Prevalence of mental retardation in urban and rural populations of the goiter zone in Northwest India.

ABSTRACT

Background: The existence of an endemic goiter belt along the southern slopes of the Himalayas has been known for a long time. Prevalence of neonatal hypothyroidism is high and there has been little work on the prevalence of mental retardation in this part of India. Objective: The study was conducted with the aim to know the prevalence of mental retardation in the urban and rural populations of Himachal Pradesh, India and to generate a hypothesis on the differential distribution (geographical) of mental retardation. Methods: This cross-sectional study was conducted in the rural and urban areas of the district of Kangra, Himachal Pradesh, India among children of 1-10 years of age. In the first phase, the children in the age group of 1-10 years were screened for mental retardation using the Ten Questions Screen, whereas in the second phase the suspects were evaluated clinically. Results: The prevalence of mental retardation was found to be 1.71% in the study population with higher prevalence (3.3%) in the 73-120 months age group. The prevalence was higher among the males in all study populations [rural 1.9%, urban (nonslum) 1.6%, and urban slum 7.14%). The prevalence was similar among the urban (nonslum) (1.75%) and rural (1.11%) populations, whereas it was higher (4%) in the urban slum population. A prevalence of 2% was seen in families from the lower middle class and 1.8% among families from the lower class in the rural population, whereas a prevalence of 2% was seen among lower middle class families of urban (nonslum) areas. Conclusion: The prevalence of mental retardation was higher in our study than in other parts of the country. The study concludes with the hypothesis that the prevalence of mental retardation is differentially distributed geographically with socioeconomic factors being important predictors.