Review of epidemiologic studies of aluminium and neurological disorders.

The epidemiological study of neurological disorders is just beginning and should he continued because of the potential public health impact of these diseases on society. The most important contribution of epidemiological research is the identification of risk factors, and specific disease entities, such as Alzheimer's disease, should be studied.Ecological analysis of geographical data have associated a small increase in mortality from Alzheimer's disease and dementia with the aluminium content of drinking water. These results must necessarily be interpreted with caution because serious errors may result from inferences based on ecological analysis,e.g. "the ecologic fallacy".Potential risk factors for Alzheimer's disease have been studied in case-comparison epidemiology studies conducted in Italy, Massachusetts, Colorado, Minnesota and North Carolina, but only two studies have considered aluminium exposure, through the use of antacids. Although no increased risk was found to be associated with aluminium exposure, only a small number of individuals in the studies reported antacid use, and the studies had an extremely limited statistical power to detect an association.Additional analytical epidemiology studies, either cohort or case-comparison, are required to better describe the possible relationship between aluminium and Alzheimer's disease. These studies should be designed according to well-established epidemiological principles, be conducted with no selection bias and minimum observation bias, consider potential confounding and modifying factors, and have sufficient statistical power to enable detection of low relative risks.