Risk of Parkinson's disease after hospital contact for head injury: population based case-control study

Abstract

Objective To determine whether a hospital contact for a head injury increases the risk of subsequently developing Parkinson’s disease.Design Population based case-control study.Setting Denmark.Participants 13 695 patients with a primary diagnosis of Parkinson’s disease in the Danish national hospital register during 1986-2006, each matched on age and sex to five population controls selected at random from inhabitants in Denmark alive at the date of the patient’s diagnosis (n=68 445).Main outcome measures Hospital contacts for head injuries ascertained from hospital register; frequency of history of head injury.Results An overall 50% increase in prevalence of hospital contacts for head injury was seen before the first registration of Parkinson’s disease in this population (odds ratio 1.5, 95% confidence interval 1.4 to 1.7). The observed association was, however, due almost entirely to injuries that occurred during the three months before the first record of Parkinson’s disease (odds ratio 8.0, 5.6 to 11.6), and no association was found between the two events when they occurred 10 or more years apart (1.1, 0.9 to 1.3).Conclusions The steeply increased frequency of hospital contacts for a head injury during the months preceding the date at which Parkinson’s disease was first recorded is a consequence of the evolving movement disorder rather than its cause.

Epidemiology and etiology of Parkinson’s disease: a review of the evidence

“…This study reported increased risk of PD following head trauma (OR 1.5, 95% CI 1.4-1.7), but the increase was almost entirely due to trauma that occurred during the three months before first hospital contact due to PD (OR 8.0, 95% CI 5.6-11.6). Head trauma that occurred between 4 months and 9 years before first hospital contact due to PD only slightly increased risk of PD (OR 1.5, 95% CI 1.3-1.7), and for traumas that occurred 10 years or more before, there was no association (OR 1.1, 95% CI 0.9-1.3) [627]. The authors interpreted these results as being due to reverse causation [627].…”

“…Head trauma that occurred between 4 months and 9 years before first hospital contact due to PD only slightly increased risk of PD (OR 1.5, 95% CI 1.3-1.7), and for traumas that occurred 10 years or more before, there was no association (OR 1.1, 95% CI 0.9-1.3) [627]. The authors interpreted these results as being due to reverse causation [627].…”

“…No association was observed between head trauma and PD [628]. The other Danish study [627] included 13,695 PD cases with a hospital discharge diagnosis after 1986 and 68,445…”

“…A small populationbased prospective study observed no association [626]. Two studies used Danish national hospital discharge data but took different approaches [627,628]. One of them [628] followed a national cohort of individuals above 20 years in 1981, identified head trauma that caused hospitalization between 1981 and 1993, and hospital discharge PD diagnoses after 1995 (8,769 cases).…”

Risk factors for dementia with Lewy bodies

“…We confined our risk factor assessment to 19 demographic, genetic, or disease characteristics associated with DLB, AD, or PD and for which data were available from the studies: age, 5 sex, 5 family history of dementia 2,7,8 or PD, 9,10 APOE e4 status (any e4 alleles vs none), 11,12 history of anxiety 13 or depression, 14,15 smoking (ever vs never in lifetime), 16,17 alcohol (ever vs never) 18,19 and caffeine consumption (ever vs never), 20,21 cancer (excluding nonmelanoma skin cancer), 22,23 diabetes mellitus, 24,25 education (9 or more years vs less than 9), 26,27 head injury, 28,29 number of children in men (more than one vs zero or one child), 30 occupation as a physician (vs all other occupations), 27 oophorectomy (uni-or bilateral, with or without hysterectomy), 31,32 oophorectomy at or before age 45, 32,33 and stroke. 34,35 Data definitions are in table e-1 on the Neurology ® Web site at www.neurology.org.…”