1. School of Medicine, Faculty of Medicine, Akita University, Akita, Japan
2. Biostatistics Unit, Clinical and Translational Research Center, Keio University Hospital, Tokyo, Japan
3. Department of Environmental Health Science and Public Health, Akita University Graduate School of Medicine, Akita, Japan
4. Laboratory of Plant Physiology, Department of Biological Production, Faculty of Bioresource Science, Akita Prefectural University, Akita City, Akita, Japan
5. Department of Nursing, Faculty of Nursing, Japanese Red Cross Akita College of Nursing, Akita, Japan
6. Department of Gynecology, Akita Red Cross Hospital, Akita, Japan
7. Department of Obstetrics and Gynecology, Akita University Graduate School of Medicine, Akita, Japan