Homocysteine and cognitive function in healthy elderly community dwellers in Italy

Elevated plasma total homocysteine (tHcy) concentrations are common in the elderly and have been suggested to be a risk factor for dementia. In an elderly population, we examined the relation between plasma tHcy and scores on the Mini-Mental State Examination (MMSE), a commonly used screening measure of cognitive impairment in general practice. Fasting plasma tHcy concentrations were measured in 650 healthy, cognitively normal Italian community dwellers aged > or = 65 y (x +/- SD: 72.8 +/- 6.0 y). Socioeconomic status; serum folate, vitamin B-12, and creatinine; other potential dietary and lifestyle determinants of tHcy; and conventional vascular disease risk factors were also assessed. Subjects with MMSE scores of 26-28 had higher plasma tHcy concentrations (12.7 micromol/L; range: 12.2-13.2 micromol/L) than did those with scores > 28 (11.9 micromol/L; 11.4-12.3 micromol/L; P < 0.01). Subjects with scores of 24-25 had higher plasma tHcy concentrations (14.5 micro mol/L; 13.5-15.6 micromol/L) than did subjects with scores of 26-28 (P < 0.01) or > 28 (P < 0.001). The risk of hyperhomocysteinemia (plasma tHcy > 15 micromol/L) was higher in subjects with scores of 24-25 (odds ratio: 3.81; 95% CI: 1.9, 7.5) or 26-28 (odds ratio: 1.96; 95% CI: 1.3, 3.0) than in those with scores > 28. The results did not change after adjustment for conventional vascular risk factors and for age, medical, dietary, and lifestyle determinants of plasma tHcy. Elevated plasma tHcy has an independent, graded association with concurrent cognitive impairment as measured with the MMSE in healthy elderly community dwellers.