{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,16]],"date-time":"2026-02-16T16:11:46Z","timestamp":1771258306710,"version":"3.50.1"},"reference-count":41,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2026,2,16]],"date-time":"2026-02-16T00:00:00Z","timestamp":1771200000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Medicina"],"abstract":"<jats:p>Background and Objectives: Variations in serum 25-hydroxyvitamin D [25(OH)D] concentrations have been described among individuals working in different settings. Moreover, published evidence suggests an association between Obstructive Sleep Apnea Syndrome (OSAS) and 25(OH)D insufficiency. The aim of this study was to assess the association between certain exposures in the occupational environment and 25(OH)D levels, in relation to OSAS severity. Materials and Methods: For a period of 12 months, 25(OH)D serum levels were assessed in subjects consecutively investigated for OSAS. These were divided into group A (control subjects working indoors), group B (control subjects working outdoors), group C (OSAS patients working indoors) and group D (OSAS patients working outdoors). Results: A total of 189 subjects were included (155 males and 34 females), comprising 129 OSAS patients and 60 non-apnoeic controls. Serum 25(OH)D levels were significantly higher in group B compared to the other groups (32 \u00b1 13 vs. 23 \u00b1 7 ng\/mL for group A, p = 0.001; vs. 15 \u00b1 8 ng\/mL for group C, p &lt; 0.001; and vs. 23 \u00b1 9 ng\/mL for group D, p &lt; 0.001). Additionally, serum 25(OH)D levels were higher in group A compared with group C (23 \u00b1 7 vs. 15 \u00b1 8 ng\/mL, p = 0.001), while no significant difference was observed between groups A and D (p &gt; 0.05). Regression analysis revealed that the apnoea\u2013hypopnoea index (\u03b2 = 0.02, OR = 1.02, 95% CI: 1.00\u20131.04, p = 0.02) and indoor occupation (\u03b2 = 1.03, OR = 2.80, 95% CI: 1.17\u20136.70, p = 0.02) were independently associated with vitamin D insufficiency. Conclusions: Serum 25(OH)D levels are decreased in OSAS patients working indoors. Thus, the working environment should also be considered in the overall assessment of 25(OH)D status in OSAS patients.<\/jats:p>","DOI":"10.3390\/medicina62020388","type":"journal-article","created":{"date-parts":[[2026,2,16]],"date-time":"2026-02-16T14:55:47Z","timestamp":1771253747000},"page":"388","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Indoor Employment as a Factor Associated with Vitamin D Levels in Obstructive Sleep Apnoea Syndrome"],"prefix":"10.3390","volume":"62","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-0381-4715","authenticated-orcid":false,"given":"Evangelia","family":"Nena","sequence":"first","affiliation":[{"name":"Laboratory of Social Medicine, Medical School, Democritus University of Thrace, 68100 Alexandroupolis, Greece"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Kostas","family":"Archontogeorgis","sequence":"additional","affiliation":[{"name":"MSc Program in Sleep Medicine, Medical School, Democritus University of Thrace, 68100 Alexandroupolis, Greece"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Maria","family":"Katsaouni","sequence":"additional","affiliation":[{"name":"MSc Program in Sleep Medicine, Medical School, Democritus University of Thrace, 68100 Alexandroupolis, Greece"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0009-0008-7253-6943","authenticated-orcid":false,"given":"Konstantina","family":"Chadia","sequence":"additional","affiliation":[{"name":"Department of Pneumonology, Medical School, Democritus University of Thrace, 68100 Alexandroupolis, Greece"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3486-8855","authenticated-orcid":false,"given":"Athanasios","family":"Voulgaris","sequence":"additional","affiliation":[{"name":"MSc Program in Sleep Medicine, Medical School, Democritus University of Thrace, 68100 Alexandroupolis, Greece"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7121-6253","authenticated-orcid":false,"given":"Paschalis","family":"Steiropoulos","sequence":"additional","affiliation":[{"name":"MSc