Next year is a red letter year for our health and social security systems. 2010 is the year that the first of the baby boomers turn 65. Not only do they become eligible for old age pension, but they start down the slippery slope for one of the deadliest incurable diseases known to modern medicine. Dementia is a class of diseases characterised by loss of mental function. The most significant dementia is (by far) Alzheimer’s disease.

Even though it’s one of the oldest known diseases, we really don’t know much about dementia. We know that that you will likely be dead within seven years of diagnosis. We know that 93 percent of cases are caused by something other than who we are related to. And we also know that the older we get the greater our chances of having it. According to a report released by Access Economics this week, we have a 1 in 4 chance of having the disease by the time we reach 85.

For a long time, researchers have known there is a strong relationship between diabetes and dementia. Estimates have varied, but you are approximately two to four times as likely to have dementia if you also have diabetes or a history of insulin resistance (the precursor to Type II Diabetes). Now a bunch of Swedish twins are starting to put some real meat on the bones of the diabetes link.

Almost 14,000 twins participated in a recently published study. The twins were part of the Swedish twin registry and were all over the age of 65. Because they had provided health data to the registry throughout their lives, the researchers had excellent information about their health over a very long period.

Twins are great for this kind of work because when one becomes ill but the other doesn’t, large tracts of potentially irrelevant causes are eliminated. Clearly the twins share the same gene pool and (usually) have been raised in an identical environment. When dementia sets in early, as it increasingly is (15,000 Australians under the age of 65 now have dementia according to the Access Economics Report), the number of possible causes is narrowed further.

The study proved beyond any doubt that diabetes is associated with dementia (at least in Swedish twins). Even more interestingly, they concluded that the longer you have had diabetes (or insulin resistance), the more likely you are to develop dementia. In a somewhat depressing footnote, the researchers suggest their estimate (that you are 125% more likely to become demented if you are diabetic) is probably a bit light on because so many diabetics die before they are old enough to notice they are losing their grip.

Research published a month after the twin study took the issue further and established a direct link between consuming sugar and “impaired cognitive function”. 2977 people suffering from Type II Diabetes, aged 55 years and older took part in that study. They were subjected to a battery of tests (part of a standardised set used for detecting early signs of dementia) designed to measure things such as how fast they performed calculations, how well they multi-tasked and the accuracy of their memory.

The researchers then compared the results of the tests to measures of each person’s average blood glucose reading over time. They found that there was a significant correlation between a person’s score on the tests and their blood sugar level. The higher the blood sugar level, the lower their score on all the tests. Just to put icing on the cake, the researchers noted that a one per cent rise in blood sugar takes you two whole years closer to dementia.

High blood sugar (and ultimately diabetes) is definitively caused by overconsumption of sugar. What this latest research tells us is that diabetes is not the end of the story (as if that weren’t enough). Lifelong sugar consumption is driving us mad — literally.

The Access Economics report was commissioned by Alzheimer’s Australia and paid for by Pfizer (a pretty big drug company). While it is a worthy document when it comes to telling us how bad the problem is getting and how very bad it is going to get (dementia will quadruple in the next four decades), the best it can come up with in the solution bucket is both predictable and insulting. We should all exercise more and keep taking hypertension drugs (hmm, I wonder who makes those?). You see people with dementia are often overweight and have hypertension, neither of which is particularly surprising once we understand the link to diabetes.

Where is the discussion of the abundant evidence on the relationship between sugar consumption and dementia? Where is the recommendation that perhaps we should throttle back public health statements suggesting it is ok to get 20% of our calories from sugar? Certainly not in the Access Economics report and certainly not in the simultaneously released National Preventive Health Taskforce Report.

In the US, public health signs are going up all over New York showing human fat being poured out of a soft drink bottle and suggesting it’s not such a good idea to drink sugar. And the American Heart Association is recommending people consume less than half the sugar suggested by Australian authorities.

But our best and brightest can only manage limp recommendations to limit alcohol advertising and tax cigarettes — oh, and keep taking our hypertension medication. It’s time we started demanding more from those in charge of our health dollars — while we can still remember who they are.

David Gillespie is lawyer and author of “Sweet Poison, why sugar makes us fat”