What is the relationship between type 1 diabetes mellitus (T1DM) and the risk of skeletal deformities?

Association Between Type 1 Diabetes Mellitus and Skeletal Deformity

Type 1 diabetes mellitus is strongly associated with increased skeletal fracture risk and low bone mass, with hip fractures occurring 4.35 times more frequently than in people without diabetes, and fractures manifesting 10-15 years earlier in life. 1

Magnitude of Skeletal Risk in Type 1 Diabetes

The skeletal complications in T1DM are substantial and affect multiple anatomical sites:

• Hip fractures are increased by 4.35-fold compared to individuals without diabetes 1
• Upper limb fractures are increased by 1.83-fold 1
• Ankle fractures are increased by 1.97-fold 1
• Vertebral fractures are notably less frequent in T1DM compared to other skeletal sites 1

Critical Age-Related Considerations

Fractures occur at significantly younger ages in T1DM—specifically 10-15 years earlier than in people without diabetes. 1 This early onset has profound implications for lifetime morbidity and quality of life, as individuals face decades of increased fracture risk and potential disability.

Hip fracture risk begins increasing after age 50 in T1DM patients, which is why the American Diabetes Association recommends considering BMD assessment after the 5th decade of life. 1

Pathophysiological Mechanisms

T1DM is characteristically associated with low bone mass, though this finding has a critical limitation: BMD measurements underestimate fracture risk in this population. 1 The exact extent of this underestimation remains unclear, as studies have not adequately quantified the discrepancy. 1

The skeletal damage in T1DM is attributed to:

• Microvascular damage affecting bone structure in patients with disease duration >26 years 1
• Macrovascular complications compromising skeletal integrity 1
• Poor glycemic control, with each 1% rise in A1C increasing fracture risk by 8% (RR 1.08,95% CI 1.03-1.14) 1, 2
• Hypoglycemic episodes, which increase fracture risk by 52% (RR 1.52,95% CI 1.23-1.88) 1, 2

Clinical Consequences and Mortality Impact

Hip fractures in diabetes patients carry substantially higher mortality rates: 28% in women and 57% in men within one year, compared to individuals without diabetes. 1 Additionally, 60% of patients do not regain their prior functionality after hip fracture, living with permanent disability. 1

Recovery is prolonged and healing is delayed in diabetic patients compared to those without diabetes. 1

Risk Factors Specific to T1DM

Beyond the general population risk factors, T1DM patients face diabetes-specific skeletal risks:

• Disease duration >26 years significantly elevates fracture risk 1
• Presence of microvascular complications (nephropathy, retinopathy, neuropathy) 1
• Frequent hypoglycemic events, with severe hypoglycemia increasing risk more than 2-fold (HR 2.24,95% CI 1.56-3.21) 1, 2
• Poor glycemic control with A1C >8% 1
• Insulin use (listed as a diabetes-specific risk factor) 1
• Peripheral and autonomic neuropathy leading to falls 1

Screening Recommendations for T1DM

The approach to bone health screening differs from type 2 diabetes:

• BMD assessment should be considered after age 50 when hip fracture risk begins increasing 1, 2
• Reassessment every 2-3 years depending on additional risk factors 1, 2
• Regular bone densitometry in youth with T1DM remains controversial according to the International Society for Pediatric and Adolescent Diabetes (ISPAD) and is not routinely recommended 1
• Exception: Consider densitometry in youth with concurrent celiac disease due to inflammatory pathway involvement 1

Important Caveat

Bone turnover markers are suppressed in diabetes and have not been shown to predict fracture risk, limiting their clinical utility. 1

Management Strategy

Maintaining tight glucose control (A1C <7%) and aggressively avoiding hypoglycemia are the cornerstones of skeletal protection in T1DM. 2

Glycemic Management

• Target A1C <7% to reduce fracture risk, as each 1% rise increases fracture risk by 8% 2
• Avoid hypoglycemic episodes aggressively, as they escalate hip fracture risk by 52% 2
• Poor glycemic control (A1C >9%) over 2 years correlates with 29% heightened fracture risk 1, 2

Lifestyle Interventions

• Engage in moderate aerobic and weight-bearing exercise to enhance muscle health, gait coordination, and balance 1, 2
• Ensure adequate daily calcium and vitamin D intake through diet or supplementation to meet recommended daily allowances 1, 2
• Maintain adequate protein intake as part of comprehensive bone health strategy 1, 2
• Smoking cessation is essential 1, 2

Pharmacological Intervention

• Consider antiresorptive medications or osteoanabolic agents for patients with T-score ≤-2.0 or prior fragility fractures 1, 2
• If fragility fracture occurs, diagnose osteoporosis regardless of DXA data and initiate therapy immediately, as subsequent fracture risk is highest in the first 1-2 years 1, 2
• Refer patients with multiple comorbidities or particularly high risk to a bone metabolic specialist 1, 2

Common Pitfalls

Do not rely solely on BMD measurements in T1DM patients, as they systematically underestimate fracture risk in this population. 1 Clinical risk factors—particularly disease duration, presence of microvascular complications, and hypoglycemia frequency—must be weighted heavily in fracture risk assessment.

Do not overlook the early age of fracture onset in T1DM. The 10-15 year earlier presentation means that fracture prevention strategies must begin earlier than in the general population. 1