The United States has less than 5% of the total world population, yet over 20% of the Alzheimers.
Typically, a cursory mainstream explanation to that statement is, ‘our life expectancy is longer and our superior health care system diagnoses earlier. Yet the reality is the life expectancy tables rank the US numbers between 40 and 50 out of 200 countries. Health system is ranked between 40 and 60 out of 200. Yep, about 50 countries live longer and have better health care systems. China is the only other country that carries the 20% world alzheimers burden yet their population is 4 times ours and almost 20% of the world. So in short, China is 20% of world population, carries 20% of alzheimers cases. Obviously China’s numbers are more symmetrical than US numbers.
We might learn something from studies comparing similar groups in and outside the US. Enter the Indianapolis-Ibaden Dementia Project. Indiana vs Nigeria. This Indiana School of Medicine (1991) research followed individuals who are cognitively normal at the time of enrollment. A sampling of Indianapolis,Indiana was one tracked group and a similar group was tracked in Ibaden, Nigeria. Which among them go on to develop alzheimers? They have published two reports so far, finding in both instances a significantly lower incidence and lower newly diagnosed cases of Alzheimers in the Nigerian cohort. If I were in the Indiana group, I would be packing to move to Nigeria.
Why is there a difference? Some people initially felt that it was due to differences in life expectancy, but that’s not the case. The percentage of individuals living past age 65 is more or less the same in the Indianapolis and Ibaden groups. Others have speculated that genetic differences may be the reason, specifically differences in the presence of the infamous ApoE-4 gene. It is risk promoter gene linked to late-onset Alzheimer’s. If you inherit two copies of the E-4 gene, you have a 95 percent chance of developing late-onset AD by age 85. But there seems to be no significant difference between E-4 gene in each group.
It’s not life expectancy, and it’s not the ApoE-4 gene. The question researchers are trying to answer is: What is accounting for this difference? Is it diet? Is it environmental? Is it lifestyle? These questions continue to be debated in scientific circles. There seems to be something about developing countries. In addition to the Indiana State Study, there is data from an ongoing study tracking dementia incidence in eastern India. It turns out that the prevalence of alzheimers in rural India is very similar to the Nigerian group. Although alzheimers is increasing rapidly in India, it’s concentration is more so in urban areas. So as the country ‘develops’ so does the incidence of alzheimers disease. Many think the low prevalence in rural India may be due to dietary influences, because a lot of Indian people are vegetarian and eat curry frequently. (Curry has an ingredient called curcumin, also called turmeric, an antioxidant that some studies have suggested may be protective against dementia). It makes sense that as people move from rural area to urban their diets become more westernized, less curry.
I believe that the benefits of turmeric are only a part of preventing alzheimers. And one must certainly consider that rural areas of India do not enter their elderly in any institutionalized systems of diagnosing or care, therefore do not get counted as any statistic. I picture indigenous rural people simply caring for their elderly where ever the aging process takes them.