By most accounts, we've achieved a relative utopia of health. Revolutions in pharmacology and medical technology, better nutrition, and improvements in public healthcare promise a longer, healthier future for our global population.
For all there is to celebrate, this prosperity comes at a cost. We live in the shadow of a looming pandemic, as age-related neurological conditions such as Parkinson's disease threaten to affect more of us than ever before, setting the stage for an unprecedented medical challenge.
"By 2040, we can truly talk about a pandemic that will result in increased human suffering, as well as rocketing societal and medical costs," warns Patrik Brundin, editor-in-chief of the Journal of Parkinson's Disease.
A call-to-arms in Brundin's journal highlights just what we're in for in coming decades, with current Parkinson's figures set to double, if not nearly triple, over the next 20 years.
The growing problem isn't limited to Parkinson's disease. Dementia, including Alzheimer's disease, is also expected to skyrocket with our ageing population, as more of us survive long enough to see our aged bodies burdened with conditions few once lived to endure.
A significant part of the problem is a lack of knowledge about how many such neurological conditions develop in the first place.
Parkinson's disease has been on our radar since the early 19th century. In 1817, an eminent British surgeon named James Parkinson outlined the characteristics of this degenerative disease in his treatise, An Essay on the Shaking Palsy.
Today, the symptoms of trembling extremities, impeded mobility, rigidity, and mood changes are linked with the loss of dopamine-producing tissues deep inside one of the brain's control centres, called the basal ganglia.
In 2016, an estimated 6.1 million people across the planet had Parkinson's 'shaking palsy' disease, more than double 1990's figures.
While a reduced production of dopamine isn't considered to be deadly, the overall loss of function – combined with the general senescence that comes with growing old – produces an average life expectancy of just seven to 14 years beyond diagnosis.
Today, roughly 200,000 individuals could be expected to die prematurely each year as a result of having the condition.
Fast-forward another twenty years, though, and the estimated number of people who could have the condition could be as high as 12 million, thanks to shifts in demographics alone.
Throw in evidence that Parkinson's starts with changes in gut microbes that usually break down the diverse soup of pesticides, medications, and pollutants in our environment, and those numbers could creep up even further.
Curiously, there's another paradoxical factor at work that might even drive the number up as high as 17 million.
More than 50 years ago, researchers observed a strange link between tobacco use and Parkinson's. The relationship is as evident today as it is confounding – risk of the disease drops by a whopping 40 percent among long-term smokers.
The exact mechanism behind the relationship is a mystery, and given the broad range of health risks known to come with cigarettes, it's not advised to take up smoking on the chance that the relationship is causal.
But if it is, generations of anti-smoking campaigns might inadvertently be contributing to what appears to be an emerging pandemic that not only carries a heavy toll in suffering, but also in making severe demands on financial and human resources.
However, in addition to the smoking link, the team also highlight that environmental factors – such as the by-products of industrialisation generally – could be responsible.
If the news seems depressing, remember this: to be forewarned is to be forearmed. We can act now, claim the researchers, to help ensure those numbers don't get so high.
"Central to the success of these efforts was unbridled activism."
Because of this, Dorsey and his colleagues invite the Parkinson's community – researchers, patients, and individuals at risk – to raise awareness on known means of prevention, advocate for funding, and to help promote or research new care models and treatments.
The pandemic isn't inevitable, the researchers say.
It'll take some effort. But that utopia of health is still within reach, if we continue to work together.
This review was published in the Journal of Parkinson's Disease.