A nationwide report on blood pressure of children and adolescents according to socioeconomic status: The CASPIAN-IV study

BACKGROUND: Hypertension is a major leading factor for global burden of diseases. Blood pressure (BP) tracks from childhood to adulthood. So, it is important to investigate its aff ecting factors. In this study we aimed to compare the BP status in the Iranian pediatric population according to the socioeconomic status (SES) of their living area. MATERIALS AND METHODS: In this nationwide study, a representative sample of 14,880 students, aged 6-18 years was chosen by multistage random cluster sampling from 30 provinces in Iran. Anthropometric indices and BP were measured. A validated questionnaire, including the questions of the World Health Organization Global School-based Student Health Survey was completed. Findings were compared across the four regions of the country, categorized based on their elevating SES: Southeast, north-northeast, west, and central. RESULTS: Participants consisted of 13,486 children and adolescents, that is, a participation rate of 90.6%, composed of 49.2% girls and 75.6% urban residents. The mean (standard deviation) age of participants was 12.47 (3.36) years. The region with highest SES (central) had the lowest rate of high BP (HBP), that is, 3.0% (95% of confidence interval [CI]: 2.4-3.9), and the region with lowest SES (southeast) had the highest rate, that is, 7.4% (4.4-12.2). The mean (95% CI) values of systolic BP for the four regions from lowest to highest SES were 100.5 (99.6-101.3), 100.9 (100.3-101.4), 101.7 (101.3-102), and 101.7 (101.2-102.1) mmHg. The corresponding mean Diastolic BP values were as follows: 65.4 (64.6-66.1), 63.4 (62.9-63.8), 65.6 (65.3-65.8), and 64.4 (64.0-64.7) mmHg. CONCLUSION: We found significant differences in mean BP and the frequency of HBP according to the SES of the living area. Further studies are necessary to find the underlying factors resulting in such differences.