Factors related to the progression of mild cognitive impairment toward Alzheimer's disease

Abstract

Objective To investigate the progression of mild cognitive impairment (MCI) to Alzheimer's disease (AD) and the factors influencing the related changes in cognitive ability. Methods Seventy-five subjects with mild cognitive impairment (the MCI group), 32 with Alzheimer's disease (the AD group) and 17 others with normal cognition (the NC group) were recruited. The Montreal Cognitive Assessment (MOCA) and the Mini-mental State Examination (MMSE) were used to assess their cognitive ability. At the same time, relevant clinical information such as their general condition and past history of disease were recorded. The subjects were followed up for 20 months on average to evaluate their annual rates of progression (APRs), and logistic regression was used to highlight any influencing factors. Results By the end of the follow-up, 9 of the 75 MCI subjects had progressed to AD, with an APR of 5.25%. Thirteen cases had recovered normal cognitive functioning (97.6 per 1, 000 person-years). Also, 2 cases in the NC group (11.76%) developed MCI (69.1 per 1, 000 person-years), but none of them had yet progressed to AD. Both hyperlipidemia and a body mass index (BMI) lower than 24 kg/m2 significantly predicted the deterioration of cognitive functioning. Heart disease was significantly correlated with cognitive improvement, and self-management of cognitive function was also a significant protective factor. Conclusions Patients with MCI are at greater risk of developing AD than normal persons. Prevention and early treatment of hyperlipidemia as well as maintaining a normal BMI may delay the deterioration of cognitive functioning. Self-management of cognitive function can improve cognition. Key words: Cognitive impairment; Alzheimer's disease