{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,31]],"date-time":"2026-10-31T17:42:55Z","timestamp":1793468575485,"version":"4.5.0"},"reference-count":34,"publisher":"Cambridge University Press (CUP)","issue":"11","license":[{"start":{"date-parts":[[2022,8,26]],"date-time":"2022-08-26T00:00:00Z","timestamp":1661472000000},"content-version":"unspecified","delay-in-days":0,"URL":"https:\/\/www.cambridge.org\/core\/terms"}],"content-domain":{"domain":["cambridge.org"],"crossmark-restriction":true},"short-container-title":["Br J Nutr"],"published-print":{"date-parts":[[2023,6,14]]},"abstract":"<jats:title>Abstract<\/jats:title><jats:p>Vitamin D seasonality has been reported in adults and children, suggesting that sunlight exposure has effects on 25(OH)D production. While vitamin D deficiency among infants has received significant attention, little is known about the extent to which vitamin D status during early infancy is affected by sunlight exposure. Here, we retrospectively analysed serum 25(OH)D levels of 692 samples obtained from healthy infants aged 1\u20132 months born at Saitama City Hospital, Japan (latitude 35\u00b79\u00b0 North) between August 2017 and September 2021. Data regarding the frequency of outdoor activities, formula intake and BMI were also collected and analysed. Month-to-month comparisons of vitamin D levels revealed significant variation in 25(OH)D levels in breastfed infants starting at 2 months, with maximal and minimal levels in September and January, respectively. An outdoor activity score of 0 was most common at 1 month (83\u00b79 %) and a score of 3 was most common at 2 months (81\u00b72 %), suggesting an increased amount of sunlight exposure at 2 months. Multiple linear regression analysis revealed the amount of formula intake to be significantly associated with vitamin D status at both 1 (<jats:italic>t<\/jats:italic> = 17\u00b796) and 2 months (<jats:italic>t<\/jats:italic> = 16\u00b730). Our results comprise the first evidence that seasonal variation of vitamin D begins at 2 months among breastfed infants from East Asia, though dietary intake appears to be the major determinant of vitamin D status. These findings provide new insights into the influence of dietary and non-dietary factors on vitamin D status during early infancy.<\/jats:p>","DOI":"10.1017\/s0007114522002744","type":"journal-article","created":{"date-parts":[[2022,8,26]],"date-time":"2022-08-26T10:33:22Z","timestamp":1661510002000},"page":"1908-1915","update-policy":"https:\/\/doi.org\/10.1017\/policypage","source":"Crossref","is-referenced-by-count":5,"title":["Seasonal variation in vitamin D status of Japanese infants starts to emerge at 2 months of age: a retrospective cohort study"],"prefix":"10.1017","volume":"129","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-2183-068X","authenticated-orcid":false,"given":"Keigo","family":"Takahashi","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Takeshi","family":"Arimitsu","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kaori","family":"Hara-Isono","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kazushige","family":"Ikeda","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"56","published-online":{"date-parts":[[2022,8,26]]},"reference":[{"key":"S0007114522002744_ref30","doi-asserted-by":"publisher","DOI":"10.1007\/s00198-011-1597-y"},{"key":"S0007114522002744_ref17","doi-asserted-by":"publisher","DOI":"10.1007\/s00774-004-0553-8"},{"key":"S0007114522002744_ref11","doi-asserted-by":"publisher","DOI":"10.1542\/peds.2007-1894"},{"key":"S0007114522002744_ref18","doi-asserted-by":"publisher","DOI":"10.1007\/s00774-011-0264-x"},{"key":"S0007114522002744_ref3","doi-asserted-by":"publisher","DOI":"10.1186\/s13229-020-00399-2"},{"key":"S0007114522002744_ref20","doi-asserted-by":"publisher","DOI":"10.1111\/apa.14155"},{"key":"S0007114522002744_ref24","unstructured":"24. Japan Meterological Agency (2020) Average values of meterological parameters in Saitama, Tokyo, Japan. https:\/\/www.data.jma.go.jp\/obd\/stats\/etrn\/view\/nml_amd_ym.php?prec_no=43&block_no=0363&year=&month=&day=&view= (accessed January 2022)."