Program in Sleep Medicine, Medical School, Democritus University of Thrace, 68100 Alexandroupolis, Greece"},{"name":"Department of Pneumonology, Medical School, Democritus University of Thrace, 68100 Alexandroupolis, Greece"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2026,2,16]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"325","DOI":"10.1378\/chest.07-0040","article-title":"Adult obstructive sleep apnea: Pathophysiology and diagnosis","volume":"132","author":"Patil","year":"2007","journal-title":"Chest"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"70","DOI":"10.1016\/j.smrv.2016.07.002","article-title":"Prevalence of obstructive sleep apnea in the general population: A systematic review","volume":"34","author":"Senaratna","year":"2017","journal-title":"Sleep Med. Rev."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"6572785","DOI":"10.1155\/2018\/6572785","article-title":"Cardiovascular Risk Assessment in a Cohort of Newly Diagnosed Patients with Obstructive Sleep Apnea Syndrome","volume":"2018","author":"Archontogeorgis","year":"2018","journal-title":"Cardiol. Res. Pract."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"1077","DOI":"10.5114\/aoms.2016.61914","article-title":"Obstructive sleep apnea predicts risk of metabolic syndrome independently of obesity: A meta-analysis","volume":"12","author":"Qian","year":"2016","journal-title":"Arch. Med. Sci."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"622","DOI":"10.1097\/JOM.0b013e3181e12b05","article-title":"Work productivity in obstructive sleep apnea patients","volume":"52","author":"Nena","year":"2010","journal-title":"J. Occup. Environ. Med."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"573","DOI":"10.5664\/jcsm.27662","article-title":"Obstructive sleep apnea and risk of motor vehicle crash: Systematic review and meta-analysis","volume":"5","author":"Tregear","year":"2009","journal-title":"J. Clin. Sleep. Med."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"698","DOI":"10.3122\/jabfm.2009.06.090037","article-title":"Vitamin D: An evidence-based review","volume":"22","author":"Kulie","year":"2009","journal-title":"J. Am. Board. Fam. Med."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"3","DOI":"10.1515\/cclm-2016-0264","article-title":"Assessment of vitamin D status\u2014A changing landscape","volume":"55","author":"Herrmann","year":"2017","journal-title":"Clin. Chem. Lab. Med."},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"Cai, Z., Rui, S., Huang, N., Feng, F., and Luo, Y. (2025). The role of vitamin D in sleep regulation: Mechanisms, clinical advances, and future directions. Front. Nutr., 12.","DOI":"10.3389\/fnut.2025.1595813"},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Gao, Q., Kou, T., Zhuang, B., Ren, Y., Dong, X., and Wang, Q. (2018). The association between vitamin D deficiency and sleep disorders: A systematic review and meta-analysis. Nutrients, 10.","DOI":"10.3390\/nu10101395"},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Abboud, M. (2022). Vitamin D supplementation and sleep: A systematic review and meta-analysis of intervention studies. Nutrients, 14.","DOI":"10.3390\/nu14051076"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"1033","DOI":"10.3945\/ajcn.115.120873","article-title":"Vitamin D deficiency in Europe: Pandemic?","volume":"103","author":"Cashman","year":"2016","journal-title":"Am. J. Clin. Nutr."},{"key":"ref_13","first-page":"zpaf077","article-title":"Serum 25-hydroxyvitamin D concentration is associated with device-estimated sleep metrics in healthy young and early middle-aged adults","volume":"6","author":"Hoopes","year":"2025","journal-title":"Sleep"},{"key":"ref_14","first-page":"301","article-title":"Vitamin D Deficiency, Its Role in Health and Disease, and Current Supplementation Recommendations","volume":"117","author":"Pfotenhauer","year":"2017","journal-title":"J. Am. Osteopath. Assoc."