2.1. Study Design:
This study was part of a national study conducted in all provinces of Iran also was a cross-sectional study entitled: " Iranian Children and Adolescents Psychiatric disorders’ (IRCAP) Survey" (13).
2.2. Sampling:
Random multi-stage cluster sampling was used to collect data in Yazd. To compare cities and villages data were collected from both of them. Participants were children and adolescents aged between 6 to 18 years, including males and females. In total, 1035 children and adolescents were randomly selected. The total sample size was 31 000 in IRCAP community-based Survey. This study is part of the primary study. To calculate the sample size for the primary study, the prevalence of psychiatric disorders was 0.3, the type one error was 0.05, accepted error of 0.05. The sample size was calculated 825 participant for each province. And considering the design effect for cluster sampling as 1.2, sample size was calculated 990 (1000) participant.
The sampling method was a multi-stage cluster. 170 blocks were randomly selected according to the postal code and 6 cases from each cluster with 3 cases of each sex at different ages (6–9 years, 10–14 years, and 15–18 years).
2.3. Procedure:
Trained researchers went to the children's home for data collection. After explaining the study to their parents and justifying them, they consented to have their children participate in the study. At first demographic data was taken, and then K-SADS-PL and life style questionnaire were completed by participants. After that anthropometrics and history of heart disease were collected and at the end the participants were sent to Afshar Hospital for specialized tests.
The nurse took venous blood to measure blood glucose, triglycerides, cholesterol, LDL and HDL after 8 to 12 hours of fasting. Then blood samples were centrifuged for serum separation. To assess fasting blood glucose and triglyceride high-density lipoprotein cholesterol and low-density lipoprotein cholesterol a biochemical auto-analyzer, model BT 3000 (Italy) and PARS Azmoon Kits (Pars Azmoon Kit, Pars Azmoon Inc., Tehran, Iran) were used. All measurements were performed in standard positions and with calibrated tools.
In order to classify dyslipidemia, percentile of serum lipid profile of IRCAP (Iranian Children and Adolescents' Psychiatric Disorders Study) and cut off points of Nelson Textbook of Pediatrics were used. Definition and classification of triglyceride, cholesterol, LDL and HDL in children and adolescents 6–18 years old based on percentile of serum lipid profile of IRCAP were; a) High: triglyceride, cholesterol and LDL at or greater than 95th percentile, b) Borderline: triglyceride, cholesterol and LDL at or greater than 75th percentile and less than 95th percentile, c)- High: HDL at or less than 5th percentileand, d)-Borderline: HDL at or less than 25th percentile and greater than 5th percentile.
Definition and classification of dyslepidemia in children and adolescents 6–18 years old based on cut off points of Nelson Textbook of Pediatrics were:
a) - High Triglyceride:
− 6–9 years old > 75
− 10–18 years old > 90
b)- High Cholesterol > 170
c)- High LDL > 110
d)- Low HDL < 45
Anthropometric indices were measured by trained nurses. These indicators include height and weight, body mass index (BMI), and Waist circumference. Height were measured while participants stood without shoe on a a standard position. Calibrated scale used to measure weight whiles the participants' wearing low costumes. Also waist circumference measured by a non-stretchable tape that way between the lowest rib and the iliac crest over minimal clothing at the end of exhalation. They recorded clinical symptoms of heart disease in children and adolescents. These symptoms include: heart palpitations, shortness of breath and chest pain. Blood pressure was taken three times from the right hand by a trained nurse. The device used to measure was the blood pressure automatic digital (Omron Co. Osaka, Japan). In this study, HTN was defined based on percentile cut-points of HTN at or greater than 95th percentile.
Data was analyzed using SPSS 20 software. Also charts were drawn by Microsoft excel 2013. STATA version 14 was used to determine the confidence interval for the prevalence. The mean of three measurements was used to report the cytolysis and diastolic blood pressure. Chi-square test was used to calculating the prevalence of HTN according to demographic variables. Binary logistic regression (BLR) was used to calculate the predictors of HTN and their crude and adjusted odds ratio (OR).
2.4. Inclusion and Exclusion Criteria:
One of the inclusion criteria in this study is the participants should be Iranian and another one is the participants have lived in Yazd for at least one year also the age range of children and adolescents was 6 to 18 years. The participants did not have severe physical and mental illness; this was a condition of exclusion criteria. I confirm that all methods were performed in accordance with the relevant guidelines and regulations to this effect.
2.5. Ethics:
Participants were enrolled in this study voluntarily. This study was approved by National Institute for Medical Research Development (NIMAD)’s ethic committee (ethical code: IR.NIMAD.REC.1395.001). We obtained informed consent from all subjects and their legal guardian(s) to participate in our study and publish data on averages or prevalence. We have not published the personal information of any of the participants in this study. And we did not provide the data individually; Rather, it was in general.
Scales:
Kiddie-SADS-Present and Lifetime Version (K-SADS-PL)
This questionnaire is a semi-structured interview that designed for children and adolescents based on DSM-IV which there has been developed in three parts. The first section contains demographic information, the second section includes questions about the criteria for disorders, and the third section provides a general assessment to determine the child's performance. The validity and reliability of the Persian version of this questionnaire was determined by Ghanizadeh et al. They show the test-retest reliability was 0.56–0.81, and the inter-rater reliability was at the level of 0.69. «Affective disorders; psychotic disorders; anxiety disorders, behavioral disorders; substance use disorders; eating disorders; tic disorders, and autism spectrum disorders» is diagnosed by (K-SADS-PL) (14–16).
Life Style Questionnaire (LSQ)
The lifestyle questionnaire is a multidimensional questionnaire and has 70 questions and the questions are in the whole likert range also there are 10 subscales in the questionnaire that include « physical health; exercise and health; weight control and nutrition, illness prevention, psychological health, spiritual health, social health, drug and alcohol avoidance, accident prevention, and environmental health». In each of the subscales, a high score is a good lifestyle for the respondent. Cronbach's alpha coefficients are in the range of 0.76 to 0.89 and the reliability coefficients of the test-retest are in the range of 0.84 to 0.94 (17, 18).
2.6. Statistical analysis
Data were analyzed using SPSS 20 statistical software. Descriptive statistics were used to describe the data with 95% confidence level. P-value less than 0.05 was used to the level of significance. The Chi-square test was used to calculate the prevalence of hypertension based on the variables studied. Statita 14 statistical software was also used to obtain confidence interval for prevalence. The figures were also drawn with Excel 2013 software. Binary logistic regression was used for modeling.