{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,23]],"date-time":"2026-02-23T12:15:23Z","timestamp":1771848923416,"version":"3.50.1"},"reference-count":81,"publisher":"MDPI AG","issue":"24","license":[{"start":{"date-parts":[[2023,12,9]],"date-time":"2023-12-09T00:00:00Z","timestamp":1702080000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Nutrients"],"abstract":"<jats:p>Several studies have reported that vitamin D may modify human reproductive functions; however, the results are conflicting. We aimed to comprehensively evaluate serum vitamin D levels and examine the relationship between serum vitamin D levels and ovarian reserve markers, and immune markers of implantation, in reproductive-aged Japanese women with infertility.in reproductive-aged women with infertility. This cross-sectional, single-center study included reproductive-aged women who underwent preconception screening for fertility. Serum vitamin D levels and reproductive and immune markers were measured. Standard and advanced statistical techniques were used. We observed a statistically significant difference in the seasonal and monthly 25(OH) vitamin D levels; the 25(OH) vitamin D level during winter was the lowest among all seasons. However, there was no linear correlation between 25(OH) vitamin D levels and ovarian reserve markers, such as follicle-stimulating hormone and anti-M\u00fcllerian hormone, or the Th1\/Th2 cell ratio, which is used as an implantation-related immunological marker. In this large-scale study, we evaluated the serum 25(OH) vitamin D concentration in reproductive-aged women with infertility in Japan; however, there was no association between reproductive function and vitamin D levels.<\/jats:p>","DOI":"10.3390\/nu15245059","type":"journal-article","created":{"date-parts":[[2023,12,11]],"date-time":"2023-12-11T13:18:21Z","timestamp":1702300701000},"page":"5059","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":5,"title":["Seasonal Serum 25(OH) Vitamin D Level and Reproductive or Immune Markers in Reproductive-Aged Women with Infertility: A Cross-Sectional Observational Study in East Japan"],"prefix":"10.3390","volume":"15","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-3984-975X","authenticated-orcid":false,"given":"Kuniaki","family":"Ota","sequence":"first","affiliation":[{"name":"Fukushima Medical Center for Children and Women, Fukushima Medical University, 1 Hikarigaoka, Fukushima 960-1295, Japan"},{"name":"Department of Obstetrics and Gynecology, Tokyo Rosai Hospital, Japan Labor Health and Safety Organization, 4-13-21 Ohmori-minami, Ohta-ku, Tokyo 143-0013, Japan"},{"name":"Reproductive Medicine, Kameda IVF Clinic Makuhari, Makuhari Techno Garden D3F, 1-3 Nakase, Mihama-ku, Chiba-City 261-8501, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Junichiro","family":"Mitsui","sequence":"additional","affiliation":[{"name":"Reproductive Medicine, Kameda IVF Clinic Makuhari, Makuhari Techno Garden D3F, 1-3 Nakase, Mihama-ku, Chiba-City 261-8501, Japan"},{"name":"Comprehensive Reproductive Medicine, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Shoko","family":"Katsumata","sequence":"additional","affiliation":[{"name":"Reproductive Medicine, Kameda IVF Clinic Makuhari, Makuhari Techno Garden D3F, 1-3 Nakase, Mihama-ku, Chiba-City 261-8501, Japan"},{"name":"Comprehensive Reproductive Medicine, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yuko","family":"Takayanagi","sequence":"additional","affiliation":[{"name":"Reproductive Medicine, Kameda IVF Clinic Makuhari, Makuhari Techno Garden D3F, 1-3 Nakase, Mihama-ku, Chiba-City 261-8501, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yurie","family":"Nako","sequence":"additional","affiliation":[{"name":"Reproductive Medicine, Kameda IVF Clinic Makuhari, Makuhari Techno Garden D3F, 