Restless legs syndrome: an early clinical feature of Parkinson disease in men.
OBJECTIVE
The association between restless legs syndrome (RLS) and Parkinson disease has been extensively studied, but the temporal relationship between the two remains unclear. We thus conduct the first prospective study to examine the risk of developing Parkinson disease in RLS.


METHODS
Prospective study from 2002-2010.


METHODS
United States.


METHODS
There were 22,999 US male health professionals age 40-75 y enrolled in the Health Professionals Follow-up Study without Parkinson disease, arthritis, or diabetes mellitus at baseline.


RESULTS
RLS was assessed in 2002 using a set of standardized questions recommended by the International RLS Study Group. Incident Parkinson disease was identified by biennial questionnaires and then confirmed by review of participants' medical records by a movement disorder specialist. We documented 200 incident Parkinson disease cases during 8 y of follow-up. Compared to men without RLS, men with RLS symptoms who had symptoms greater than 15 times/mo had higher risk of Parkinson disease development (adjusted relative risk = 1.47; 95% confidence interval: 0.59, 3.65; P = 0.41). This was statistically significant only for cases diagnosed within 4 y of follow-up (adjusted relative risk = 2.77; 95% confidence interval: 1.08, 7.11; P = 0.03).


CONCLUSIONS
Severe restless legs syndrome may be an early feature of Parkinson disease.
Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA.
Janice C
JC
Wong
Department of Nutrition, Harvard School of Public Health, Boston, MA.
Yanping
Y
Li
Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA.
Michael A
MA
Schwarzschild
Department of Nutrition, Harvard School of Public Health, Boston, MA ; Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA.
Alberto
A
Ascherio
Department of Nutrition, Harvard School of Public Health, Boston, MA ; Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA ; School of Public Health, Peking Union Medical College, Beijing, China.
Xiang
X
Gao
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D042241:Early Diagnosis; D005500:Follow-Up Studies; D006282:Health Personnel; D006801:Humans; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000150:complications* / Q000175:diagnosis / Q000453:epidemiology; D011446:Prospective Studies; D012148:Restless Legs Syndrome / Q000150:complications* / Q000175:diagnosis / Q000453:epidemiology; D012307:Risk Factors; D011795:Surveys and Questionnaires; D014481:United States / Q000453:epidemiology
Parkinson disease; Restless legs syndrome; prospective study