Objective: To assess iodine status and goitre prevalence in a sample of schoolchildren in Melbourne.
Design: Cross-sectional study of urinary iodine excretion and presence of goitre in a sample of schoolchildren from Years 5–12 attending two urban schools.
Participants: 607 children aged 11–18 years consented to thyroid gland palpation and 577 provided a urine sample on the day of examination in August 2001.
Outcome measure: Iodine status of the study population, based on median urinary iodine values categorised as normal (≥ 100 μg/L), mild (50–99 μg/L) or moderate–severe (< 50 μg/L), and classified according to sex, school year and presence of goitre.
Results: 76% (439/577) of students had abnormal urinary iodine values, with 27% (156/577) having values consistent with moderate–severe deficiency. The median urinary iodine excretion for the total group was 70μg/L, with values for school years 5–12 ranging from 62 μg/L (Year 12) to 76 μg/L (Year 9). The median urinary iodine value in girls was lower than that in boys (64μg/L v 82 μg/L), and girls had significantly lower urinary iodine values overall (P < 0.002). There was no association between goitre grade and moderate–severe (< 50 μg/L; P = 0.39) or mild (50–99 μg/L; P = 0.07) urinary iodine deficiency.
Conclusions: We found mild iodine deficiency in a cohort of schoolchildren in Melbourne. Our results support other data showing mild iodine deficiency in Sydney and Tasmania and the argument for a national study of iodine nutrition.
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