1-3 Nakase, Mihama-ku, Chiba-City 261-8501, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Makiko","family":"Tajima","sequence":"additional","affiliation":[{"name":"Reproductive Medicine, Kameda IVF Clinic Makuhari, Makuhari Techno Garden D3F, 1-3 Nakase, Mihama-ku, Chiba-City 261-8501, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Akira","family":"Komiya","sequence":"additional","affiliation":[{"name":"Reproductive Medicine, Kameda IVF Clinic Makuhari, Makuhari Techno Garden D3F, 1-3 Nakase, Mihama-ku, Chiba-City 261-8501, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0955-4248","authenticated-orcid":false,"given":"Toshifumi","family":"Takahashi","sequence":"additional","affiliation":[{"name":"Fukushima Medical Center for Children and Women, Fukushima Medical University, 1 Hikarigaoka, Fukushima 960-1295, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5009-3207","authenticated-orcid":false,"given":"Kiyotaka","family":"Kawai","sequence":"additional","affiliation":[{"name":"Reproductive Medicine, Kameda IVF Clinic Makuhari, Makuhari Techno Garden D3F, 1-3 Nakase, Mihama-ku, Chiba-City 261-8501, Japan"},{"name":"Comprehensive Reproductive Medicine, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2023,12,9]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"266","DOI":"10.1056\/NEJMra070553","article-title":"Vitamin D deficiency","volume":"357","author":"Holick","year":"2007","journal-title":"N. Engl. J. Med."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"709","DOI":"10.1016\/j.autrev.2010.06.009","article-title":"Vitamin D and musculoskeletal health, cardiovascular disease, autoimmunity and cancer: Recommendations for clinical practice","volume":"9","author":"Souberbielle","year":"2010","journal-title":"Autoimmun. Rev."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"3015","DOI":"10.1093\/humrep\/des248","article-title":"Relevance of vitamin D in reproduction","volume":"27","author":"Luk","year":"2012","journal-title":"Hum. Reprod."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"312","DOI":"10.1097\/GME.0000000000000312","article-title":"Association between serum 25-hydroxyvitamin D and ovarian reserve in premenopausal women","volume":"22","author":"Jukic","year":"2015","journal-title":"Menopause"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"2450","DOI":"10.1210\/jc.2012-1213","article-title":"The level of serum anti-M\u00fcllerian hormone correlates with vitamin D status in men and women but not in boys","volume":"97","author":"Dennis","year":"2012","journal-title":"J. Clin. Endocrinol. Metab."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"4139","DOI":"10.3390\/nu7064139","article-title":"The Role of Vitamin D in Reproductive Health\u2014A Trojan Horse or the Golden Fleece?","volume":"7","author":"Dabrowski","year":"2015","journal-title":"Nutrients"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"369","DOI":"10.1210\/jc.2018-00750","article-title":"Vitamin D Deficiency Is Associated With Poor Ovarian Stimulation Outcome in PCOS but Not Unexplained Infertility","volume":"104","author":"Butts","year":"2019","journal-title":"J. Clin. Endocrinol. Metab."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"199","DOI":"10.23736\/S0026-4806.18.05946-3","article-title":"Vitamin D improves in-vitro fertilization outcomes in infertile women with polycystic ovary syndrome and insulin resistance","volume":"110","author":"Zhao","year":"2019","journal-title":"Minerva Med."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"208","DOI":"10.1093\/humrep\/det424","article-title":"Vitamin D deficiency may be a risk factor for recurrent pregnancy losses by increasing cellular immunity and autoimmunity","volume":"29","author":"Ota","year":"2014","journal-title":"Hum. Reprod."