Incidence of early-onset dementias in Cambridgeshire, United Kingdom.
OBJECTIVE
To estimate the incidence of early-onset dementias in a defined area of Cambridgeshire served by Addenbrooke's Hospital.


METHODS
The area selected for the study was that covered by the local authority areas of Cambridge City, East Cambridgeshire, and South Cambridgeshire. Cases were identified from the specialist memory and dementia clinics held at Addenbrooke's Hospital and were defined as those patients resident in the target area at the time of diagnosis, who were diagnosed with dementia before the age of 65 years between June 1, 2000, and May 31, 2006.


RESULTS
No obvious pattern by sex was present. The incidence for all cases of primary dementia for the age range 45-64 years was estimated to be 11.5 cases per 100,000 person-years (95% CI 8.6-15.0). The incidence of frontotemporal dementia for the age range 45-64 years was estimated to be 3.5 cases per 100,000 person-years (95% CI 2.0-5.7); for Alzheimer disease the incidence for the same group was 4.2 (95% CI 2.5-6.6) and for Huntington disease the incidence rate of cases becoming affected (with or without dementia) was 0.8 (95% CI 0.2-2.3).


CONCLUSIONS
If the incidence rates were extrapolated across England and Wales, in the region of 460 new cases of frontotemporal dementia and 550 new cases of Alzheimer disease could be expected each year in the 45-64 years age group.
Mercy
L
L
MFPH, Institute of Public Health, University of Cambridge, University Forvie Site, Robinson Way, Cambridge, UK. Linda.Mercy@nhs.net
Hodges
J R
JR
Dawson
K
K
Barker
R A
RA
Brayne
C
C
D017668:Age of Onset; D000544:Alzheimer Disease / Q000175:diagnosis / Q000453:epidemiology* / Q000503:physiopathology; D003704:Dementia / Q000175:diagnosis / Q000453:epidemiology* / Q000503:physiopathology; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D006113:United Kingdom / Q000453:epidemiology