The metabolic syndrome in type 1 diabetes: does it exist and does it matter? Margaret McGill 4 , Lynda Molyneaux, Stephen M. Twigg, Dennis K. Yue Department of Endocrinology, Diabetes Centre, Royal Prince Alfred Hospital, Camperdown, NSW 2050, Australia Discipline of Medicine, University of Sydney, NSW 2006, Australia Received 6 June 2006; received in revised form 6 October 2006; accepted 10 October 2006 Abstract The significance of the metabolic syndrome in type 1 diabetes is not well understood. This study aimed to estimate its prevalence and attendant complications. Four hundred twenty-seven type 1 diabetic subjects were grouped according to the presence or absence of metabolic syndrome (WHO criteria). Macro- and microvascular complications were compared between the groups as individual and as composite endpoints. Data were analyzed for the total cohort and in subgroups according to duration of diabetes quartiles (b6.9, 7– 12.9, 13–19.9, and N20 years) and year of presentation. Fifteen percent of individuals fulfilled the WHO criteria for metabolic syndrome, and of these, 26.9% were insulin resistant, as compared with 3.4% of those without metabolic syndrome [odds ratio (OR)=8.9, P=.001]. Both BMI and metabolic syndrome showed an increasing trend from 1992 to 2003. Those with metabolic syndrome required significantly higher insulin dosage [0.9 (0.7–1.2) vs. 0.6 (0.5–0.9) units/kg, P=.03], were older [35.0 (26.2–47.3) vs. 29.7 (23.4–36.4) years, P=.002], and had longer duration of diabetes [19.7 (10.7–25.6) vs. 12.1 (6.3–17.9) years, P=.0001]. They also had a significantly higher macrovascular composite endpoint (OR=3.3, P=.02) as well as higher macrovascular and microvascular composite endpoint (OR=3.1, P=.0001). The prevalence of stroke (OR=22.8, P=.008), peripheral vascular disease (OR=7.3, P=.05), and severe retinopathy (OR=3.7, P=.01) is higher in subjects with metabolic syndrome in the z20-year quartile group; in addition, these subjects have higher macrovascular composite endpoint (OR=3.9, P=.03) and macrovascular and microvascular composite endpoint (OR=2.9, P=.03). This remained so even when subjects with albuminuria were excluded. Some individuals with type 1 diabetes can also have metabolic syndrome. They are more prone to complications and require even more intensive glycemic control and reduction of macrovascular risk factors. D 2008 Elsevier Inc. All rights reserved. Keywords: Type 1 diabetes; Metabolic syndrome; Insulin resistance; Complications; Obesity 1. Introduction The metabolic syndrome is a controversial and much- debated clinical and public health issue that has generated more than 5000 research publications in recent years (Gale, 2005; Kahn, Buse, Ferrannini, & Stern, 2005). The syndrome is characterized by a cluster of cardiovascular risk factors that confer an increased risk not only for cardiovascular morbidity and mortality but also for the development of type 2 diabetes (Bonora et al., 2004; Bruno et al., 2004; Isomaa, Almgren, et al., 2001; Scuteri, Najjar, Morrell, & Lakatta, 2005). Factors such as central obesity and low physical activity can elicit insulin resistance and contribute to metabolic syndrome in genetically susceptible individuals. The age-unadjusted prevalence of the metabolic syndrome in the United States is approximately 30%, and up to 80% of people with type 2 diabetes have features of the syndrome (Alexander et al., 2003; Isomaa, Henricsson, et al., 2001). 1056-8727/08/$ – see front matter D 2008 Elsevier Inc. All rights reserved. doi:10.1016/j.jdiacomp.2006.10.005 4 Corresponding author. Diabetes Centre, Royal Prince Alfred Hospi- tal, Camperdown, NSW 2050, Australia. Tel.: +61 2 95155888; fax: +61 2 95155820. E-mail address: marg@email.cs.nsw.gov.au (M. McGill). Journal of Diabetes and Its Complications 22 (2008) 18 – 23