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"3188","DOI":"10.1002\/eji.201545541","article-title":"1,25-Dihydroxy-vitamin D3 regulates NK-cell cytotoxicity, cytokine secretion, and degranulation in women with recurrent pregnancy losses","volume":"45","author":"Ota","year":"2015","journal-title":"Eur. J. Immunol."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"906","DOI":"10.3109\/09513590.2012.683062","article-title":"Effect of 1,25(OH)2 vitamin D3 on cytokine production by endometrial cells of women with repeated implantation failure","volume":"28","author":"Rajaei","year":"2012","journal-title":"Gynecol. Endocrinol."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"599","DOI":"10.1016\/0960-0760(95)00106-A","article-title":"Immunomodulatory actions of 1,25-dihydroxyvitamin D3","volume":"53","author":"Lemire","year":"1995","journal-title":"J. Steroid Biochem. Mol. Biol."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"252","DOI":"10.1172\/JCI1050","article-title":"Inhibition of IL-12 production by 1,25-dihydroxyvitamin D3. Involvement of NF-kappaB downregulation in transcriptional repression of the p40 gene","volume":"101","author":"Cippitelli","year":"1998","journal-title":"J. Clin. Investig."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"7861","DOI":"10.1073\/pnas.93.15.7861","article-title":"1,25-Dihydroxyvitamin D3 reversibly blocks the progression of relapsing encephalomyelitis, a model of multiple sclerosis","volume":"93","author":"Cantorna","year":"1996","journal-title":"Proc. Natl. Acad. Sci. USA"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"135","DOI":"10.1006\/abbi.2000.1765","article-title":"In vivo upregulation of interleukin-4 is one mechanism underlying the immunoregulatory effects of 1,25-dihydroxyvitamin D3","volume":"377","author":"Cantorna","year":"2000","journal-title":"Arch. Biochem. Biophys."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"338","DOI":"10.1038\/ejcn.2013.268","article-title":"Effect of vitamin D supplementation on cathelicidin, IFN-\u03b3, IL-4 and Th1\/Th2 transcription factors in young healthy females","volume":"68","author":"Das","year":"2014","journal-title":"Eur. J. Clin. Nutr."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"943","DOI":"10.1016\/j.autrev.2016.07.015","article-title":"Humoral and cellular autoimmunity in women with recurrent pregnancy losses and repeated implantation failures: A possible role of vitamin D","volume":"15","author":"Skariah","year":"2016","journal-title":"Autoimmun. Rev."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"713","DOI":"10.1093\/humrep\/15.3.713","article-title":"Cytokine production by maternal lymphocytes during normal human pregnancy and in unexplained recurrent spontaneous abortion","volume":"15","author":"Raghupathy","year":"2000","journal-title":"Hum. Reprod."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"77","DOI":"10.1034\/j.1600-0897.2002.01105.x","article-title":"Expression of intracellular Th1 and Th2 cytokines in women with recurrent spontaneous abortion, implantation failures after IVF\/ET or normal pregnancy","volume":"48","author":"Ng","year":"2002","journal-title":"Am. J. Reprod. Immunol."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"8","DOI":"10.1111\/aji.12493","article-title":"Unexplained Recurrent Miscarriage and Recurrent Implantation Failure: Is There a Place for Immunomodulation?","volume":"76","author":"Mekinian","year":"2016","journal-title":"Am. J. Reprod. Immunol."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"767","DOI":"10.1093\/humrep\/deg156","article-title":"Increased T helper 1 cytokine responses by circulating T cells are present in women with recurrent pregnancy losses and in infertile women with multiple implantation failures after IVF","volume":"18","author":"Ng","year":"2003","journal-title":"Hum. Reprod."