The word pandemic is now everywhere we look, courtesy of COVID-19. In their book Ending Parkinson's disease, Ray Dorsey, Todd Sherer, Michael Okun, and Bastiaan Bloem talk about a figurative pandemic though. The number of individuals to be diagnosed with Parkinson's disease could increase dramatically in the coming years due to population ageing and because of environmental factors; this book is a call to action, with a prescriptive list on how to prevent these factors.
The authors are acknowledged experts, each bringing his own area of expertise to bear on the causes of the condition. Three of them are from the USA, which would explain why the book is centred on North America. This focus extends to the actions that need to be taken; for example, the petition for new legislation on the use of pesticides in the USA. The authors cite a whole range of environmental factors linked to disease development, including chemical agents used in agriculture, industry, and even domestically, as well as mild head injury, which characterises many contact sports. While a laudable approach, causality is not clear cut. For example, repetitive head injuries can lead to chronic traumatic encephalopathy, of which a-synuclein pathology (the hallmark of Parkinson's disease) is only a part. Thus, tackling this risk factor is important not solely for the Parkinson's disease community but for society at large. An analogy can be drawn to smoking, which is most strongly associated with lung cancer and chronic lung disease, but has detrimental effects on almost all body systems (paradoxically it has been shown to be protective for Parkinson's disease). Stopping smoking is good not just for those with respiratory disorders. The same holds true for environmental toxins, air pollution, and head trauma. This is where I take issue with this otherwise excellent read—namely the slightly sensationalist claims. In the initial chapters, many papers are cited in support of the claims, but these studies are of differing quality and the authors themselves row back on this evidence later in the book, when they acknowledge that more studies are needed. Furthermore, while genetic risk is clearly discussed, the role of age is not—which is surprising given that age is the most important risk factor for Parkinson's disease. Obviously, it is not modifiable, but whatever underlies the ageing process can inform pathophysiology and new therapeutic insights, and could also better inform us on the crucial environmental issues driving incidence. Inspiring case studies are included throughout—they put a human face on this condition and enable readers to understand the impact that the disease has not only on patients but also on their families. Cases are often of patients with young disease onset. But it is worth remembering that the average age of onset is around 70 years, that most patients would die with the disease and not because of it, and that efficacious symptomatic therapies exist.
This book attempts to rev up the Parkinson's disease community to action, such as the HIV community did with great success in the late 20th century. Much of what is advocated is urgently needed: improvements in the regulation of polluting toxins and universal access to good health care (including access to levodopa across the globe). The take-home messages are important for a healthy future, of which risk of Parkinson's disease is only one element.
