J.-M. KIM*, R. STEWART**#, I.-S. SHIN***, J.-S. YOON***

* Department of Psychiatry, Chosun University Hospital, Kwangju, Republic of Korea. ** Section of Epidemiology, Institute of Psychiatry, London, United Kingdom. *** Department of Psychiatry & Research Institute of Medical Science, Chonnam National University Medical School, Kwangju, Republic of Korea. # Correspondence: Dr Robert Stewart, Section of Epidemiology, Box 60, Institute of Psychiatry, De Crespigny Park, London, SE5 8AF, UK; Fax: +44 (0)20 7277 0283; E-mail: r.stewart@iop.kcl.ac.uk

BACKGROUND: The association between cholesterol levels, cognitive impairment and dementia is controversial. OBJECTIVES: To investigate differences in serum total cholesterol levels between mild and moderate cognitive impairment and between dementia syndromes. To investigate the association between cholesterol level and progression of Alzheimer's disease (AD). DESIGN: Non-fasting cholesterol levels were measured in two groups: a) 291 participants in a community study in South Korea, aged 65 or over, and scoring below 25 on the Mini-Mental State Examination (Korean version: MMSE-K); and b) 79 patients with AD attending a local hospital. In the community sample, associations were investigated between cholesterol level and both cognitive function and dementia (DSM-IV). For the hospital sample, associations were investigated between cholesterol level and decline in cognitive function (MMSE-K) and/or functional activities of daily living (ADL, Blessed Dementia Scale) over one year. RESULTS: Lower serum cholesterol level was associated with worse cognitive function in the community sample. Associations with dementia were specific to AD rather than other subtypes. No cross-sectional association was found between cholesterol levels and cognitive function in AD groups from either sample. No prospective associations were found between cholesterol level and decline of cognitive function or functional ADL in hospital attenders with AD. Adjustment for age, gender, education, past occupation, disablement, duration of dementia, and the presence of APOE e4 made little difference to the associations in the hospital sample. CONCLUSION: Lower serum cholesterol level may be a state marker of AD but does not appear to influence its rate of progression.

Keywords: Cholesterol, Alzheimer disease, dementia, cognitive impairment, cognitive decline.