From the available evidence, it would appear that the number of cases of Alzheimers disease in Asia, and particularly in India and Africa, is lower than that reported from studies in developed countries. This raises a major question - why?
There are several possible reasons. Perhaps physicians do not diagnose Alzheimers disease but use non-specific terms such as senility. Other postulates refer to the socioeconomic realities and the lack of awareness of Alzheimers disease in the populations studied. It is likely that there is a low survival rate after the onset of the disease. Poor access to technologically-advanced health care may especially hasten the demise of patients, resulting in lower estimates of number of cases. Some have also speculated that the traditional attitude towards the elderly being one of respect, "family members will not force medical care or even food on an older relative who takes to his bed and refuses to eat" - a contributory factor in low survival.
It is possible that there is a lower occurrence of underlying risk factors (or the concomitant presence of protective factors) in the populations surveyed. For example, there is some evidence that the occurrence of a specific gene, Apolipoprotein EÎ4, which is a known risk factor in Alzheimers disease, is lower in the Indian population than elsewhere. This theory seems to be corroborated by the preliminary results from a genetic study of patients and comparable subjects without Alzheimers disease, which indicated a lower occurrence of Apolipoprotein EÎ4 gene in North India compared to the west. Additionally, gene-environment interactions have also been postulated as responsible factors for the lower number of cases in eastern countries.