Study of biochemical prevalence indicators for the assessment of iodine deficiency disorders in adults at field conditions in Gujarat (India)

Abstract

The main objective of this study was to assess the severity of iodine deficiency disorders (IDD) in the adult populations of the Baroda and Dang districts from Gujarat, western India using biochemical prevalence indicators of IDD. The other aim of this study was to establish a biochemical baseline for adequate iodine intake as a result of program evolution in the face of multiple confounding factors, like malnutrition and goitrogens responsible for goiter. A total of 959 adults (16-85 years) were studied from two districts (Baroda and Dang) and data was collected on dietary habits, anthropometric and biochemical parameters such as height, weight, urinary iodine (UI) and blood thyroid stimulating hormone (TSH). Drinking water and cooking salt were analyzed for iodine content. All subjects, irrespective of sex and district, showed median UI = 73 microg/L and mean blood TSH +/- SD = 1.59+/-2.4 mU/L. Seven per cent of the studied population had blood TSH values > 5 mU/L. Females in Baroda and males from Dang district were more affected by iodine deficiency as shown by a lower median UI. Mean TSH was significantly higher in women from both districts as compared to men (P = 0.001). The blood spots TSH values > 5 mU/L were seen in 20% of women from Dang. The normative accepted WHO values for UI and TSH for the severity of IDD as a significant health problem are not available for target population of adults. Urinary iodine normative limits and cut-offs are established for school-aged children. Blood spot TSH upper limit and cut-off values are available for neonate populations. The IDD has not been eliminated so far, as more than 20% of both male and female subjects had UI < 50 microg/L. Males were more malnourished than females in both districts (P < 0.05). Pearl millet from Baroda contained flavonoids like apigenin, vitexin and glycosyl-vitexin. Dang district water lacked in iodine content. Iodine deficiency disorder is a public health problem in Gujarat, with the Baroda district a new pocket of IDD. High amounts of dietary flavonoids in Baroda and Dang, malnutrition and an additional lack of iodine in Dang water account for IDD.

Thyroid disorders in India: An epidemiological perspective

“…[16] In the state of Gujarat, the same group had reported that iodine deficiency continues to be a problem, as more than 20% of the population had a very low median urinary iodine of <50 ΅g/l. [17] In the same population, the prevalence of hypothyroidism has been reported to be about 7%. [17] The use of ultrasound in population studies of thyroid gland size is an exciting new area for research in the field of thyroid epidemiology.…”

“…[17] In the same population, the prevalence of hypothyroidism has been reported to be about 7%. [17] The use of ultrasound in population studies of thyroid gland size is an exciting new area for research in the field of thyroid epidemiology. [18–20]…”

Thyroid Ultrasonography Consistently Identifies Goiter in Adults Over the Age of 30 Years Despite a Diminished Response with Aging of the Thyroid Gland to the Effects of Goitrogenesis

“…Despite the high prevalence of goiter, urinary iodine levels were found to be in the mild to moderate range. Based on these results, the Dang district would be categorized as having moderate iodine deficiency and Baroda as having mild iodine deficiency [7,8]. This would support the argument that goiter in this population is multifactorial in nature, including iodine deficiency, malnutrition, and the ingestion of goitrogenic compounds.…”

“…Iodine deficiency is a national health problem in India. We have recently reported on the severity of IDD in adults and children in Gujarat province [7,8,9,10]. We found that the prevalence of IDD in children was extreme and was explained by a combination of factors, including iodine deficiency, coincident ingestion of goitrogens, and malnutrition.…”

“…The results were expressed as micrograms of iodine per liter of urine (µg/l). This method has several potential sources of error and does not separate out the interfering substances (goitrogens) from iodine, hence the former were removed from the urine samples prior to the assays to arrive at true urinary iodine value [7,8].…”