Goiter Prevalence and Thyroid Autoimmunity in School Children of Delhi

Several studies from India, performed prior to 2010, have reported a goiter prevalence of greater than five per cent in school going children. There has been considerable success in universal salt iodization efforts in the past decade. We studied the prevalence of goiter and thyroid autoimmunity in school going children in Delhi between 2010 and 2014 to assess the impact of salt iodization.

The study employed the population proportionate to size (PPS) cluster sampling methodology to select subjects between the age of six and 14 years, from all 34 wards of 9 districts of Delhi. Cluster randomization sampling design was followed and in this way we identified 30 wards, from each of which 90 children were recruited for the study. The total sample size was 2700 children. Estimation of fT3, fT4, TSH, anti-TPO antibodies and urine iodine concentration (UIC) was done for 10% of the study population.

The prevalence of goiter in this study in the 6-14 years age group was 6.4%. The prevalence of goiter was higher in females (7.7% compared to 5.3% in males, P = 0.01). In the 270 subjects who were selected for biochemical evaluation, subclinical hypothyroidism was seen in 18.4% and positive anti-TPO antibodies were seen in 14.8%. The median UIC was 150 μg/L.

There is improvement in goiter prevalence in the post-iodization period in Delhi. But still, residual goiter rates are above five per cent suggesting presence of other causes of goiter in this area. There is a high prevalence of thyroid autoimmunity in this population.