ENDEMIC INFANTILE HYPOTHYROIDISM IN A SEVERE ENDEMIC GOITRE AREA OF CENTRAL AFRICA

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Abstract
Thyroid function and exposure to dietary goitrogenic factors (iodine deficiency and thiocyanate overload) were studied at birth and from birth to 7 years in 200 neonates and 347 children living in the severe endemic goitre area of Ubangi, Northern Zaire. Serum T4 was at the lower limit of normal at birth (104 ± 4 nmol/1) and stayed at that level during the first year of life (123 ± 9) (NS), but decreased to 75 ± 8 (P < 0·001) at 2–4 years and to 62 ± 6 (P < 0·001) at 5–7 years of age. Mean serum FT4 decreased from 10·4 ± 0·9 pmol/1 during the first year to 8·2 ± 1·0 (NS) at 2–4 years (NS) and to 7·7 ± 0·9 (P < 0·05) at 5–7 years. Mean serum TSH was 10·4 (8·4‐12·9) m U/1 (geometric mean ± 1 SEM) during the first year, 10·1 (7·5‐13·7) (NS) at 2–4 years and 24·3 (18·5–31·9) (P < 0·05) at 5–7 years. Mean serum T3 was 3·23 ± 0·12 nmol/1 during the first year and remained stable thereafter. The frequencies of low T4 (T4 < 77 nmol/1), high TSH TSH (TSH > 50 mU/1), and low T4 and T3 (T3 < 1·69 nmol/l) were twice as high at 5–7 years as in the first year (respectively 65%, 42% and 15%). The urinary iodide concentration of the children was stable and low throughout the study period. By contrast, serum thiocyanate concentration which was high at birth (129 ± 5 ųmol/1) decreased to normal values between 3 and 12 months of age and increased again during and after weaning (1 to 3 years of age) to reach a value of 138 ųmol/l which was comparable to that observed in adults in the same area. Thiocyanate concentration was high (133 ± 7 ųmol/l) in the mothers' serum but low in the mothers' milk (57 ± 3 ųmol/1) (P < 0·01). Multivariate analysis