1. Graduate School of Technology, Industrial and Social Sciences, Tokushima University, Tokushima, Japan.
2. Department of Environmental Medicine and Public Health, Faculty of Medicine, Shimane University, Shimane, Japan.
3. Unit of Public Health and Preventive Medicine, School of Medicine, Yokohama City University, Yokohama, Japan.
4. Department of Epidemiology, Fukushima Medical University, Fukushima, Japan.
5. Teikyo University Graduate School of Public Health, Tokyo, Japan.