{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,7]],"date-time":"2026-03-07T02:14:43Z","timestamp":1772849683512,"version":"3.50.1"},"reference-count":59,"publisher":"Wiley","issue":"8","license":[{"start":{"date-parts":[[2022,4,28]],"date-time":"2022-04-28T00:00:00Z","timestamp":1651104000000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by-nc\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100004954","name":"Augustinus Fonden","doi-asserted-by":"publisher","id":[{"id":"10.13039\/501100004954","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["American J Hum Biol"],"published-print":{"date-parts":[[2022,8]]},"abstract":"<jats:title>Abstract<\/jats:title><jats:sec><jats:title>Objectives<\/jats:title><jats:p>Ethnic groups differ in prevalence of calcium\u2010related diseases. Differences in the physiology and the endogenous circadian rhythm (CR) of calcium and bone homeostasis may play a role. Thus, we aimed to investigate details of CR pattern in calcium and bone homeostasis in East African Maasai.<\/jats:p><\/jats:sec><jats:sec><jats:title>Methods<\/jats:title><jats:p>Ten clinically healthy adult Maasai men and women from Tanzania were examined. Blood samples were collected every 2nd hour for 24\u2009h. Serum levels of total calcium, albumin, parathyroid hormone (PTH), 25(OH)D, creatinine, C\u2010terminal telopeptide (CTX), bone\u2010specific alkaline phosphatase (BSAP), procollagen type 1\u2009N\u2010terminal propeptide (P1NP), and osteocalcin were measured. Circadian patterns were derived from graphic curves of medians, and rhythmicity was assessed with Fourier analysis.<\/jats:p><\/jats:sec><jats:sec><jats:title>Results<\/jats:title><jats:p>PTH\u2010levels varied over the 24\u2009h exhibiting a bimodal pattern. Nadir level corresponded to 65% of total 24\u2010h mean. CTX and P1NP showed 24\u2010h variations with a morning nadir and nocturnal peak with nadir levels corresponding to 23% and 79% of the 24\u2010h mean, respectively. Albumin\u2010corrected calcium level was held in a narrow range and alterations were corresponding to alterations in PTH. There was no distinct pattern in 24\u2010h variations of 25(OH)D, creatinine, osteocalcin, or BSAP.<\/jats:p><\/jats:sec><jats:sec><jats:title>Conclusions<\/jats:title><jats:p>All participants showed pronounced 24\u2010h variations in PTH and bone turnover markers CTX and P1NP. These findings support that Maasai participants included in this study have typical patterns of CR in calcium and bone homeostasis consistent with findings from other ethnic populations.<\/jats:p><\/jats:sec>","DOI":"10.1002\/ajhb.23756","type":"journal-article","created":{"date-parts":[[2022,4,28]],"date-time":"2022-04-28T11:49:04Z","timestamp":1651146544000},"update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":6,"title":["The circadian rhythm of calcium and bone homeostasis in Maasai"],"prefix":"10.1002","volume":"34","author":[{"given":"Anne","family":"Schou","sequence":"first","affiliation":[{"name":"Diabetes and Bone\u2010Metabolic Research Unit, Department of Endocrinology Rigshospitalet  Copenhagen Denmark"},{"name":"Department of Public Health, Global Health Section University of Copenhagen  Copenhagen Denmark"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Niklas Rye","family":"J\u00f8rgensen","sequence":"additional","affiliation":[{"name":"Department of Clinical Biochemistry Rigshospitalet Glostrup  Copenhagen Denmark"},{"name":"Faculty of Health Sciences University of Copenhagen  Copenhagen Denmark"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Venance Phillip","family":"Maro","sequence":"additional","affiliation":[{"name":"Department of Internal Medicine Kilimanjaro Christian Medical University College  Moshi Tanzania"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Kajiru","family":"Kilonzo","sequence":"additional","affiliation":[{"name":"Department of Internal Medicine Kilimanjaro Christian Medical University College  Moshi Tanzania"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Kaushik","family":"Ramaiya","sequence":"additional","affiliation":[{"name":"Department of Internal Medicine Shree Hindu Mandal Hospital  Dar es Salaam Tanzania"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Joseph","family":"Sironga","sequence":"additional","affiliation":[{"name":"Department of Internal Medicine Kilimanjaro Christian Medical University College  Moshi Tanzania"},{"name":"Department of Internal Medicine Monduli District Hospital  Monduli Tanzania"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Andreas Kryger","family":"Jensen","sequence":"additional","affiliation":[{"name":"Department of Public Health, Global Health Section University of Copenhagen  Copenhagen Denmark"},{"name":"Faculty of Health Sciences University of Copenhagen  Copenhagen Denmark"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2142-522X","authenticated-orcid":false,"given":"Dirk Lund","family":"Christensen","sequence":"additional","affiliation":[{"name":"Department of Public Health, Global Health Section University of Copenhagen  Copenhagen Denmark"},{"name":"Faculty of Health Sciences University of Copenhagen  Copenhagen Denmark"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Peter","family":"Schwarz","sequence":"additional","affiliation":[{"name":"Diabetes and Bone\u2010Metabolic Research Unit, Department of Endocrinology Rigshospitalet  Copenhagen Denmark"},{"name":"Faculty of Health Sciences University of Copenhagen  Copenhagen Denmark"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"311","published-online":{"date-parts":[[2022,4,28]]},"reference":[{"key":"e_1_2_10_2_1","doi-asserted-by":"publisher","DOI":"10.1016\/s8756-3282(02)00952-3"},{"key":"e_1_2_10_3_1","volume-title":"The Last of The Maasai","author":"Amin M.","year":"1987"},{"issue":"4","key":"e_1_2_10_4_1","first-page":"297","article-title":"Magnitude and pattern of osteoporotic fractures among adults in Tigiray, Ethiopia; a retrospective hospital based study","volume":"50","author":"Bayray A.","year":"2012","journal-title":"Ethiopian Medical Journal"},{"key":"e_1_2_10_5_1","doi-asserted-by":"publisher","DOI":"10.1007\/s001980170156"},{"key":"e_1_2_10_6_1","volume-title":"Primer on the Metabolic Bone Diseases and Disorders of Mineral Metabolism","author":"Bilezikian J. 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