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"136","DOI":"10.1016\/S0015-0282(99)00457-4","article-title":"The role of T-helper cytokines in human reproduction","volume":"73","author":"Lim","year":"2000","journal-title":"Fertil. Steril."},{"key":"ref_23","doi-asserted-by":"crossref","unstructured":"Ikemoto, Y., Kuroda, K., Nakagawa, K., Ochiai, A., Ozaki, R., Murakami, K., Jinushi, M., Matsumoto, A., Sugiyama, R., and Takeda, S. (2018). Vitamin D Regulates Maternal T-Helper Cytokine Production in Infertile Women. Nutrients, 10.","DOI":"10.3390\/nu10070902"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"669","DOI":"10.1016\/j.beem.2018.09.014","article-title":"Vitamin D insufficiency: Definition, diagnosis and management","volume":"32","author":"Bouillon","year":"2018","journal-title":"Best. Pract. Res. Clin. Endocrinol. Metab."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"1153","DOI":"10.1210\/jc.2011-2601","article-title":"Guidelines for preventing and treating vitamin D deficiency and insufficiency revisited","volume":"97","author":"Holick","year":"2012","journal-title":"J. Clin. Endocrinol. Metab."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"928","DOI":"10.1017\/S0007114518000491","article-title":"Vitamin D deficiency and insufficiency among US adults: Prevalence, predictors and clinical implications","volume":"119","author":"Liu","year":"2018","journal-title":"Br. J. Nutr."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"150","DOI":"10.1093\/ajcn\/nqz037","article-title":"Vitamin D status in the United States, 2011\u20132014","volume":"110","author":"Herrick","year":"2019","journal-title":"Am. J. Clin. Nutr."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"101017","DOI":"10.1016\/j.eclinm.2021.101017","article-title":"Vitamin D status in Mainland of China: A systematic review and meta-analysis","volume":"38","author":"Liu","year":"2021","journal-title":"EClinicalMedicine"},{"key":"ref_29","doi-asserted-by":"crossref","unstructured":"Hu, Y., Chen, J., Wang, R., Li, M., Yun, C., Li, W., Yang, Y., Piao, J., Yang, X., and Yang, L. (2017). Vitamin D nutritional status and its related factors for Chinese children and adolescents in 2010\u20132012. Nutrients, 9.","DOI":"10.3390\/nu9091024"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"10","DOI":"10.1016\/j.bone.2014.12.064","article-title":"Impact of demographic, environmental, and lifestyle factors on vitamin D sufficiency in 9084 Japanese adults","volume":"74","author":"Nakamura","year":"2015","journal-title":"Bone"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"2775","DOI":"10.1007\/s00198-013-2372-z","article-title":"Profiles of vitamin D insufficiency and deficiency in Japanese men and women: Association with biological, environmental, and nutritional factors and coexisting disorders: The ROAD study","volume":"24","author":"Yoshimura","year":"2013","journal-title":"Osteoporos. Int."},{"key":"ref_32","first-page":"4243","article-title":"Vitamin D in human reproduction: The more, the better? An evidence-based critical appraisal","volume":"21","author":"Vitale","year":"2017","journal-title":"Eur. Rev. Med. Pharmacol. Sci."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"151","DOI":"10.1016\/S0140-6736(02)09417-5","article-title":"Female subfertility","volume":"360","author":"Evers","year":"2002","journal-title":"Lancet"},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1007\/s00774-016-0805-4","article-title":"Assessment criteria for vitamin D deficiency\/insufficiency in Japan: Proposal by an expert panel supported by the Research Program of Intractable Diseases, Ministry of Health, Labour and Welfare, Japan, the Japanese Society for Bone and Mineral Research and the Japan Endocrine Society [Opinion]","volume":"35","author":"Okazaki","year":"2017","journal-title":"J. Bone Min. Metab."