Brain Week is underway (16-22 March), with the aim of consolidating a shared strategy to respond to the growing burden of neurological pathologies. Numerous topics are discussed, from cognitive impairment to Alzheimer’s disease, cerebrovascular diseases and Parkinson’s disease, which is now one of the main neurodegenerative diseases in the world and represents the second cause of motor disability in adults after stroke.
The experts of the Sin (Italian Society of Neurology) take stock on the occasion of the Brain Awareness Week and together with the Italian Red Cross and the Aletheia Foundation they promote an agreement to promote neurological prevention, through healthy lifestyles and correct nutrition.
Parkinson’s, between age, gender and genetics
The disease, although there are also juvenile cases, mainly strikes after the age of 60 and its incidence is increasing. There is no single cause: the disease is the result of the combination of genetic predisposition, environmental factors and lifestyle conditions. Age is the main risk factor. With aging, oxidative stress, the accumulation of abnormal proteins and the vulnerability of dopaminergic neurons increase, the cells which progressively undergo degeneration in Parkinson’s.
Symptoms appear when more than half of these neurons have already been lost. Gender also has an impact: the disease is approximately twice as common in men. Estrogens, according to various evidence, exert a neuroprotective action by modulating inflammation, dopamine metabolism and oxidative stress. Genetically, most cases are sporadic, but a family history significantly increases the risk. Mutations have been identified in genes involved in the control mechanisms of protein quality and mitochondrial function, such as SNCA, LRRK2 and GBA1. However, genetics alone is rarely enough: it is the interaction with the environment that determines, in most cases, the final outcome.
The role of the environment
Among environmental factors, exposure to pesticides and herbicides is among the most solid associations: numerous studies indicate an increased risk in those who have had prolonged contact, especially in agriculture. Industrial solvents such as trichlorethylene and heavy metals, including lead, have also been implicated.
Air pollution represents a further critical element: the individual increase in risk is modest, but exposure is widespread and constant, with significant implications on a population scale.
Head trauma, especially if repeated or severe, is associated with a greater likelihood of developing the disease in subsequent years. Injuries can trigger inflammatory processes and promote the accumulation of pathological proteins in the brain.
The weight of metabolism
In recent years, attention has also shifted to metabolic factors. A recent meta-analysis highlighted that metabolic syndrome – a combination of abdominal obesity, hypertension, dyslipidemia and altered glycemia – is associated with a 30% increase in the risk of Parkinson’s. Insulin resistance, oxidative stress and chronic systemic inflammation are the main hypothesized mechanisms.
Type 2 diabetes, in particular, not only increases risk, but is associated with more severe forms and more rapid progression. High blood pressure and cardiovascular disease can also contribute to brain damage over time. More and more studies also indicate a role for chronic inflammation and intestinal dysbiosis: the alteration of the microbiota could promote neuroinflammation and contribute to the first stages of the disease. Further confirmation of the increasingly close connection between the intestine and the brain.
How to prevent
The list of these items shows that some factors are not editable. But for others there is concrete room for intervention. Regular physical activity is one of the most solid protective factors: several studies show a lower risk in those who practice moderate or intense exercise continuously. Aerobic exercise supports neuronal function, reduces inflammation and can slow the progression of symptoms.
On a nutritional level, a model inspired by the Mediterranean diet – rich in fruit, vegetables, legumes, fish and “good” fats – is associated with a lower risk and a slower course. Coffee and caffeine have been associated with a reduction in risk, probably due to an action on dopaminergic circuits. Quality sleep also plays a key role: during rest the brain activates “cleaning” systems that help eliminate potentially harmful proteins.
In short: Parkinson’s does not depend on a single element, but on a combination of genetic vulnerability and environmental pressures that accumulate over time. To date, there is no prevention aimed exclusively at the disease, but many of the useful strategies coincide with general public health recommendations: reducing toxic exposures, promoting physical activity and a balanced diet, controlling diabetes and blood pressure, treating sleep and reducing pollution. While waiting for therapies capable of decisively modifying the course of the disease, the most concrete prevention remains that which protects the brain throughout life. An integrated approach which, while not eliminating the risk, can help reduce the number of new cases and gain years of neurological health.
