About the Authors

Tomoko Kobayashi

Affiliation Department of Epidemiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan

Etsuji Suzuki

Affiliation Department of Epidemiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan

Tuula Oksanen

Affiliation Centre of Expertise for Development of Work and Organizations, Finnish Institute of Occupational Health, Helsinki, Finland

Ichiro Kawachi

Affiliation Department of Social and Behavioral Sciences, Harvard School of Public Health, Boston, Massachusetts, United States of America

Soshi Takao

s-takao@md.okayama-u.ac.jp

Affiliation Department of Epidemiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan

Competing Interests

The authors have declared that no competing interests exist.

Author Contributions

Conceived and designed the experiments: TK ST. Performed the experiments: TK ST. Analyzed the data: TK. Contributed reagents/materials/analysis tools: TK ST IK ES TO. Wrote the paper: TK ST IK. Reviewed manuscript: IK ES TO. Approved submitting the final version of manuscript: TK ST.