TABLE 1.
Work hours and sleep in relation to injury
| Study | Year | Sample | Country (region) | Population description | Method of report | Stated study focus | Findings related to work hours, sleepa |
|---|---|---|---|---|---|---|---|
| Work hours | |||||||
| Browning | 2013 | 1149 | USA (Kentucky) | Beef cattle operators and workers | Self-report (survey) | Cattle-related injuries and farm management practices | OR = 2.01 injury for principal operator when 40+ h/week, 95% CI (1.3–3.24) OR = 1.72 injury for all workers when 36–60 h/week, 95% Cl (1.05–2.81) OR = 2.52 injury for all workers when 60+ h/week, 95% CI (1.55–4.09) |
| DeWit | 2015 | 1135 | Canada (Saskatchewan) | Farm youth and young adults, 12–29b | Self-report (survey) | Farm activities and agricultural injuries | Risk ratio = 10.3 injury for hours of farm work, 30+ h/week, 95% CI (2.2–47.5), (p = 0.003) |
| Erkal | 2008 | 32,602 | USA (Minnesota, Wisconsin, North Dakota, South Dakota, and Nebraska) | Farm householdsc | Self-report (interview) | Animal-related injuries | Animal-related injury event rates per 1000 persons per year: >40–60 h/week = 55.9, 95% CI (47.0–66.6) >60–80 h/week = 78.5, 95% CI (66.9–92.1) >80 h/week = 100.9, 95% CI (78.4–130.0) |
| Gerberich | 1998 | 13,144 | USA (Minnesota, Wisconsin, North Dakota, South Dakota, and Nebraska) | Farm householdsd | Self-report (interview) | Machine-related injuries | Machine-related injury rate per 100,000 persons: 40–59 h/week = 2254, rate ratio: 12.52, 95% CI (6.20–25.29) 60–79 h/week = 3664, rate ratio: 20.66, 95% CI (10.50–40.62) 80+h/week = 2716, rate ratio: 15.16, 95% CI (6.91–33.26) |
| Heaton | 2010 | 756 | USA (Kentucky and South Carolina) | Farmers aged 50 and oldere,f | Self-report (survey) | Sleep apnea indicators and injury | OR = 1.017 injury per 1-h increase in work hours, 95% CI not given (p = 0.0047) (found to be not statistically significant in final multivariable logistic regression model) |
| Hwang | 2001 | 1706 | USA (New York) | Farm owners/workersg | Self-report (interview) | Severe farm injuries | OR = 9.54 injury for those working >8 h/day (54.0% of participants), 95% CI (4.48–21.2), (p = <0.0001) |
| Ichihara | 2019 | 337 | Japan | Farm workers | Self-report (survey) | Risk factors for occupational accidents | OR = 1.76 occupational accidents for those working ≥8 h/day, 95% CI (1.15–2.68) |
| Lilley | 2012 | 4439 | Canada (Saskatchewan) | Farm owners/workers aged 16 and olderb | Self-report (survey) | Relationship between fatigue-related factors and work-related injuries | Percentage of workers injured in peak season by work hours: 30–59 h/week = 6.7%, 60–79 = 9.1%, ≥80 = 10.1% (p = <0.0001) Percentage of workers injured in nonpeak season by work hours: 30–59 h/week = 2.6%, 60–79 = 4.6%, ≥80 = 2.6% (p = <0.001) |
| McCurdy | 2004 | 135 | USA (California) | Farm operators | Self-report (survey) | Nonfatal occupational injury | OR = 2.63 injury farmed 1441–3500 h in the last year, 95% CI (1.43–4.83) OR = 3.77 injury farmed >3500 h in the last year, 95% CI (1.63–8.69) |
| McCurdy | 2012 | 489 | USA (California) | Youth (grades 9–12) enrolled in agriculture sciences curriculum | Self-report (survey) | Risk factors for injury | OR = 5.09 injury for those who worked 1501+ h/year, 95% CI (1.61–16.1) |
