Diabetes mellitus and elevated copeptin levels in middle age predict low cognitive speed after long-term follow-up

A quick test of cognitive speed (AQT): regression-based norms for cognitively healthy 80 to 94-year olds

Slowed processing speed is part of normal aging but also a symptom of many diseases, including dementia. A Quick Test of Cognitive Speed (AQT) consists of three conditions: color naming (AQT1), form naming (AQT2) and dual color-form naming (AQT3) and offers a user-friendly assessment of processing speed that is used internationally to identify cognitive impairment in elderly patients. Appropriate age-norms have however been lacking. This study provides regression-based norms derived from a Swedish sample of 158 cognitively healthy 80 to 94-year olds. The results show age effects in all three conditions, a non-linear education effect in AQT1, and age by gender interactions in AQT2 and AQT3: men performed worse with increasing age, but women remained on a par. However, irrespective of age and gender, AQT2 and AQT3 mean raw and predicted scores were slower than the hitherto recommended cutoff criteria for suspected cognitive impairment.

Two Liters a Day Keep the Doctor Away? Considerations on the Pathophysiology of Suboptimal Fluid Intake in the Common Population

Suboptimal fluid intake may require enhanced release of antidiuretic hormone (ADH) or vasopressin for the maintenance of adequate hydration. Enhanced copeptin levels (reflecting enhanced vasopressin levels) in 25% of the common population are associated with enhanced risk of metabolic syndrome with abdominal obesity, type 2 diabetes, hypertension, coronary artery disease, heart failure, vascular dementia, cognitive impairment, microalbuminuria, chronic kidney disease, inflammatory bowel disease, cancer, and premature mortality. Vasopressin stimulates the release of glucocorticoids which in turn up-regulate the serum- and glucocorticoid-inducible kinase 1 (SGK1). Moreover, dehydration upregulates the transcription factor NFAT5, which in turn stimulates SGK1 expression. SGK1 is activated by insulin, growth factors and oxidative stress via phosphatidylinositide-3-kinase, 3-phosphoinositide-dependent kinase PDK1 and mTOR. SGK1 is a powerful stimulator of Na+/K+-ATPase, carriers (e.g. the Na+,K+,2Cl- cotransporter NKCC, the NaCl cotransporter NCC, the Na+/H+ exchanger NHE3, and the Na+ coupled glucose transporter SGLT1), and ion channels (e.g. the epithelial Na+ channel ENaC, the Ca2+ release activated Ca2+ channel Orai1 with its stimulator STIM1, and diverse K+ channels). SGK1 further participates in the regulation of the transcription factors nuclear factor kappa-B NFκB, p53, cAMP responsive element binding protein (CREB), activator protein-1, and forkhead transcription factor FKHR-L1 (FOXO3a). Enhanced SGK1 activity fosters the development of hypertension, obesity, diabetes, thrombosis, stroke, inflammation including inflammatory bowel disease and autoimmune disease, cardiac fibrosis, proteinuria, renal failure as well as tumor growth. The present brief review makes the case that suboptimal fluid intake in the common population may enhance vasopressin and glucocorticoid levels thus up-regulating SGK1 expression and favouring the development of SGK1 related pathologies.

Estimating the cognitive effects of prevalent diabetes, recent onset diabetes, and the duration of diabetes among older adults

BACKGROUND

Little evidence is available on the effects of incident diabetes or diabetes duration on cognitive aging.

METHODS

We evaluated the effects of prevalent and incident diabetes on deteriorations in cognitive function, based on participants (n = 8,671) aged 65+ in the Health and Retirement Study in 2000. Inverse probability weighting was used to account for selective attrition and time-varying confounding of incident diabetes.

RESULTS

Prevalent diabetes predicted higher odds of dementia [odds ratio 1.27; 95% confidence interval (CI) 1.03-1.58] and worse memory (-0.06 in z-score units; 95% CI -0.10 to -0.02), but incident diabetes or diabetes duration up to 8 years of follow-up was not predictive.

CONCLUSION

Prevalent diabetes predicted lower cognition but not recent onset diabetes.