Table 1

 Characteristics and results of the included articles

Cohort (first author) quality scoreStudy populationAssessment duration of computer useCase definition(s)ResultsResults continued
*hours per week
BIT, Jensen20 (42%)Employees from Danish companies and institutions. Selected companies provided employees with different types of computer work (data entry, word processing, graphic work, etc). Analyses were restricted to subjects working full time (32–41 hours(week), who had not changed jobs during follow-up. n = 203–916Self-report “How much of your work time do you work with your computer (including overtime and working at home)” Response categories: Seldom; 25%; 50%; 75%; 100%Self-reported symptoms for more than 7 days within the last year of the follow-up period. Body regions studied: neck and hand-wristNeck Total computer use: —0–25% of work time OR 1 —50% of work time OR 1.5 (0.7–3.1) —75% of work time OR 1.3 (0.6–2.7) —100% of work time OR 1.6 (0.8–3.3) Mouse use: —Seldom OR 1.3 (0.4–4.3) —25% of work time OR 1 —50–100% of work time OR 1.7 (0.5–5.7)Hand-wrist Total computer use: — 0–25% of work time OR 1.5 (0.7–2.4) —50% of work time OR 1 —75% of work time OR 2.0 (1.1–3.9) —100% of work time OR 2.3 (1.2–4.3) Mouse use: —Seldom OR 4.0 (1.1–14.4) —25% of work time OR 1 —50–100% of work time OR 4.0 (1.0–15.5)
BIT,See JensenSee JensenDuration outcome:Shoulder duration outcomeElbow duration outcome:
Juul-Kristensen21 (42%)Analyses restricted to workers who held the same job during follow-up. n = 2002Self-reported symptoms <8 days in the past 12 months at baseline and >7 days during follow-up Intensity outcome: Self-reported symptom intensity <4 (scale 0–9) during last 3 months at baseline and ⩾4 during last 3 months at baseline + non-symptomatic at both sides (left and right) and non-symptomatic in nearby body regions Body regions studied: elbow and shoulderTotal computer use: —0–25% of work time OR 1 —50% of work time OR 1.23 (0.63–2.40) —75% of work time OR 1.00 (0.51–1.94) —Almost all work time OR 0.69 (0.34–1.39) Shoulder intensity outcome Total computer use: —0–25% of work time OR 1 —50% of work time OR 1.07 (0.60–1.90) —75% of work time OR 0.95 (0.53–1.70) —Almost all work time OR 0.78 (0.43–1.43)Total computer use: —50% of work time OR 1.11 (0.51–2.40) —75% of work time OR 0.95 (0.43–2.10) —Almost all work time OR 1.08 (0.48–2.39) Elbow intensity outcome: Total computer use: —50% of work time OR 1.12 (0.58–2.18) —75% of work time OR 0.90 (0.47–1.74) —Almost all work time OR 1.08 (0.48–2.39)
NUDATA Andersen22 50%Employees from the Danish Association of Professional Technicians, ie,—technical assistants (draughtsmen) and machine technicians from 3527 public and private companies. Job tasks included technical drawing tasks, administrative and graphical tasks. n = 5658Self-report Participants estimated their average hours per week doing specified work tasks during the past four weeks (separately for tasks using the computer and tasks not using the computer). Questions for keyboard use and mouse use separately. Computer use ( = mouse use +keyboard use) not used in the analysis due to high correlation with mouse use.Possible carpal tunnel syndrome (CTS): Self-reported tingling or numbness in the right hand at least once a week within the last 3 months, with no or minor tingling/numbness at baseline. Body regions studied: wrist (possible CTS)Wrist (possible CTS) Mouse use: —0–<2.5 hrs/wk* OR 1 —2.5–<5 hrs/wk OR 0.7 (0.3–1.9) —5–<10 hrs/wk OR 1.9 (0.9–4.0) —10–<15 hrs/wk OR 1.6 (0.8–3.3) —15–<20 hrs/wk OR 2.0 (0.9–4.2) —20–<25 hrs/wk OR 2.6 (1.2–5.5) —25–<30 hrs/wk OR 3.2 (1.3–7.9) Keyboard use: —0–<2.5 hrs/wk OR 1
