Aims: Type 1 diabetes mellitus is associated with increased fracture risk, whereas the risk associated with type 2 diabetes is less obvious. Elevated fasting blood glucose (FBG) and high 2-hour glucose during an oral glucose tolerance test (OGTT) indicate impaired glucose tolerance or diabetes. The associations between FBG, 2-h glucose and the risk of fracture were investigated.

Methods: The Malmö Preventive Project consists of 22 444 men (44 ± 6.6 yrs) and 10 902 women (50 ± 7.4 yrs), with a follow-up of 19 (±3.9)years and 15 (±4.5) years for incident fractures. Baseline assessment included multiple examinations and lifestyle information. A logistic regression model was used. Adjustments were made for age, BMI, and smoking.

Results: Low-energy fractures were recorded in 1246 men and 1236 women. A 2-h glucose measurement between 4.3 and 6.2 mmol/L in men (2^nd and 3^rd quartiles), and above 6.5 mmol/L in women (3^rd and 4^th quartiles), adjusted for age, BMI, and smoking, was significantly associated with decreased risk of multiple fractures, in men (ORs 0.57–0.71) and women (ORs 0.38–0.66). In women, a 2-h glucose measurement above 7.5 mmol/L was associated with a decreased risk of osteoporotic fractures (OR 0.57, CI 95% 0.44–0.74).

Conclusions: In middle-aged men and women, elevated 2-h glucose levels were associated with decreased risks of multiple and osteoporotic fractures, independent of age, BMI, and smoking. A high 2-h glucose level is characterized by peripheral insulin resistance with a high insulin level. Our findings indirectly suggest a positive effect on bone from hyperglycemia.