Soy Formula andthe Management of Congenital Hypothyroidism

Abstract

Endocrinology| June 01 2004 Soy Formula andthe Management of Congenital Hypothyroidism AAP Grand Rounds (2004) 11 (6): 68–69. https://doi.org/10.1542/gr.11-6-68-a Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Twitter LinkedIn Tools Icon Tools Get Permissions Cite Icon Cite Search Site Citation Soy Formula andthe Management of Congenital Hypothyroidism. AAP Grand Rounds June 2004; 11 (6): 68–69. https://doi.org/10.1542/gr.11-6-68-a Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search nav search search input Search input auto suggest search filter All PublicationsAll JournalsAAP Grand RoundsPediatricsHospital PediatricsPediatrics In ReviewNeoReviewsAAP NewsAll AAP Sites Search Advanced Search Topics: congenital hypothyroidism Source: Conrad SC, Chiu H, Silverman BL. Soy formula complicates management of congenital hypothyroidism. Arch Dis Child. 2004;89:37–40. Two case reports from 1995 and 1997 described children with congenital hypothyroidism and prolonged abnormal thyroid function tests while on soy formula.1,2 This retrospective study done at Northwestern Medical School in Chicago, Ill, was designed to evaluate the hypothesis that infants with congenital hypothyroidism who were fed soy formula have a prolonged thyroid-stimulating hormone (TSH) increase when compared to similarly affected infants who were fed a non-soy formula. The subjects were identified by their thyroid scan records, as these studies were performed on all patients at Children’s Memorial Hospital in Chicago suspected of having congenital hypothyroidism. Based on the dietary history recorded in the medical record, subjects were separated into either the soy or non-soy diet group, with the soy group consistently recorded as being on a soy formula throughout the first year of life. Ninety-nine patients with congenital hypothyroidism were identified between 1990 and 1998. Twenty-one children were excluded due to incomplete records or discontinuation of clinic visits before the age of 1 year. Of the remaining seventy-eight patients, 8 were in the soy diet group and 70 in the non-soy group. Seventy-one percent of the infants had thyroid dysgenesis and 17% had dyshormonogenesis. The levothyroxine dose used in both groups was comparable both initially and throughout the first year of life. Treatment in the soy group was started at 15 days and the non-soy group at 17 days. There was no difference in either the TSH or total thyroxine (T4) levels prior to treatment initiation. The first total T4 levels checked after the treatment initiation were similar in the 2 groups, but there was a marked difference in the first TSH measured after treatment was started. The soy diet group had a median TSH of 42.6 mU/l compared to 6.6 mU/l in the non-soy group. The first T4 and TSH were drawn at a median age of 50 days in both groups and the normalization of TSH was evaluated. The time that it took to achieve TSH of <10 mU/l differed, with the soy diet group taking a median of 150 days (range 54–229) compared to 40 days (19–189) in the non-soy diet group. At 4 months of age, 62.5% of the soy diet group continued to have increased TSH levels compared to 17% of the non-soy diet group, and this trend persisted throughout the first year of life. The authors concluded that infants with congential hypothyroidism who were fed a soy formula need close monitoring of free T4 and TSH and may require increased levothyroxine doses to achieve normal thyroid function tests. As normal development is critically dependent upon rapid normalization of thyroid function,3,4 the finding that ingestion of a soy formula is a possible barrier to achieving this goal has important implications. Although doses of levothyroxine of 7.4–9.3 μg/kg/day used to treat the... You do not currently have access to this content.