Features of the metabolic syndrome and the risk of non-vertebral fractures: The Tromso study

Introduction: We wanted to examine whether the features of the metabolic syndrome carried an increased risk of non-vertebral fracture. Methods: This is a population-based, 6-year follow-up of 27,159 subjects from the municipality of Tromso, followed from 1994 until 2001. Age range was 25-98 years. Non-fasting serum levels of high-density lipoprotein (HDL), triglycerides and glucose, blood pressure (BP), weight and height were measured at baseline. All non-vertebral fractures were registered by computerised search in radiographic archives. Results: A total of 1,249 non-vertebral fractures were registered. Increasing number of metabolic syndrome features was associated with significantly reduced fracture risk in both men and women, p= 0.004 and p < 0.0001, respectively. High BP was protective against fracture in men [relative risk (RR) 0.89; 95% confidence interval (CI) 0.8-0.99)] while increased body mass index (BMI) was protective in women (RR 0.91; 95% CI 0.84-0.98). Increasing non-fasting serum levels of HDL increased fracture risk in women (RR 1.12; 95% CI 1.05-1.21). BMI modified the effect of HDL in men. Accordingly, high HDL increased fracture risk in men with high BMI (RR 1.51; 95% CI 1.2-1.9). Conclusions: Increasing burden of metabolic syndrome features protects against non-vertebral fractures. Reduced non-vertebral fracture risk was associated with high BP in men and increased body mass in women. Lower non-fasting serum levels of HDL protect against fractures in women and obese men.