Osteoarthritis (OA) is a leading cause of pain and disability and leads to a reduced quality of life. The aim was to determine the current evidence on risk factors for onset of knee pain/OA in those aged 50 and over. A systematic review and meta-analysis was conducted of cohort studies for risk factors for the onset of knee pain. Two authors screened abstracts and papers and completed data extraction. Where possible, pooled odds ratios (OR) were calculated via random effects meta-analysis and population attributable fractions (PAFs) derived. 6554 papers were identified and after screening 46 studies were included. The main factors associated with onset of knee pain were being overweight (pooled OR 1.98, 95% confidence intervals (CI) 1.57-2.20), obesity (pooled OR 2.66 95% CI 2.15-3.28), female gender (pooled OR 1.68, 95% CI 1.37-2.07), previous knee injury (pooled OR 2.83, 95% CI 1.91-4.19). Hand OA (pooled OR 1.30, 95% CI 0.90-1.87) was found to be non-significant. Smoking was found not to be a statistically significant risk or protective factor (pooled OR 0.92, 95% CI 0.83-1.01). PAFs indicated that in patients with new onset of knee pain 5.1% of cases were due to previous knee injury and 24.6% related to being overweight or obese. Clinicians can use the identified risk factors to identify and manage patients at risk of developing or increasing knee pain. Obesity in particular needs to be a major target for prevention of development of knee pain. More research is needed into a number of potential risk factors.

One in 10 adults report chronic widespread pain with potential sociocultural variation. Cultural differences in pain reporting should be considered in future research.Supplemental Digital Content is Available in the Text.

Objectives: To determine patterns of clinical comorbidity in general practice consulters with OA and compare them with comorbidity in consulters without OA. Methods: A case-control study nested in a one-year prevalence survey of consultations in 60 general practices in England and Wales. Cases were 11 375 subjects aged 50 and over who had consulted with OA during the study year. Controls were 11 780 subjects matched for age and sex who had consulted during the study year, but not for OA. Morbidity outcomes were based on a standard clinical classification system.

The KNEST is a simple tool for the identification of individuals with knee pain and their health-care use. Focusing only on chronic knee pain will underestimate the total need and demand for health-care in knee pain sufferers in the general older population, as non-chronic as well as chronic knee pain has a significant impact on people's lives and on their use of primary health-care. The KNEST, when combined with the WOMAC, identifies population groups who have potentially diverse health-care needs and who might benefit from effective health-care. These data can be used alongside evidence on effective treatments by service planners when considering needs for the care of older adults in primary care.

The onset of knee pain is associated with a substantial and persistent reduction of physical function in older adults living in the community. Since knee pain is common, and reduced physical function in mid to older ages is a strong predictor of future disability and dependency, effective prevention or early treatment of knee pain at these ages is likely to have a major influence on healthy ageing in the population.