女子栄養大学

Japan is an iodine-replete country without iodine fortification. To characterize the current iodine status and thyroid function in healthy adults, a nationwide cross-sectional observational survey was conducted between 2016 and 2023. Iodine concentration in urine (UIC), serum and scalp hair as well as serum TSH, FT4 and FT3 concentrations, thyroid antibody (ThAb), thyroid volume by sonography, dietary iodine intake by diet study and anthropometry were evaluated. A total of 2,845 adults with the mean age of 45.6 years were recruited from 20 regions across Japan. The median UIC (mUIC) was 295.0 μg/L and within the WHO’s adequacy range of iodine intake. There was a regional difference in indices of iodine status, thyroid function and prevalence of ThAb positivity throughout all of the regions. The mUIC was lowest in Tanegashima Island (169 μg/L) and highest in Fukui (943 μg/L). The highest median TSH (2.11 μIU/mL) with the lowest FT4 (1.22 ng/dL) was observed in Ishikawa, Hokuriku while the lowest TSH (1.06 μIU/mL) was in Rebun Island, Hokkaido although the median values of TSH, FT4 and FT3 were within their reference range. The prevalence of ThAb positivity was 12.6%. A significant positive correlation was observed only between mUIC and median TSH. Japanese adults consume more iodine than the average intake of other ethnic groups and there were some areas with high iodine intake. Current average iodine intake was estimated to be 400 μg per day in this study population. A large-scaled epidemiological survey is required in future.

Achieving sustainable food systems that align with planetary and human health goals requires assessments of dietary patterns, supply structures, and environmental impacts. This study presents the first comprehensive evaluation of Japan’s food system, using the EAT-Lancet Healthy Reference Diet (EHRD) as a benchmark. First, this study developed an adjusted version of the EHRD for Japan, accounting for sex- and age-specific energy requirements, and calculated three sufficiency rates using the National Health and Nutrition Survey and the Food Balance Sheet in Japan: intake sufficiency rate (ISR), supply sufficiency rate (SSR), and food self-sufficiency rate (FSR). Second, the environmental impacts of transitioning to EHRD were evaluated using four environmental footprint models. Our analysis identifies a dual challenge of the current Japanese food system: traditional Japanese diet is known for its high consumption of plants, and yet there is a persistent deficit in the consumption and supply of recommended plant-based foods (e.g., legumes, fruits), alongside a severe oversupply and overconsumption of red meat sustained by imports. Results further show that shifting Japanese adults’ diets toward the EHRD would reduce CO2 emissions, water use, and relevant biodiversity impacts, while the direction and magnitude of change vary by food group. The findings also highlight telecoupling: given Japan’s heavy dependence on global supply chains, an EHRD transition would shift some environmental burdens abroad—potentially increasing impacts for under-consumed, import-dependent items (e.g., legumes, fruits, nuts) while alleviating pressures through reduced red meat consumption. Based on these findings, the study proposes three policy implications, including the development of a culturally acceptable dietary guideline, price interventions for recommended foods, and a reevaluation of the animal protein supply chain, including feed sustainability. Our results provide an evidence-based foundation for designing a unique path toward a healthier and more sustainable food system in Japan.

