title: Iodine deficiency and subclinical hypothyroidism are common in cystic fibrosis patients.
abstract: BACKGROUND
  Disorders of thyroid function have been inconsistently described in cystic fibrosis (CF) patients and in CF transmembrane regulator protein knockout animals. The literature lacks reports on iodine status of CF individuals. We hypothesize, that iodine deficiency is common in CF and account for abnormal thyroid function in CF patients.
  
  
  METHODS
  We investigated 129 children, adolescents, and adults with CF, who were living in the northern part of Bavaria/Germany. Malnutrition and lung function were analyzed. Urinary iodine excretion, TSH (thyroid-stimulating hormone), and ft4 (free thyroxine) were measured and set in relation to population-based, age-adjusted reference ranges.
  
  
  RESULTS
  Subclinical hypothyroidism (normal fT4, elevated TSH) was found in 11.6% of subjects, and iodine deficiency in 83.7%. No correlations were found with age, BMI, status of malnutrition, or lung function.
  
  
  CONCLUSIONS
  Dramatic iodine deficiency was found in our cohort of CF patients. This condition can cause subclinical hypothyroidism; therefore, an individual iodine supplementation program is necessary and should be started immediately.
authors.affiliation: Department of Pediatrics, Justus-Liebig-University Giessen, Giessen/Germany, Feulgenstrasse 12, Giessen, Germany. lutz.naehrlich@paediat.med.uni-giessen.de
authors.forename: Lutz
authors.initials: L
authors.lastname: Naehrlich
authors.forename: Helmuth-Günther
authors.initials: HG
authors.lastname: Dörr
authors.forename: Azadeh
authors.initials: A
authors.lastname: Bagheri-Behrouzi
authors.forename: Manfred
authors.initials: M
authors.lastname: Rauh
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D002648:Child; D002675:Child, Preschool; D003550:Cystic Fibrosis / Q000097:blood / Q000150:complications* / Q000652:urine; D005260:Female; D006801:Humans; D007037:Hypothyroidism / Q000097:blood / Q000209:etiology* / Q000652:urine; D007223:Infant; D007454:Iodides / Q000652:urine; D007455:Iodine / Q000172:deficiency*; D008297:Male; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000097:blood; D055815:Young Adult
chemical_list: D007454:Iodides; D013972:Thyrotropin; D007455:Iodine; D013974:Thyroxine