Epidemiology of Parkinson's disease and movement disorders in India: problems and possibilities.

Improving economy and health in developing countries like India, has increased the life span and changed the emphasis from communicable to noncommunicable diseases. This is likely to increase the prevalence of movement disorders and, age-related diseases like Parkinson's disease (PD). We review Indian epidemiological studies to describe: a) Prevalence of movement disorders, b) methodological issues and c) potential of epidemiological research in a country with multiple ethnic races and environmental risks for PD. Most Indian epidemiological studies do not specifically assess PD and figures are from studies evaluating all neurological diseases. Well-designed Indian studies on PD and essential tremors estimate prevalence rates in Parsis who are ethnically different from Indians. We compare Indian prevalence studies with other parts of the world to examine the role of ethnicity in PD. Lack of accurate epidemiological data on PD and movement disorders creates an urgent need for properly designed and conducted epidemiological studies in India. This will help find out their load, identify areas of focus, create public health policies for elderly Indians and, possibly, provide etiological clues to the pathogenesis of PD.