Serum levels of 25-hydroxyvitamin D are associated with cognitive impairment in type 2 diabetic adults

Abstract

Hypovitaminosis D is highly prevalent in type 2 diabetes. The aim of this study is to determine the serum levels of 25-hydroxyvitamin D [25(OH)D] in type 2 diabetic patients with and without mild cognitive impairment (MCI), and examine the relationship of 25(OH)D and MCI with other clinical factors. One hundred and sixty-five diabetic patients were enrolled in this study. Among whom, 95 patients were considered as MCI [Montreal Cognitive Assessment score (MoCA) < 26] and the other 70 as no MCI (MoCA ≥ 26). Subjects were assessed clinically. Diabetic patients with MCI had a longer duration of DM, fewer years of education, elevated fasting blood glucose (FBG), resistant index (RI) of carotid, and lower levels of 25(OH)D {[17.35 (13.02-25.92) vs 28.00 (19.67-34.30)] ng/ml, P < 0.001}. The MoCA score was positively correlated with log10[25(OH)D], education year, and inversely correlated with duration of DM, history of hypertension, intima-media thickness (IMT), FBG, max-RI, and min-RI. Log10[25(OH)D] was positively correlated with MoCA score, and inversely correlated with IMT, in multivariate regression analysis adjusted for age, sex, and education year, 25(OH)D (β = 0.210, P = 0.003), history of hypertension (β = -0.191, P = 0.007), IMT (β = -0.194, P = 0.007), and FBG (β = -0.157, P = 0.026) independently predicted MoCA score. In conclusion, our results suggest that levels of serum 25(OH)D are inversely associated with the cognitive impairment in diabetic patients. Vitamin D may be a potential protective factor for cognitive impairment in patients with type 2 diabetes.

25-hydroxyvitamin D Levels are Associated with Cognitive Dysfunction in Type 2 Diabetes and the Metabolic Syndrome: A Preliminary Examination

“…Cognitive dysfunction is common in both T2DM [10] and metabolic syndrome [11] and the current findings suggest that persons meeting criteria for both conditions may be especially likely to exhibit impairment on testing. Past research has also found that cognitive impairment (as defined by a broadband screening measure) in individuals with T2DM is associated with insufficient 25-hydroxyvitamin D [12]. Consistent with expectations and past findings, a positive association between 25-hydroxyvitamin D and cognition was noted in the current sample, though only executive function demonstrated this relationship.…”

“…Similarly, the current study cannot determine the extent to which the association between 25hydroxyvitamin D and cognitive function in independent of other factors. For example, indices for obesity, hypertension, and insulin resistance are known to be associated with poorer cognitive outcomes [12,15] and their specific and combined influence on the current findings is unclear. Prospective studies utilizing 25-hydroxyvitamin D supplementationmay answer the question of causality, particularly if controlling for abnormalities in glucoregulation.…”

An Update on Type 2 Diabetes Mellitus as a Risk Factor for Dementia

“…High BMI, high 2-hour postprandial glucose, and poor glycemic control were significant independent predictors of cognition impairments in patients with both T2DM and MCI [76]. T2DM patients with MCI had a longer duration of diabetes [77,78,79], fewer years of education [77], higher HbA1c [78,79], higher low density lipoprotein (LDL) cholesterol [78], higher triglyceride [78] and higher fasting blood glucose (FBG) [77] than T2DM patients without cognitive impairment. Cognition functions were inversely correlated with T2DM duration [77], FBG [77], history of hypertension [77], non-high-density lipoprotein cholesterol [71], and total cholesterol [78].…”

Vitamin D insufficiency and cognitive impairment in Asians: a multi‐ethnic population‐based study and meta‐analysis

“…The results of our original study, although attenuated, are in agreement with the overall finding from the meta-analysis. The definition of cognitive disorders differed in some of the included studies and was based on an abnormal cognitive score as in our study [11][12][13], a diagnosis of mild cognitive impairment [14] or a diagnosis of AD [9,10]. Despite the variety of cognitive outcomes, which is likely to account for the high degree of heterogeneity of the meta-analysis, our results are consistent with recent neuroepidemiological evidence of an association between decreased 25OHD concentrations and reduced global cognitive performance amongst older adults in Europe and the USA [2][3][4][5]8].…”

“…abnormal cognitive score or mild cognitive impairment) and AD as the outcome were included. This search strategy identified six previous studies [9][10][11][12][13][14] as well as the present one; all included crosssectional analyses.…”