Table 1

 Characteristics of cohort at baseline assessment. Values are numbers (percentages) unless stated otherwise

CharacteristicsEntire cohort (n=2200)Excluded participants (n=445)Included participants (n=1755)P value*
Median (interquartile range) age (years)71 (64-78)77 (71-83)70 (63-76)<0.001
Women1585 (72.0)286 (64.3)1299 (74.0)<0.001
Median (interquartile range) hip pain1363 (62.8)1074 (61.2)289 (64.9)0.146
Median (interquartile range) knee pain1913 (87.0)1531 (87.2)382 (85.8)0.436
Median (interquartile range) body mass index28 (24-31)27 (23-30)28 (25-32)<0.001
Urban dwelling965 (43.9)211 (47.4)754 (43.0)0.091
Living conditions:
 Lives alone720 (32.7)160 (36.0)560 (31.9)<0.001
 Lives with others1439 (58.7)261 (58.7)1178 (67.1)
 Lives in long term care facility41 (1.9)24 (5.4)17 (1.0)
Income ($C):
 >20 000654 (29.7)126 (28.3)528 (30.1)0.477
 ≤20 0001150 (52.3)244 (54.8)906 (51.6)
 Missing396 (18.0)75 (16.9)321 (18.3)
Smoker:
 Never1030 (48.2)195 (45.7)835 (48.9)0.406
 Former792 (37.1)170 (39.8)622 (36.4)
 Current313 (14.7)62 (14.5)251 (14.7)
NSAID use822 (37.4)157 (35.3)665 (37.9)0.309
No of comorbidities:
 095 (4.3)15 (3.4)80 (4.6)<0.001
 1398 (18.1)62 (13.9)336 (19.1)
 2686 (31.2)131 (29.4)555 (31.6)
 3584 (26.5)120 (27.0)464 (26.4)
 ≥4437 (19.9)117 (26.3)320 (18.2)
Pre-existing cardiovascular disease274 (12.5)129 (29.0)145 (8.3)<0.001
Diabetes400 (18.2)127 (28.5)273 (15.6)<0.001
Depression747 (34.0)168 (37.8)579 (33.0)0.058
Hypertension1394 (63.4)321 (72.1)1073 (61.1)<0.001
Median (interquartile range) SF-3647 (30-67)50 (35-67)40 (25-57)<0.001
Median (interquartile range) WOMAC score42 (27-54)46 (31-56)41 (26-53)<0.001
Pre-baseline total joint arthroplasty235 (10.7)44 (9.9)191 (10.9)0.544

$C1.00 (£0.60; $0.96; €0.71).

NSAID=non-steroidal anti-inflammatory drug; SF-36=short-form-36 general health survey; WOMAC=Western Ontario and McMaster Universities arthritis index.

*Comparison of included and excluded groups; excluded participants had a cardiovascular event or died within the exposure period (three years after baseline questionnaire).