ABSTRACT
<p><b>OBJECTIVE</b>To explore the impact of obesity level and the level change in childhood on hypertension incidence.</p><p><b>METHODS</b>A perspective cohort study was conducted. As part of Beijing Child and Adolescent Metabolic Syndrome Study, 2189 aged 6 - 16 year non-hypertensive children was followed up in December, 2010. In this study, height, weight, waist circumference (WC) and blood pressure was measured at follow-up, and body mass index (BMI) and WC was respectively used to assess overweight, obesity and abdominal obesity. Non-conditional logistic regression was used to evaluate the association between baseline obesity status, change of obesity status and hypertension incidence. OR and 95%CI were computed in the model using obese status as dummy variable and hypertension at follow up visit as dependent variable.</p><p><b>RESULTS</b>The total hypertension incidence of 1184 subjects during 6 years follow-up was 19.9% (236/1184). The hypertension incidence in male (23.2%, 149/643) was higher than that in female (16.1%, 87/541) (χ(2) = 9.257, P = 0.002). The hypertension incidence of non-overweight, overweight and obese children at baseline was 8.7% (45/519), 19.3% (35/181) and 32.4% (156/484) respectively (χ(2) = 9.332, P < 0.001), and the incidence of non-obese and abdominal obese children at baseline was respectively 10.3% (63/613) and 30.7% (173/567) (χ(2) = 77.753, P < 0.001). Hypertension incidence in the baseline obesity group was higher than the non-overweight (BMI: OR = 4.9, 95%CI: 3.4 - 7.0) and non-obese group (WC: OR = 3.9, 95%CI: 2.8 - 5.3). The hypertension incidence increased with the follow-up BMI/WC level, based on the same baseline level of BMI and WC. The hypertension risk increased to 0.21 and 0.07 times respectively with elevation of baseline BMI level by 1 kg/m(2) and WC level by 1 cm, and OR (95%CI) were 1.21 (1.16 - 1.26) and 1.07 (1.05 - 1.09), respectively. Similarly, the hypertension risk increased 0.16 and 0.05 times respectively with the elevation of BMI level change by 1 kg/m(2) and 1 cm, and OR (95%CI) were 1.16 (1.11 - 1.22) and 1.05 (1.03 - 1.07), respectively.</p><p><b>CONCLUSION</b>Obesity and increased obesity level change in childhood can increase the risk of incident hypertension.</p>