Prevalence of Parkinson disease among the Navajo: a preliminary examination.

BACKGROUND

The prevalence of Parkinson disease (PD) varies by geographic location and ethnicity, but has never been studied among the Navajo.

METHODS

Period prevalence was calculated using the number of people diagnosed with PD in the Shiprock Service Unit Indian Health Service database during 1995-1999, 2000-2004, and 2005-2009 as the numerator, and the number seen for any reason as the denominator. Age-standardized rates were calculated using the 2000 US population.

RESULTS

During 2005-2009, 126 people were seen with PD (crude prevalence = 203.7/100,000 population). The age-adjusted rate was 335.9 (95% C. I. 277.8-394.0) overall, 438.5 (95% C.I. 336.5-540.5) in men and 259.7 (95% C.I. 192.8-326.7; p = 0.004) in women. The adjusted rate increased with age: 788.8 (95% C.I. 652.0-925.7) for age 40 and above to 1964.9 (95% C.I. 1613.7-2316.1) for age 60 and above. Adjusted rates were 246.6 (95% C.I. 187.2-306.0) in 1995-1999 and 284.7 (95% C.I. 227.0-342.4) in 2000-2004.

CONCLUSION

Parkinson disease appears common among the Navajo. Estimates increased with age and time, and were higher in men. In-person interviews are needed to confirm these estimates, and to determine incidence, quality of care, and risk factors for PD among the Navajo.