| Dr. Harman 2005-07-11, 5:54 pm |
| unn N, Mullee M, Perry VH, Holmes C.
>From the *Senior Lecturer in Primary Medical Care, university of
Southampton; daggerSenior Research Fellow in Medical Statistics,
University of Southampton; double daggerProfessor and Head of CNS
Inflammation Group, university of Southampton; section signSenior
Lecturer in Psychiatry of the Elderly, university of Southampton, UK.
Inflammation plays a part in the etiology of dementia. Whether this is
the primary pathogenesis, or a secondary reaction is unclear. We
postulate that since systemic infection can provoke the enhanced
synthesis of inflammatory mediators in the brain, such diseases may
promote the onset of dementia.We carried out a nested case-control
study using the General Practice Research Database. Cases were patients
with incident dementia, and controls without such a diagnosis.
Infectious episodes in the four years preceding diagnosis were counted
using diagnostic codes, or prescription codes for anti-infective drugs.
We considered age, sex, smoking, diabetes mellitus, and frequency of
consultation as potential confounders.There were 9954 valid cases, and
9374 valid controls. Cases were on average older, more likely to be
female, to smoke and to have diabetes, than the controls. There was an
increased risk of diagnosis of dementia in those patients older than 84
with infections (OR for 2 or more infections compared with 0 or 1 =
1.4, 95% CI 1.2 to 1.7). Smoking and diabetes mellitus were also shown
to markedly increase the risk of diagnosis of dementia.We have shown a
positive association between episodes of infection and increased
likelihood of diagnosis of dementia in the very elderly. Smoking and
diabetes mellitus are associated with onset of dementia in the elderly.
The evidence from this study may represent cause and effect, since
there is a credible biologic explanation.
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