What are Common Risk Factors for Parkinson's?

Parkinson’s disease (PD) is the second most common degenerative neurological disease, with Alzheimer’s disease being the first. PD affects approximately one million people in the United States.¹

Risk factors for Parkinson's disease

While the exact causes aren’t fully understood, researchers have identified characteristics that increase a person’s risk of developing Parkinson’s, including gender, age, race, and genetic factors. However, it is worth noting that the vast majority of cases of PD are considered idiopathic Parkinson’s disease. “Idiopathic” means a condition that arises spontaneously or for which the cause is currently unknown. Major advances in research and science are continuing to reveal more underlying causes for PD.^1,2

Gender

Many studies have identified that the incidence of PD is more common in men than women.^3,4 The reasons for the differences in men and women with PD are unclear, although one suggested explanation is the protective effect of estrogen in women. Other theories to explain the difference between PD in men and women include the higher rate of minor head trauma and exposure to occupational toxins in men and genetic susceptibility genes on the sex chromosomes.⁴

Age

Increasing age is a risk factor for PD, as the incidence of PD increases with age. PD affects 1 percent of the population over the age of 60, and this increases to 5 percent of the population over the age of 85. Only about 5 percent of all people with PD are diagnosed before the age of 60, which is considered early onset PD.¹

Family history and genetics

Approximately 15 percent to 25 percent of people with PD have a relative with the disease.⁵ People with a close family member with Parkinson’s have a small increased risk (2 percent to 5 percent) of developing the disease. About 15 percent to 25 percent of people with PD have a known relative with the disease.⁵ A number of genetic mutations have been identified that are associated with PD. Some of these appear to be more causal, while others simply increase a person’s risk for the disease.⁵

Ethnicity

Several studies have found that PD is more common in Whites than in Blacks or Asians. It is estimated that the prevalence of PD is 50 percent lower in Blacks and Asians than in Whites. However, the highest incidence of PD is found in Hispanics, followed by non-Hispanic Whites, Asians, and Blacks. According to one analysis, the incidence of PD in Hispanics is 16.6 per 100,000 persons, compared to 13.6 per 100,000 in non-Hispanic Whites, 11.3 per 100,000 in Asians, and 10.2 per 100,000 in Blacks.^6,7

Head trauma

Trauma to the head, neck, or upper cervical spine seems to increase a person’s risk of developing PD. While the research is not conclusive, several studies have shown a link between head trauma and an increase in a person’s risk of developing the disease.⁸

Environmental pesticides

While there have been theories that rural living may be a risk factor for PD, urban areas have a higher prevalence and incidence of PD.⁶ A number of studies have looked at the relationship between exposure to environmental factors, like pesticides, and the development of neurological conditions, including PD and Alzheimer’s disease. Several studies have found associations between PD and exposure to pesticides, but there are also studies that have shown no association. At this time, the evidence is inconclusive.⁹