Ergonomic Risk Factors for Musculoskeletal Disorders among Ethnic Lychee–Longan Harvesting Workers in Northern Thailand

Abstract

Musculoskeletal disorders (MSDs) are one of the leading causes of occupational injuries and disabilities. The purpose of this study was to assess the prevalence of MSDs and occupational factors affecting MSDs among ethnic lychee–longan harvesting workers in northern Thailand. A cross-sectional study was conducted in the areas of three upper northern provinces of Thailand. The study areas are located in the highlands and rural plains, where many ethnic minority groups live, including Indigenous, Mien, Karen, and Lua. The majority of them work in a farm of perennial fruit trees, mainly lychee and longan. During the harvest season, 404 participants were recruited for the study using the convenience sampling technique. Data were collected using questionnaires that included general information, an ergonomic risk assessment, and a standardized Nordic questionnaire for assessing MSDs in 10 body parts. The average age of lychee–longan harvesting workers was 48.8 years. Almost all (99.5%) reported MSDs in one or more body regions in the previous seven days of work. The prevalence of MSDs was highest in the hands (82.9%), followed by the shoulders (82.2%) and the neck (79.7%). The total ergonomic risk scores, which included awkward posture, heavy carrying and lifting, repetitive activity, land slope, and equipment, were found to be significantly associated with MSDs in part of the neck (AOR = 1.17, 95%CI = 1.11–1.23), shoulder (AOR = 1.15, 95%CI = 1.10–1.21), elbow (AOR = 1.18, 95%CI = 1.12–1.24), hand (AOR = 1.12, 95%CI = 1.07–1.18), finger (AOR = 1.33, 95%CI = 1.24–1.44), upper back (AOR = 1.14, 95%CI = 1.09–1.20), lower back (AOR = 1.16, 95%CI = 1.11–1.22), hip (AOR = 1.11, 95%CI = 1.06–1.15), knee (AOR = 1.18, 95%CI = 1.12–1.24), and feet (AOR = 1.21, 95%CI = 1.15–1.28) when adjusting for ethnicity, sex, age, BMI, and work experience. Many parts of ethnic workers’ bodies have been affected by occupational injuries, with a high risk of upper extremity injury. As a result, using an ergonomic approach to improving the working environment and appropriate posture movement is very beneficial in preventing MSDs among ethnic harvesting workers.