Alcohol consumption and transition of mild cognitive impairment to dementia

Aim: Mild cognitive impairment (MCI) is a prodrome for dementia. Alcohol drinking patterns may affect cognitive functions and the effects may accumulate to a significant level at an advanced age. This study investigated the relationship between alcohol consumption and risks for dementia in a cohort of elderly patients with MCI. Methods: Patients with suspected cognitive impairment were screened. One hundred and seventy-six patients who met the MCI criteria were enrolled. Lifetime and daily alcohol consumptions were assessed at baseline using a self-report questionnaire answered by patients and their caregivers. Patients were classified according to alcohol consumptions as abstainers, light-moderate and heavy drinkers. Global cognitive functions were assessed periodically with Mini-Mental State Examination (MMSE). Enrolled patients were followed for 2 years. Results: Of the 176 patients diagnosed as having MCI, 15 (8.5%) died, 13 (7.4%) were lost to follow up, and 66 (37.5%) developed dementia during follow up. Light-moderate alcohol drinkers had better MMSE performance than abstainers (P < 0.05) and heavy drinkers (P < 0.01) 2 years after MCI diagnosis. Patients who consumed a total of ≤300 kg alcohol prior to MCI diagnosis had less cognitive decline than patients who consumed no (P < 0.05) or >300 kg alcohol (P < 0.01). Heavy drinkers had a higher risk for dementia than abstainers (P < 0.05) and light-moderate drinkers (P < 0.05) 2 years after MCI diagnosis. Conclusions: A J-shaped relationship may exist between alcohol consumption and cognitive decline in MCI patients. Light-moderate alcohol drinking may be associated with decreased risks for dementia in elderly patients with MCI.