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Head or brain injuries and Alzheimer's disease: A nested case‐control register study
Author(s) -
Tolppanen AnnaMaija,
Taipale Heidi,
Hartikainen Sirpa
Publication year - 2017
Publication title -
alzheimer's and dementia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.713
H-Index - 118
eISSN - 1552-5279
pISSN - 1552-5260
DOI - 10.1016/j.jalz.2017.04.010
Subject(s) - odds ratio , medicine , nested case control study , head injury , confidence interval , disease , proxy (statistics) , alzheimer's disease , closed head injury , case control study , traumatic brain injury , surgery , psychiatry , machine learning , computer science
Many previous studies have been limited by self‐ or proxy‐reported injury or short follow‐up. We investigated whether head or brain injuries are associated with Alzheimer's disease (AD), possible modifying factors and dose‐response relationship. Methods Nested register‐based case‐control study of all community dwellers who received clinically verified AD diagnosis in Finland in 2005 to 2011 ( n = 70,719) and one to four matched controls for each case ( n of controls = 282,862). Results The magnitude of association between hospital‐treated head and/or brain injuries was strongly dependent on the lag time between exposure and outcome. With a 5‐year lag time, head injury (adjusted odds ratio; 95% confidence interval 1.19; 1.15–1.23) or brain injury (1.23; 1.18–1.29) was associated with higher risk of AD. Dose‐response relationship with number and severity of injuries was observed. Associations were stronger in those with earlier onset of AD. Conclusions Stronger associations with shorter lag times indicate that head and/or brain injuries may also reflect the ongoing AD disease process.