The Relationship Of Blood Pressure And Obesity Among Adolescents: A Cross-sectional Study

Objective: There is little information regarding the obesity epidemic with therisk childhood hypertension (HTN) in China. The present study aimed to determine theprevalence of HTN/prehypertension (PHTN), as well as the associated risk factors,among adolescents in Changsha city, China.Methods: A total of88,974adolescents from49middle schools in Changshacitybetween12and17years of age were examined during2009.Body weight, height, andblood pressure (BP) were measured in all adolescents. HTN and PHTN were definedaccording to sex-and age-specific Chinese reference data. Overweight and obesity werealso defined according to sex-and age-specific Chinese reference data.Results:(1) Both systolic and diastolic BP level of the adolescents were increasing with thegrowth of age from12-17years. Systolic BP increased more significantly comparedwith diastolic BP. Sexual disparity was found both in BP level (SBP and DBP) and BPincrement, and boy had a significant higher BP level and increment than girls at thesame age (P<0.001).(2) Among88974adolescents aged12-17years, the total prevalence of HTN was3.1%(n=2740) including4.7%(n=2069) of boys and1.5%(n=671)of girls; the totalprevalence of PHTN was7.2%(n=6364) including7.6%(n=3374) of boys and6.7%(n=2990) of girls; the difference of HTN/PHTN between boys and girls werestatistically significant(P<0.001). Boys had higher prevalence of HTN/PHTN than thatof girls at each age group. Moreover, an increasing trend of prevalent HTN/PHTN with age was found both among boys and girls.(3) Of88974adolescents aged12-17years,4.9%and11.6%of the adolescents wereoverweight and obesity, respectively.7.0%and14.6%out of44211boys wereoverweight and obesity as well as2.9%and8.6%out of44763girls. The prevalence ofHTN among normal weight, overweight and obesity adolescents were1.8%，6.0%and18.7%(boys2.6%,7.5%and21.7%, girls1.0%,3.3%and11.5%), respectively. Theprevalence of PHTN among normal weight, overweight and obesity adolescents were1.8%，6.0%and18.7%(boys2.6%,7.5%and21.7%, girls1.0%，3.3%and11.5%) aswell. The rates of prevalent HTN/PHTN among boys and girls were apparentlyincreasing along with raising BMI rank.(4) Results of logistic regression analysis indicated that there was a strongassociation between excess weight gain (i.e.overweight and obesity) and prevalentHTN/PHTN among both boys and girls adjusted for age and height. The risk ratio (RR)of HTN were significantly higher in overweight (RR:2.8,95%CI:2.6–3.2) and obese(RR:8.7,95%CI:8.1–9.5) adolescents adjusted for age, sex, and height. Additionally,the relationship between overweight/obesity and systolic HTN was demonstrated moreclosely than that of diastolic HTN. The overweight and obese boys were associated witha higher RR of prevalent systolic HTN than that of prevalent diastolic HTN and thesame trend was found among overweight and obese girls. The RRs of systolic HTNwere detected3.6(95%CI:3.1~4.1) and12.0(95%CI:10.7~13.4) in overweight andobese boys while the RR of diastolic HTN were2.0(95%CI:1.8~2.4) and5.8(95%CI:5.0~6.6). Similarly, the RRs of systolic HTN were detected4.4(95%CI:3.5~5.7)and17.8(95%CI:14.2~22.1) in overweight and obese girls while the RR of diastolicHTN were2.3(95%CI:1.7~3.2) and11.1(95%CI:8.7~14.5) adjusted for age and height.Conclusion(1) The prevalence of HTN was higher in boys than girls at each age during12-17years. Higher prevalence of HTN/PHTNwas associated with higher BMI percentiles.(2) Being overweight or obese markedly increased the risk of both HTN and PHTNamong adolescents between12and17years of age in Changsha city, China.