Effects of basal insulin glargine and omega-3 fatty acid on cognitive decline and probable cognitive impairment in people with dysglycaemia: a substudy of the ORIGIN trial.

BACKGROUND: Diabetes and non-diabetic dysglycaemia are risk factors for accelerated cognitive decline. In this planned substudy of the Outcome Reduction with Initial Glargine Intervention (ORIGIN) trial, we assessed whether normalising glucose with insulin glargine or administering omega-3 fatty acids in this population may slow this process or affect the development of cognitive impairment. METHODS: The ORIGIN trial recruited participants older than 50 years with dysglycaemia who were taking either no or one oral glucose-lowering drug, who had additional risk factors for cardiovascular events, whose HbA1c was less than 9%, and who were not taking insulin. Participants were recruited from 573 sites in 40 countries. Participants were randomly assigned to either titrated basal insulin glargine targeting a fasting plasma glucose concentration of 5.3 mmol/L or lower or standard care and to either omega-3 fatty acid (1 g) or placebo by a factorial design. Outcome adjudicators and data analysts were masked to treatment allocation. Cognitive function was assessed by the Mini-Mental State Examination (MMS) and Digit Symbol Substitution (DSS). The effect of insulin glargine or omega-3 fatty * acid on cognitive function over time, the annualised change in test scores, and the development of probable cognitive impairment were measured. All analyses were restricted to those participants who had a cognitive measurement at both baseline and at least one follow-up visit. The ORIGIN trial is registered with ClinicalTrials.gov, NCT00069784. FINDINGS: Participants were randomly assigned between Sept 1, 2003, and Dec 15, 2005. MMSE and DSS were assessed in 11,685 and 3392 ORIGIN participants (mean age 63.4 years [SD 7.7]), who were followed up for a median of 6.2 years (IQR 5.8-6.7). There was no difference in the rate of change of cognitive test scores between the insulin glargine and standard care groups (for the MMSE 0.0046, 95% CI -0.0132 to 0.0224, p=0.39; and for the DSS -0.0362, -0.2180 to 0.1455, p=0.34) or between the omega-3 fatty acid and placebo groups (for the MMSE 0.0013, 95% CI -0.0165 to 0.0191, p=0.21; and for the DSS -0.0605, -0.2422 to 0.1212, p=0.72). Similarly, the incidence of probable cognitive impairment did not differ between the insulin glargine and standard care groups (p=0.065) or the omega-3 fatty acid and placebo groups (p=0.070). In a subgroup analysis, allocation to insulin glargine versus standard care seemed to reduce the decline in the MMSE (but not the DSS) in participants with dysglycaemia but without evidence of diabetes (pinteraction=0.024). INTERPRETATION: In this relatively young cohort of people with dysglycaemia, insulin mediated normoglycaemia and omega-3 fatty acid for over 6 years had a neutral effect on the rate of cognitive decline and on incident cognitive impairment. Future studies should assess the effect of these interventions in an older cohort or the effect of other glucometabolic interventions on cognitive decline. FUNDING: Sanofi.

The relation of serum 25-hydroxyvitamin-D levels with severity of obstructive sleep apnea and glucose metabolism abnormalities.

Obstructive sleep apnea (OSA) and 25-hydroxyvitamin-D3 (25-OH-D) deficiency are two separate disorders associating with obesity, inflammation, and impaired glucose metabolism. We aimed to investigate the vitamin D status of OSA patients regarding to potential links between lower vitamin D levels and abnormal glucose metabolism, which is one of the main adverse outcomes of OSA. Study group is composed of 190 non-diabetic subjects who were suspected of having OSA. Subjects undergone polysomnography and were grouped due to apnea-hypopnea indices (AHI) as controls (AHI < 5, n = 47), mild OSA (5 ≤ AHI < 15, n = 46), moderate OSA (15 ≤ AHI < 30, n = 47), and severe OSA (AHI ≥ 30, n = 50). Serum 25-OH-D, HbA1c, insulin levels were measured and 75-g oral glucose tolerance test was performed. Serum 25-OH-D level (ng/ml) of OSA patients were lower than control subjects (17.4 ± 6.9 vs. 19.9 ± 7.8), and decrement was parallel to severity of OSA; as 18.2 ± 6.4 (5 ≤ AHI < 15), 17.5 ± 7.4 (15 ≤ AHI < 30), and 16.3 ± 6.9 (AHI > 30), respectively (P = 0.097, r = -0.13). However, severe female OSA patients had significantly lower 25-OH-D levels (11.55 ng/ml), while control males had the highest mean value (21.7 ng/ml) (P < 0.001). Frequency of insulin resistance (IR) was 48%, prediabetes 41%, diabetes 16% in OSA patients. Mean 25-OH-D level of insulin resistant subjects (HOMA-IR ≥ 2.7, n = 77, AHI = 35.5) was lower than non-insulin resistant subjects (HOMA-IR < 2.7, n = 113, AHI = 19.8) as 16.18 ± 7.81 versus 19.2 ± 6.6, respectively (P = 0.004). 25-OH-D level of 91 non-diabetic subjects (n = 91, AHI = 19.7) was 19.5 ± 7.4, prediabetics (n = 75, AHI = 28.7) was 17.45 ± 6.9, and diabetics (n = 24, AHI = 46.3) was 13.8 ± 5.3 (P = 0.02). We showed that subjects with more severe OSA indices (AHI ≥ 15) tended to present lower vitamin D levels correlated to increased prevalence of IR, prediabetes, and diabetes. Vitamin D deficiency may play a role and/or worsen OSA's adverse outcomes on glucose metabolism. OSA patients may be considered for supplementation treatment which was shown to ameliorate abnormal glucose metabolism and inflammation.

