Table 3. Subgroup analyses for special occupational exposures.
| Occupation | Number of studies (participants) | Summary meta-analysis, OR (95% CI) |
Heterogeneity, % (Cochran Q, P value) |
|
|---|---|---|---|---|
| Job categories | ||||
| Heavy physical work | 17 (52,984) | 1.65 (1.43, 1.91) | 76.8% (<0.01) | |
| Low to moderate physical work | 5 (190,123) | 1.48 (1.23, 1.78) | 53.5% (0.02) | |
| Sedentary work | 4 (2,789) | 1.02 (0.80, 1.30) | 4.5% (0.40) | |
| Job titles | ||||
| Agriculture, forestry and fishery | ||||
| - Agriculture, forestry and fishery | 8 (4,585) | 1.94 (1.56, 2.42) | 0.0% (0.84) | |
| - Agriculture | 9 (46,326) | 1.64 (1.33, 2.01) | 62.8% (<0.01) | |
| - Forestry | 3 (7,346) | 1.43 (0.99, 2.05) | 0.0% (0.44) | |
| - Fishery | 2 (40,317) | 1.16 (0.84, 1.61) | 48.0% (0.10) | |
| Construction trades | ||||
| - Building and construction | 8 (76,648) | 1.63 (1.39, 1.92) | 0.0% (0.42) | |
| - Metal worker | 5 (13,567) | 1.85 (1.25, 2.76) | 49.9% (0.05) | |
| - Floor- and brick layer | 5 (11,422) | 2.51 (1.79, 3.52) | 81.2% (<0.01) | |
| - Carpenter | 4 (43,696) | 2.49 (1.66, 3.74) | 0.0% (0.45) | |
| - Machine operator | 3 (14,050) | 1.36 (0.97, 1.92) | 0.0% (0.79) | |
| - Plumber | 2 (16,727) | 1.52 (0.60, 3.85) | 60.8% (0.11) | |
| - Electrician | 4 (21,339) | 0.88 (0.59, 1.32) | 0.0% (0.44) | |
| - Technician | 4 (4,121) | 1.31 (0.99, 1.70) | 0.0% (0.26) | |
| Commerce | 6 (10,002) | 1.22 (0.95, 1.57) | 9.7% (0.35) | |
| Healthcare professional | 5 (1,252) | 1.19 (0.96, 1.47) | 29.8% (0.22) | |
| Miner | 4 (2,602) | 1.47 (1.11, 1.95) | 7.6% (0.36) | |
| Cleaner | 4 (8,722) | 1.51 (1.14, 2.01) | 14.5% (0.32) | |
| Postman | 4 (3,757) | 1.29 (0.86, 1.94) | 0.0% (0.47) | |
| Painter | 3 (16,027) | 1.60 (0.97, 2.66) | 0.0% (0.70) | |
| Waitress and hairdresser | 3 (7,546) | 1.26 (0.78, 2.03) | 0.0% (0.93) | |
| Housework | 3 (1,608) | 1.93 (1.31, 2.84) | 0.0% (0.53) | |
| Service worker | 3 (1,749) | 1.79 (1.36, 2.37) | 1.6% (0.40) | |
| Craftsman | 2 (1,404) | 1.56 (1.17, 2.09) | 0.0% (0.46) | |
| Driver | 2 (3,732) | 1.67 (0.90, 3.08) | 0.0% (0.49) | |
| Occupational activities | ||||
| Lifting (>10 kg/day) | 17 (102,813) | 1.39 (1.22, 1.59) | 76.8% (<0.01) | |
| Kneeling (>30 mins/day) | 14 (94,762) | 1.29 (1.05, 1.57) | 85.8% (<0.01) | |
| Standing (>2 hours/day) | 12 (9,709) | 1.30 (1.09, 1.53) | 72.4% (<0.01) | |
| Climbing (>15 flights/day) | 10 (5,653) | 1.49 (1.20, 1.86) | 73.4% (<0.01) | |
| Squatting (>30 mins/day) | 10 (6,244) | 1.48 (1.21, 1.81) | 52.4% (0.02) | |
| Walking (>2 hours/day, or >2 kms/day) | 10 (6,097) | 1.23 (1.01, 1.52) | 68.1% (<0.01) | |
| Sitting (>2 hours/day) | 13 (13,996) | 0.77 (0.70, 0.84) | 35.3% (0.09) |
Bold values denote statistical significance at the P < 0.05 level.
The percentage values for heterogeneity were calculated using the I2 tests and the P values are from the Cochran Q test.
Reference group: non-exposed workers or those exposed to the lowest physical level possible.
For studies (Allen 2000, Callahan 2011, Ezzat 2013, Felson 1991, Jesen 2005, Kim 2010, Kwon 2017, Lawrence 1955, Tangtrakulwanich 2006) that reported radiographic and symptomatic knee osteoarthritis together, only symptomatic knee osteoarthritis outcomes were included in the meta-analysis.