| Paulson | 2006 | 16,538 | USA (Minnesota, Wisconsin, North Dakota, South Dakota, and Nebraska) | Farm householdsc | Self-report (interview) | Fall-related injuries | Fall-related injury event rate per 1000 persons per year: >40–60 h/week = 49.2, 95% CI (38.6–62.6) >60–80 h/week = 52.1, 95% CI (40.6–66.8) >80 h/week = 55.6, 95% CI (37.9–81.6) |
| Pratt | 1992 | 600 | USA (New York) | Dairy farm owners/workers | Self-report (interview) | Risk factors for occupational accidents | Relative risk = 2.76 injury for owners who worked more than 60 h/week and had 30+ acres under tillage/worker. Injured workers were: older (p = 0.01), worked more hours (p = 0.001), and had heavier workloads than noninjured workers (p = 0.001) |
| Reiner | 2016 | 32,598 | USA (Minnesota, Wisconsin, North Dakota, South Dakota, and Nebraska) | Farm householdsc | Self-report (interview) | Large machinery-related injuries | Large machine-related injury events per year per 1000 persons: 20–39 h/week = 18.88, 95% CI (14.93–23.88) 40–59 h/week = 40.25, 95% CI (32.83–49.35) 60–79 h/week = 43.15, 95% CI (35.17–52.92) 80+ h/week = 43.19, 95% CI (30.56–61.05) |
| Spengler | 2004 | 1004 | USA (Kentucky) | Part-time farmers age 19 and oldere | Self-report (interview) | Sleep deprivation and injuries | OR = 1.43 injury for 41–50 h/week, 95% CI (0.73–2.80) OR = 1.02 injury for >50 h/week, 95% CI (0.44–2.39) |
| Spince | 2003 | 431 | USA (Iowa) | Farmers | Self-report (interview) | Risk factors for injury | OR = 1.65 injury for farmers working >50 h/week in the last year, 95% CI (1.23–2.21) |
| Svendsen | 2014 | 2699 | Norway (2 counties) | Farmers | Self-report (survey) | Risk factors for injury | OR = 1.54 injury for working >3500 h at farm, 95% CI not given (p = <0.01) |
| Insufficient sleep (less than 8h of sleep per night) | |||||||
| DeWit | 2015 | 1135 | Canada (Saskatchewan) | Farm youth and young adults, 12–29b | Self-report (survey) | Farm activities and agricultural injuries | 9.5% injury rate for ≤6 h sleep per night, CI (6.3–12.6), (p = 0.0002) |
| Lilley | 2012 | 4439 | Canada (Saskatchewan) | Farm owners/workers aged 16 and olderb | Self-report (survey) | Relationship between fatigue-related factors and work-related injuries | OR = 1.43 injury for 7–6 h per night sleep during peak season, 95% CI (0.96–2.12) OR = 1.48 injury for ≤5 h per night sleep during peak season, 95% CI (0.93–2.34) OR = 1.41 injury for 7–6 h per night sleep during nonpeak season, 95% CI (0.86–2.32) OR = 2.40 injury for ≤5 h per night sleep during nonpeak season, 95% CI (1.02–5.68), (p = 0.04) |
| Spengler | 2004 | 1004 | USA (Kentucky) | Part-time farmers age 19 and oldere | Self-report (interview) | Sleep deprivation and injuries | OR = 1.01 injury for 7 h/day average sleep past year, 95% CI (0.64–1.59) OR = 1.25 injury for 6 h/day average sleep past year, 95% CI (0.73–2.15) OR = 1.12 injury for ≤5 h/day average sleep past year, 95% CI (0.47–2.64) |
| Shipp | 2009 | 390 | USA (Texas) | Migrant farm worker families | Self-report (interview and survey) | Chronic back pain and associated work and nonwork variables | OR = 2.26 chronic back pain for <8 h/day sleep at home, 95% CI (1.16–8.12), (p = 0.024) OR = 3.25 chronic back pain for fairly bad/very bad quality of sleep while migrating, 95% CI (1.78–10.25), (p = 0.001) |
