What are the three best things about having Alzheimer’s disease?

You make new friends every day. You can hide your own Easter eggs and you can plan your own surprise parties.

We make jokes about the disease, as with many things that terrify us, to try assuage our fears.

Yet there’s nothing funny about the spectacular rise in Alzheimer’s rates. Just over 100 years ago, the first case was described in a paper by Dr. Alois Alzheimer, in Germany. In the 1950s, it rated little more than a single line in most medical texts.

Currently in North America, Alzheimer’s strikes 10 per cent of those over 65 years of age, rising to more than 50 per cent in those over 80. Despite huge strides in life expectancy this last century, the thought of living longer is not nearly as attractive as it once was. But there is good news. After decades of spiralling Alzheimer’s rates, the worst is, perhaps, over. We seem to have turned a corner.

In a study of 11,000 Americans aged 70 and older, published last Wednesday in the online journal Alzheimer’s and Dementia, it was reported “the prevalence of cognitive impairment went down by 3.5 percentage points between 1993 and 2002.” The rates dropped to 8.7 per cent from 12.2 per cent, according to the findings.

Dr. Kenneth Langa, of the University of Michigan Medical School and lead author of the study, said reasons for the decline are not fully known.

But he added that “what we may be seeing here is the accumulated effects of better education and better cardiovascular prevention among the people who were over age 70 in 2002, compared with those who were over age 70 in 1993.”

This is wonderful news – if the study holds up. It is the first indication of any drop, after more than 50 years of annually rising rates.

“From these results, we can say that brain health among older Americans seems to have improved in the decade studied, and that education and wealth may be a big piece of the puzzle,” Langa said.

It appears, then, that those things that contribute to one’s physical and mental activity help reduce the risk of contracting Alzheimer’s. Or, if we fall victim, it will happen to us later in life.

But, in the final analysis, no one can say why this was a rare disease in the 1950s that became so common by the ’90s.

It may well turn out to be like the infamous “sweating disease.”

This was an affliction that attacked the peoples of England, and only England, on three or four occasions in the mid-15th century.

Those afflicted felt fine in the morning, had a high fever and sweats in the afternoon, and were often dead by evening.

To this day no one knows what caused the disease – or why, within a few years of arriving, it vanished and was never seen again.

We may have to once again accept that there are limits to our scientific knowledge.

Yet, I certainly hope that this latest study is the beginning of a trend that will allow us to look forward to living longer and being aware of the fact that we are doing so.

Originally published in The Toronto Star.