},{"key":"S0007114522002744_ref28","doi-asserted-by":"publisher","DOI":"10.1038\/sj.ejcn.1600697"},{"key":"S0007114522002744_ref25","doi-asserted-by":"publisher","DOI":"10.3389\/fendo.2019.00103"},{"key":"S0007114522002744_ref29","doi-asserted-by":"publisher","DOI":"10.1371\/journal.pone.0065785"},{"key":"S0007114522002744_ref32","doi-asserted-by":"publisher","DOI":"10.3390\/nu13020573"},{"key":"S0007114522002744_ref33","first-page":"3713","article-title":"The dependency of vitamin D status on body mass index, gender, age and season","volume":"29","author":"Lagunova","year":"2009","journal-title":"Anticancer Res"},{"key":"S0007114522002744_ref34","first-page":"353","article-title":"Dietary intake of vitamin D in obese children aged 1\u20133 years","volume":"66","author":"Struci\u0144ska","year":"2015","journal-title":"Rocz Pa\u0144stwowego Zak\u0142adu Hig"},{"key":"S0007114522002744_ref12","first-page":"267","article-title":"Vitamin D deficiency in healthy breastfed term infants at 3 months and their mothers in India: seasonal variation and determinants","volume":"133","author":"Jain","year":"2011","journal-title":"Indian J Med Res"},{"key":"S0007114522002744_ref4","doi-asserted-by":"publisher","DOI":"10.1001\/jama.2018.5729"},{"key":"S0007114522002744_ref26","doi-asserted-by":"publisher","DOI":"10.1515\/jpem-2018-0275"},{"key":"S0007114522002744_ref22","unstructured":"22. Ministry of Health, Labour and Welfare of Japan (2012) An Evaluation Manual of Growth and Development during Infancy. https:\/\/www.niph.go.jp\/soshiki\/07shougai\/hatsuiku\/index.files\/katsuyou.pdf (accessed January 2022)."},{"key":"S0007114522002744_ref16","doi-asserted-by":"publisher","DOI":"10.1017\/S0007114518002258"},{"key":"S0007114522002744_ref8","doi-asserted-by":"publisher","DOI":"10.1007\/s11154-017-9424-1"},{"key":"S0007114522002744_ref7","doi-asserted-by":"publisher","DOI":"10.1136\/bmj.i6583"},{"key":"S0007114522002744_ref21","first-page":"xxxvii","volume-title":"Vitamin D: Biochemistry, Physiology and Diagnostics","volume":"1","author":"David","year":"2018"},{"key":"S0007114522002744_ref13","doi-asserted-by":"publisher","DOI":"10.1515\/jpem-2016-0223"},{"key":"S0007114522002744_ref9","doi-asserted-by":"publisher","DOI":"10.1016\/B978-0-12-809965-0.00004-5"},{"key":"S0007114522002744_ref6","doi-asserted-by":"publisher","DOI":"10.1016\/j.semcdb.2011.05.004"},{"key":"S0007114522002744_ref23","unstructured":"23. Japan Meteorological Agency (2020) Average values of meterological parameters in Tokyo, Tokyo, Japan. https:\/\/www.data.jma.go.jp\/obd\/stats\/etrn\/view\/nml_sfc_ym.php?prec_no=44&block_no=47662 (accessed January 2022)."},{"key":"S0007114522002744_ref14","doi-asserted-by":"publisher","DOI":"10.1136\/archdischild-2012-302351"},{"key":"S0007114522002744_ref15","doi-asserted-by":"publisher","DOI":"10.1542\/peds.2010-3502"},{"key":"S0007114522002744_ref27","doi-asserted-by":"publisher","DOI":"10.1016\/B978-0-12-809965-0.00040-9"},{"key":"S0007114522002744_ref10","doi-asserted-by":"publisher","DOI":"10.1016\/j.jsbmb.2017.01.023"},{"key":"S0007114522002744_ref31","doi-asserted-by":"publisher","DOI":"10.1016\/j.bone.2006.05.010"},{"key":"S0007114522002744_ref1","doi-asserted-by":"publisher","DOI":"10.1097\/MPG.0b013e31828f3c05"},{"key":"S0007114522002744_ref2","doi-asserted-by":"publisher","DOI":"10.1111\/nbu.12108"},{"key":"S0007114522002744_ref5","doi-asserted-by":"publisher","DOI":"10.1079\/BJN20051544"},{"key":"S0007114522002744_ref19","first-page":"1563","article-title":"Assessment of vitamin D sufficiency in breastfed infants in one area in northern Japan","volume":"122","author":"Tomimoto","year":"2018","journal-title":"J Jpn Pediatr Soc"}],"container-title":["British Journal of Nutrition"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.cambridge.org\/core\/services\/aop-cambridge-core\/content\/view\/S0007114522002744","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2023,5,12]],"date-time":"2023-05-12T11:54:53Z","timestamp":1683892493000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.cambridge.org\/core\/product\/identifier\/S0007114522002744\/type\/journal_article"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2022,8,26]]},"references-count":34,"journal-issue":{"issue":"11","published-print":{"date-parts":[[2023,6,14]]}},"alternative-id":["S0007114522002744"],"URL":"https:\/\/doi.org\/10.1017\/s0007114522002744","relation":{},"ISSN":["0007-1145","1475-2662"],"issn-type":[{"value":"0007-1145","type":"print"},{"value":"1475-2662","type":"electronic"}],"subject":[],"published":{"date-parts":[[2022,8,26]]},"assertion":[{"value":"\u00a9 The Author(s), 2022. Published by Cambridge University Press on behalf of The Nutrition Society","name":"copyright","label":"Copyright","group":{"name":"copyright_and_licensing","label":"Copyright and Licensing"}}]}}