Metabolic syndrome and cognitive function: a population-based follow-up study in elderly women

To test the hypothesis that metabolic syndrome predicts cognitive impairment, and to examine the association of single metabolic risk factors with cognitive functioning.

We performed a 12-year follow-up study in a population-based sample of 101 women aged 60-70 years at baseline. Metabolic syndrome was defined by the National Cholesterol Education Program criteria (> or =3 out of 5 risk factors). Global cognitive function was measured by the Mini-Mental State Examination both at baseline and follow-up. A detailed neuropsychological evaluation for memory and cognitive speed was performed at follow-up.

The prevalence of metabolic syndrome increased from 13% at baseline to 49% at follow-up (p < 0.001). Women with metabolic syndrome at baseline had a 4.27 (95% confidence interval: 1.02-17.90; p = 0.047) times higher risk of poor memory at follow-up after adjustment for age, education and depression. The increasing number of metabolic risk factors was associated with worsening of memory at follow-up (p = 0.034 for linear trend). Women with low baseline levels of high-density lipoprotein (HDL) cholesterol were more likely to have poor memory at follow-up than those with higher HDL levels (p = 0.028). The risk of having poor memory increased by 46.5% (95% confidence interval: 15-66%; p = 0.008) with 1 SD decrease in HDL cholesterol level.

In elderly women, metabolic syndrome may be an important contributor to worsening of memory, which is an essential part of mild cognitive impairment.