Effect of α-lipoic acid and exercise training on cardiovascular disease risk in obesity with impaired glucose tolerance.

Obese subjects with impaired glucose tolerance (IGT) are more susceptible than healthy individuals to oxidative stress and cardiovascular disease. This randomised controlled investigation was designed to test the hypothesis that α-lipoic acid supplementation and exercise training may elicit favourable clinical changes in obese subjects with IGT. All data were collected from 24 obese (BMI ≥ 30 kg/m2) IGT patients. Following participant randomisation into two groups, fasting venous blood samples were obtained at baseline, and before and following intervention. The first group consisted of 12 participants who completed a 12 week control phase followed by 12 weeks of chronic exercise at 65% HRmax for 30 minutes a day, 5 days per week, while ingesting 1 gram per day of α-lipoic acid for 12 weeks. The second group consisted of 12 participants who completed the same 12 week control phase, but this was followed by 12 weeks of 1 gram per day of α-lipoic acid supplementation only (no exercise). The main findings show a comparatively greater rate of low density lipoprotein (LDL) oxidation in the group consisting of α-lipoic acid only (p < 0.05 vs. pre intervention), although total oxidant status was lower post intervention (p < 0.05 vs. baseline) in this group. However, exercise and α-lipoic acid in combination attenuates LDL oxidation. Furthermore, in the α-lipoic acid supplement plus exercise training group, total antioxidant capacity was significantly increased (p < 0.05 vs. baseline and pre intervention). Body fat percentage and waist and hip circumference decreased following exercise training (p < 0.05 vs. post intervention). There were no selective treatment differences for a range of other clinical outcomes including glycaemic regulation (p > 0.05). These findings report that α-lipoic acid ingestion may increase the atherogenicity of LDL when ingested in isolation of exercise, suggesting that in IGT the use of this antioxidant treatment does not ameliorate metabolic disturbances, but instead may detrimentally contribute to the pathogenesis of atherosclerosis and development of CVD. However, when α-lipoic acid is combined with exercise, this atherogenic effect is abolished.

Glucose metabolism in early onset versus late onset Alzheimer's disease: an SPM analysis of 120 patients.

The aims of this cross-sectional study were (i) to compare the overall glucose metabolism between early onset and late onset Alzheimer's disease in a large sample of patients; and (ii) to investigate the pattern of glucose metabolism as a function of dementia severity in early onset versus late onset Alzheimer's disease, using a statistical parametric mapping (SPM) analysis. Subjects consisted of four groups: 74 patients with early onset Alzheimer's disease, 46 patients with late onset of the disease, and two control groups age matched to each patient group. All the subjects underwent 2-[(18)F]fluoro-2-deoxy-d-glucose (FDG)-PET under the same scanning conditions. Severity of dementia was rated with the Clincial Dementia Rating (CDR). Voxel-based SPM99 was used for statistical analyses. Overall glucose hypometabolism of early onset Alzheimer's disease patients was much greater in magnitude and extent than that of late onset patients, though both groups were similar in dementia severity: the early onset group showed more severe hypometabolism in parietal, frontal and subcortical (basal ganglia and thalamus) areas. When the decline of glucose metabolism was compared as a function of CDR stage, the slope was steeper in early onset than in late onset Alzheimer's disease. The rapid decline occurred at CDR 0.5-1 in the early onset group, whereas similar changes occurred at CDR 2-3 in the late onset group. The greater hypometabolism in early onset than in late onset patients is required to reach the same severity of dementia, probably reflecting greater functional reserve in younger than in older subjects. Alternatively, the metabolic decline curve suggests that the early onset patients may take a more rapid course in the reduction of glucose metabolism than the late onset patients.