Adverse lipid profiles in older people are associated with lower dementia risk: Epidemiology / Risk and protective factors in MCI and dementia.

Background: Dyslipidaemia in mid‐life is associated with incident dementia but evidence is conflicting on whether dyslipidaemia in late‐life increases dementia risk. This may be due to the large heterogeneity in cholesterol measures and study designs employed. We used detailed data from a large prospective cohort of older people to comprehensively assess the relation between a broad range of cholesterol measures and incident dementia, addressing potential biases, confounders and modifiers. Method: In 3392 community‐dwelling individuals, without dementia, aged 70‐78 years, total cholesterol, low‐density lipoprotein cholesterol (LDL‐C), high‐density lipoprotein cholesterol (HDL‐C), triglycerides and apolipoprotein A1 and B were assessed. Over a median of 6.7 years follow‐up, dementia was established by clinical diagnosis confirmed by independent outcome adjudication. Hazard ratios (HR) for dementia and mortality were calculated using Cox regression. Result: Dementia occurred in 231 (7%) participants. Dyslipidaemia, particularly high LDL‐C/HDL‐C, was associated with lower dementia risk, independent of age, cardiovascular risk factors, cognitive function, apolipoprotein E genotype and cholesterol lowering drugs. This association was not influenced by the competing risk of mortality. One SD increase in LDL/HDL conveyed a 19% lower dementia risk (HR=0.81, 95%CI=0.69‐0.96) and a 10% lower risk of dementia/mortality combined (HR=0.90, 95%CI=0.82‐0.98). Strong and consistent interactions suggested these associations were predominant in individuals with low BMI and education and potentially reversed in high BMI and education subgroups. Conclusion: Dyslipidaemia in older individuals conveyed a lower risk of dementia. Differentiating between subgroups seems essential when assessing the risk of poor outcome associated with dyslipidaemia. This may have important implications for dementia risk prediction. [ABSTRACT FROM AUTHOR]