Sample Characteristics at Baseline by Occurrence of All-Cause Death (values are numbers and percentages unless otherwise stated).

*Univariable hazard ratios, 95% confidence intervals and P values were derived from Cox regression models; missing baseline data was either imputed from responses on the year 1 follow-up assessment or incorporated as a ‘missing’ dummy variable. Hazard ratios >1 indicate lower mortality in reference category.†Hazard ratios are per doubling of the number of visits in the pre-baseline year.‡Hazard ratios are per 10-point increase in WOMAC subscale score.