Iodine deficiency alone cannot account for goitre prevalence among pregnant women in Modhupur, Bangladesh

Abstract

We wished to determine the contributing causes of goitre among pregnant women in rural Bangladesh to provide baseline data before instituting iodine supplementation. DESIGN: All pregnant women in a subdistrict of Modhupur, Bangladesh were assessed for goitre size and were asked to give blood and urine samples for measurement of iodine status and thyroid hormones. SETTING: Field study in 72 villages in rural Modhupur. SUBJECTS: 356 women at all stages of gestation. RESULTS: Total goitre prevalence was 99%, and 79% of the women had goitres of grade 2 or 3. Nevertheless, urinary iodine levels indicated only moderate iodine deficiency with 23% below 0.16 mumol/l and 62% below 0.39 mumol/l. Plasma thyroid-stimulating hormone was elevated in 19% of the women. Other dietary factors which could potentially contribute to goitre--vitamin A or selenium deficiency or intake of large amounts of thiocyanate-producing goitrogens--were found not to be a problem among these women. Multiple regression analysis of the causes of goitre, including measures of iodine status and anthropometric variables, could account for only 12% of the variability in goitre grade. CONCLUSIONS: High goitre prevalence can occur even in the absence of severe iodine deficiency. Therefore, iodine supplementation may not completely solve a community goitre problem