},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Sowah, D., Fan, X., Dennett, L., Hagtvedt, R., and Straube, S. (2017). Vitamin D levels and deficiency with different occupations: A systematic review. BMC Public Health, 17.","DOI":"10.1186\/s12889-017-4436-z"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"8468742","DOI":"10.1155\/2018\/8468742","article-title":"Are Shiftwork and Indoor Work Related to D3 Vitamin Deficiency? A Systematic Review of Current Evidences","volume":"2018","author":"Coppeta","year":"2018","journal-title":"J. Environ. Public Health"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"100","DOI":"10.1016\/j.sleep.2017.10.016","article-title":"Vitamin D and obstructive sleep apnea: A systematic review and meta-analysis","volume":"43","author":"Neighbors","year":"2018","journal-title":"Sleep Med."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"563","DOI":"10.1007\/s42000-023-00481-3","article-title":"Obstructive sleep apnea and vitamin D: An updated systematic review and meta-analysis","volume":"22","author":"Loh","year":"2023","journal-title":"Hormones"},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Archontogeorgis, K., Economou, N.T., Bargiotas, P., Nena, E., Voulgaris, A., Chadia, K., Trakada, G., Romigi, A., and Steiropoulos, P. (2024). Sleepiness and Vitamin D Levels in Patients with Obstructive Sleep Apnea. Healthcare, 12.","DOI":"10.20944\/preprints202402.1448.v1"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"311","DOI":"10.1016\/j.smrv.2013.07.001","article-title":"The link between vitamin D metabolism and sleep medicine","volume":"18","author":"McCarty","year":"2014","journal-title":"Sleep Med. Rev."},{"key":"ref_21","doi-asserted-by":"crossref","unstructured":"World Medical Association (2013). World Medical Association Declaration of Helsinki: Ethical principles for medical research involving human subjects. JAMA, 310, 2191\u20132194.","DOI":"10.1001\/jama.2013.281053"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"91","DOI":"10.1055\/s-2004-829632","article-title":"Greek version of the Epworth Sleepiness Scale","volume":"8","author":"Tsara","year":"2004","journal-title":"Sleep Breath."},{"key":"ref_23","unstructured":"Berry, R.B., Brooks, R., Gamaldo, C., Harding, S.M., Lloyd, R.M., Quan, S.F., Troester, M.T., and Vaughn, B.V. (2017). The AASM Manual for the Scoring of Sleep and Associated Events: Rules, Terminology and Technical Specifications, American Academy of Sleep Medicine. Version 2.4."},{"key":"ref_24","doi-asserted-by":"crossref","unstructured":"(1999). Sleep-related breathing disorders in adults: Recommendations for syndrome definition and measurement techniques in clinical research. The Report of an American Academy of Sleep Medicine Task Force. Sleep, 22, 667\u2013689.","DOI":"10.1093\/sleep\/22.5.667"},{"key":"ref_25","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_26","doi-asserted-by":"crossref","first-page":"e085080","DOI":"10.1136\/bmjopen-2024-085080","article-title":"Is there an association between serum 25-hydroxyvitamin D concentrations and obstructive sleep apnoea? A cross-sectional analysis of NHANES 2007\u20132008 data","volume":"14","author":"Li","year":"2024","journal-title":"BMJ Open"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"53","DOI":"10.1007\/s11325-024-03167-1","article-title":"Serum 25(OH)D levels and obstructive sleep apnea syndrome severity in patients without comorbidities: A systematic review and meta-analysis","volume":"29","author":"Serafin","year":"2024","journal-title":"Sleep Breath."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"28","DOI":"10.1186\/s40557-014-0028-x","article-title":"Vitamin D status and associated occupational factors in Korean wage workers: Data from the 5th Korea national health and nutrition examination survey (KNHANES 2010\u20132012)","volume":"26","author":"Jeong","year":"2014","journal-title":"Ann. Occup. Environ. Med."