Identifying risk for dementia across populations: A study on the prevalence of dementia in tribal elderly population of Himalayan region in Northern India

INTRODUCTION: Studies have suggested that dementia is differentially distributed across populations with a lower prevalence in developing regions than the developed ones. A comparison in the prevalence of dementia across populations may provide an insight into its risk factors. Keeping this in view, a study was planned to evaluate the prevalence of dementia in tribal elderly population. MATERIALS AND METHODS: A cross-sectional comprehensive two-phase survey of all residents aged 60 years and older was conducted. Phase one involved screening of all individuals aged 60 and above with the help of a cognitive screen specifically developed for the tribal population. Phase two involved clinical examination of individuals who were suspected of dementia as per the developed cognitive screening test. RESULTS: The results revealed that no individual above 60 years of age in the studied population was diagnosed as a case of dementia. Thereby, pointing out at some unknown factors, which are responsible for prevention of dementia. DISCUSSION: The differences between the prevalence rate in this study and other studies in India appear to be a function of a valid regional difference. Environmental, phenotypic and genetic factors may contribute to regional and racial variations in dementia. Societies living in isolated hilly and tribal areas seem less predisposed to dementia, particularly age related neurodegenerative and vascular dementia, which are the most common causes for dementia in elderly. This may be because some environmental risk factors are much less prevalent in these settings.