Longitudinal Study of Thyroid Function in Children with Mild Hyperthyrotropinemia at Neonatal Screening for Congenital Hypothyroidism

• Published in: The journal of clinical endocrinology and metabolism Vol. 93; no. 7; pp. 2679 - 2685
• Main Authors: Leonardi, Daniela, Polizzotti, Nunziella, Carta, Anna, Gelsomino, Rossella, Sava, Lidia, Vigneri, Riccardo, Calaciura, Francesca
• Format: Journal Article
• Language: English
• Published: Bethesda, MD Endocrine Society 01.07.2008
• Subjects: Biological and medical sciences; Child; Child, Preschool; Congenital Hypothyroidism - diagnosis; Congenital Hypothyroidism - physiopathology; Endocrinopathies; False Positive Reactions; Feeding. Feeding behavior; Fundamental and applied biological sciences. Psychology; Humans; Infant, Newborn; Longitudinal Studies; Medical sciences; Neonatal Screening; Non tumoral diseases. Target tissue resistance. Benign neoplasms; Thyroid Gland - physiopathology; Thyroid. Thyroid axis (diseases); Thyrotropin - blood; Thyroxine - blood; Triiodothyronine - blood; Vertebrates: anatomy and physiology, studies on body, several organs or systems; Vertebrates: endocrinology; Endocrinopathy; Human; Obesity; Neonatal; Congenital; Nutrition; Thyroid diseases; Nutrition disorder; Metabolic diseases; Medical screening; Hypothyroidism; Congenital disease; Newborn; Follow up study; Thyroid function; Child; Endocrinology; Nutritional status
• ISSN: 0021-972X; 1945-7197
• DOI: 10.1210/jc.2007-2612

Objective: Long-term outcome of thyroid function in children with very short-lasting neonatal hyperthyrotropinemia (“false positive” at neonatal screening) was studied in an observational, prospective study. Thyroid function and morphology were evaluated in 44 “false positive” children up to advanced childhood (8.0 ± 0.7 yr of age). In these children a high prevalence (50%) of subclinical hypothyroidism in early childhood (2.8 ± 0.5 yr) had already been described. Results: At an average of 5.3 yr, subclinical hypothyroidism persisted in 19 of 44 (43.2%) children and, more specifically, in two of three of those who had increased TSH in early childhood. Euthyroidism was present in all cases that were euthyroid in early childhood, although they had TSH and free T3 values significantly higher than control children with a normal TSH at birth (TSH = 2.6 ± 0.7 vs. 1.5 ± 0.6 mU/liter, P < 0.001; free T3 = 4.9 ± 0.8 vs. 3.9 ± 0.9 pmol/liter, P < 0.01). Thyroid morphology alterations were frequent in the group of children with subclinical hypothyroidism. At an average of 8.0 yr, subclinical hypothyroidism persisted in 14 of 44 (31.8%) children. In all other children, TSH and thyroid hormones were confirmed within the normal range. Conclusions: This prospective longitudinal study confirms that newborns “false positive” at neonatal screening have a high risk to develop persistent subclinical hypothyroidism. The prevalence of hypothyroidism decreases with increasing age, but it is still high (>30%) in late childhood. Even those “false positive” children that maintain euthyroidism in late childhood have an average TSH value that, although within the normal range, is higher than in normal controls, a possible marker of minor congenital thyroid function abnormalities.