Alvarez-Pedrerol Mar, Ribas-Fitó Núria, Torrent Maties, Julvez Jordi, Ferrer Carlos, Sunyer Jordi
Centre for Research in Environmental Epidemiology - IMIM, Barcelona, Spain.
Clin Endocrinol (Oxf). 2007 Jun;66(6):890-8. doi: 10.1111/j.1365-2265.2007.02871.x.
Thyroid hormone concentrations outside the normal range affect brain development, but their specific influence on behaviour and mental abilities within normal values is unknown. The objective of this study was to investigate whether thyroid hormone concentrations are related to neurodevelopment and ADHD (attention deficit and hyperactivity disorder) symptoms in healthy preschoolers. DESIGN SUBJECTS AND MEASUREMENTS: Children from two general population birth cohorts in Menorca (n = 289) and Ribera d'Ebre (n = 53), Spain, were assessed in a cross-sectional study at the age of 4. Thyroid hormones (free T4 and T3) and TSH concentrations were measured and mental and motor development was assessed using McCarthy's scales for neuropsychological outcomes and ADHD-DSM-IV for attention deficit and hyperactivity/impulsivity symptoms.
Children with TSH concentrations in the upper quartile of the normal range performed lower on McCarthy's scales and were at higher risk for attention deficit and hyperactivity/impulsivity symptoms. In the Menorca cohort, a decrease of 5.8 (P < 0.05) and 6.9 (P < 0.01) points was observed in memory and quantitative skills, respectively. In contrast, high T4 concentrations were associated with decreased risk of having 1-5 attention deficit symptoms (odds ratio: 0.25; P < 0.01); these findings were observed in both cohorts despite differences in mean TSH concentrations. No associations were observed with T3.
Despite being within the normal range, high TSH concentrations are associated with a lower cognitive function and high TSH and low free T4 with ADHD symptoms in healthy preschoolers. Statistically significant differences were observed in the highest quartiles of TSH, suggesting a need for re-evaluation of the upper limit of the normal TSH range.
甲状腺激素浓度超出正常范围会影响大脑发育，但其在正常范围内对行为和心理能力的具体影响尚不清楚。本研究的目的是调查健康学龄前儿童的甲状腺激素浓度是否与神经发育及注意力缺陷多动障碍（ADHD）症状相关。
设计、研究对象与测量方法：在一项横断面研究中，对西班牙梅诺卡岛（n = 289）和埃布罗河畔里韦拉（n = 53）两个普通人群出生队列中的儿童在4岁时进行了评估。测量了甲状腺激素（游离T4和T3）和促甲状腺激素（TSH）浓度，并使用麦卡锡神经心理量表评估心理和运动发育情况，使用ADHD-DSM-IV评估注意力缺陷和多动/冲动症状。
TSH浓度处于正常范围上四分位数的儿童在麦卡锡量表上的得分较低，且出现注意力缺陷和多动/冲动症状的风险较高。在梅诺卡岛队列中，记忆和定量技能分别下降了5.8分（P < 0.05）和6.9分（P < 0.01）。相比之下，高T4浓度与出现1 - 5种注意力缺陷症状的风险降低相关（优势比：0.25；P < 0.01）；尽管平均TSH浓度存在差异，但在两个队列中均观察到了这些结果。未发现与T3有关联。
在健康学龄前儿童中，尽管TSH浓度处于正常范围内，但高TSH浓度与较低的认知功能相关，高TSH和低游离T4与ADHD症状相关。在TSH的最高四分位数中观察到了具有统计学意义的差异，这表明需要重新评估正常TSH范围的上限。
