Background/Purpose: Metabolic factors may have a negative effect on cartilage, and may be especially relevant in the pathogenesis of hand OA. Our aim was to investigate whether metabolic syndrome and its components were associated with prevalent and incident hand OA in a large community-based sample.

Methods: We included participants from the Framingham Offspring cohort, who were examined for OA at exam 5 (1991-95) and 7 (1998-2001). Inclusion criteria were: available data on symptomatic hand OA, clinical data, no anti-hypertensive, anti-diabetic and lipid-lowering treatment, no rheumatoid arthritis, and age 50-75 years at exam 5. Symptomatic hand OA was defined as Kellgren-Lawrence grade ≥2 and pain in the same joint(s). Metabolic syndrome was defined as central obesity (men: ≥37.0 inches, women: ≥31.5 inches waist circumference) plus two of the following: hypertension (systolic ³130 mmHg and/or diastolic ³85 mmHg), elevated fasting blood glucose (>100 mg/dL), elevated triglycerides (>150 mg/dL) and low HDL (men: <40 mg/dL, women: <50 mg/dL). In cross-sectional analyses, we examined whether metabolic syndrome and its components were associated with presence of symptomatic hand OA using logistic regression. In longitudinal analyses, we examined the associations between metabolic syndrome and incident symptomatic hand OA at exam 7. We adjusted for age and sex.

Results: Of the 748 participants who fulfilled the inclusion criteria, 74 (9.9%) had symptomatic hand OA. Participants with symptomatic hand OA were older than those without (mean (SD) 62.2 (5.9) vs. 57.7 (6.0) years) and more likely to be women (75.7% vs. 51.0%). There was no significant association between metabolic syndrome and symptomatic hand OA (Table). The strength of association between metabolic syndrome and symptomatic hand OA was attenuated when we adjusted for body mass index (BMI) (cross-sectional association: OR 1.19, 95% CI 0.68-2.10). When evaluating the individual components of metabolic syndrome separately, we found a significant association between central obesity and symptomatic hand OA in the adjusted cross-sectional analyses (Table). In the longitudinal analyses, we found a statistically significantly lower risk of incident symptomatic hand OA associated with elevated triglycerides (Table). The association remained after adjustment for lipid-lowering treatment (data not shown). Similar results were found when we included BMI in the adjusted models (data not shown).

Conclusion: Metabolic syndrome was not associated with higher probability of presence or development of hand OA. If anything, we observed a lower probability of incident symptomatic hand OA in participants with high triglycerides.

Table. Associations between metabolic syndrome and hand OA.

¹ n=674 and n=74 without and with symptomatic hand OA at exam 5, respectively,

² n=430 and n=92 without and with incident symptomatic hand OA at exam 7, respectively (n=152 lost to follow-up),