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"51","DOI":"10.4161\/derm.24494","article-title":"Sunlight and Vitamin D: A global perspective for health","volume":"5","author":"Wacker","year":"2013","journal-title":"Dermato-Endocrinol."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"7","DOI":"10.4103\/2229-516X.149220","article-title":"Prevalence of vitamin D deficiency in north-west Punjab population: A cross-sectional study","volume":"5","author":"Bachhel","year":"2015","journal-title":"Int. J. Appl. Basic. Med. Res."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"870","DOI":"10.1016\/S0899-9007(99)00208-7","article-title":"Serum 25-hydroxyvitamin D levels in active women of middle and advanced age in a rural community in Japan","volume":"15","author":"Nakamura","year":"1999","journal-title":"Nutrition"},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"157","DOI":"10.1210\/jc.2002-020978","article-title":"Body fat content and 25-hydroxyvitamin D levels in healthy women","volume":"88","author":"Arunabh","year":"2003","journal-title":"J. Clin. Endocrinol. Metab."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"256","DOI":"10.1111\/j.1445-5994.2009.01900.x","article-title":"Body mass index determines sunbathing habits: Implications on vitamin D levels","volume":"39","author":"Kull","year":"2009","journal-title":"Intern. Med. J."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"651","DOI":"10.1038\/ijo.2012.112","article-title":"Expression of vitamin D-metabolizing enzymes in human adipose tissue -- the effect of obesity and diet-induced weight loss","volume":"37","author":"Wamberg","year":"2013","journal-title":"Int. J. Obes."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"690","DOI":"10.1093\/ajcn\/72.3.690","article-title":"Decreased bioavailability of vitamin D in obesity","volume":"72","author":"Wortsman","year":"2000","journal-title":"Am. J. Clin. Nutr."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"90","DOI":"10.1007\/s12020-008-9051-4","article-title":"Vitamin D(3) in fat tissue","volume":"33","author":"Blum","year":"2008","journal-title":"Endocrine"},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"1444","DOI":"10.1038\/oby.2011.404","article-title":"Volumetric dilution, rather than sequestration best explains the low vitamin D status of obesity","volume":"20","author":"Drincic","year":"2012","journal-title":"Obesity"},{"key":"ref_38","doi-asserted-by":"crossref","unstructured":"Rybchyn, M.S., Abboud, M., Puglisi, D.A., Gordon-Thomson, C., Brennan-Speranza, T.C., Mason, R.S., and Fraser, D.R. (2020). Skeletal muscle and the maintenance of vitamin D status. Nutrients, 12.","DOI":"10.20944\/preprints202008.0685.v1"},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"nzz087","DOI":"10.1093\/cdn\/nzz087","article-title":"The role of skeletal muscle in maintaining vitamin D status in winter","volume":"3","author":"Mason","year":"2019","journal-title":"Curr. Dev. Nutr."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"144","DOI":"10.1164\/ajrccm.157.1.9706079","article-title":"Effects of age on sleep apnea in men: I. Prevalence and severity","volume":"157","author":"Bixler","year":"1998","journal-title":"Am. J. Respir. Crit. Care Med."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"265","DOI":"10.1111\/j.1365-2265.2005.02226.x","article-title":"Vitamin D and the elderly","volume":"62","author":"Mosekilde","year":"2005","journal-title":"Clin. Endocrinol."}],"container-title":["Medicina"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1648-9144\/62\/2\/388\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,2,16]],"date-time":"2026-02-16T15:19:16Z","timestamp":1771255156000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1648-9144\/62\/2\/388"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,2,16]]},"references-count":41,"journal-issue":{"issue":"2","published-online":{"date-parts":[[2026,2]]}},"alternative-id":["medicina62020388"],"URL":"https:\/\/doi.org\/10.3390\/medicina62020388","relation":{},"ISSN":["1648-9144"],"issn-type":[{"value":"1648-9144","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,2,16]]}}}