Perceived discrimination and low back pain among 28,532 workers in South Korea: Effect modification by labor union status

Abstract

Objectives: This study investigated the association between workplace discrimination and low back pain among Korean workers and explored the role of labor union in the association. Methods: We analyzed a cross-sectional survey of 28,532 workers from the 3rd Korean Working Conditions Survey (2011), a nationally representative dataset in South Korea. Experience of workplace discrimination for five different reasons was assessed using the questions: "Over the past 12 months, have you ever experienced workplace discrimination based on your: (a) age, (b) education, (c) birth region, (d) sex, and (e) employment status?" Experience of low back pain within a 12 month period was measured using a yes/no question. Labor union membership was coded into three categories: (1) workers at workplaces without a labor union; (2) workers without union membership at workplaces with a labor union; (3) workers with union membership. Results: In workplaces without a labor union, low back pain was statistically significantly associated with workplace discrimination based on age (OR: 2.02, 95% CI: 1.73, 235), education (OR: 1.45, 95% CI: 1.23, 1.71), birth region (OR: 1.42, 95% CI: 1.10,1.84), sex (OR: 2.22, 95% CI: 1.81, 2.73), and employment status (OR: 2.33, 95% CI: 1.99, 2.72) after adjusting for covariates including physical work factors. However, no significant association was observed among workers at workplaces with a labor union regardless of workers' union membership. Conclusions: Workplace discrimination was associated with low back pain only in workplaces without a labor union. Presence of labor union at workplaces may have a protective effect on workers' low back pain against workplace discrimination. (C) 2017 Elsevier Ltd. All rights reserved.