ABSTRACT
OBJECTIVES: To determine whether pregnant women and their newborns show evidence of iodine deficiency, and to examine the correlation between maternal urine iodine concentration (UIC) and newborn thyroid-stimulating hormone (TSH) level. DESIGN: A cross-sectional study. SETTING: Hospital antenatal care services (March-May 2004) and private obstetrician clinics (June 2004) in the Central Coast area of New South Wales. PARTICIPANTS: 815 pregnant women (> or = 28 weeks' gestation) and 824 newborns. MAIN OUTCOME MEASURES: World Health Organization/International Council for the Control of Iodine Deficiency Disorders criteria for assessing severity of iodine deficiency (recommended levels: < 20% of urine samples in a population with UIC < 50 microg/L; and < 3% of newborns with whole-blood TSH level > 5 mIU/L). RESULTS: The median UIC for pregnant women was 85 microg/L, indicating mild iodine deficiency. Almost 17% of pregnant women had a UIC < 50 microg/L, and 18 newborns (2.2%) had TSH values > 5 mIU/L. There was no statistically significant linear correlation between neonatal whole-blood TSH level and maternal UIC (r = - 0.03; P = 0.4). Mothers with a UIC < 50 microg/L were 2.6 times (relative risk = 2.65; 95% CI, 1.49-4.73; P = 0.01) more likely to have a baby with a TSH level > 5 mIU/L. CONCLUSION: The pregnant women surveyed were mildly iodine deficient. TSH values for their newborns were mostly within acceptable limits. Ongoing surveillance of the iodine status of NSW communities to establish trends over time is recommended.
Subject(s)
Infant, Newborn/blood , Iodine/urine , Pregnancy/urine , Thyrotropin/blood , Adult , Cross-Sectional Studies , Deficiency Diseases/blood , Deficiency Diseases/epidemiology , Deficiency Diseases/urine , Female , Health Surveys , Hospitals, Private/statistics & numerical data , Hospitals, Public/statistics & numerical data , Humans , Iodine/deficiency , New South Wales/epidemiology , Pregnancy Complications/epidemiology , Pregnancy Complications/urine , Risk FactorsABSTRACT
OBJECTIVE: To determine the prevalence of iodine deficiency in primary school children in an Australian urban population. DESIGN AND SETTING: A cross-sectional survey of school children aged 5-13 years attending a public school on the Central Coast of New South Wales in November 2000. PARTICIPANTS: 324 (70%) of the 465 children enrolled in the school (180 boys; 144 girls). MAIN OUTCOME MEASURES: Thyroid volumes compared with World Health Organization/International Council for the Control of Iodine Deficiency Disorders (WHO/ICCIDD) thyroid volume reference values. Iodine status based on WHO/ICCIDD urinary iodine concentration (UIC) categories (normal, >/= 100 microg per litre of urine [microg/L]; mild iodine deficiency, 50-99 microg/L; moderate deficiency, 20-49 microg/L; severe deficiency, < 20 microg/L); not more than 20% of the population should have a UIC below 50 microg/L. RESULTS: Median UIC for school children was 82 microg/L, and 14% of children had UICs below 50 microg/L. Thyroid volume reference values indicated a prevalence of goitre of zero. In girls, only four (3%) and one (1%) had thyroid volumes above the WHO/ICCIDD medians by age and body surface area (BSA), respectively (P < 0.001). In boys, three (2%) and one (1%) had thyroid volumes above WHO/ICCIDD medians by age and BSA, respectively (P < 0.001). CONCLUSION: Despite the median UIC being less than ideal, most children were not goitrous. This underscores the importance of using physiological outcome measures in areas where iodine deficiency is marginal before concluding the need for iodine supplementation based purely on median UIC. We call for a systematic national survey to determine iodine status using a combination of iodine deficiency indicators.
