Impact of protein energy malnutrition on thyroid size in an iodine deficient population of Gujarat (India): Is it an aetiological factor for goiter?

Abstract

To assess the severity of protein energy malnutrition (PEM) in iodine deficient subjects and to assess the impact of PEM on thyroid size. 1002 subjects (530 school-aged children and 472 adults) were assessed for PEM by direct anthropometric measurements of height, weight, triceps skinfold (TSF) thickness, mid upper arm circumference (MUAC) and thigh circumference (TC), and derived indices of body surface area (BSA), body mass index (BMI), and Z-scores for weight-for-age (WAZ), height-for-age (HAZ), and weight-for-height (WHZ). Severity of PEM was based on the World Health Organization (WHO) criteria and the threshold on the Waterlow classification. Thyroid size was measured by ultrasonography to determine the thyroid volume (TV). Linear regression analysis was performed between TV and anthropometric parameters. Children had severe PEM as evident from the WHO percentage prevalence of stunting (HAZ<-2SD)=64% (where <-2SD is the Z-score deficit), wasting (WHZ<-2SD)=43%, underweight (WAZ<-2SD)=82% and BMI<16 kg/m=90%. Waterlow classification showed that children were either stunted or wasted, or stunted and wasted, or stunted and obese. Nearly 100% (529/530) of the children had goiter as evidenced from enlarged TV-for-BSA when compared with the WHO reference. There was a weak but statistically significant (P<0.05) positive correlation between TV and BSA, weight, height, MUAC, TC and HAZ but a negative correlation between TV and WHZ, BMI and TSF (r=-0.1-0.2). Adults had PEM as evident from BMI<18.5 kg/m in 54% subjects. Median MUAC=22.7 cm reveals prolonged severe PEM. Eighty-two percent had enlarged TV (>20 ml). There was a significant (P=0.01) negative correlation between TV and MUAC. (i) The severity of acute (wasting) and chronic (stunting) PEM is very high in Gujarati children. They are stunted or wasted, or stunted and wasted, or stunted and obese. Gujarati adults are thin with low protein and fat reserves. (ii) Anthropometric parameters showed a significant (P<0.001) correlation (r=0.1-0.2) with thyroid size. (iii) Higher prevalence of goiter may be due to macro-nutrient malnutrition (PEM) in the face of micro-nutrient malnutrition (iodine deficiency disorders, IDD).