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"353","DOI":"10.1111\/aji.12338","article-title":"Immunosuppression with tacrolimus improved reproductive outcome of women with repeated implantation failure and elevated peripheral blood TH1\/TH2 cell ratios","volume":"73","author":"Nakagawa","year":"2015","journal-title":"Am. J. Reprod. Immunol."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"139","DOI":"10.1038\/nm1551","article-title":"A brief history of TH17, the first major revision in the TH1\/TH2 hypothesis of T cell\u2013mediated tissue damage","volume":"13","author":"Steinman","year":"2007","journal-title":"Nat. Med."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"452","DOI":"10.1038\/bmt.2012.244","article-title":"Investigation of the freely available easy-to-use software \u2018EZR\u2019 for medical statistics","volume":"48","author":"Kanda","year":"2013","journal-title":"Bone Marrow Transpl."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"1911","DOI":"10.1210\/jc.2011-0385","article-title":"Evaluation, treatment, and prevention of vitamin D deficiency: An Endocrine Society clinical practice guideline","volume":"96","author":"Holick","year":"2011","journal-title":"J. Clin. Endocrinol. Metab."},{"key":"ref_39","unstructured":"Del Valle, H.B., Yaktine, A.L., Taylor, C.L., and Ross, A.C. (2011). Dietary Reference Intakes for Calcium and Vitamin D, National Academies Press."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"26","DOI":"10.1016\/j.nut.2016.02.024","article-title":"Serum 25-hydroxyvitamin D and metabolic syndrome in a Japanese working population: The Furukawa Nutrition and Health Study","volume":"36","author":"Akter","year":"2017","journal-title":"Nutrition"},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"464","DOI":"10.1007\/s00774-015-0694-y","article-title":"Association between vitamin D status and serum parathyroid hormone concentration and calcaneal stiffness in Japanese adolescents: Sex differences in susceptibility to vitamin D deficiency","volume":"34","author":"Tsugawa","year":"2016","journal-title":"J. Bone Miner. Metab."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"615","DOI":"10.1007\/s00774-011-0264-x","article-title":"High prevalence of hypovitaminosis D in pregnant Japanese women with threatened premature delivery","volume":"29","author":"Shibata","year":"2011","journal-title":"J. Bone Miner. Metab."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"420","DOI":"10.3177\/jnsv.60.420","article-title":"Demographic and lifestyle factors associated with vitamin D status in pregnant Japanese women","volume":"60","author":"Shiraishi","year":"2014","journal-title":"J. Nutr. Sci. Vitaminol."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"525","DOI":"10.1111\/mcn.12063","article-title":"Validity of a self-administered diet history questionnaire for estimating vitamin D intakes of J apanese pregnant women","volume":"11","author":"Shiraishi","year":"2015","journal-title":"Matern. Child Nutr."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"1042","DOI":"10.1111\/jog.13620","article-title":"Effect of prolonged hospitalization for threatened preterm labor on maternal and fetal vitamin D levels","volume":"44","author":"Yonetani","year":"2018","journal-title":"J. Obstet. Gynaecol. Res."},{"key":"ref_46","doi-asserted-by":"crossref","unstructured":"Kanatani, K.T., Nakayama, T., Adachi, Y., Hamazaki, K., Onishi, K., Konishi, Y., Kawanishi, Y., Go, T., Sato, K., and Kurozawa, Y. (2019). High frequency of vitamin D deficiency in current pregnant Japanese women associated with UV avoidance and hypo-vitamin D diet. PLoS ONE, 14.","DOI":"10.1371\/journal.pone.0213264"},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"128","DOI":"10.2152\/jmi.66.128","article-title":"Seasonal variation of serum 25 (OH) vitamin D levels in maternal and umbilical cord blood in Japanese women","volume":"66","author":"Sogawa","year":"2019","journal-title":"J. Med. Investig."