ABSTRACT: BACKGROUND:The metabolic syndrome (MetS) is an established cardiovascular risk factor. Here, we investigated its role in cognitive impairment. METHODS:Baseline data from 202 participants (aged 65 to 87?years) of the BioCog study were used. All were free of clinical dementia (MMSE?24/30). Cognitive impairment was defined as the lowest tertile of a cognitive summary score. Multiple logistic regression analyses examined associations of body mass index (BMI), triglycerides (TG), high-density lipoprotein (HDL-C), glucose and glycated hemoglobin A1c (HbA1c) levels with the odds of cognitive impairment. MetS was defined as ?3 of its 5 components obesity (BMI???30?kg/m2), elevated TG (TG ?1.7?mmol/L), reduced HDL-C (males: ?0.05). Results for HDL-C were similar when HDL-C, glucose, BMI and TG were entered into a single model (OR 2.56 per 1?mmol/L reduction, 95% CI 1.09, 5.88, p?=?0.031) and when cerebrovascular disease and coronary heart disease were additionally controlled for (OR 2.56 per 1?mmol/L reduction, 95% CI 1.06, 6.25, p?=?0.036). Among the 5 MetS components, participants with elevated TG were at 2-fold increased odds of impairment (OR 2.09, 95% CI 1.08, 4.05, p?=?0.028) including when the remaining 4 MetS components were entered (OR 2.23, 95% CI 1.07, 4.65, p?=?0.033), but the finding was no longer statistically significant when cerebrovascular disease and coronary heart disease were additionally controlled for (p?=?0.11). Presence of MetS and of obesity, reduced HDL-C, elevated glucose or elevated blood pressure were not significantly associated with impairment (all p?>?0.05). CONCLUSION:Our findings support low HDL-C as an independent risk marker of cognitive impairment in older age. The need for research into mediatory and confounding factors, and re-evaluation of traditional cut-off points is highlighted. TRIAL REGISTRATION:The study was registered on 15th October 2014 at clinicaltrials.gov ( NCT02265263 ).
