Reports of a positive association between diabetes and osteoarthritis are hard to interpret because being overweight or obese strongly increases the risk of both conditions.

A systematic review that identified 31 studies with a total of nearly 300,000 participants suggests that if body mass index (BMI) is taken into account, there is little evidence that diabetes is a cause of osteoarthritis.

Comparing participants who had diabetes with participants who did not, an increased risk of arthritis was found only in cross sectional studies – not in case-control or cohort studies.

Research Paper Title

Diabetes mellitus is not a risk factor for osteoarthritis.

Background

Association between diabetes mellitus (DM) and risk of osteoarthritis (OA) can be confounded by body mass index (BMI), a strong risk factor for both conditions.

The researchers evaluate the association between DM or hyperglycaemia with OA using systematic review and meta-analysis.

Methods

The researchers searched PubMed and Web of Science databases in English for studies that gave information on the association between DM and OA.

Two meta-analysis models were conducted to address:

1. Risk of DM comparing subjects with and without OA; and
2. Risk of OA comparing subjects with and without DM.

As far as available, risk estimates that adjusted for BMI were used.

Results

31 studies with a pooled population size of 295 100 subjects were reviewed. 16 and 15 studies reported positive associations and null/ negative associations between DM and OA. 68.8% of positive studies had adjusted for BMI, compared with 93.3% of null/negative studies.

In meta-analysis model 1, there was an increase prevalence of DM in subjects with OA compared with those without (OR 1.56, 95% CI 1.28 to 1.89). In meta-analysis model 2, there was no increased risk of OA (OR 1.14, 95% CI 0.98 to 1.33) in subjects with DM compared with those without, regardless of gender and OA sites.

Comparing subjects with DM to those without, an increased risk of OA was noted in cross-sectional studies, but not in case-control and prospective cohort studies.

Conclusions

This meta-analysis does not support DM as an independent risk factor for OA.

BMI was probably the most important confounding factor.

Reference

Khor, A., Ma, C-A., Hong, C., L.Y.L. & Leung, Y.Y. (2020) Diabetes mellitus is not a risk factor for osteoarthritis. RMD Open. 6(1). https://rmdopen.bmj.com/content/6/1/e001030.