Cases of Alzheimer's are on the rise. The Alzheimer's associations says:
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The number of Americans with Alzheimer’s and other dementias is increasing every year because of the steady growth in the older
population. This number will continue to increase and escalate rapidly in the coming years as the baby boom generation ages.
So there's more old people, so more Alzheimer's. Also, as we make strides in other causes of deaths, like heart disease and cancer, the less people die of those, and more people die of Alzheimer's for which there are no good treatments.
Some people have suggested that water fluoridation might be linked to Alzheimer's. Tehy generally fail to realize that water fluoridation is a local thing, and many communities do NOT have water fluoridation. Look at the distribution here:
Note that California has under 50% of its residents with fluoridated water. Texas has over 75%. So if fluoride was related, you'd expect to find higher rates of Alzheimer's in Texas.
From the Alzheimer's association statewide figures.
State Population Cases Deaths Cases/1000 pop Death/1000 pop CA 37691000 480000 8497 12.7 0.225 TX 25674000 340000 4814 13.2 0.187
So despite having a 50% higher rate of fluoridation, Texas has only a slightly higher ratio of cases of Alzheimers as California, and a MUCH lower ratio of deaths. The difference most likely being to age demographics.
This lack of correlation of fluoridation with cases of Alzheimers indicates is not a significant factor.