Utako Okamoto was married to Shosuke Okamoto and at her death was survived by one daughter, Kumi Nakamura.
She had one miscarriage, which she said was not related to overworking but "coming home late from work".
Ian Roberts, Professor of Epidemiology and Public Health at the London School of Hygiene & Tropical Medicine who had been coordinating the 2010 trauma trial visited Okamoto, then about 92 in Japan. He said that he "found a fascinating character, really lively and vigorous and still very much engaged with research, meeting with researchers, and reading journal articles".