What are the causes of Parkinson’s disease?

What are the causes of Parkinson’s disease?

causes of Parkinson's disease

Parkinson’s disease is the 2nd most common neurodegenerative disease in the world that interferes with an individual’s movement.

The key symptoms of the disease include tremor, slowness of movement, rigidity, and abnormal gait. These symptoms appear when the brain lost a special group of cells called dopaminergic neurons. These cells produce dopamine, which is a well-known neurotransmitter responsible for movement.

While the exact cause of Parkinson’s disease is unknown, several factors are reported to play a role in its development. These are the following:

Aging

Increasing age is the strongest known risk factor for Parkinson’s disease. The chances of developing the disease increase significantly as the person gets older.

The current estimate shows that 1% of the population over the age of 60 is affected by Parkinson’s disease. And it reaches to 5% with over age 80.

Presently, Parkinson’s is considered to be the second most common age-related neurodegenerative disease after Alzheimer’s. And as life expectancy has tremendously increased, it is believed that the number of people with the disease will double by 2050.

There is no certain reason to explain why Parkinson’s disease is more common in old people. Researchers think that brain regions populated by dopaminergic neurons are more sensitive to lose with aging compared to other brain regions. And so, old people are more susceptible to develop disease symptoms than young people.

Genetics

Genetics has become an increasingly important cause of Parkinson’s disease development.

Approximately 15% of Parkinson’s disease cases have a clear-cut genetic origin. Although the rest 85% of cases appear with no apparent cause, researchers believe that it mostly involved some genetic components.

To date, more than 15 genes have been identified that are linked to Parkinson’s condition. Some of these genes are certainly the cause of the disease, while others can increase the risk of developing it.

The genes that are directly involved in the development of Parkinson’s disease include SNCA, LRRK2, PRKN, PINK1, DJ-1, and ATP13A2. These genes are mainly expressed in the brain. People carrying a mutation in these genes can develop the disease symptoms either before the 40s (for example in the case of SNCA and PRKN) or after the age of 50s. In most cases, the disease progression is slow and the patient shows a good response to medication.

Environment

Researchers have identified several environmental factors that are linked to the onset of Parkinson’s disease. These include the following.

Pesticides

Pesticides are the leading environmental factors that contribute to the development of Parkinson’s disease. These chemicals access the body via inhalation, eating/drinking, or skin contact.

Rotenone and paraquat are well-known pesticides that are strongly linked to Parkinson’s disease. Rotenone acts by damaging the mitochondria, which are parts of the cell that produce energy. Whereas, paraquat produces free radicals that caused damage to cell vital components.

A study published in the Journal of Environmental Health Perspectives has reported that people who use either of these pesticides are at higher risk (2.5 times) of developing the disease symptoms than those who don’t.

Stress

Emotional or extreme psychological stress has been suggested to play a role in the onset of Parkinson’s disease. Several studies have reported that those who had gone through stressful life events are at high risk of developing Parkinson’s disease later in life.

A recent report published in the Journal of Neuropsychiatric disease and treatment has shown clear evidence that stress is directly involved in the development of Parkinson’s disease. In this report, a 38-years old woman experienced sudden strong tremor in her left arm 1 week after knowing that her husband had an affair with another woman. The woman was in a healthy condition and had no history of brain diseases. Her symptoms were relieved when given Parkinson’s disease medications. After clinical examination, the woman was diagnosed with early-onset Parkinson’s disease.

Diet-related factors

Accumulating evidence indicates that diet also plays a role in the development of Parkinson’s disease. Several animal and human research studies have started to explore the role of some specific foods in the progression of Parkinson’s. Researchers have found that consuming food that is deficient of coenzyme Q10 and vitamin D highly increases the chances of developing the disease symptoms.

Coenzyme Q10 (CoQ10)

CoQ10 is an organic compound that is distributed throughout the body. Its highest amount can be found in the cells of heart, brain, liver, and kidney.

People with Parkinson’s disease are reported to have a reduced level of Coenzyme Q10.

Researchers think that its deficiency could lead to Parkinson’s disease development.

A study published in the Journal of Annals of Neurology found a 35% lower level of CoQ10 in the blood from Parkinson’s disease patients than in the blood from control subjects. Similar kinds of results were also observed in other studies.

Vitamin D

Vitamin D is another dietary component that plays a role in the development of Parkinson’s disease.

A study published in 2010 by researchers at the National Institute for Health and Welfare in Finland reported showed a link between low levels of vitamin D and Parkinson’s disease. The study, which was published in the peer-reviewed medical journal Archives of Neurology, reported that people with the lowest levels of vitamin D had a three-fold higher risk of developing Parkinson’s disease than those with the highest.

There are numerous other studies that support the link between vitamin D deficiency and the risk of Parkinson’s disease. Researchers have now started to explore the mechanism through vitamin D deficiency leads to Parkinson’s disease.

Traumatic brain injury

Traumatic brain injury (TBI) is one of the potential risk factors for Parkinson’s disease development. There is an increasing number of studies that have reported the link between traumatic brain injury and Parkinson’s disease.

A recent study published in the Journal of Neurology reported that mild TBI increases the risk of Parkinson’s up to 56% and moderate to severe TBI increases the risk of Parkinson’s up to 83%.

Although the cause of this is unknown, it is observed that people with TBI have abnormally lower levels of dopamine in the brain areas involved in Parkinson’s disease.

Exercise

The link between exercise and Parkinson’s disease has been increasingly acknowledged in recent years. There have been several studies published that provide evidence that the lack of exercise increases the risk of developing Parkinson’s disease.

One meta-analysis included 8 prospective studies has reported that physical activity, especially moderate to vigorous physical activity, is associated with a significantly reduced risk of developing PD.

Researchers are now trying to explore the mechanism and looking in detail at the preventive effects of exercise against Parkinson’s disease.


Disclaimer: The information shared here should not be taken as medical advice. The opinions presented here are not intended to treat any health conditions. For your specific medical problem, consult with your health care provider.

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