Association of Workplace Stressors with Salivary Alpha-Amylase Activity Levels among Fresh Fruit Bunch Cutters in Selangor

Abstract

Background: A cross sectional study was conducted to determine the association between occupational stress risk factors and salivary alpha-amylase activity levels among fresh fruit bunch (ffb) cutters at oil palm plantation. 

Methods: A total of 109 ffb cutters were selected from two oil palm plantations in Pulau Carey, Selangor at west coast of Malaysia in 2015. Questionnaires were used to determine socio-demographics and occupation information, distress level were determined by using translated 12-items-General Health Questionnaire (GHQ). Kestrel Heat Stress Tracker 4400 was used to measure wet bulb globe temperature (WBGT) for heat stress exposure. Posture analysis was examined based on Rapid Upper Limb Assessment (RULA) method in evaluating working posture and Borg CR-10 scale was rated by ffb cutters to determine exerted force during harvesting process. Stress response system was determined by measuring salivary alpha-amylase (sAA) activity by using sAA kinetic enzyme assay kit (Salimetrics).

Results: 35.8% of ffb cutter had high score indicating psychological distress. 49.5% of the cutters had high heat stress exposure. 91.8% used force exertion of 50%MVC and above to cut fresh fruit bunches and 62.4% were classified in Action Level 4 under RULA. 77.0% of the ffb cutters showed high levels of sAA activity after cutting fresh fruit bunches. 

Conclusion: Workplace stressors such as working environment and ergonomics risk factors play a role to develop stress at workplace among ffb cutters. Therefore, stress preventive measures are needed to reduce the stressors at workplace.

Keywords: Psychological distress, Salivary alpha-amylase, Heat stress exposure, Oil palm plantation