Table 1 Characteristics of eligible cohort studies on the association between physically demanding occupations and the development of osteoarthritis

Åkesson 1999

Sweden [30]

Female dentists working in the public dental care service

N=120

Age: median dentists: 40 (range 28-57) years; dental assistants: 37.3 (range 25-37) years, median dental hygienists: 41.5 (range 28-52) years

Female: 100 %

Dentists/ dental hygienists (from the same country, with a similar organization and working environment, matching age)/ dental assistance (same population, matching to dentists (sex and age ± 5 years)) vs.

female medical nurses (aged 41.7 (26- 60) years) chosen of varied and physically work load

Musculoskeletal symptoms, pain rating via Nordic questionnaire

Clinical diagnostic examination using a standardized protocol for diagnoses in the hip region

Follow-up: 5 years

8 (2/1/2/3)

Andersen 2012

Denmark [31]

Population-based register data of 5 occupational groups, ≥ 16 years (1981-2006)

N=2 117 298

Age (median, IQR); % Women:

Farmer: 44 (32-59) years; 55 132 (25.4 %)

Construction worker: 38 (27-52) years; 38 485 (7.9 %)^a

Healthcare assistants: 39 (28-51) years; 411 580 (82.9 %)^a

Office workers: 36 (25-51) years; 595 685 (65.3 %)^a

Register data of the income register in the basis on work skills/position and education (1981-2006)

Floor layers/bricklayers/pavers, construction workers, farmers, healthcare assistants) vs.

office workers

Surgically treated HOA (ICD, 1996 to 2006)

Follow-up: 8.1-9.2 years

15 (4/3/3/5)

Hubertsson 2017

Sweden [13]

Population-based register data of included occupational groups, 40-70 years (2008-2012)

N=165 179

Age (mean): 55 years

% Women: 96 272 (58 %)^a

Health care: 45 211 (90 %)

Child care: 16 308 (93 %)

Cleaning: 8043 (83 %)

Register data with classifications of current jobs (12/2012)

7 occupational groups at a higher risk of HOA including more female-dominated occupations vs.

business and administration (e.g. business and finance professionals, mathematicians, statisticians, computing professionals, secretaries and numerical clerks)

Sick leave and disability pension due to HOA (ICD, 2007-2012)

Follow-up: ≤ 6 years

12 (4/3/2/3)

Johansson 2018

Sweden [32]

Patient register data (1987), ≥ 35 years; Follow up until 2002

N= 3 560 496 total

N=97 136 farmer

% women: 24 284^a (25 %)

Age 58.3 ± 12.2 years

Population and Housing Census 1975 an 1985 provided self-reported profession based on Nordic class profession (NYK)-farmers, foresters, market gardeners (ISCO Code 401)

vs. all other occupations

HOA

Follow up until 2002 (15 years), death or emigration

11(2/2/4/3)

Solovieva 2018

Finland [22]

Population-based register data from a random sample of persons with gainful jobs, 30-60 years (01/2005)

N= 1 135 654

Age (mean): 43.8-47.5 years in occupational groups

% Women: 561 037 (49.4 %)^a

Professionals: 57 226^a (42.6 %)

Agricultural and fishery workers: 17 953^a (34.6 %)

Construction worker, electricians and plumbers: 2244^a (4.2 %)

Environmental officers and nurses: 42 639 (88.6 %)

Shop worker: 28 052^a (67.6 %)

Customer service clerks: 17 953^a (91.8 %)

Building caretakers, cleaners, assistant nurses, and kitchen workers: 43 761^a (72.8 %)

Craft worker: 4.488^a (36 9%)

Teaching professionals: 48 249^a (66.9%)

Unskilled transport, construction, and manufacturing workers: 6732^a (25.8%)

Register data of longitudinal employer-employee data with classifications (12/2004)

18 occupational groups vs.

professionals (e.g. physical, mathematical, and engineering science professionals,

life science and health professionals, as well as others )

Full-time disability retirement due to HOA (ICD, 2005-2013)

Follow-up: 9 years

14 (4/2/4/4)

Vingard 1991

Sweden [33]

Register sampling of persons, born 1905-1945 with the same occupation in 1960 and 1970 (1980)

N: 250 217

Age (range): 35-75 years

% Women: 42 579 (17.0 %)^a

Low exposure blue-collar workers: 24.145 (21.0 %)^a

Farmer: 1739 (4.6 %)^a

Waitresses and hairdressers: 7243 (99.8 %)^a

Cleaner: 7625 (100 %)^a

Blue-collar occupations with high (more than average) (14 for males, 5 for females) vs.

low (less than average) exposure to dynamic or static forces acting on lower extremity

Hospital care for HOA (ICD, 1981-83)

Follow-up ≥ 15 years

13 (4,2,2,5)