Serum Level of Alkaline Phosphatase Correlates Negatively with Mini-Mental State Examination Score in the Very Elderly of Ashikaga City: Part of the Results of the Ashikaga Longevity Study

Objective: An important medical issue in both Japan and Ashikaga City is how to extend healthy life expectancy. To determine factors associated with healthy life expectancy, we established a joint study between Ashikaga City and the Ashikaga University Faculty of Nursing called the Ashikaga Longevity Study, using new biomarkers such as Diacron reactive oxygen metabolites (d-ROMs) and biological antioxidant potential (BAP) tests as indicators of oxidative stress. In this study, factors related to cognitive function were clarified. Methods: Participants comprised 95 individuals (36 men; mean age, 91.0±5.1 years and 59 women; mean age, 92.2±5.9 years). Cognitive impairment was assessed using the Mini-Mental State Examination (MMSE). Results: MMSE score was ≤23 in 28 subjects (29.5%) and ≥24 in 67 subjects (70.5%). MMSE score showed significant negative correlations with age (p<0.0096), plasma alkaline phosphatase (p=0.0007), and peripheral leukocyte-to-lymphocyte ratio (p=0.0119), and positive correlations with plasma albumin (p=0.0096) and BAP-to-d-ROMs ratio (p=0.0427). Conclusions: These results suggest that cognitive decline may involve brain cell dysfunction due to inflammation based on a reduced ability to control oxidative stress. Not only anti-oxidative aerobic exercise but also anti-oxidative foods, may be necessary to maintain cognitive function.