[The effect of chronic health conditions on work performance in Japanese companies].

Chronic disease has a significant impact on workers' productivity. The aim of this study was to determine the prevalence of chronic health conditions, the work impairment score, and the total lost working hours absent at companies in Japan. Eligible participants were all 544 workers of 4 manufacturing companies in the Kanto area. The Stanford Presenteeism Scale that was developed by Merck & Co., Inc and Stanford University was translated into Japanese and was given to the workers at a periodic health examination between April and June 2006. A total of 433 workers completed the questionnaire, and 48.9% of the participants reported having one or more chronic health conditions which affected their work performance. Allergy (13.3%) was the highest primary chronic health condition followed by back/neck disorders (9.7%). The work impairment score was higher for individuals with depression and migraine/chronic headache. The total lost working hours due to the primary chronic health conditions were 1.4% of the total working hours among the participants. The total lost working hours was highest for those with allergy followed by back/neck disorders and depression. These results should make it possible to develop an occupational health program that can reduce the effects of chronic health conditions on work performance.