About the Authors

Kyoko Kondo

Roles Conceptualization, Data curation, Formal analysis, Funding acquisition, Methodology, Project administration, Software, Validation, Visualization, Writing – original draft, Writing – review & editing

kyou@med.osaka-cu.ac.jp

Affiliation Osaka City University Hospital Administration Division, Osaka, Japan

Satoko Ohfuji

Roles Conceptualization, Data curation, Formal analysis, Methodology, Project administration, Software, Validation, Visualization, Writing – review & editing

Affiliation Department of Public Health, Osaka City University Graduate School of Medicine, Osaka, Japan

Kenji Watanabe

Roles Investigation, Methodology, Resources, Writing – review & editing

Affiliations Department of Intestinal Inflammation Research, Hyogo College of Medicine, Hyogo, Japan, Department of Gastroenterology, Osaka City University Graduate School of Medicine, Osaka, Japan

Hirokazu Yamagami

Roles Investigation, Methodology, Resources, Writing – review & editing

Affiliation Department of Gastroenterology, Osaka City University Graduate School of Medicine, Osaka, Japan

Wakaba Fukushima

Roles Conceptualization, Data curation, Formal analysis, Methodology, Software, Validation, Visualization, Writing – review & editing

Affiliation Department of Public Health, Osaka City University Graduate School of Medicine, Osaka, Japan

Kazuya Ito

Roles Data curation, Formal analysis, Software, Validation, Writing – review & editing

Affiliation Department of Public Health, Osaka City University Graduate School of Medicine, Osaka, Japan

Yasuo Suzuki

Roles Conceptualization, Funding acquisition, Investigation, Project administration, Resources, Supervision, Visualization, Writing – review & editing

Affiliation Inflammatory Bowel Disease Center, Toho University Sakura Medical Center, Chiba, Japan

Yoshio Hirota

Roles Conceptualization, Methodology, Supervision, Visualization, Writing – review & editing

Affiliation College of Healthcare Management, Fukuoka, Japan

for the Japanese Case-Control Study Group for Crohn's disease

Membership of the Japanese Case-Control Study Group for Crohn's disease is provided in the Acknowledgments.

Competing Interests

The authors have declared that no competing interests exist.