Type 2 diabetes mellitus and spinal degenerative disorders (SDD) are common conditions that often occur together. However, a new study, reported in The Journal of Bone & Joint Surgery provides evidence that type 2 diabetes does not play a causative role in the development of SDD. The journal is published in the Lippincott portfolio by Wolters Kluwer.
Different methods of data analysis produce conflicting results in assessing the association between type 2 diabetes and SDD, according to the new research by Tao-Lan Zhang, PhD, and Jiang-Hua Liu, MD, PhD, of Hengyang Medical School, University of South China and colleagues.
Observational and Mendelian randomization analyses explore diabetes-SDD link
Spinal degenerative disorders, most commonly intervertebral disc degeneration, are the most frequent cause of low back pain. Some previous studies have reported that patients with type 2 diabetes are more likely to develop SDD. However, it remains unclear whether the increased risk of SDD is related to diabetes itself or to shared risk factors.
Drs. Zhang and Liu and colleagues performed a series of observational analyses to explore and compare associations between type 2 diabetes and SDD. Each analysis included data on thousands of individuals, drawn from the population-based UK Biobank database.
The researchers also performed Mendelian randomization analyses to assess cause-and-effect relationships between exposures and outcomes, including data on more than 407,000 participants from the UK Biobank and 227,000 from the FinnGen Consortium database. In addition, genetic predisposition to type 2 diabetes was analyzed with use of data from a pooled genomewide association study including more than 1.4 million individuals.
Association between diabetes and SDD appears 'analysis-dependent'
In the observational analyses, rates of SDD were 17.8% among individuals with type 2 diabetes versus 9.3% in nondiabetic individuals. On multivariable analysis, type 2 diabetes was an independent contributor to SDD (odds ratio, 1.84).
Based on 13-year follow-up data, type 2 diabetes was independently associated with an increased risk of developing SDD (hazard ratio, 1.88). In both analyses, SDD susceptibility was related to baseline (e.g., sex, age, and body mass index) and lifestyle characteristics (e.g., smoking, alcohol use, and physical activity).
In contrast, Mendelian randomization analysis showed "no causal association" between type 2 diabetes and SDD. "Our further 2-sample Mendelian randomization analyses disclosed no potential causal effects of genetically predicted type 2 diabetes mellitus on SDD incidence," the researchers write.
Drs. Zhang and Liu and colleagues add: "This confirms our earlier hypothesis that the association between type 2 diabetes mellitus and SDD may be analysis-dependent." Although further study is needed, the findings suggest a possible root predisposition in both diseases that leads to a metabolic syndrome with type 2 diabetes mellitus and SDD as its end-stage manifestations."
The findings have important research and clinical implications for understanding the association between the two diagnoses, the researchers believe. From a clinical standpoint, rather than routinely screening for the risk of SDD among patients with type 2 diabetes, "Addressing the well-established overlapping risk factors of type 2 diabetes mellitus and SDD may be beneficial in the early prevention and effective treatment of both conditions."
(Newswise/PL)
