Age and Ageing Advance Access originally published online on March 24, 2007
Age and Ageing 2007 36(3):350-351; doi:10.1093/ageing/afm038
Impaired glucose tolerance and the risk of ischaemic stroke: another focus
SIR—We applaud Kaarisalo et al. in their efforts to link the risk of impaired glucose tolerance (IGT) with the increased likelihood of ischaemic stroke [1]. Their study demonstrates that statistically significant risk factors for stroke in elderly people are previous transient cerebral ischaemic attacks (TIA) or stroke, diabetes mellitus (DM) and atrial fibrillation (AF). However, strokes tended to happen more often in the IGT group than in the normal group, but the difference was not statistically significant [1]. This has particular inference from a cardiovascular perspective, given the role of deranged glucose metabolism and the risk of new-onset AF [2, 3].Indeed, previous reports have demonstrated that high glucose levels had a positive significant association with the risk of AF. Nearly a decade ago, Psaty et al., using step-wise models, demonstrated that high glucose levels were associated with AF [2]. Of note, the Framingham study found that DM was a significant independent risk factor for AF with an Odds Ratio of 1.4 and levels of blood glucose were more important predictors than the diagnoses of DM [2]. More recently, in a large-scale study involving a far larger number of patients over a long duration of 10 years, Movahed et al. [2] showed that AF occurred in 43,674, (14.9%) patients with DM versus 57,077, (10.3%) in the control group (P<0.0001). Atrial flutter occurred in 11,852, (4%) patients with DM versus 13,554, (2.5%) of the control group (P<0.0001) and using multi-variant analysis, DM remained independently associated with AF with an OR = 2.13, (95% CI: 2.10–2.16; P<0.0001) and atrial flutter (OR = 2.20, 95% CI: 2.15–2.26; P<0.0001). The fluctuating level of glycaemic control may be a putative association, if we take into consideration the perspectives on epidemiological and pathophysiological links between DM and AF [3].
We should not forget that the pathophysiology of complications in the setting of DM is multifactorial, and in addition to the high coexistence of ‘conventional’ cardiovascular risk factors (such as hypertension, dyslipidaemia and obesity) in patients with DM, there are other processes such as urine albumin excretion, endothelial damage/dysfunction, and chronic inflammation which are implicated [4]. These are closely inter-related processes that develop in parallel, progress with time, and are strongly and independently associated with the risk of death in a background of deranged glycaemic control [4]. Interestingly, the prothrombotic risk of DM in the setting of AF (Figure 1) has been demonstrated to be of significant relevance lately, and DM has been found to independently contribute to the endothelial damage/dysfunction seen in patients with AF [5]. The presence of DM as an additive risk factor for endothelial damage/dysfunction may reflect the increased prothrombotic and vascular risk seen in this high-risk population [1, 5], hence IGT will undoubtedly and invariably be pertinent in the context of risk factors for stroke.
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1 Specialist Registrar in Diabetes & Endocrinology, C/o Ward 61–The Metabolic Unit–North Buildings, University Hospital of North Staffordshire, Stoke-on-Trent ST4 6QG, UK
2 Consultant Physician in Diabetes & Endocrinology/Senior Lecturer (Keele University), C/o Ward 61–The Metabolic Unit–North Buildings, University Hospital of North Staffordshire, Stoke-on-Trent ST4 6QG, UK
* To whom correspondence should be addressed Email: georgeiv{at}doctors.org.uk
References
- Kaarisalo MM, Raiha I, Arve S, Lehtonen A. Impaired glucose tolerance as a risk factor for stroke in a cohort of non-institutionalised people aged 70 years. Age Ageing (2006) 35:592–6. PMID: 16943263.
[Abstract/Free Full Text] - Varughese GI, Scarpello JH. The role of deranged glucose metabolism. Arch Intern Med (2006) 166:1784–5. PMID: 16983060.
[Free Full Text] - Lip GY, Varughese GI. Diabetes mellitus and atrial fibrillation: perspectives on epidemiological and pathophysiological links. Int J Cardiol (2005) 105:319–21. PMID: 16274776.[CrossRef][Web of Science][Medline]
- Varughese GI, Tomson J, Lip GY. Type 2 diabetes mellitus: a cardiovascular perspective. Int J Clin Pract (2005) 59:798–816. PMID: 15963208.[CrossRef][Web of Science][Medline]
- Varughese GI, Patel JV, Tomson J, Lip GY. The prothrombotic risk of diabetes mellitus in atrial fibrillation and heart failure. J Thromb Haemost (2005) 3:2811–13. PMID: 16359522.[CrossRef][Web of Science][Medline]
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