GEOGRAPHICAL-DISTRIBUTION OF ALZHEIMERS-DISEASE CASES AT BIRTH AND THE GEOCHEMICAL PROFILE OF SAGUENAY-LAC-SAINT-JEAN QUEBEC, CANADA (IMAGEPROJECT)

Accepting as founded the hypothesis of a multifactorial origin for the Alzheimer's disease (AD), we explore the possible links between the g eographical distribution of AD cases according to their birth place an d the geochemical profile of the Saguenay-Lac-Saint-Jean (SLSJ) territ ory in the province of Quebec. The method used for factor analysis of correspondances (FAC) and another one based on the differences between the residential and municipal geochemical concentrations (DRMC) have been used for this purpose. The geochemical matrix of SLSJ relates the highest concentrations of nickel, copper and zinc to the sector surro unding the Jonquiere municipality. Moreover, high concentration of iro n, lead and manganese were found in the northern sector of the Lac Sai nt-Jean. The DRMC method corroborates this strong correlation between iron, lead and manganese. Furthermore, these concentrations do not dif fer from the north-american geochemical standards. No single geochemic al element seems to be associate with the spatial distribution of case s. It is, however, still possible that a certain synergistic effect be tween two or several elements could be implied in the development of t he disease. According to the results of the soil analysis, there does not seem to be any association between the spatial distribution of cas es and the concentration of aluminum, a chemical element that has been thought to be implied in the etiology of AD. These results are compar ed with those obtained by other workers in the micronesian islands, wh ere abnormally high frequencies of amyotrophic lateral sclerosis and p arkinsonism dementia have already been observed.