Population Health Sciences Institute, Newcastle University, Sir James Spence Institute, Royal Victoria Infirmary, Newcastle upon Tyne, United Kingdom.
Royal Hospital for Children, Glasgow, United Kingdom.
Thyroid. 2021 Jun;31(6):876-883. doi: 10.1089/thy.2020.0005. Epub 2020 Dec 29.
The etiology of most cases of congenital hypothyroidism (CHT) due to thyroid dysgenesis (DG) is unknown. If transient environmental factors can impact on thyroid gland development, then clustering of cases in time and/or space may occur, and this would be more likely in thyroid DG than dyshormonogenesis (DHG). The newborn screening program for CHT in Scotland is linked to a central database that includes case details such as postcode. The etiology of CHT is investigated in many cases of CHT using scintigraphy and/or ultrasonography. We looked for evidence of a change in CHT incidence with year of birth and according to season of the year. We then undertook space-time clustering analysis (using a method based on -functions, with nearest neighbor thresholds) of CHT in Scotland between 1979 and 2015. We also looked for evidence of overall changes associated with sex and area-based birth density. Of 531 cases with CHT during the study period, 290 cases had been categorized as DG ( = 229) or DHG ( = 61) following more detailed investigation. The incidence of CHT increased with year of birth and was in part linked to changing methodology, but there was no seasonality. There was no evidence of overall space-time clustering ( = 0.06), but there was evidence of clustering in babies with DG ( = 0.007). This picture appeared to be most closely linked to underlying thyroid gland hypoplasia rather than thyroid gland agenesis or ectopia. There was significant space-time clustering for both males and females, but clustering was restricted to lesser birth density areas. There was also evidence of clustering for unknown cases ( < 0.001). Clustering of these cases was restricted to females but was present for cases from both greater and lesser birth density areas. There was no evidence of clustering in cases of DHG. These data suggest that an unidentified environmental factor or factors may be involved in the etiology of thyroid DG in Scotland. The variation in CHT incidence observed internationally may reflect environmental as well as genetic factors.
大多数由甲状腺发育不良（DG）引起的先天性甲状腺功能减退症（CHT）的病因尚不清楚。如果短暂的环境因素可以影响甲状腺的发育，那么病例在时间和/或空间上可能会聚集，而在甲状腺 DG 中比在激素生成障碍（DHG）中更有可能发生这种情况。苏格兰的先天性甲状腺功能减退症新生儿筛查计划与一个中央数据库相关联，该数据库包含病例详细信息，例如邮政编码。在许多先天性甲状腺功能减退症病例中，使用闪烁扫描和/或超声检查来研究先天性甲状腺功能减退症的病因。我们根据出生年份和一年中的季节寻找先天性甲状腺功能减退症发病率变化的证据。然后，我们在 1979 年至 2015 年期间对苏格兰的先天性甲状腺功能减退症进行了时空聚类分析（使用基于 -函数的方法，带有最近邻阈值）。我们还寻找了与性别和基于区域的出生密度相关的整体变化的证据。在研究期间，有 531 例患有先天性甲状腺功能减退症的病例，其中 290 例经过更详细的调查后被归类为 DG（ = 229）或 DHG（ = 61）。先天性甲状腺功能减退症的发病率随着出生年份的增加而增加，部分原因与不断变化的方法有关，但没有季节性。没有整体时空聚类的证据（ = 0.06），但在患有 DG 的婴儿中存在聚类的证据（ = 0.007）。这种情况似乎与甲状腺发育不全而不是甲状腺发育不全或异位密切相关。男性和女性都有明显的时空聚类，但聚类仅限于出生密度较低的地区。对于未知病例也有聚类的证据（ < 0.001）。这些病例的聚类仅限于女性，但存在于出生密度较大和较小的地区的病例中。DHG 病例中没有聚类的证据。这些数据表明，在苏格兰，甲状腺 DG 的病因可能涉及未识别的环境因素或因素。国际上观察到的先天性甲状腺功能减退症发病率的变化可能反映了环境和遗传因素。
