population of the eight cities, according to 2001 national census data. Willing participants signed a written informed consent. Participants were excluded if they were pregnant, or had any acute or chronic systemic illnesses as judged by the study investigator.
The study was approved by a Central Ethics Committee (CEC) and carried out in accordance with the approved protocol, principles of Declaration of Helsinki and Good Clinical Practices. It was registered with the Clinical Trials Registry India (registration no: CTRI/2011/11/002180).
Thyroid abnormalities were diagnosed by measuring the status of thyroid hormones - serum FT3, FT4 and thyroid stimulating hormone [TSH].
Hypothyroidism, commonly categorized under the cluster of iodine deficiency disorders (IDDs), is a common health issue in India, as it is worldwide. Since the time India adopted the universal salt iodization program in 1983, there has been a decline in goiter prevalence in several parts of the country which were endemic in the pre-iodization period. With a majority of households (83.2% urban and 66.1% rural) now consuming adequate iodized salt, India is supposedly undergoing a transition from iodine deficiency to sufficiency state (WHO 2004).[4,5,6] A recent review of studies conducted in the post-iodization phase gives some indication of the corresponding change in the thyroid status of the Indian population, and thyroid disorders seem to be increasing despite India being an iodine sufficient country now.