STUDY QUESTION:What updates of the International Glossary on Infertility and Fertility Care are required, to reflect contemporary scientific knowledge, social needs, and inclusive definitions, while harmonizing international communication across clinical, research, policy, and public domains? SUMMARY ANSWER:This 4th edition presents 348 consensus-based terms and definitions, including numerous revisions from the previous edition and 79 newly introduced definitions reflecting advances in reproductive science, technology, and evolving social contexts. WHAT IS KNOWN ALREADY:Previous glossary editions (2006, 2009, 2017) established internationally recognized definitions related to clinical practice, research, and policy. The 2017 edition comprised 283 terms and, among many others, expanded the concept of infertility to include not only its recognition as a disease, but also as an impairment of function generating disability. The glossary has been extensively used worldwide and has contributed to international standardization of data collection, appropriate comparison of outcome measures, and provided a reference for all stakeholders including policy makers. STUDY DESIGN, SIZE, DURATION:Under guidance of the organizing committee, 21 professionals from across the world, and representing expertise in different sub-specialties, formed five working groups: clinical definitions; outcome measures; embryology laboratory; clinical and laboratory andrology; and epidemiology, public health and gender related definitions. The definitions from the previous glossary were evaluated and new terms identified. All definitions were then reviewed by an international advisory panel of nine experts that evaluated the glossary from scientific, ethical, cultural, and policy perspectives. PARTICIPANTS/MATERIALS, SETTING, METHODS:Between November 2024 and October 2025, periodical virtual meetings were held within and between working groups and the organizing committee. Following circulation of the first consensually agreed draft, a one-day in-person meeting with representatives of all working groups and members of the international advisory panel was held at ESHRE, June 2025. Most terms and definitions were discussed and agreed. In the absence of agreement, further discussions were held between the organizing committee, working group chairs and members of the advisory panel. It had been determined at the outset that final disagreement would be resolved via a two-third majority vote. All terms and definitions were, however, reached by consensus and adopted following a final round of review and approval by all authors. MAIN RESULTS AND THE ROLE OF CHANCE:The glossary now includes 348 terms. Compared to the previous edition, 14 terms were deleted, numerous terms modified and 79 new terms were added. Modifications reflect current scientific knowledge, technological advancements, and inclusivity related to gender and family structures. Chance does not play a role, as all definitions are consensus-based. LIMITATIONS, REASONS FOR CAUTION:Some terms may require future refinement as scientific knowledge evolves and societal contexts change. The glossary reflects consensus rather than empirical testing of all definitions. WIDER IMPLICATIONS OF THE FINDINGS:This glossary provides a global reference for standardized terminology, supporting clinical care, research, international comparisons, policy making, patient communication, and reproductive health literacy. STUDY FUNDING/COMPETING INTEREST(S):Neither ICMART, responsible for conducting this project, nor any of the participants received specific financial support for their activities in this project. Ferring provided ICMART with a fixed amount to cover venue costs and a one-day hotel accommodation for participants attending the in-person meeting held prior to the ESHRE Congress in June 2025. Disclosures were provided by all authors, and none reported any conflict of interest related to this manuscript. TRIAL REGISTRATION NUMBER:N/A.

Context:The association of iodine nutritional status with thyroid function in iodine-replete countries is controversial and more sensitive biomarkers than urinary iodine concentration is required. Objective:To evaluate the use of scalp hair and serum iodine concentration as measure of iodine status through their association with thyroid indices. Methods:A nationwide survey was conducted between 2016 and 2023. Iodine concentration in serum (SIC), hair (HIC), urine (UIC) and estimated 24-hour urinary iodine excretion (eUIE), dietary iodine intake (DII) as well as serum TSH, FT4, and FT3 concentrations, thyroid antibody (ThAb) was measured in Japanese adults. Results:The median UIC in 2771 adults was 295.0 μg/L and within the WHO's adequacy range of iodine intake. The high iodine intake assessed by UIC, eUIE and SIC was associated with higher TSH and lower thyroid hormone levels. Urinary iodine concentration, eUIE and DII were higher in the group with a high TSH level. The subjects with positive ThAbs had significantly higher SIC, DII, TSH and slightly lower FT4 levels. The median HIC correlated positively but weakly with SIC, eUIE and DII, while SIC correlated modestly with eUIE, UIC and weakly with DII. The 5th percentile of the SIC reference (49.9 μg/L) coincided with the threshold value of median UIC (<100 μg/L) for iodine deficiency by WHO. Conclusion:Higher iodine intake results in changes of TSH and thyroid hormones within their referenced range. Serum and hair iodine concentrations might be feasible indicators for a population's iodine intake and further research is needed to validate their availability.