Assessment of iodine deficiency disorders using the 30 cluster approach in district Kangra, Himachal Pradesh, India

Iodine deficiency is an important public health problem in Himachal Pradesh. District Kangra is a known iodine deficiency endemic area. A survey conducted in 1956 reported a goitre prevalence of 55 per cent in the district. A more recent pilot study (1994) in four blocks of the district reported the total goitre rate (TGR) as 7 per cent. A continued prevalence of goitre in more than 5 per cent of school-aged children was found in pilot study, in spite of the distribution of iodised salt. The present study was conducted to assess the prevalence of iodine deficiency disorders (IDD) and to estimate the iodine content of salt consumed by the population in district Kangra. The '30 cluster' sampling methodology and indicators for assessment of IDD, as recommended by the joint WHO/UNICEF/ICCIDD consultation, were utilized for the survey. A confidence level of 95 per cent, a relative precision of 10 per cent and a design effect of three were taken into account for calculation of the sample size. A total of 23,348 school children in the age group 6-11 years were included in the study. The total goitre prevalence rate was found to be 12.1 per cent. The median urinary iodine excretion of the children studied was found to the 15.00 mcg/dl. About 12.7 per cent of families consumed salt with an iodine content of less than 15 ppm. The results of the present study indicated that the population of district Kangra is in a transition phase from iodine deficient to iodine sufficient nutrition and that there is a need for further strengthening of the system of monitoring the quality of iodised salt made available to the population to eliminate IDD from the Kangra Valley.