Obesity and season as determinants of high blood pressure in a school-based screening study

This school-based screening study assessed the prevalence of high blood pressure (BP) levels according to the European Society of Hypertension (ESH) 2016 guidelines. Moreover, risk factors for BP elevation, and the effect of geographic and seasonal factors on BP screening were investigated. BP and anthropometric measurements were obtained from 2832 children and adolescents, aged 6-18 years, during the period 2013-2016. Three BP measurements were performed using a mercury sphygmomanometer, and the mean of the last two was used for the analysis. Obesity was defined according to the International Obesity Task Force (IOTF) criteria. The prevalence of high-normal BP/hypertension and overweight/obesity was 3.7%/0.9%, and 22.9%/8.5%, respectively. The majority of the participants presenting high BP (>= 90th percentile) were overweight or obese. Increased prevalence of high BP was observed during spring (5.5%) and winter (5%) compared with 2.5% in autumn (P<0.05). SBP z scores were higher in males, during spring and summer, and in urban areas. In conclusion, a low rate of high-normal and hypertensive BP levels was found despite the high prevalence of overweight and obesity. Overweight and obesity were associated with higher BP levels, but there was also a seasonal difference in the prevalence of high BP levels.