[1] Teikyo Univ, Sch Med, Dept Publ Hlth, Itabashi Ku, Tokyo 1738605, Japan
[2] Univ Tokyo, Fac Med, Dept Publ Hlth, Tokyo 113, Japan
[3] Inagaki Clin, Tokyo, Japan
[4] Harvard Univ, Sch Publ Hlth, Robert B Brigham Multiple Arthrit & Musculoskelet, Boston, MA 02115 USA