The death rate from Parkinson's disease (PD) has increased about 63% over the past two decades in the United States, according to what the investigators say is the most comprehensive study of temporal trends in PD mortality in the United States.
"The reason behind the rising death rates from PD is not clear at present and warrants further investigation," Wei Bao, MD, PhD, with the University of Iowa, in Iowa City, told Medscape Medical News.
"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," Bao added in a statement.
"Understanding why more people are dying from this disease is critical if we are going to reverse the trend," Bao said.
The study was published online October 27 in Neurology.
The researchers used data from the National Vital Statistics System to determine national trends in PD mortality overall and in several key subgroups. The analyses included 479,059 people who died of PD between 1999 and 2019.
Over the 21-year period, the age-adjusted mortality from PD rose from 5.4 per 100,000 in 1999 to 8.8 per 100,000 in 2019. The average annual percent change (APC) was 2.4% for the entire period.
During the study period, the number of deaths from PD more than doubled, from 14,593 to 35,311.
The death rate from PD increased significantly across all age groups. The average APC was 5.0% among adults younger than 65 years, 1.9% among those aged 65 to 74 years, 2.2% among those 75 to 84 years, and 2.7% among those 85 and older.
The death rate increased in both men and women, but age-adjusted PD mortality was twice as high in men as in women. The researchers say one possible explanation for the sex difference is estrogen, which leads to higher dopamine levels in areas of the brain that control motor responses and may protect women from PD.
The study also showed that White people are more likely to die from PD than persons of other racial and ethnic groups. In 2019, the death rate per 100,000 was 9.7 for Whites, 6.5 for Hispanics, and 4.7 for non-Hispanic Blacks.
Previous studies have shown that compared to White people, Black and Hispanic people are less likely to see a neurologist, owing to socioeconomic barriers. This suggests that White people may be more likely to receive a PD diagnosis, the researchers note.
"It's important to continue to evaluate long-term trends in Parkinson's death rates," Bao said.
"This can inform future research that may help pinpoint why more people are dying of the disease. Also, updating vital statistics about Parkinson's death rates may be used for priority setting and financing of healthcare and policy," Bao added.
1.2 Million Patients by 2030
Reached for comment, James Beck, PhD, chief scientific officer for the Parkinson's Foundation, said these findings are not surprising.
"They are aligned with the work the Parkinson's Foundation has done to show that the number of people with PD has increased over time. We are working on an improved estimate of PD incidence and predict that PD will continue to rise as the population ages, so an increase in mortality rates would be expected," Beck told Medscape Medical News.
Beck noted that much of the public health statistics regarding PD are outdated and that the Parkinson's Foundation has been partnering with others to update them.
"For instance, to calculate an accurate estimate of the prevalence of PD, the Parkinson's Foundation Prevalence Project was formed. The findings from this group demonstrated that the number of people living with PD will rise to nearly 1.2 million by 2030, a substantial increase from the estimate of 930,000 for 2020," Beck said.
"The overarching message is that more people are being diagnosed with PD, not that more people are dying from the disease," he added.
"Over the last 20 years, our understanding of PD has changed and developed, so clinicians are more aware and better able to properly diagnose PD. This could mean that the cause is likely due to an increase in diagnosis rates and better recognition of PD, which would lead to higher rates of identifying PD as a cause of death," said Beck.
The study had no targeted funding. Bao and Beck have indicated no relevant financial relationships.
Neurology. Published online October 27, 2021. Abstract
For more Medscape Neurology news, join us on Facebook and Twitter.
Lead Image: Getty Images
Medscape Medical News © 2021
Cite this: Parkinson's Death Rate Rising, Reasons Unclear - Medscape - Oct 28, 2021.