| Shipp | 2013 | 410 | USA (Texas) | Farmworkers aged 13–19 years | Self-report (survey) | Acute occupational injury | HR = 2.10 injury for <8 per night, 95% CI (1.09–4.04), (p = 0.026) |
| Epworth Sleepiness Scale (ESS) | |||||||
| Day | 2009 | 252 | Australia (Victoria) | Farm owners/workers aged 16 and older | Self-report (interview) | Risk factors for work related injury among male farmers | OR = 0.51 injury for ESS > 10, 95% CI (0.32–0.82) |
| King | 2014 | 2392 | Canada (Saskatchewan) | Farm owners/workers aged 16 and olderb | Self-report (survey) | Impact of excessive daytime sleepiness on safety and health | OR = 1.34 injury for ESS > 10, 95% CI (0.92–1.96) |
| Spince | 2003 | 431 | USA (Iowa) | Farmers | Self-report (interview) | Risk factors for agricultural injury | OR = 1.27 injury for ESS > 15, 95% CI (0.98–1.66) |
| Sleep disorder (diagnosed and symptoms) | |||||||
| Dosman | 2013 | 5502 | Canada (Saskatchewan) | Farm owners/workersb | Self-report (survey) | Loud snoring and occupational injury | HR = 0.79 injury for diagnosed sleep apnea, 95% CI (0.43–1.47) HR = 1.45 injury for loud snoring, 95% CI (1.07–1.99) |
| Heaton | 2010 | 756 | USA (Kentucky and South Carolina) | Farmers aged 50 and oldere,f | Self-report (survey) | Sleep apnea indicators and injury | OR = 1.861 injury for stop breathing while sleeping, 95% CI (1.035–3.346), (p = 0.038) OR = 2.246 injury for problems staying awake last month, 95% CI (1.244–4.055), (p = 0.007) |
| Lilley | 2012 | 4439 | Canada (Saskatchewan) | Farm owners/workers aged 16 and olderb | Self-report (survey) | Relationship between fatigue-related factors and work-related injuries | OR = 1.20 injury for loud snoring, 95% CI (0.79–1.83) |
| King | 2014 | 2392 | Canada (Saskatchewan) | Farm owners/workers aged 16 and olderb | Self-report (survey) | Impact of excessive daytime sleepiness on safety and health | OR = 0.96 injury for diagnosed sleep apnea, 95% CI (0.47–1.96) |
| Marcum | 2011 | 1394 | USA (Kentucky and South Carolina) | Farmers aged 50 and oldere,f | Self-report (survey) | Injury among farmers 50 years and older | OR = 1.32 injury for 1–2 days restless nights in past week, 95% CI (0.96–1.81), (p = 0.0883) OR = 2.02 injury for 3–4 days restless nights in past week, 95% CI (1.32–3.09), (p = 0.0011) OR = 1.89 injury for 5–7 days restless nights in past week, 95% CI (1.28–2.80), (p = 0.0012) |
| Spengler | 2004 | 1004 | USA (Kentucky) | Part-time farmers age 19 and oldere | Self-report (interview) | Sleep deprivation and injuries | OR = 2.28 injury for sleep medication used in the past month, 95% CI (1.67–4.47) OR = 2.17 injury for three sleep apnea signs and symptoms, 95% CI (1.03–4.56) |
a
Adjusted values used when available.
b
Saskatchewan Farm Injury Cohort.
c
Regional Rural Injury Study II (RRIS-II) Cohort.
d
Regional Rural Injury Study I (RRIS-I) Cohort.
e
Kentucky Farm Family Health and Hazard Surveillance Project.
f
African-American farmers from the Kentucky and South Carolina Agricultural Statistics Services.
g
New York State Farm Family Health and Hazard Surveillance Project.