台灣尿液篩檢陽性之高血壓兒童及青少年追蹤研究

Abstract

高血壓是常見的慢性疾病之一，也是心血管疾病的重要危險因子。隨著兒童與青少年肥胖盛行率的增加，青少年高血壓也有增加的趨勢。若能在兒童或青少年時期就發現高血壓，早期控制，有助於預防或改善成年高血壓，防制心血管疾病。目前台灣學童例行身體檢查並未包括血壓量測，相關的本土兒童與青少年高血壓研究也不多。本研究為了探討兒童與青少年高血壓的相關因子，並透過追蹤少年高血壓來探討兒童及青少年高血壓的後續發展，特別是衍生心血管疾病或代謝異常危險。 本研究利用1992-2000年的台灣省中小學生尿液篩檢陽性(包括尿蛋白、尿糖及血尿)資料，包括人體量測學檢查、血壓量測及血液生化分析等資料探討中小學生高血壓的特徵和危險因子，進而取樣做追蹤研究。本研究因之分為兩部分：(1)利用這些尿液篩檢陽性學生的基線資料，依照美國國家高血壓教育工作小組標準分類，找出高血壓病例組(N=17548)，再以年級和性別的頻數配對方式，自無高血壓的學生中隨機抽取對照組(N=17548)，進行巢式病例對照研究。(2)邀請居住在台北及台中地區的尿液篩檢陽性學生來醫院做追蹤檢查，包括人體學量測、血壓、血液檢查、尿液檢查及動脈硬化檢查等，將過去學生時期有高血壓的學生視為暴露組(N=347)，無高血壓的學生做為非暴露組(N=641)，進行前瞻性追蹤研究。 結果顯示：(1)病例組的肥胖盛行率約為對照組的3倍(17.9% vs. 6.1%, p <0.0001)。在多變項羅吉斯迴歸中，肥胖與高血壓危險有最強的相關(OR = 3.45，95% CI = 3.20-3.72)，其次是膽固醇過高，兩者與高血壓都有劑量效應的關係(p<0.0001)。高血壓危險比與出生體重呈現V-型關係。非肥胖學生中，相較於出生體重正常學生，低出生體重(OR=1.10，95% CI=0.96-1.27)與高出生體重(OR=1.19，95% CI=1.05-1.34)都有較高的高血壓危險比。相較於有最低IgA 10位數的學生，最高IgA 10分位數的學生有較高的高血壓(OR = 1.20，95% CI = 1.08-1.34)、高膽固醇(OR = 1.22, 95% CI = 1.11-1.34)及空腹血糖異常危險比(OR=1.77，95% CI = 1.62-1.93)。最高 10分位數的肥胖學生的空腹血糖異常危險比增加到2.93 (95% CI = 1.93-4.44)。(2)在追蹤研究中發現，相較於中小學時無高血壓的人，有高血壓的人在成年後仍有較高的高血壓危險(OR=4.19，95% CI=2.42-7.28)，空腹血糖異常(OR=4.70，95% CI=1.62-13.6)及代謝症候群(OR=4.20，95% CI=1.23-14.3)的危險也較高。 本研究顯示肥胖是兒童與青少年高血壓的主要危險因子，出生體重與IgA也與兒童及青少年高血壓有關。有高血壓的兒童及青少年在成年後較有心血管代謝的健康問題。

Hypertension is one of common chronic diseases and an important risk factor of cardiovascular disease. With the increasing prevalence of childhood obesity, the childhood hypertension is increasing as well. Early detection and control of hypertension for children and adolescent may help to prevent the adulthood hypertension and other cardiovascular diseases. Blood pressure measurement is not included in the regular health checkup for school children and there are limited studies on hypertension in children and adolescents. This study is to investigate factors associated with childhood hypertension using data obtained from a mass urine screening campaign among school children in Taiwan Province, 1992-2000. We also conducted a follow-up study among children with hypertension to investigate the impact of childhood hypertension on the early adulthood health, 10 years after the screening campaign, especially the cardiovascular metabolic abnormalities. This study therefore consists of two projects: (1) The first study is a case-control study. We identified school children with urine screening positive in the 1992-2000 campaign. We used the childhood hypertension criteria of American National High Blood Pressure Education Program Working Group to determine hypertensive cases. The available information included anthropometrics, measurement of blood pressure, and selected biochemicals. We selected non-hypertensive children also from urine screening positive children as controls, frequency matched by age and sex to conduct nested case-control analyses for risks associated with childhood hypertension. (2) The second part of study is a follow-up study. Urine screening positive students who lived in Taipei and Taichung were invited for a follow-up health examination including questionnaire interviews, anthropometric measures and blood pressure, blood tests, urine screenings, and exams of atherosclerosis. In this prospective cohort study, we considered those hypertensive children identified from the mass urine screening campaign as exposed group and non-hypertensive students as non-exposed controls for comparison. In the case-control study we found: (1) The prevalence of obesity in cases was three times higher than that in controls (17.9% vs. 6.1%, p <0.0001). The multivariate logistic regression showed that the strongest risk for childhood hypertension was associated with obesity (OR = 3.45, 95% CI = 3.20-3.72). High cholesterol was also a factor associated with childhood hypertension. Both factors had the dose-response relationship with hypertension (p <0.0001). (2) A V-shape relationship was found between birth weight and hypertension risk. Among non-obese children, those with higher birth weight (OR = 1.19, 95% CI = 1.05-1.34) or low birth weight (OR = 1.1, 95% CI = 0.96-1.27) had higher risk of hypertension compared with children with the weight of 2500-2999 gram. (3)Compared with children with the lowest IgA decile, children with the highest IgA decile had higher risks for hypertension (OR = 1.20, 95% CI = 1.08-1.34), hypercholesterol (OR = 1.22, 95% CI = 1.11-1.34), and impaired fasting glucose (OR = 1.77, 95% CI = 1.62-1.93). The risk of impaired fasting glucose increased to 2.93 (95% CI = 1.93-4.44) among obese children with the highest decile of IgA. In the follow-up study, those with childhood hypertension at the baseline remained at a high risk of hypertensive than children without childhood hypertension (OR = 4.19, 95% CI = 2.42-7.28). They were also at higher risks of impaired fasting glucose (OR = 4.70, 95% CI = 1.62-13.6), and developing metabolic syndrome (OR = 4.20, 95% CI = 1.23-14.3). This study shows that obesity is the significant risk factor of hypertension for children and adolescents. High levels of IgA and birth weight are also associated with childhood hypertension. Childhood hypertension increases the risk of remaining hypertension and developing metabolic abnormalities later in young adulthood.