—2.5–<5 hrs/wk OR 0.9 (0.4–1.8)
—5–<10 hrs/wk OR 0.8 (0.4–1.5)
—10–<15 hrs/wk OR 1.2 (0.6–2.5)
—15–<20 hrs/wk OR 0.8 (0.4–1.5)
—> = 20 hrs/wk OR 1.4 (0.5–4.3)
NUDATA Kryger23 42%See AndersenSelf-report See AndersenAt least moderate to severe self-reported pain in the forearm within the past 7 days combined with quite a lot pain/discomfort during the past 12 months and at baseline none or less than moderate pain in the forearm in the past 7 days combined with less than “some” pain/tenderness during the past 12 months Body regions studied: forearmForearm Mouse use: —0–9 hrs/wk OR 1 —10–19 hrs/wk OR 2.2 (1.0–4.7) —20–29 hrs/wk OR 2.6 (1.0–6.6) —> = 30 hrs/wk OR 8.4 (2.5–29) Keyboard use: —0–4 hrs/wk OR 1 —5–9 hrs/wk OR 1.2 (0.5–2.9) —10–14 hrs/wk OR 1.3 (0.5–3.4) —> = 15 hrs/wk OR 2.6 (0.9–7.3)
NUDATA Brandt24 42%See AndersenSelf-report See AndersenSelf-reported pain in the last 7 days of at least moderate degree and pain during the last 12 months of follow-up that bothered at least quite a lot and no complaints in the region during the 12 months prior to the baseline examination and less than moderate pain in the regional area during the last 7 days at baseline Body regions studied: neck and shoulderNeck Mouse use: —0–9 hrs/wk OR 1 —10–19 hrs/wk OR 1.1 (0.6-1.9) —20–29 hrs/wk OR 0.9 (0.4–1.9) —> = 30 hrs/wk OR 2.4 (0.8–6.8) Keyboard use:Shoulder Mouse use: —0–9 hrs/wk OR 1 —10–19 hrs/wk OR 1.2 (0.7–2.1) —20–29 hrs/wk OR 1.9 (1.0–3.5) —> = 30 hrs/wk OR 3.3 (1.2–8.9) Keyboard use:
—0–4 hrs/wk OR 1 —5–9 hrs/wk OR 1.1 (0.5–2.2)—0–4 hrs/wk OR 1 —5–9 hrs/wk OR 1.3 (0.7–2.6)
—10–14 hrs/wk OR 1.0 (0.4–2.2)- 10–14 hrs/wk OR 1.6 (0.8–3.3)
—> = 15 hrs/wk OR 1.8 (0.8–3.9)—> = 15 hrs/wk OR 2.2 (1.0–4.9)
NUDATASee AndersenSelf-reportCaseElbow caseHand-wrist case
Lassen25 42%See AndersenAny self-reported pain or discomfort during the past 12 months, but not at baseline Severe case Self-reported pain or discomfort lasting for >30 days and causing at least “quite a lot of trouble” during the past 12 months at follow-up, but not at baseline Body region studied: elbow and hand-wristMouse use: —<2.5 hrs/wk OR 1 —20–<25 hrs/wk OR 3.21 (2.03–5.17) —25–<30 hrs/wk OR 4.83 (2.79–8.40) —> = 30 hrs/wk OR 4.74 (2.51–8.95) Keyboard use: —0–<2.5 hrs/wk OR 1 —2.5–<5 hrs/wk OR 1.04 (0.65–1.69) —5–<10 hrs/wk OR 1.47 (0.98–2.26) —10–<15 hrs/wk OR 1.33 (0.85–2.11) —15–<20 hrs/wk OR 1.29 (0.78–2.17) —> = 20 hrs/wk OR 1.98 (0.96–3.95) Hand-wrist case Keyboard use (continued): —10–<15 hrs/week OR 0.80 (0.53–1.20)Mouse use: —<2.5 hours/week OR 1 —2.5–<5 hrs/wk OR 1.57 (0.99–2.51) —5–<10 hrs/wk OR 2.16 (1.46–3.22) —10–<15 hrs/wk OR 2.05 (1.37–3.07) —15–<20 hrs/wk OR 2.46 (1.65–3.72) —20–<25 hrs/wk OR 2.07 (1.32–3.26) —25–<30 hrs/wk OR 3.16 (1.82–5.46) —> = 30 hrs/wk OR 3.05 (1.63–5.67) Keyboard use: —Increase of 10 hrs/wk OR 1.29 (1.06–1.57) —0–<2.5 hrs/wk OR 1 —2.5–<5 hrs/wk OR 0.63 (0.41–0.98) —5–<10 hrs/wk OR 0.73 (0.50–1.07)
