Increased fasting serum glucose concentration is associated with adverse knee structural changes in adults with no knee symptoms and diabetes

Objective There is evidence to suggest that elevated glucose concentration and clinical diabetes are associated with osteoarthritis (OA). However, the association may be confounded by knee symptoms, concomitant treatment for OA or diabetes. We performed a longitudinal cohort study to examine the relationship between serum glucose concentration and knee structure in adults with no knee symptoms or diabetes. Methods 179 participants who had fasting serum glucose measurements at 1990–4, with no knee symptoms or diabetes (physician-diagnosed or fasting serum glucose ≥7 mmol/L), underwent knee MRI in 2003–4 and 2 years later. Body mass index was measured at 1990–4 and 2003–4. Cartilage volume and bone marrow lesions were determined from MRI at 2003–4 and 2006–7. Results Fasting serum glucose concentration was positively associated with the rate of tibial cartilage volume loss over 2 years in women (B = 44.2 mm3, 95% CI 4.6, 83.8) but not in men (B = 6.0 mm3, 95% CI −68.5, 80.6). Fasting serum glucose concentration was positively associated with incident bone marrow lesions in women (OR = 5.76, 95% CI 1.06, 31.21) but not in men (OR = 0.11, 95% CI 0.01, 1.79) with significant gender difference (p = 0.001 for interaction). Conclusion Increased fasting serum glucose concentration in a non-diabetic population was associated with adverse structural changes at the knee in women but not in men, suggesting that there may be susceptibility to knee structural change even below the arbitrary "diabetic range" of serum glucose levels. The sex differences warrant further investigation as this may be one mechanism underlying the sex difference in knee OA.