Modifiable Predictors of the Onset of either Amnestic Mild Cognitive Impairment or Alzheimer's Dementia and Cognitive Changes in Subjective Cognitive Decline

Abstract

Subjective cognitive decline (SCD) refers to individuals’ perceived decline in the cognitive domain(s) compared to their previous abilities in the context of normal neuropsychological functions. The presence of subjective cognitive decline may imply a risk of future cognitive deterioration. There are modifiable vascular and neuropsychiatric risk factors determined by literature on established risk factors of the onset of either amnestic mild cognitive impairment (aMCI) or Alzheimer’s disease (AD) dementia. They include diabetes mellitus, hypercholesterolemia, hypertension, overweight/obesity, a history of cigarette smoking, anxiety, and depression. This study was conducted because firm conclusions were not drawn about those modifiable risk factors associated with clinical progression (i.e., conversion from SCD to either aMCI or AD dementia) as well as cognitive changes in persons with SCD. Current smoking (reference: no lifetime smoking) and depression were predictive of clinical progression as opposed to obesity as measured with body mass index. Current smoking and depression were associated with low episodic memory, which is typically affected early in AD pathological changes, but hypercholesterolemia and former smoking were associated with high episodic memory over time. For neuropsychiatric risk factors (reference: without anxiety and depression), depression only was associated with low episodic memory and executive function over time. Depression accompanied by anxiety was associated with low attention scores over time. The findings of the study implied that adequate management of current smoking and depression may have a major public health impact as it may potentially prevent or delay the process of AD dementia in persons with SCD.