The MDS-UPDRS total score — which integrates motor and nonmotor aspects of the disease – showed a greater mean increase in the endemic cohort (mean ± SD: 4 ± 3.19) relative to the nonendemic cohort (2.24 ± 2.99), with a near-significant P = 0.08.
Although the mean disease duration since onset was numerically higher in the endemic cohort compared to the nonendemic cohort, this difference did not reach statistical significance, suggesting comparable disease chronicity across groups at the time of assessment.
Similarly, UPDRS part 1, reflecting nonmotor symptoms such as sleep disturbances, mood changes, and autonomic dysfunction, was higher in the endemic subset (7.0 ± 2.06) with respect to the nonendemic subset (5.85 ± 2.07), although the ( P = 0.051) was just above the conventional threshold for statistical significance – suggesting a strong trend toward increased nonmotor symptom burden among the fluoride-exposed cohort.
While both groups showed a trend toward clinical worsening, the extent of progression varied, with the endemic group generally demonstrating a greater increase in symptom burden across most domains.