Five-year Stability of Job Characteristics Scale Scores among a Japanese Working Population

Abstract

BACKGROUND: The job characteristics scale of job strain, which combines high job demands and low decision latitude based on Karasek’s model, has been applied to studies on health care and cardiovascular disease. However, little is known about the long-term stability of this scale with exposure of workers to job. We investigated the 5-year intraindividual variation in job characteristics scores among healthy community workers. METHODS: Subjects of the study were 458 community dwelling persons forming part of the Jich Medical School Cohort Study at Yamato (currently, Minami-Uonuma city), Niigata prefecture. The Japanese version of the World Health Organization Multinational Monitoring of Trends and Determinants in Cardiovascular Disease (WHO-MONICA) Psychosocial Study Questionnaire was implemented twice (from 1992 through 1995, and in 1999) to measure job demands and decision latitude levels. Intraclass correlation coefficients were computed to evaluate stability of scores of the questionnaire. RESULTS: Intraclass correlation coefficient of the decision latitude scores was 0.629 (95% confidence interval: 0.564 - 0.686) and that of the job demands scores was 0.551 (0.476 - 0.617). Subgroup analyses by age, sex, education level, years since first employment, number of co-workers, and job category and status at baseline revealed similar results. In contrast, subjects who experienced position changes within the same enterprise or changed jobs showed lower correlation coefficients of both decision latitude and job demands scores compared to those who experienced no change in job contents. CONCLUSION: The Japanese version of the WHO-MONICA Psychosocial Study Questionnaire showed statistically significant long-term stability and could be to some extent responsive to change in job strain levels.

Influence of job strain on changes in body mass index and waist circumference—6-year longitudinal study

“…Prior research showed stability for scores of the job content questionnaire on two occasions, before and after an average interval of 6.6 years among 2490 Europeans who remained in the same job (15). In addition, the scores of the work characteristics for the same persons did not change appreciably over a 5-year interval in Japan (36). However, the Japanese study also found that the scores were less stable when there was a position change even within the same company.…”

Metabolic Syndrome and C-Reactive Protein in the General Population JMS Cohort Study

“…27 Our colleagues have reported lower levels of CRP in Japanese compared with studies conducted in other Western countries, 28 as well as intra-individual stability of CRP levels over an interval of 5 years. 29 In Western countries, MS is associated with mortality in older women, 3 and with CVD in middle-aged 1,4 and elderly people. 2,5 In diabetic patients, the new definition of MS in Japan was not predictive for CVD in either male or female patients in a prospective study, but a positive relationship according to WHO or NCEP-ATP III criteria was documented.…”

Low Control at Work and the Risk of Suicide in Japanese Men: A Prospective Cohort Study

“…The present study related job demands at baseline with suicide during an average 9-year follow-up. As the less stable test-retest reliability indicates [43], job demands can change from time to time. Therefore, this study does not exclude the possibility that workers are at higher risk of suicide when they work extremely long hours or under extremely high job demands.…”

“…Cronbach’s coefficient alphas for the job control index and psychological demand index were 0.65 and 0.69, respectively. Job characteristics were also assessed as part of this cohort during the follow-up, demonstrating a moderate degree of stability with 5-year interval correlations of 0.63 (n = 377) for job control and 0.57 (n = 378) for job demands [43]. The variables were divided in such a way that the most adverse tertile indicated low control or high demands.…”

“…For those not offered physical examinations at their workplace, such as workers with preindustrial occupations or those who are self-employed, the mass screening examination program is an opportunity to have their health status determined. As part of this cohort, we inferred from repeated surveys that changes in occupation or job position are not frequent in the rural settings included here [43]. Some part-time employees might have been included in the study population, but this was not ascertained.…”