The authors said long-term trends in Parkinson disease were previously unknown and that the findings are important to determining national health care priorities.
The death rate from Parkinson disease (PD) has risen about 63% in the United States over the past 2 decades, according to a study released Thursday.
Although the increase was regardless of age, sex, race/ethnicity, urban-rural classification, and geographic location, some groups were affected more than others—namely men and White individuals. In addition, city residents had higher death rates than rural ones.
The authors, writing in Neurology, said it is the most comprehensive study to date on the issue, that long-term trends were previously unknown, and that the findings are key to determining health care priorities, including financing and research.
In the United States, about 1 million individuals have PD, and nearly 60,000 new cases are diagnosed each year.
The investigators used data on 479,059 deaths due to PD from 1999 to 2019 from the National Vital Statistics System (NVIS), a nationwide, population-based death registry. More than 99% of US deaths are recorded in the database, which is part of the CDC’s National Center for Health Statistics.
After adjusting for age, the researchers found that the number of people who died from the disease increased from 5.4 per 100,000 people in 1999 to 8.8 per 100,000 people in 2019. The average annual increase was 2.4%.
During that time, the number of deaths from PD more than doubled, from 14,593 to 35,311.
White individuals were more likely to die from PD than other racial and ethnic groups. In 2019, the death rate for White patients was 9.7 per 100,000, followed by Hispanic patients with PD at 6.5 per 100,000, and non-Hispanic Black patients at 4.7 per 100,000.
However, in a statement, one of the authors noted that previous studies have shown that compared with Whites, Black and Hispanic populations are less likely to see an outpatient neurologist, suggesting that Whites have a greater likelihood of receiving a diagnosis for the disease.
Last month, The Michael J. Fox Foundation for Parkinson’s Research (MJFF) issued a call for more action to reduce health disparities, including those related to socioeconomics or ethnicity.
“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,” said study author Wei Bao, MD, PhD, who conducted the research at the University of Iowa in Iowa City.
The authors said one possible explanation for the sex difference in death rates between men and women is the protective effect of estrogen, which leads to higher dopamine levels in parts of the brain that control motor responses. In addition, men receive their diagnosis earlier and die earlier, which would “offset other competing risk events in men.”
Globally, brain disorders ranked as the second-leading cause of deaths in 2016, and the number of deaths from neurological disorders rose 39% from 1990 to 2015, even as age-standardized rates of death decreased by 28%. PD had the largest increase of age-standardized rates of deaths among brain disease, rising 29% between 1990 and 2016, the authors said.
A limitation of the study is that only 1 underlying cause of death was recorded on each death certificate, so only people who were recorded as having died of PD were included. This may not accurately reflect prevalence if several co-existing diseases were present at the time of death, the authors said.
Rong S, Xu G, Liu B, et al. Trends in mortality from Parkinson disease in the United States, 1999 2019. Neurology. Published online October 27, 2021. doi:10.1212/WNL.0000000000012826