Spatiotemporal dynamics and climate correlates of Parkinson disease mortality among older U.S. adults: national trends and forecasts to 2035

Background Parkinson disease (PD) is an increasing cause of mortality among older adults, but national studies have generally examined mortality trends, forecasts, spatial variation, or environmental associations separately. We integrated these components to characterize U.S. PD mortality and its regional climate correlates. Methods This ecological time-series study used CDC WONDER mortality data for U.S. adults aged 65 years or older from 1999 to 2024. Joinpoint regression, exponential smoothing state-space forecasting with rolling-origin validation, state-level Moran's I, lagged count models, nonlinear spline analyses, and principal component analysis of regional climate metrics were applied. Nominal and Benjamini-Hochberg-adjusted P values were reported. Results From 1999 to 2024, PD deaths increased from 14,225 to 39,671, and the age-adjusted mortality rate increased from 41.42 to 71.58 per 100,000 population (average annual percent change, 1.99%; 95% confidence interval [CI], 1.54%-2.45%; P < 0.001). The conditional 2035 projection was 91.35 per 100,000 (95% prediction interval, 75.89–110.89). Across 7,502 rolling-origin predictions, mean absolute error was 9.24, root mean squared error was 12.12, mean bias was -6.48, and 95% interval coverage was 51.7%. State-level spatial autocorrelation was not evident in 2024 (Moran's I = 0.022; permutation P = 0.326). Primary lag 0–3 temperature estimates did not remain significant after multiplicity correction (adjusted P = 0.304), whereas Northeast lag 0–1 mean and apparent temperature estimates remained significant (rate ratios, 0.920 and 0.932 per 10 degrees F; both adjusted P = 0.010). No precipitation or sunlight estimate survived correction (minimum adjusted P = 0.142 and 0.308, respectively), and 2 of 72 PCA associations remained significant after correction (adjusted P = 0.027 and 0.035). Conclusions PD mortality increased markedly among older U.S. adults. Forecasts suggested a continued rise but showed limited long-horizon calibration. Climate associations were regional and largely attenuated after multiplicity correction, supporting cautious, hypothesis-generating interpretation.