Musculoskeletal disorders in the U.S. agricultural sector

Davis KG,
2007, Understanding the ergonomic risk for musculoskeletal disorders in the United States agricultural sector, Am J Ind Med. 50(7):501-11.

Injuries

Regarding injuries in the sector, fractures, lacerations and internal bleeding occurs far too often in farmers; e.g. lacerations has been reported to range between 12,5 en 34%. The highest rate of lost-time injuries occurred in beef, hog and sheep farmers, followed by: cash grain farmers, field crop farmers, dairy farmers and vegetable, fruit and nut farmers. The most often causes of injury are related to machinery (18 to 35%), animals (12 to 33%), tractors (up to 40%) and falls (16 to 25%). Of the machine-related injuries, injuries to the hand make up the largest portion (26%). Regarding costs, musucloskeletal injuries cost the farming industry in excess of $ 168 million, not inlcuding lost productivity and human costs.

Musculoskeletal disorders

Regarding musculoskeletal disorders, 70% of operators of farm equipment suffer in one or more body regions. And the prevalence rate of MSD in agriculture is 1,5 times that of the general US industry. Also long-term consequences may not be forgotten, since the prevalence of osteoarthritis and arthropathy is slightly greater in a farm cohort.

Low Back Pain (LBP)
The prevalence of LBP in farmers has been reported to be 50%, which is higher than other manual labourers (37%). Some tasks may contribute more significant to LBP:
  • The prevalence of LBP in farmers that are exposed to extensive tractor driving is approximately 40%. Two types of tractor driving tasks were found to be particularly related: silage chopping and ploughing which both require long static postruers, twisted trunk while looking backwards and high vibration. Another important risk factor is the age of the tractors (older types do not have an ergonomic design in the seat to minimize vibration).
  • Pruning, weeding and labeling are particulary stressful due to prolonged extreme flexion onf the trunk, as also harvesting crops
  • Carrying bins fully loaded in the fields, often above 20 kg
  • Fruit harvesters, especially if trees are below 3,4 m (more flexion of the back) or above 5,8 (more extension)
  • Harvesting grapes causes sustained back flexion and heavy lifting of the bins.

Upper extremities
Also regarding shouder pain, this seems to be greater in farming than other manual or non-manual labor. Almost 30% prevalence is reported in several types of farming (e.g. dairy farmers). Some tasks may contribute more significant to upper extremity disorders:
  • Crop harvesting: high hand forces when pulling vegetables or fruit off plants or using cutting tools;
  • Vineyard workers: high stress on the hands during pruning of the grapevines and cutting grapes from the vine;
  • Dairy farms (although highly automated): attachment of the milking machine to the utters of the cow;
  • Use of chain saws, saws and other mechanical hand equipment: hand vibration;
  • Fruit harvesting: reaching up to pick fruit above shoulder height, carrying bags placing load on shoulder through strap use and carrying the ladder from tree to tree.

Initiatives

In 1990, NIOSH (National Institute for Occupational Safety and Health) embarked on a major initiative to address health and safety in farming by establishing 9 geographically distinct Centers for Agricultural Disease and Injury Research. The objectives of these centers are:
  • Conduct research into prevention
  • Develop educational programs to provide training
  • Develop interventions for common farm-related problems
  • Disseminate information to farmers
  • Provide consultation services.
Furthermore, there are also non-profit organisations and societies that aim to educate and disseminate information.
Some intervention studies were performed (e.g. the effect of utilizing smaller and lighter weight bins during harvesting of wine grapes or the impact of a tub cart for the transferring of tubs between fields and truck or collector bin).
There are several sources of suggestions for engineering design changes, although they are not all completely validated with respect to actual effectiveness in reducing MSD. Also, lack of knowledge and resources to implement them are confounders. Much is left to do.