Zinc status in goitrous school children of Semirom, Iran.

BACKGROUND: Iodine deficiency produces the spectrum of iodine deficiency disorders (IDDs) including endemic goiter, hypothyroidism, cretinism and congenital anomalies. Other factors, including goitrogens and micronutrient deficiencies may influence the prevalence and severity of IDDs and response to iodine supplementation. An association between zinc and goiter has previously been reported. METHODS: A cross sectional study investigating an association between goiter and serum zinc status was performed in 2003 in a mountainous region of Iran. One thousand eight hundred twenty-eight children were selected by multistage cluster sampling. Goiter staging was performed by inspection and palpation. Serum zinc, total thyroxine, thyroid stimulating hormone and urinary iodine concentration were measured in a group of these children. RESULTS: Thirty six and seven tenth percent of subjects were classified as goitrous. Serum zinc level in goitrous and nongoitrous children was 82.80 ± 17.85 and 83.38 ± 16.25 µg/dl, respectively (p = 0.81). The prevalence of zinc deficiency (serum zinc ≤65 µg/dl) in goitrous and nongoitrous children did not differ significantly (9.3 % vs. 10.8%, p = 0.70). CONCLUSIONS: Goiter is still a public health problem in Semirom. According to the present study zinc status may not play a role in the etiology of goiter in Semirom school children. However, the role of other goitrogens or micronutrient deficiencies should be investigated in this region.

High prevalence of goiter in an iodine replete area: do thyroid auto-antibodies play a role?

INTRODUCTION: Despite long standing iodine supplementation in Iran the prevalence of goiter remains high in some areas. This may suggest that causes other than iodine deficiency, such as autoimmune thyroid diseases, should also be considered. We therefore assessed the prevalence of anti-thyroid antibodies in children living in an inland area in Iran and correlated these findings with prevalence of goiter within this region. METHODS: In a cross-sectional study, 1948 students were selected by multistage random cluster sampling from the 108 primary schools (age, 7-13 year-old) of the urban and rural areas of Semirom. After obtaining written consent from their parents, the children were examined by endocrinologists for goiter grading. Grade 2 goitrous children (108 cases) were compared with non-goitrous children (111 children as control group) for anti-thyroid antibodies. RESULTS: Overall, 36.7% of 1948 students had goiter. The mean urinary iodine excretion level was 1.49+/-0.7 micromol/L. This was within normal limits. Of 219 children studied, 4.3% presented with subclinical hypothyroidism, and 7.3% had positive anti-thyroid antibodies. There was non-significant difference of positive thyroperoxidase antibody (anti-TPO) (Odds Ratio= 3.2, p= 0.13) but significant difference of anti Tg between goitrous and non goitrous children (Odds Ratio: 5.6, 95% CI: 1.18-26.0, p: 0.015). CONCLUSION: This study suggests that autoimmunity may be one of the mechanisms responsible for goiter persistence after iodine replenishment in this iodine deficient region, but the role of other factors should also be considered.