Negative associations for fasting blood glucose, cholesterol and triglyceride levels with the development of giant cell arteritis

Objectives. To investigate metabolic features that may predispose to GCA in a nested case-control study. Methods. Individuals who developed GCA after inclusion in a population-based health survey (the Malmö Preventive Medicine Project; N ¼ 33 346) were identified and validated through a structured review of medical records. Four controls for every validated case were selected from the database. Results. A total of 76 cases with a confirmed incident diagnosis of GCA (61% female, 65% biopsy positive, mean age at diagnosis 70 years) were identified. The median time from screening to diagnosis was 20.7 years (range 3.0-32.1). Cases had significantly lower fasting blood glucose (FBG) at baseline screening compared with controls [mean 4.7 vs 5.1 mmol/l (S.D. overall 1.5), odds ratio (OR) 0.35 per mmol/l (95% CI 0.17, 0.71)] and the association remained significant when adjusted for smoking [OR 0.33 per mmol/l (95% CI 0.16, 0.68)]. Current smokers had a reduced risk of GCA [OR 0.35 (95% CI 0.18, 0.70)]. Both cholesterol [mean 5.6 vs 6.0 mmol/l (S.D. overall 1.0)] and triglyceride levels [median 1.0 vs 1.2 mmol/l (S.D. overall 0.8)] were lower among the cases at baseline screening, with significant negative associations with subsequent GCA in crude and smoking-adjusted models [OR 0.62 per mmol/l (95% CI 0.43, 0.90) for cholesterol; 0.46 per mmol/l (95% CI 0.27, 0.81) for triglycerides]. Conclusion. Development of GCA was associated with lower FBG and lower cholesterol and triglyceride levels at baseline, all adjusted for current smoking, suggesting that metabolic features predispose to GCA.