Non-linear relationship between serum 25-hydroxyvitamin D concentration and subsequent hip fracture

Area of Science:

• Orthopedics
• Endocrinology
• Geriatrics

Background:

• Vitamin D plays a critical role in bone metabolism.
• The association between serum 25-hydroxyvitamin D (25-OH vitamin D) and hip fracture risk is debated.
• Understanding this relationship is vital for preventing fractures, especially in aging populations.

Purpose of the Study:

• To investigate the association between serum 25-OH vitamin D levels and the risk of hip fracture.
• To determine if a specific threshold of 25-OH vitamin D concentration modifies this risk.

Main Methods:

• A case-control study was conducted with 254 hip fracture patients and 2,402 matched controls.
• Serum 25-OH vitamin D levels were measured within six months prior to hospital admission.
• Statistical analysis, including multiple linear and spline regression, was used to examine the association.

Main Results:

• A significant inverse association between 25-OH vitamin D and hip fracture was observed.
• This association was only significant for serum 25-OH vitamin D levels below 70 nmol/L.
• An increase of 10 nmol/L in 25-OH vitamin D below this threshold was associated with an 19% reduced odds of hip fracture (OR=0.81, 95% CI 0.86-0.93).

Conclusions:

• The predictive value of serum 25-OH vitamin D for hip fracture risk is dependent on the concentration threshold.
• Measurement of 25-OH vitamin D may be most useful for identifying individuals at higher risk when levels are below 70 nmol/L.
• These findings highlight the importance of maintaining adequate vitamin D levels to mitigate hip fracture risk.