Deaths From Parkinson’s Rising in US Over Two Decades, Study Reports
The death rate from Parkinson’s disease in the U.S. has gradually and significantly increased — by 63% — over two decades across all age groups, sexes, and racial and ethnic groups, according to a study based on nationwide mortality data.
In the same period, men died twice as much from the disease as women, and a higher death rate was also seen among white people relative to those from other racial and ethnic backgrounds.
“We know that people are living longer and the general population is getting older, but that doesn’t fully explain the increase we saw in the death rate in people with Parkinson’s,” Wei Bao, MD, PhD, the study’s senior author and an associate professor in the department of epidemiology at the University of Iowa’s College of Public Health, said in a press release.
“Understanding why more people are dying from this disease is critical if we are going to reverse the trend,” Bao added.
“It’s important to continue to evaluate long-term trends in Parkinson’s death rates,” Bao said, as these studies can “help pinpoint why more people are dying of the disease” and “be used for priority setting and financing of health care and policy.”
The study, “Trends in Mortality From Parkinson Disease in the United States, 1999–2019,” was published in the journal Neurology.
Parkinson’s disease affects nearly 1 million Americans and more than 6 million people around the world.
According to the World Health Organization, Alzheimer’s disease and other dementias — such as those related to Parkinson’s — were the second-most common cause of death in high-income countries in 2019, a sharp raise since 2000.
However, the death rate from Parkinson’s itself and its long-term trends in the U.S. remain unknown.
To address this, Bao and his team, along with colleagues in China, analyzed 1999–2019 data from the National Vital Statistics System, a nationwide, population-based death registry.
The data showed that during that 20-year period, Parkinson’s disease was reported as the cause of death of 479,059 people.
After adjusting for age (a potential influencing factor), the researchers found that the death rate from Parkinson’s increased from 5.4 deaths per 100,000 people in 1999 to 8.8 deaths per 100,000 people in 2019 — reflecting a 2.4% annual raise and a total increase of 63%.
A significantly increased mortality due to Parkinson’s was seen among both men and women of all ages, races, and ethnicities and across urban and rural places, all geographic locations, and in every U.S. state.
However, men were two times more likely to die from the progressive neurodegenerative disease than women, a finding that Bao said may be explained by the high levels of estrogen produced by women.
Estrogen, a hormone responsible for female physical features and reproduction, is known to increase the levels of dopamine, the chemical messenger gradually lost in motor-controlling brain regions of Parkinson’s patients. As such, high levels of estrogen may protect women from developing the disease.
A notably higher mortality rate was also seen among white people (9.7 per 100,000 people) compared with Hispanics (6.5 per 100,000) and non-Hispanic Black people (4.7 per 100,000).
These ethnic and racial differences in mortality may reflect disparities in access to neurology care, Bao said, as previous studies showed that compared with whites, Blacks and Hispanics are less likely to see a neurologist due to socioeconomic barriers and therefore may have a lower chance of being diagnosed with the disease.
This is consistent with an October report from the Michael J. Fox Foundation for Parkinson’s Research that emphasized Parkinson’s-related health disparities across different socioeconomic and ethnic backgrounds and proposed ways to shorten them.
These findings highlight that “from 1999 to 2019, the mortality from PD [Parkinson’s] in the United States has increased significantly … regardless of age, sex, race/ethnicity, urban-rural classification and geographic location,” the researchers wrote.
“A comprehensive evaluation of long-term trends in PD mortality is important for health care priority setting,” the team added.
While further studies are needed to clarify the causes of this overall increase in Parkinson’s-related deaths, the researchers suggested it may be related to a rising risk of Parkinson’s due to greater exposure to environmental risk factors and to improved accuracy on determining cause of death.
Only one underlying cause of death is also recorded on each death certificate, and this may prevent the accurate assessment of the number of patients dying from Parkinson’s, as some people may have co-existing diseases at the time of death, they added.