Table 3

 Definitions of physical demand of the job in the literature and their association with primary OA

Author, yearSite of OASurvey population and methodTime period and unit of exposureDefinition of physical demand†OR‡
†Italicised items are those statistically significant and counted in table 4.
‡OR = highest odds ratios reported: *crude OR reported as statistically significant; **adjusted OR statistically significant; ***adjusted OR statistically significant, suggesting a dose-response profile.
(***)As above but statistical significance not reported.
OR reported as not statistically significant are not shown in the table.
Anderson JJ et al, 19885KneePopulation survey HANES Ix ray diagnosed OA Self administered questionnaireAll job titles during lifetime Exposure estimated by experts using job titlesPhysical demand:OR: 3.1**
 Light work
 Medium work
 Heavy work
 Very heavy work
Knee bending requirements:OR: 3.5***
 Some (1–50% of job titles)
 Much (⩾50% of job titles)
Coggon D et al, 199813HipCase-control study Patients listed for hip replacement because of OA Interview questionnaireAll jobs held for longer than a year since leaving school and up to 10 years before study Maximum level of exposure achievedLifting: for more than 10 times in average working week, for at least 10 years:
 <10 kg
 10–24 kg
 25–49 kg
 ⩾50 kgOR: 2.1**
Number of years (0, 1–9, 10–19, ⩾20):
Climbing >30 flights of stairs/day OR: 1.7**
Walking >2 miles/day
Driving >4 h/day
Squatting >1 h/day
Kneeling >1 h/day
Standing >2 h/day
Sitting >2 h/day
Coggon D et al, 200014HipCase-control study Patients listed for hip replacement because of OA Interview questionnaireAll jobs held for longer than a year since leaving school and up to ten years before study Occupational activities performed for over one yearLifting for more than 10 times in average working week:
⩾10 kg.OR: 1.7**
⩾25 kg.OR: 1.7**
 ⩾50 kg.
Kneeling >1 h/dayOR: 1.8**
Squatting >1 h/dayOR: 2.3**
Walking >2 miles/dayOR: 1.9**
Standing or walking >2 h/day
Sitting >2 h/day
Driving >4 h/day
Climbing ladder or stairs >30 times/day
All results comparable between males and females
Cooper C et al, 199415KneeCase-control study Symptomatic, x ray diagnosed OA Interview questionnaireJob held for the longest time before onset of symptoms Exposure in an average day Squatting >30 min/day OR: 6.9**
Kneeling >30 min/day OR: 3.4**
Stairs climbing >10 flights of stairs/day OR: 2.7**
Lifting weights >25 kg
Walking >2 miles/day
Standing >2 h/day
Sitting >2 h/day
Driving >4 h/day
Croft P et al, 199216HipCase-control study Hip replacement or x ray diagnosed OA Interview questionnaireLifetime occupational history Number of years of exposureDuration in years:
Lifting weights >25 kg by hand: <1, 1–19, ⩾20OR: 2.5**
Standing >2 h/day: <20, 20–39, ⩾40OR: 2.7***
Sitting >2 h/day: <1, 1–19, ⩾20
Bending >2 h/day: <1, 1–19, ⩾20
Kneeling >30 min/day: <1, 1–19, ⩾20
Walking >2 miles/day: <1, 1–19, ⩾20
Walking rough ground >2 miles/day: <1, 1–19, ⩾20
Climbing ladders: <1, 1–19, ⩾20
Squatting >30 min/day: <1, ⩾1
Running >1 h/day: <1, ⩾1
Climbing >30 flights stairs/day: <1, ⩾1
Driving > 4 h/day: <1, ⩾1
Felson DT et al, 19916KneePopulation survey Framingham cohortx ray diagnosed OACurrent occupation in six successive questionnaires (1948–61)Exposure estimated by experts using job titlesPhysical demand:
Sedentary: lifting <10lb; occasional walking-standing
Light: lifting <20l.; frequent lifts10lb; frequent walking-standing
Medium: as in “light” with lifts <50 lb
Heavy: as in “light” with lifts <100 lb
Very heavy: as in “light” with lifts 100+ lb
+ knee bending /kneeling /crouching/crawling required in job OR: 2.4**
Heliovaara M et al, 199317HipPopulation survey (cohort)Clinical diagnosis of OA Self-administered questionnaireLast, present or previous occupation of longest duration (if not the last one) involving one of the factors Number of factors (stresses) summed (0 to5)Lifting/carrying heavy objects
Stooping/twisting/awkward posture
Vibration whole body/equipment continuously repeated series movements
Working speed determined by machine
Total number of stresses:OR: 2.9***
Holte H et al, 200018AnyNational disability pensioners survey Clinically diagnosed OAOccupation in year previous to disability pension Physical demand coded by expertsManual, skilled and unskilled labour (heavy lifting and bending).OR: 1.9**
Jacobsson B et al, 198719HipCase-control study Patients on waiting list for hip replacement Self-administered questionnaireHaving been subjected to a factor any time during life (yes/no) Heavy labour OR: 1.2*
Heavy lifting OR: 1.2*
Much tractor driving OR: 1.5*
Much walking
Much standing
Lau EC et al, 200020Hip or kneeCase-control studyx ray diagnosed OA Interview questionnaireHaving been engaged in activities (with at least one physical demand) during the occupation held for the longest time(and at least one year) before onset of symptoms (yes/no)No marked difference between hip and knee Climbing ⩾15 flights of stairs/day OR: 5.1**
