{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,10]],"date-time":"2026-07-10T22:01:25Z","timestamp":1783720885165,"version":"3.55.0"},"reference-count":23,"publisher":"MDPI AG","issue":"5","license":[{"start":{"date-parts":[[2026,3,6]],"date-time":"2026-03-06T00:00:00Z","timestamp":1772755200000},"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>Background: Small intestinal bacterial overgrowth (SIBO) has been linked to systemic inflammation and vitamin D deficiency, but its independent clinical relevance remains uncertain. Methods: In this cross-sectional study, 162 adults undergoing hydrogen breath testing were evaluated. Serum 25-hydroxyvitamin D [25(OH)D], leukocyte count, red blood cell distribution width\u2014standard deviation (RDW-SD), and C-reactive protein were analyzed. Associations were assessed using unadjusted comparisons and multivariable regression models adjusted for age, sex, and BMI. Hydrogen increment was additionally examined as a continuous variable. Results: In unadjusted analyses, SIBO-positive individuals had lower 25(OH)D levels and higher leukocyte counts. However, after adjustment for age, sex, and BMI, SIBO status was not independently associated with 25(OH)D, leukocyte count, or RDW-SD. BMI was independently associated with leukocyte count, and age with RDW-SD. Hydrogen increment was not correlated with laboratory parameters. Conclusions: SIBO was not independently associated with vitamin D status or systemic hematological markers. Host-related factors, particularly BMI and age, appeared to have a greater influence on laboratory variability than SIBO.<\/jats:p>","DOI":"10.3390\/nu18050859","type":"journal-article","created":{"date-parts":[[2026,3,6]],"date-time":"2026-03-06T17:25:59Z","timestamp":1772817959000},"page":"859","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":2,"title":["Small Intestinal Bacterial Overgrowth and Systemic Laboratory Parameters: A Multivariable Cross-Sectional Analysis"],"prefix":"10.3390","volume":"18","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-4939-1466","authenticated-orcid":false,"given":"Monika","family":"Wa\u015bkow","sequence":"first","affiliation":[{"name":"Institute of Health Sciences, Pomeranian University of Slupsk, 76-200 Slupsk, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7655-2050","authenticated-orcid":false,"given":"Krzysztof S.","family":"Malinowski","sequence":"additional","affiliation":[{"name":"Department of Neurophysiology, Neuropsychology and Neuroinformatics, Medical University of Gdansk, 80-210 Gdansk, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2796-8639","authenticated-orcid":false,"given":"Magdalena","family":"Ta\u0144ska","sequence":"additional","affiliation":[{"name":"Institute of Health Sciences, Pomeranian University of Slupsk, 76-200 Slupsk, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3140-6313","authenticated-orcid":false,"given":"Sebastian","family":"Glowinski","sequence":"additional","affiliation":[{"name":"Institute of Physical Culture, The State Academy of Applied Sciences in Koszalin, 75-582 Koszalin, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5180-7224","authenticated-orcid":false,"given":"Magdalena","family":"Wsz\u0119dyby\u0142-Winklewska","sequence":"additional","affiliation":[{"name":"Institute of Health Sciences, Pomeranian University of Slupsk, 76-200 Slupsk, Poland"},{"name":"Department of Neurophysiology, Neuropsychology and Neuroinformatics, Medical University of Gdansk, 80-210 Gdansk, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,3,6]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Takakura, W., and Pimentel, M. 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