Risk of dementia associated with the ApoE ɛ4 allele and falls causing head injury without explicit traumatic brain injury


Heikki Luukinen, Department of Public Health Science and General Practice, University of Oulu, Unit of General Practice, Oulu University Hospital, P.B. 5000, FIN-90014, Finland
Tel.: +358 8 5375644
Fax: +358 8 5375661
e-mail: heikki.luukinen@oulu.fi


Objectives –  Severe head injury (HI) and the apolipoprotein E (ApoE) ɛ4 allele are risk factors for dementia. The corresponding effect of falls causing HI without explicit traumatic brain injury (TBI) in association with the ApoE ɛ4 is not known.

Materials and methods –  Altogether 134 persons aged 70 years or older constituted a retrospective population sample, who scored ≥26 in the MiniMental State Examination (MMSE) test at baseline and were clinically examined for dementia 9 years afterward. Fall-related HI causing superficial laceration or bruises or wounds that require suturing were prospectively recorded during the 9-year follow-up. We used Cox regression with age at the diagnosis of dementia as a dependent variable.

Results –  Twenty-eight (21%) subjects had falls causing HI without explicit TBI, the ApoE ɛ4 allele was seen in 44 (33%), and clinical dementia was diagnosed in 25 (19%). Adjusted for the baseline MMSE score, sex and educational status, the hazard ratio for subsequent dementia in subjects having falls with HI without explicit TBI and the ApoE ɛ4 allele as compared with those who do not possess these characteristics was 2.70 (95% confidence interval, 1.02–7.16).

Conclusions –  According to the results of this small retrospective study, falls with HI without explicit TBI in connection with the ApoE ɛ4 allele is associated with subsequent dementia among older adults.