—15–<20 hrs/week OR 0.87 (0.55–1.38) —> = 20 hrs/week OR 1.04 (0.51–2.04) Severe elbow case Mouse use: —<2.5 hrs/wk OR 1 —2.5–<5 hrs/wk OR 1.16 (0.34–3.54) —5–<10 hrs/wk OR 1.42 (0.58–3.64) —10–<15 hrs/wk OR 2.14 (0.93–5.32) —15–<20 hrs/wk OR 1.45 (0.59–3.78) - 20 to <25 hrs/wk OR 2.88 (1.18–7.54) —25 to <30 hrs/wk OR 4.16 (1.45–12.13) —> = 30 hrs/wk OR 6.91 (2.21–22.53) Keyboard use: —<2.5 hrs/wk OR 1 —2.5–<5 hrs/wk OR 1.09 (0.44–3.00) —5–<10 hrs/wk OR 1.58 (0.71–4.03) —10 to <15 hrs/wk OR 2.49 (1.08–6.53) —15 to <20 hrs/wk OR 2.86 (1.08–8.12) —> = 20 hrs/wk OR 3.79 (0.91–14.11)Severe hand-wrist case Mouse use: —<2.5 hrs/week OR 1 —2.5–<5 hrs/wk OR 0.73 (0.23–2.01) —5–<10 hrs/wk OR 1.55 (0.74–3.34) —10–<15 hrs/wk OR 1.40 (0.68–3.01) —15–<20 hrs/wk OR 1.68 (0.82-3.58) —20 to <25 hrs/wk OR 4.21 (2.12–8.85) —25 to <30 hrs/wk OR 4.81 (2.18–10.99) —> = 30 hrs/wk OR 2.30 (0.83–6.26) Keyboard use: —<2.5 hrs/wk OR 1 —2.5–<5 hrs/wk OR 1.14 (0.58–2.38) —5–<10 hrs/wk OR 0.99 (0.54–1.95) —10 to <15 hrs/wk OR 1.46 (0.76–2.98) —15 to <20 hrs/wk OR 1.89 (0.90–4.10) —> = 20 hrs/wk OR 1.60 (0.43–4.94)
Bergqvist et al Bergqvist19 42%Employees working for seven companies in Stockholm, Sweden: travel agencies, a newspaper production company, postal office, and an insurance company. Included employees worked at least 75% of a full time contract. n = 341Self-report “How many hours per week did you work at the Visual Display Terminal?” Responses were categorized into three categories: no or occasional; <30 hours/week; >30 hours/weekCurrent self-reported pain or discomforts. Symptoms that occurred only occasionally and were of insignificant intensity were not taken into account. Body regions studied: neck-shoulder; hand-wristNeck-shoulder Total computer use: —>30 hrs/wk versus no or occasional total computer use RR 1.25 (0.76–2.05) [univariate analysis] Hand-wrist Total computer use —>30 hrs/wk versus no or occasional total computer use
RR 3.75 (0.89–15.81) [univariate analysis]
Marcus et al Marcus26 75%Newly hired workers who 1) anticipated using a computer for at least 15 hrs/wk, and 2) anticipated using a computer keyboard for at least as many hrs/wk as in their previous job. Job sectors included insurance, finance, food production, health care, and education. n = 436–520Self-report, daily diary on hours spent keyingMusculoskeletal symptoms Self-reported discomfort in weekly diary which was present at least one day during previous week and pain score (VAS) >6 or using medication for control of the discomfort. Musculoskeletal disorders Positive if case definition for musculoskeletal symptoms was met and physical examination was positive. Body regions studied: hand-arm, neck-shoulderNeck-shoulder symptoms Total computer use: —Increase of 1 hr/wk HR 1.01 (0.99–1.03) —35 hrs/wk versus 15 hrs/wk HR 1.22 (0.82–1.81) Neck-shoulder disorders Total computer use: —Increase of 1 hr/wk HR 1.01 (0.99–1.04) —35 hrs/wk versus 15 hrs/wk HR 1.22 (0.82–2.19)Hand-arm symptoms Total computer use: —Increase of 1 hr/wk HR 1.04 (1.02–1.06) —35 hrs/wk versus 15 hrs/wk HR 2.19 (1.49–3.20) Hand-arm disorders Total computer use: —Increase of 1 hr/wk HR 1.04 (1.02–1.06) —35 hrs/wk versus 15 hrs/wk HR 2.19 (1.49–3.20)
Korhonen et al Korhonen27 50%Full time working employees from three municipal administrative units. n = 138Estimate how many percent of your working time during the preceding month you have used for each task of the following tasks (VDU work includes using keyboard or other input or control device, including short thinking periods and checking the results on the screen). Response categories: <50%, >50% of work timeLocal or radiating self-reported neck pain at follow-up for at least 8 days during the last 12 months AND experiencing local or radiating neck pain <8 days at baseline. Body regions studied: neckNeck Total computer use: —<50% of work time OR 1 —> = 50% of work time OR 1.0 (0.6–2.9) [univariate analysis]