Risk factors for incident dementia in England and Wales: The Medical Research Council Cognitive Function and Ageing Study. A population-based nested case-control study.
OBJECTIVE
To investigate a number of prospectively collected factors (sociodemographic, medical and behavioural) and their association with incident dementia in a population-based cohort.


METHODS
Nested case-control analysis (at 2 and 6 years) of a population-based cohort study.


METHODS
Individuals aged 65 years and above from five centres in England and Wales: two rural (Cambridgeshire and Gwynedd) and three urban (Nottingham, Newcastle and Oxford).


METHODS
A total of 4,075 individuals from a detailed assessment group, with risk measured at baseline.


METHODS
Incident dementia at 2 and 6 years.


METHODS
Logistic regression was used to calculate crude odds ratios (ORs) for various risk factors and ORs adjusted for age, sex, education and social class.


RESULTS
Age (90+ versus 65-69 years OR = 25.6, 95% confidence interval (CI) = 11.6-56.9) and sex (women versus men OR = 1.6, 95% CI = 1.1-2.4) were directly associated with dementia, with a trend by years of education (P(trend) = 0.02) but not social class. Poor self-perceived health (versus good) increased the risk for incident dementia (OR = 3.9, 95% CI = 2.2-6.9). Alcohol and smoking (never, past and current) were neither strongly protective nor predictive. Stroke was strongly related to incident dementia (OR = 2.1, 95% CI = 1.1-4.2), as was Parkinson's disease (OR = 3.5, 95% CI = 1.3-9.3), and exposure to general anaesthesia (GA) was inversely associated with dementia development (OR = 0.6, 95% CI = 0.4-0.9, with a trend with increasing GA exposure; P = 0.003).


CONCLUSIONS
In this large multicentre and long-term population-based study, some well-known risk factors for dementia, of vascular and Alzheimer's type, are confirmed but not others. The association between self-perceived health-a robust predictor of later health outcomes-and incident dementia, independently of other potential risks, warrants further study.
Yip
Agustin G
AG
University of Cambridge, Department of Public Health and Primary Care, Cambridge, UK.
Brayne
Carol
C
Matthews
Fiona E
FE
D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D016022:Case-Control Studies; D003071:Cognition; D015331:Cohort Studies; D016001:Confidence Intervals; D003704:Dementia / Q000453:epidemiology* / Q000209:etiology / Q000503:physiopathology; D004739:England / Q000453:epidemiology; D005260:Female; D015577:Geriatric Assessment / Q000706:statistics & numerical data*; D006801:Humans; D015994:Incidence; D016015:Logistic Models; D008297:Male; D016017:Odds Ratio; D011446:Prospective Studies; D012307:Risk Factors; D012737:Sex Factors; D012907:Smoking / Q000009:adverse effects; D012959:Socioeconomic Factors; D014852:Wales / Q000453:epidemiology