Lifting ⩾10 kg, >10 times/weekOR: 5.4**
Use vibration tools ⩾1 h/day(No marked difference between hip and knee)
Walking ⩾2 h/day
Squatting ⩾1 h/day
Kneeling ⩾1 h/day
Driving ⩾4 h/day
Manninen P et al, 200221KneeCase-control study Patients with first knee arthroplasty Interview questionnaireAverage exposure in jobs held up to age 49Physical workload :
Sweating/rapid heart beat: FrequentOR: 2.0***
Not at all
Standing: almost all the time
 > half of average work day
 < half an average work day
Kneeling/squatting: >4 h/dayOR: 1.7**
 2–4 h/day
 <2 h/day
 not at all
Climbing: muchOR: 1.6**
 none or very little
Cumulative exposure summed for all jobs up to age 49Regular walking: average km/week
Regular lifting: average weight × no. lifts/day
Regular driving: average h/day or week
Olsen O et al, 199422HipCase-control study Recipients of a hip prosthesis Telephone interview questionnaireCumulative exposures summed from the start of the occupational career to age 49 or the year of OA diagnosisLifting: kg/week
Number of lifts >40 kg/weekOR: 2.5(***)
Static & dynamic work (not defined): h/weekOR: 2.4(***)
Jumping : no. jumps/week
Roach KE et al, 199423HipCase-control study Outpatient symptomatic OA Self-administered questionnaireCumulative lifetime exposure, as the sum number of years exposed to physical demands, on average more than half of their work day. Individual classified positive if cumulative exposure greater or equal to 15 yearsHeavy workload:OR: 2.4***
 Heavy work standing
 Work walking
 Work kneeling/crouching
Light workload: if no heavy workload and:
 Light work standing
 Work sitting
Intermediate workload: all other than the above
Sandmark H et al, 200024KneeCase-control study Patients with prosthetic surgery due to primary tibiofemoral OA Telephone interview questionnaireCumulative lifetime exposure from age 15 to50. Sum of duration or frequency divided in quartiles of exposure Kneeling: h/day OR: 1.6**
Squatting/bending: no./day OR: 2.0**
Jumping: no./day OR: 2.0***
Standing: h/day
Sitting: h/day
Whole body vibrations: h/day
Climbing: no. stairs/day
Lifting: kg × no. lifts/day
Schouten JSAG et al, 199225KneePopulation survey–cohort followed for 12 yearsx ray defined OA Self-administered questionnaire.Cumulative lifetime exposure. Score computed as intensity (not defined) of exposure times duration in years summed over all jobs with the exposure. Scores divided in tertiles (low, medium, high)Lifting heavy objects
Knocking one’s knee
Standing OR: 3.8**
Thelin A et al, 199726HipCase-control studyx ray diagnosed OA Self-administered questionnaireFull time working with what they themselves regarded as heavy physical work for a period longer than half a year before 16 years of ageHeavy physical work at young ageOR: 2.1*
Vingard E et al, 199127HipCase-control study Recipients of hip prosthesis Interview and self-administered questionnairesCumulative exposure calculated separately in three categories: from start of career to age 29, from age 30 to 49 and over the age of 49. Exposure expressed as summed duration or frequency reported. No difference between age categoriesDynamic workload (all below):OR: 2.2**
Lifting: kg/week;OR: 1.8**
no. lifts>40 kg/weekOR: 2.4**
 Jumping: no. jumps/week
 Walking with burden: h/week
 Stairs climbing: h/week
Static workload (all below):OR: 2.9**
 Standing: h/week
 Sitting: h/week
 Biking: h/week
 Driving: h/week
 Twisted position: h/week
Vingard E et al, 19917Hip or kneeRegister-based Population cohort study Hospital care for OAOccupation within 10 years of hospital admission for OA Exposure estimated by experts using job titles and expressed as high or low dynamic or static forces (not defined) acting on the lower extremityBlue collar with dynamic forces and/or static compression:
“High” versus “low”:
HipOR: 2.2*
KneeOR: 1.9*
Vingard E et al, 199728HipRegister-based case- control study Women who underwent total hip replacement for primary OA Interview questionnaireCumulative exposure between the age of 16 to 50. Sum of duration of exposure or number of lifts times the weight lifted in an average working week.Sitting: h/day
Standing: h/day
Working in twisted posture: h/day
Lifting: 1–5 kg
 6–10 kg
 11–15 kg
 16–20 kg
Jumping/movements between different levels: no./week OR: 2.1**
Climbing: no. flights of stairs/week OR: 2.1**
Yoshimura N et al, 200029HipCase-control study Patients listed for total hip arthroplasty due to OA Interview questionnaireExposure in first job and main job (not defined) defined as a job regularly involving each of the physical demand (yes/no). Little difference was found between the results on first job and main jobLifting: ⩾10 kg more than once/week
 ⩾25 kg more than once/week
⩾50 kg more than once/weekOR: 4.1**
Sitting ⩾2 h/?
Standing ⩾2 h/?
Kneeling ⩾1 h/?
Squatting ⩾1 h/?
Driving ⩾4 h/?
Walking ⩾3 km/?
Climbing ⩾30 flights of stairs/?