1 Department of Dermatology, The University of Tokyo Graduate School of Medicine, Tokyo, Japan.
2 Department of Dermatology, The University of Tokyo Graduate School of Medicine, and Systemic Sclerosis Center, The University of Tokyo Hospital, Tokyo, Japan. ayuyoshi@me.com.
3 Department of Biostatistics, School of Public Health, Graduate School of Medicine, The University of Tokyo, Japan.
4 Department of Dermatology, The University of Tokyo Graduate School of Medicine, and Systemic Sclerosis Center, The University of Tokyo Hospital, Tokyo, Japan.