ESPE Abstracts

Introduction: Reliable reference values for thyroid ultrasound measurements are essential to effectively guide individual diagnostics and direct health care measures at the population level, such as iodine fortification programs. However, the latest reference values for total thyroid volume (Tvol) provided by the WHO in 2004 are only applicable to the 6 to 12-year-old age group. Moreover, these values are derived from countries with a long history of iodine sufficiency, which doesn't reflect the situation in most European countries, including Germany.

Methods: Data from the baseline assessment of a nationwide study in German children and adolescents (KiGGS) conducted between 2003 and 2006 was used to determine sex-specific reference values for Tvol in thyroid-healthy participants aged 6 to 18 years by age and body surface area (BSA) according to the Lambda-Mu-Sigma (LMS) method.

Results: After exclusion of 5005 participants who did not meet the inclusion criteria, mainly due to missing information, and 994 datasets from three examiners who provided deviant Tvol measurements, data from 5559 participants was available for reference chart construction (girls: 2509 (45.1%)| reference charts according to age - Nmedian: 469.5, Nmin: 398, Nmax: 573 | BSA - Nmedian: 874, Nmin: 62, Nmax: 1061). The data show a continuous increase in Tvol for boys up to the age of 18 years, a pattern also seen in girls, albeit with a slowing trend at advanced ages. Additionally, although girls have larger Tvol during early puberty, this trend reverses later on. This effect is partially mediated by BSA. On average, the 97th percentile is 33.4% and 28.5% higher than the corresponding WHO’s reference values for boys and girls, respectively. This is consistent with most other studies in German and European children and adolescents at a similar time of investigation. Notably, the sample used for this study was iodine-sufficient according to WHO criteria.

Conclusions: We present the most recent reference values for Tvol for German children and adolescents under iodine-sufficient conditions. The reference values provided by the WHO are overly conservative for this population, possibly for reasons of long-term iodine supply. Given the methodological strengths of this study - including its representativeness, sample size, and comprehensive information, including laboratory findings - these reference values could potentially be applicable to other European countries with a similar history of iodine supply.