Vitamin D sufficiency is associated with low incidence of limb and vertebral fractures in community-dwelling elderly Japanese women: the Muramatsu Study - Nakamura, K; Saito, T; Oyama, M; Oshiki, R; Kobayashi, R; Nishiwaki, T; Nashimoto, M; Tsuchiya, Y (Osteoporos Int, 2011)