The prevalence and predictors of hypertension in a National Survey of Australian Children

Purpose: To determine the prevalence of hypertension and predictors of blood pressure (BP) in a population based survey of Australian children. Subjects and methods: We analysed cross-sectional data for 2071 children, aged 5–17 years, from the Australian Health Survey 2011–13. Hypertension and high-normal BP were defined by a systolic or diastolic BP greater than the 95th and 90th centiles respectively, using the National High Blood Pressure Education Program fourth report reference data. We also examined the association of several predictor variables (age, sex, remoteness, socioeconomic status, body mass index) with BP as a continuous variable. Results: A total of 5.8% (95%CI 4.4–7.2) of children had hypertension, and a further 6.8% (95%CI 5.4–8.3) had high-normal BP. The strongest predictor of BP was body mass index. After adjustment, children in the overweight and obese categories had a BP that was on average 4 (95%CI 2–6) and 8 mmHg (95%CI 6–11) higher than those of normal weight. Socio-economic status was a statistically significant predictor of BP, but the effect size was more modest (2 mmHg [95%CI 0–4] between the highest and lowest tertile). Conclusions: Hypertension or high-normal BP is present in 12.6% of Australian children. Body mass index is the most important predictor of BP, followed by low socioeconomic status. These at-risk children may be suitable for screening and intervention studies.