},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"99","DOI":"10.1007\/s00774-019-01032-w","article-title":"25-Hydroxyvitamin D profiles and maternal bone mass during pregnancy and lactation in Japanese women","volume":"38","author":"Yoshikata","year":"2020","journal-title":"J. Bone Miner. Metab."},{"key":"ref_49","doi-asserted-by":"crossref","unstructured":"Takaoka, N., Nishida, K., Sairenchi, T., Umesawa, M., Noguchi, R., Someya, K., and Kobashi, G. (2020). Changes in vitamin D status considering hemodilution factors in Japanese pregnant women according to trimester: A longitudinal survey. PLoS ONE, 15.","DOI":"10.1371\/journal.pone.0239954"},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"3540","DOI":"10.1111\/jog.14972","article-title":"Ineffectiveness of antenatal guidance intervention for vitamin D insufficiency and deficiency in pregnant women in Kyoto, Japan","volume":"47","author":"Yamade","year":"2021","journal-title":"J. Obs. Gynaecol. Res."},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"1807","DOI":"10.1007\/s00198-009-0954-6","article-title":"Global vitamin D status and determinants of hypovitaminosis D","volume":"20","author":"Mithal","year":"2009","journal-title":"Osteoporos. Int."},{"key":"ref_52","doi-asserted-by":"crossref","first-page":"23","DOI":"10.1017\/S0007114513001840","article-title":"A systematic review of vitamin D status in populations worldwide","volume":"111","author":"Hilger","year":"2014","journal-title":"Br. J. Nutr."},{"key":"ref_53","doi-asserted-by":"crossref","first-page":"1903","DOI":"10.1007\/s00198-017-3967-6","article-title":"Total 25-hydroxyvitamin D levels predict fracture risk: Results from the 15-year follow-up of the Japanese Population-based Osteoporosis (JPOS) Cohort Study","volume":"28","author":"Tamaki","year":"2017","journal-title":"Osteoporos. Int."},{"key":"ref_54","doi-asserted-by":"crossref","first-page":"302","DOI":"10.1024\/0300-9831.71.5.302","article-title":"Vitamin D insufficiency in Japanese female college students: A preliminary report","volume":"71","author":"Nakamura","year":"2001","journal-title":"Int. J. Vitam. Nutr. Res."},{"key":"ref_55","doi-asserted-by":"crossref","first-page":"620","DOI":"10.1007\/s00774-017-0879-7","article-title":"Optimal vitamin D intake for preventing serum 25-hydroxyvitamin D insufficiency in young Japanese women","volume":"36","author":"Ohta","year":"2018","journal-title":"J. Bone Min. Metab."},{"key":"ref_56","doi-asserted-by":"crossref","first-page":"666687","DOI":"10.3389\/fendo.2021.666687","article-title":"Relationship Between Vitamin D and Hormones Important for Human Fertility in Reproductive-Aged Women","volume":"12","author":"Chu","year":"2021","journal-title":"Front. Endocrinol."},{"key":"ref_57","doi-asserted-by":"crossref","first-page":"1627","DOI":"10.1038\/s41430-021-00880-y","article-title":"Prevalence and predictors of vitamin D deficiency in a nationally representative sample of Australian adolescents and young adults","volume":"75","author":"Dunlop","year":"2021","journal-title":"Eur. J. Clin. Nutr."},{"key":"ref_58","doi-asserted-by":"crossref","first-page":"1588","DOI":"10.1093\/humrep\/dew082","article-title":"International Committee for Monitoring Assisted Reproductive Technologies world report: Assisted Reproductive Technology 2008, 2009 and 2010","volume":"31","author":"Dyer","year":"2016","journal-title":"Hum. Reprod."},{"key":"ref_59","doi-asserted-by":"crossref","first-page":"3","DOI":"10.1002\/rmb2.12358","article-title":"Assisted reproductive technology in Japan: A summary report for 2018 by the Ethics Committee of the Japan Society of Obstetrics and Gynecology","volume":"20","author":"Ishihara","year":"2021","journal-title":"Reprod. Med. Biol."