Elsevier

Archives of Medical Research

Volume 36, Issue 5, September–October 2005, Pages 594-597
Archives of Medical Research

Original article
Epidemiological
Workload and Health Complaints in Overtime Workers: A Survey

https://doi.org/10.1016/j.arcmed.2005.03.048Get rights and content

Background

In epidemiological studies on workload and complaints on health, the dose-response relationship should be assessed to design a strategy for the prevention of disease or disability. Evaluation for the relationship between workload and complaints were urgently required.

Methods

The study population consisted of 109 male workers at a car manufacturer workplace. These observations were analyzed to determine exposure to load and subjective complains by standardized questionnaire. Workloads of the target subjects were divided into four groups (A to D), according to the scores of a self-administered questionnaire.

Results

Percentage of feeling stressful to each of seven items such as overtime work, irregular work, official trip, nighttime work, no rest and/or no nap, mental workload, and physical workload were 62.4, 34.9, 0.9, 23.9, 18.3, 65.1, and 33.9%, respectively. Pearson's moment correlation coefficient between workload and health complaint was 0.585. After adjusting for age, it became 0.586. Furthermore, odds ratio of the subjects who were grouped into C or D were 13.6 (95% confidence interval 3.0 to 61.4) and 48.0 (95% confidence interval 4.3 to 537.3) against group A, which were all significant.

Conclusions

There was a significant relationship between workload and health complaints in this questionnaire survey. To prevent or lower complaints of workers, improvements of working conditions such as overtime work are recommended to reduce health risk.

Introduction

Overtime work is a major health problem in many workplaces. Generally, it leads to physical and mental load and becomes a significant contributing factor to health problems (1). Despite the existence of many cases of adverse health effects by overtime work for the past several decades in Japan, quantitative dose-response relations between overtime work and health problems are not so clear. Several methods have become available to assess workload in the workplace, such as observation, self-reports, or monitoring devices. Observational techniques have the advantage of being applicable in many workplaces to detect physical load (2), though these require technique and time to detect. In order to clarify dose-response relationships between workload and health complaints, the authors conducted a health survey for manufacturing workers by using the self-administered questionnaire, which was recently prepared by the occupational experts (3). This questionnaire was politically introduced by the Ministry of Health, Labour and Welfare for the prevention of overwork-related sudden death for all employees. Although not punishable by law, the workers were intended not to work more than 45 h overtime per month. Furthermore, administrative guidance to employees and their employers should be conducted if overtime exceeds 100 h per month. This action was targeted to all workers without consideration of any risk factors.

Workload is divided into physical and mental characteristics, which are sometimes difficult to judge in regard to their relationship to work. Increase of workload in intensity or duration of exposure results in an increased risk of illness or disease. When describing dose-response relations for workload, a U-shaped pattern is predicted for the nature of the associations between load and complaints (4).

In Japan, overtime work in a month is regulated within 45 h by law. Ministry of Health, Labour and Welfare presented a strategy to prevent adverse health effects by severe workload in the year 2002. In that document, the level of fatigue for each worker should be evaluated quantitatively by a simple method such as a self-administered questionnaire.

The purpose of the present study is to evaluate the relationship between workload and complaints by dose-response manner.

Section snippets

Population

The subjects in the present study (n = 109) were car-manufacturing male workers in Gunma Prefecture, Japan. They were categorized into overtime workers who spent an extra 45 h or more in a month for 3 consecutive months and intended to participate in the special health examination. As the ordinal working time was 40 h per week, all subjects worked for more than 50 h a week.

Assessment of Workload and Complaints by Questionnaire

Information on workload and health complaints in the past 3 months was gathered by the self-administered questionnaires. The

Results

Frequency distribution for workload and health complaints is presented in Table 1. When the cut-off point was set at 5/6, the percentage of positive workload was 14.7%. Percentage of feeling stressful to each of the seven items such as overtime work, irregular work, official trip, nighttime work, no rest and/or no nap, mental workload, and physical workload were 62.4, 34.9, 0.9, 23.9, 18.3, 65.1, and 33.9%, respectively.

The relationship between workload and complaints is shown in Figure 1.

Discussion

To identify the relationship between workload and health complaints, a questionnaire survey was conducted. We evaluated the effects of workload on health by logistic regression analysis. Though the estimates for exposure to workload by questionnaire survey may have been affected by the perception of each subject, it seems acceptable and has validity from past research (2).

Workload showed significant associations with health complaints when the total score of the workload was used. Though not

References (9)

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