Long-Term Subclinical Hyperglycemia and Hypoglycemia as Independent Risk Factors for Mild Cognitive Impairment in Elderly People

Long-Term Subclinical Hyperglycemia and Hypoglycemia as Independent Risk Factors for Mild Cognitive Impairment in Elderly People

FENG WANG,¹ MINGHUI ZHAO,¹ ZHAOLI HAN,¹ DAI LI,¹ SHISHUANG ZHANG,¹ YONGQIANG ZHANG,¹ XIAODONG KONG,¹ QIANG ZHANG¹ and PING LEI¹

¹Department of Geriatrics, Tianjin Medical University General Hospital, Tianjin Geriatrics Institute, Tianjin, China

Dementia is one of the most common geriatric diseases, and mild cognitive impairment (MCI) is considered to be incipient dementia. MCI patients have elevated risk of progressing to dementia. Multiple metabolic abnormalities have an unconfirmed effect on MCI risk, and taking adequate measures against metabolic abnormalities might prevent the developing of MCI. Thus, the present study explored the association of MCI risk with common metabolic abnormalities, such as hyperglycemia, hypoglycemia, hyperlipidemia and hypouricemia, and to provide the basis for MCI prevention. A total of 1,262 elderly outpatients with normal cognitive function and without confirmed diabetes mellitus, hyperlipoidemia and gout were enrolled. During the five-year follow-up period, 142 subjects were diagnosed with MCI according to Mini Mental State Examination and Montreal Cognitive Assessment. Furthermore, annual blood glucose, glycated hemoglobin, lipids and uric acid values were obtained, and mean of each indicator was calculated. Only mean values were included in the study to reflect long-term effect of metabolic abnormalities on MCI risk. Thus, the increased risk of MCI was associated with the mean values of blood glucose < 4.7 mmol/L (RR: 1.57, 95% CI: 1.14-2.32), blood glucose ≥ 6.3 mmol/L (RR: 1.49, 95% CI: 1.03-2.39), glycated hemoglobin ≥ 5.9% (RR: 2.28, 95% CI: 1.59-3.91), triglycerides ≥ 2.0 mmol/L (RR: 2.79, 95% CI: 2.14-3.79), total cholesterol ≥ 5.5 mmol/L (RR: 2.37, 95% CI: 1.69-3.39) and uric acid ≤ 380 μmol/L (RR: 1.62, 95% CI: 1.08-2.51). In conclusion, long-term subclinical hyperglycemia, hypoglycemia, hyperlipidemia, and hypouricemia are independent risk factors for MCI in elderly people.

keywords —— hyperglycemia; hyperlipidemia; hypoglycemia; hypouricemia; mild cognitive impairment

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Tohoku J. Exp. Med., 2017, 242, 121-128

Correspondence: Ping Lei M.D., Ph.D., Department of Geriatrics, Tianjin Medical University General Hospital, Tianjin Geriatrics Institute, No. 154, Anshan Road, Heping District, Tianjin 300052, China.

e-mail: leiping1974@163.com