},{"key":"ref_60","doi-asserted-by":"crossref","first-page":"720","DOI":"10.1016\/j.mayocp.2013.05.011","article-title":"Vitamin D for health: A global perspective","volume":"88","author":"Holick","year":"2013","journal-title":"Mayo. Clin. Proc."},{"key":"ref_61","doi-asserted-by":"crossref","unstructured":"Asakura, K., Etoh, N., Imamura, H., Michikawa, T., Nakamura, T., Takeda, Y., Mori, S., and Nishiwaki, Y. (2020). Vitamin D Status in Japanese Adults: Relationship of Serum 25-Hydroxyvitamin D with Simultaneously Measured Dietary Vitamin D Intake and Ultraviolet Ray Exposure. Nutrients, 12.","DOI":"10.3390\/nu12030743"},{"key":"ref_62","doi-asserted-by":"crossref","first-page":"854","DOI":"10.1007\/s00774-018-0984-2","article-title":"A simple questionnaire for the prediction of vitamin D deficiency in Japanese adults (Vitaimn D Deficiency questionnaire for Japanese: VDDQ-J)","volume":"37","author":"Kuwabara","year":"2019","journal-title":"J. Bone Min. Metab."},{"key":"ref_63","doi-asserted-by":"crossref","first-page":"147","DOI":"10.1007\/s00774-004-0553-8","article-title":"Seasonal changes of serum 25-hydroxyvitamin D and intact parathyroid hormone levels in a normal Japanese population","volume":"23","author":"Ono","year":"2005","journal-title":"J. Bone Miner. Metab."},{"key":"ref_64","doi-asserted-by":"crossref","first-page":"577624","DOI":"10.1016\/j.jneuroim.2021.577624","article-title":"Seasonal fluctuations in serum levels of vitamin D in Japanese patients with multiple sclerosis","volume":"357","author":"Niino","year":"2021","journal-title":"J. Neuroimmunol."},{"key":"ref_65","doi-asserted-by":"crossref","first-page":"404","DOI":"10.1093\/ageing\/aft042","article-title":"Seasonality of vitamin D status in older people in Southern Germany: Implications for assessment","volume":"42","author":"Klenk","year":"2013","journal-title":"Age Ageing"},{"key":"ref_66","doi-asserted-by":"crossref","first-page":"41","DOI":"10.1016\/j.jsbmb.2017.12.011","article-title":"Vitamin D: Effects on human reproduction, pregnancy, and fetal well-being","volume":"180","author":"Heyden","year":"2018","journal-title":"J. Steroid Biochem. Mol. Biol."},{"key":"ref_67","doi-asserted-by":"crossref","first-page":"276","DOI":"10.1080\/09637486.2019.1661978","article-title":"Vitamin D, reproductive disorders and assisted reproduction: Evidences and perspectives","volume":"71","author":"Fichera","year":"2020","journal-title":"Int. J. Food Sci. Nutr."},{"key":"ref_68","doi-asserted-by":"crossref","first-page":"725","DOI":"10.1016\/S2213-8587(18)30153-0","article-title":"Association of preconception serum 25-hydroxyvitamin D concentrations with livebirth and pregnancy loss: A prospective cohort study","volume":"6","author":"Mumford","year":"2018","journal-title":"Lancet Diabetes Endocrinol."},{"key":"ref_69","doi-asserted-by":"crossref","first-page":"302","DOI":"10.1016\/j.fertnstert.2017.05.037","article-title":"Association of vitamin D intake and serum levels with fertility: Results from the Lifestyle and Fertility Study","volume":"108","author":"Fung","year":"2017","journal-title":"Fertil. Steril."},{"key":"ref_70","doi-asserted-by":"crossref","first-page":"468","DOI":"10.1159\/000443397","article-title":"Serum levels of 25-hydroxyvitamin D and time to natural pregnancy","volume":"81","author":"Somigliana","year":"2016","journal-title":"Gynecol. Obstet. Investig."},{"key":"ref_71","doi-asserted-by":"crossref","first-page":"862","DOI":"10.1038\/ejcn.2012.18","article-title":"Effects of 25OHD concentrations on chances of pregnancy and pregnancy outcomes: A cohort study in healthy Danish women","volume":"66","author":"Streym","year":"2012","journal-title":"Eur. J. Clin. Nutr."