Dundar Bumin, Oktem Faruk, Arslan Meltem Koyuncu, Delibas Namik, Baykal Bahattin, Arslan Cağatay, Gultepe Mustafa, Ilhan Inci Ergurhan
Department of Pediatrics, Faculty of Medicine, Suleyman Demirel University, Merkez 32040, Isparta, Turkey.
Environ Res. 2006 May;101(1):140-5. doi: 10.1016/j.envres.2005.10.002. Epub 2005 Dec 19.
This study investigated blood lead (Pb-B) levels and Pb-B effects on thyroid functions in long-term low-level-lead-exposed male adolescents who work as auto repairers. Pb-B and ALAD index (logarithm of activated delta-aminolaevulinic acid dehydratase/nonactivated delta-aminolaevulinic acid dehydratase) were measured as indicators of exposure to lead. Thyroid function tests including free thyroxine (FT4), free triiodothyronine (FT3), and thyrotrophin (TSH) were conducted and thyroid ultrasounds were performed in 42 lead-exposed adolescents and 55 healthy control subjects. Mean Pb-B levels and ALAD index were found significantly higher in the study group than in the normal control group (7.3+/-2.92 microg/dl vs. 2.08+/-1.24 microg/dl, P < 0.001 and 0.44+/-0.26 vs. 0.29+/-0.23, P < 0.05, respectively). FT4 levels were found significantly lower in the study group (1.02+/-0.18 mI/mL and 1.12+/-0.14 mIU/mL, P < 0.05). No subject in the control group had an abnormal FT4 level, but FT4 levels were found under normal limits in 11 subjects (26%) in the study group. FT3 and TSH levels in the study and control groups did not differ (P > 0.05). Thyroid volumes in the study and control groups did not exhibit any significant differences (P > 0.05). Pb-B was found to be negatively correlated to FT4 levels (r = -0.20, P = 0.044). This study revealed that long-term low-level lead exposure may lead to reduced FT4 level without significant changes in TSH and T3 levels in adolescents even at low Pb-B levels.
本研究调查了长期低水平铅暴露的男性青少年汽车修理工的血铅（Pb-B）水平及其对甲状腺功能的影响。测量血铅和ALAD指数（活化δ-氨基乙酰丙酸脱水酶/非活化δ-氨基乙酰丙酸脱水酶的对数）作为铅暴露指标。对42名铅暴露青少年和55名健康对照者进行了包括游离甲状腺素（FT4）、游离三碘甲状腺原氨酸（FT3）和促甲状腺激素（TSH）在内的甲状腺功能测试，并进行了甲状腺超声检查。研究组的平均血铅水平和ALAD指数显著高于正常对照组（分别为7.3±2.92μg/dl对2.08±1.24μg/dl，P<0.001；0.44±0.26对0.29±0.23，P<0.05）。研究组的FT4水平显著较低（1.02±0.18mI/mL和1.12±0.14mIU/mL，P<0.05）。对照组中无受试者FT4水平异常，但研究组中有11名受试者（26%）的FT4水平低于正常范围。研究组和对照组的FT3和TSH水平无差异（P>0.05）。研究组和对照组的甲状腺体积无显著差异（P>0.05）。发现血铅与FT4水平呈负相关（r=-0.20，P=0.044）。本研究表明，长期低水平铅暴露可能导致青少年FT4水平降低，即使血铅水平较低时TSH和T3水平也无显著变化。
