motivational interviewing is able to change health behaviors. The purpose of this study was to investigate the effects of a brief intervention based on motivational interviewing in promoting oral health self-care behaviors among adolescents in Qazvin city. Material & Method: In a quasi-experimental study based on a multi-stage sampling with random selection of 4 boy-specific schools, 40 students were assigned to each of the experimental and control groups. Intervention protocol was conducted in treatment group in accordance with the recommendations of Miller and Rowling included 6 sessions (60 minute per session) based on the initial need assessment and in order to coping skills and problem solving development. Demographic variables, psychological constructs were measured using self report questionnaire before, 2 and 6 month after motivational interviewing. Finally, the data were entered into SPSS 17.0 software and was analyzed using descriptive and inferential analyses. Results: The results indicated that a significant change in the attitude (from 14.82±3.86 to 25.75 ± 3.86), behavioral intention ( from 11.03 ± 4.15 to 18.80 ± 3.37) and self efficacy (from 37.65 ± 9.43 to 52.93 ± 7.48) were seen in the experimental group 6 months after motivational interviewing (P< 0.001). furthermore, the average of brushing (from 0.79± 0.33 to 1.24 ± 0.37) and dental flossing (from 0.30 ± 0.32 to 0.42 ± 0.37) showed a significant increase in the experimental group after interviewing (P< 0.001). Conclusion: The findings of this study showed that motivational interviewing in the individual level can lead to a better antecedent psychological constructs and promote oral health self care behavior and as an effective component of prevention and promotion programs can play an important role in oral health.