},{"key":"ref_72","doi-asserted-by":"crossref","first-page":"460","DOI":"10.1016\/j.fertnstert.2014.04.046","article-title":"Role of vitamin D in ovarian physiology and its implication in reproduction: A systematic review","volume":"102","author":"Irani","year":"2014","journal-title":"Fertil. Steril."},{"key":"ref_73","doi-asserted-by":"crossref","unstructured":"Moridi, I., Chen, A., Tal, O., and Tal, R. (2020). The Association between Vitamin D and Anti-M\u00fcllerian Hormone: A Systematic Review and Meta-Analysis. Nutrients, 12.","DOI":"10.37766\/inplasy2020.4.0204"},{"key":"ref_74","doi-asserted-by":"crossref","first-page":"816","DOI":"10.1095\/biolreprod.106.054056","article-title":"Effects of 25-Hydroxyvitamin D3 and 1,25-Dihydroxyvitamin D3 on Cytokine Production by Human Decidual Cells1","volume":"75","author":"Evans","year":"2006","journal-title":"Biol. Reprod."},{"key":"ref_75","doi-asserted-by":"crossref","first-page":"4974","DOI":"10.4049\/jimmunol.167.9.4974","article-title":"1\u03b1,25-Dihydroxyvitamin D3 has a direct effect on naive CD4+ T cells to enhance the development of Th2 cells","volume":"167","author":"Boonstra","year":"2001","journal-title":"J. Immunol."},{"key":"ref_76","doi-asserted-by":"crossref","first-page":"305","DOI":"10.1093\/humrep\/deaa317","article-title":"Definition, diagnostic and therapeutic options in recurrent implantation failure: An international survey of clinicians and embryologists","volume":"36","author":"Cimadomo","year":"2021","journal-title":"Hum. Reprod."},{"key":"ref_77","doi-asserted-by":"crossref","unstructured":"ESHRE Working Group on Recurrent Implantation Failure, Cimadomo, D., de los Santos, M.J., Griesinger, G., Lainas, G., Le Clef, N., McLernon, D.J., Montjean, D., Toth, B., and Vermeulen, N. (2023). ESHRE good practice recommendations on recurrent implantation failure. Hum. Reprod. Open, 2023, hoad023.","DOI":"10.1093\/hropen\/hoad023"},{"key":"ref_78","doi-asserted-by":"crossref","unstructured":"he Guideline Group on Unexplained Infertility, Romualdi, D., Ata, B., Bhattacharya, S., Bosch, E., Costello, M., Gersak, K., Homburg, R., Mincheva, M., and Norman, R.J. (2023). Evidence-based guideline: Unexplained infertility. Hum. Reprod., 38, 1881\u20131890.","DOI":"10.1093\/humrep\/dead150"},{"key":"ref_79","doi-asserted-by":"crossref","first-page":"107","DOI":"10.2188\/jea.16.107","article-title":"Impact of the revision of a nutrient database on the validity of a self-administered food frequency questionnaire (FFQ)","volume":"16","author":"Ishihara","year":"2006","journal-title":"J. Epidemiol."},{"key":"ref_80","doi-asserted-by":"crossref","first-page":"1151","DOI":"10.1016\/j.fertnstert.2020.09.134","article-title":"Testing and interpreting measures of ovarian reserve: A committee opinion","volume":"114","author":"Penzias","year":"2020","journal-title":"Fertil. Steril."},{"key":"ref_81","doi-asserted-by":"crossref","unstructured":"Mrozikiewicz, A.E., O\u017carowski, M., and J\u0119drzejczak, P. (2021). Biomolecular Markers of Recurrent Implantation Failure\u2014A Review. Int. J. Mol. Sci., 22.","DOI":"10.3390\/ijms221810082"}],"container-title":["Nutrients"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-6643\/15\/24\/5059\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T21:36:09Z","timestamp":1760132169000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-6643\/15\/24\/5059"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2023,12,9]]},"references-count":81,"journal-issue":{"issue":"24","published-online":{"date-parts":[[2023,12]]}},"alternative-id":["nu15245059"],"URL":"https:\/\/doi.org\/10.3390\/nu15245059","relation":{},"ISSN":["2072-6643"],"issn-type":[{"value":"2072-6643","type":"electronic"}],"subject":[],"published":{"date-parts":[[2023,12,9]]}}}