To study the total goitre rate (TGR), urinary iodine concentration (UIC) and salt iodine content among schoolchildren in a previously endemic area for severe iodine deficiency disorder (IDD).

Cross-sectional epidemiological study.

The study was carried out in the Gonda district (sub-Himalayan region) of North India.

Nine hundred and seventy-seven schoolchildren (6–12 years) were studied for parameters such as height, weight, UIC and salt iodine content. Thyroid volume (TV) was measured by ultrasonography to estimate TGR.

The overall TGR in the study population was 2·8 % (95 % CI 1·8, 3·8). No significant difference in TGR was observed between boys and girls (3·5 % v. 1·9 %, P = 0·2). There was a non-significant trend of increasing TGR with age (P = 0·05). Median UIC was 157·1 μg/l (interquartile range: 94·5–244·9). At the time of the study, 97 % of salt sample were iodised and nearly 86 % of salt samples had iodine content higher than or equal to 15 part per million. Overall, TGR was significantly lower (2·8 % v. 31·0 %, P < 0·001), and median UIC was significantly higher (157·1 v. 100·0 μg/l, P < 0·05) than that reported in the same area in 2009.

A marked improvement was seen in overall iodine nutrition in the Gonda district after three and a half decades of Universal Salt Iodisation (USI). To sustainably control IDD, USI and other programmes, such as health education, must be continuously implemented along with putting mechanisms to monitor the programme at regular intervals in place.