Does type 2 diabetes mellitus promote intervertebral disc degeneration?

Area of Science:

• Orthopedics and Musculoskeletal Health
• Endocrinology and Metabolism
• Epidemiology

Background:

• Low back pain is frequently caused by lumbar intervertebral disc degeneration (LDD).
• A potential link between type 2 diabetes (T2D) and LDD is widely suspected.
• This study investigates the epidemiological evidence for an association between T2D and LDD.

Purpose of the Study:

• To determine if type 2 diabetes (T2D) is associated with lumbar intervertebral disc degeneration (LDD).
• To investigate T2D as an independent risk factor for LDD, considering other factors like age and BMI.

Main Methods:

• Utilized a population sample of 956 twin volunteers from the TwinsUK cohort.
• Assessed LDD using spine magnetic resonance (MR) scans and T2D status.
• Employed both population-based analysis and a cotwin case-control study design for discordant twin pairs.

Main Results:

• The prevalence of T2D in the study sample was 6.6%.
• Twins with T2D exhibited higher LDD scores (14.9 vs 13.1, p=0.04).
• However, T2D was not an independent risk factor for LDD when age and BMI were included in multivariable analysis. Discordant twin analysis showed no significant difference in LDD between affected and unaffected twins.

Conclusions:

• While twins with T2D showed higher LDD scores, this effect was not independent of BMI.
• The findings suggest that T2D is unlikely to be a significant independent risk factor for LDD.
• Any potential effect of T2D on LDD is likely small, with 80% power to detect a difference of 1.8 in LDD score.