Osteoarthritis (OA) is the most common form of arthritis, with at least 30 million adults in the United States diagnosed with clinical OA. Previous studies have suggested an association between metabolic syndrome factors and incident OA. This longitudinal study, nested within the Osteoarthritis Initiative (OAI), explored the association between blood pressure and incident OA.

Eligible subjects were participants of the OAI with no OA at baseline. Blood pressure was measured at baseline, and at 12 and 36 months′ follow-up, with pulse pressure (PP) calculated as systolic blood pressure (SBP) minus diastolic blood pressure (DBP). Data were also recorded for physical activity, medication use, and knee radiographs. Radiographic OA (ROA) was defined as a Kellgren and Lawrence grade of two or higher. Covariates included gender, age and body mass index (BMI).

Data were available for 1，930 participants with a mean age of 59.2 years and mean BMI of 27.2 kg/m². A significant increase in the annual rates of ROA was noted with increased SBP and PP quartiles. This was not true of DBP. This association persisted after adjusting for age, gender, BMI and medication use.

This study found that higher systolic blood pressure and pulse pressure, but not diastolic blood pressure, are associated with an increased risk of osteoarthritis of the knee.