Shin-ichi Toyabe*, Toshiki Shioiri, Hideki Kuwabara, Taroh Endoh, Naohito Tanabe, Toshiyuki Someya and Kouhei Akazawa
* Corresponding author: Shin-ichi Toyabe toyabe@med.niigata-u.ac.jp
BMC Public Health 2006, 6:230 doi:10.1186/1471-2458-6-230