探讨肥胖患儿血清同型半胱氨酸(homocysteine, Hcy)、氧化低密度脂蛋白(oxidize low-density lipoprotein, OX-LDL)、丙二醛(malondialdehyde, MDA)及体重指数(body mass index, BMI)的相关性及其临床意义。

选择2007年1月至2007年12月本院门诊就诊，并按照儿童肥胖症诊断标准确诊，即采用WHO关于儿童肥胖诊断标准，体重超过同性别、同身高正常儿童平均值20%以上，具有与肥胖相应的多食少动等病史，体态匀称，无心、肺疾患，排除内分泌、代谢及中枢神经系统疾病引起的继发性肥胖的30例患儿纳入肥胖组(A组，n＝30)。其中，男性患儿为17例，女性为13例，年龄为7～12岁。选取同期在本院行体格检查的同年龄段健康儿童30例纳入对照组(B组，n＝30)。其中，男性儿童为16例，女性为14例，年龄为7～12岁(本研究遵循的程序符合本院人体试验委员会所制定的伦理学标准，得到该委员会批准，取得受试对象的知情同意，并与试验患儿监护人签署临床研究知情同意书)。两组儿童年龄、性别等比较，差异无显著意义(P>0.05)。血清氧化低密度脂蛋白、血清同型半胱氨酸采用双抗体夹心酶联免疫吸附测定法(enzyme linked immunosorbent assay，ELISA)，硫代巴比妥酸反应物质法测定丙二醛含量。本研究所有儿童抽血前3 d避免高蛋白饮食，并空腹12 h。

两组不同性别儿童血清同型半胱氨酸浓度比较，差异无显著意义(P>0.05)。A组儿童体重指数，血清同型半胱氨酸、氧化低密度脂蛋白、丙二醛水平明显高于B组，差异有显著意义(P<0.05)。直线相关分析表明，A组儿童血清同型半胱氨酸水平与体重指数明显相关(r＝0.44，P<0.05)，血清同型半胱氨酸水平与丙二醛的表达水平明显相关(r＝0.47, P<0.01)，血清同型半胱氨酸水平与氧化低密度脂蛋白水平无相关性(r＝0.30, P>0.05)。

肥胖儿童氧化应激加剧，血清同型半胱氨酸水平的增高与脂质过氧化有关。肥胖儿童存在脂质代谢异常。

To investigate the correlation of plasma homocysteine(Hcy), oxidized low-density lipoprotein(OX-LDL), malondialdehyde (MDA), and body mass index(BMI) in obese children and their clinical significances.

From January 2007 to December 2007, 30 children, 17 boys and 13 girls, aged 7-12, were diagnosed as secondary obesity (group A, n=30) according to the diagnosis standard of children's obesity, that is, the height and weight exceed 20% of the ordinary children of the same age, and they have illness history of having much food and little exercise which corresponds with the adiposity. They have well-proportioned body and no heart or lung diseases, no consequent fatness caused by incretion, metabolism, or central nervous system diseases. Meanwhile, another 30 healthy children, 16 boys and 14 girls, aged 7-12, were chosen to control group (group B, n=30). Informed consent was obtained from all participants. The whole procedure of this study was conformed to the ethic standard set by the human body experiment committee of the hospital and the study has been approved by this committee. The children involved in this experiment are clear about the whole process and their guardians have signed an agreement. There had no statistic significance in age and gender between two groups (P>0.05). Levels of oxidized low-density lipoprotein, homocysteine were measured by enzyme linked immunosorbent assay(ELISA). The concentration of plasma malondialdehyde was measured by thiobarbituric acid reactive substance(TBARS) method. All children were avoided to eat high-protein food for 3 days and fasted for 12 hours before the blood samples were taken.

No significant homocysteine level differences were found in boys and girls between two groups(P>0.05). Body mass index, homocysteine, malondialdehyde, oxidized low-density lipoprotein in group A were significantly higher than those of group B. Significant correlation between homocysteine level and body mass index (r=0.44, P<0.05), homocysteine level and malondialdehyde (r=0.47, P<0.01) were found in group A. There was not any relations between homocysteine levels and oxidized low-density lipoprotein (r=0.30, P>0.05).

There was an increased oxidative stress in obese children, and the increase of homocysteine level was closely associated with lipid peroxidation. Abnormal lipid metabolism exists in obese children.