Urine and milk iodine concentrations in healthy and congenitally hypothyroid neonates and their mothers.
BACKGROUND
In view of the high prevalence of Congenital Hypothyroidism (CH) in Iran, in this study we evaluated the role of iodine in the aetiology of CH by comparing urine and milk iodine concentrations in healthy and congenitally hypothyroid neonates and their mothers.


METHODS
In a cross-sectional study, urinary iodine concentrations (UIC) in newborns with CH, as well as UIC and the milk iodine concentrations (MIC) of their mothers, were measured and compared with a control group. The lower, mid, and upper range of UIC for neonates and lactating mothers was considered to be < 150 μg/L, 150-230 μg/L, and > 230 μg/L, and lower, mid, and upper range of MIC was considered to be < 150 μg/L, 150-180 μg/L, and > 180 μg/L, respectively.


RESULTS
The median UICs in subjects with CH (n = 68) and healthy subjects (n = 179) were 300.5 and 290.5 μg/L, respectively (P > 0.05). The median UICs in the case and control groups were 150 and 130 μg/L, respectively (P > 0.05). The median MIC in the case group was higher than in the control group (210 μg/L v. 170 μg/L, P < 0.05).There was a positive correlation between newborn UIC and MIC. There was no significant correlation between newborn UIC and serum TSH, maternal UIC and maternal MIC, or newborn UIC and serum TSH.


CONCLUSIONS
There is no inadequacy in iodine intake in the studied population. Iodine excess could be a possible risk factor for CH, but there were findings, such as lack of correlation between maternal MIC and UIC, and the median neonatal UIC, which was similar in the two groups, so, drawing conclusions should be done with some caution and requires further studies.
Hashemipour
Mahin
M
Endocrine and Metabolism Research Centre, Isfahan University of Medical Sciences, Isfahan, Iran.
Nasri
Peyman
P
Hovsepian
Silva
S
Hadian
Rezvane
R
Heidari
Kamal
K
Attar
Hossein Movahedian
HM
Amini
Massoud
M
Moohebat
Leili
L
Sajadi
Ali
A
Ajami
Ali
A
D000328:Adult; D003409:Congenital Hypothyroidism / Q000453:epidemiology / Q000652:urine*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D007455:Iodine / Q000032:analysis* / Q000652:urine; D007492:Iran / Q000453:epidemiology; D008895:Milk, Human / Q000737:chemistry*; D009035:Mothers; D012016:Reference Values
D007455:Iodine