{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,27]],"date-time":"2026-10-27T09:56:26Z","timestamp":1793094986957,"version":"4.5.0"},"reference-count":39,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2020,3,20]],"date-time":"2020-03-20T00:00:00Z","timestamp":1584662400000},"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: Although laparoscopic sleeve gastrectomy (LSG) is effective for obesity management, postoperative vitamin B12 (B12) deficiency is of major concern. In this cross-sectional study, we assessed the levels of B12 and its related functional biomarkers, namely, total homocysteine (tHcy), methylmalonic acid (MMA), folate, methylcitric acid (MCA), and hemoglobin (Hb), in one-year postoperative LSG patients and matched controls. Materials and Methods: Plasma B12, tHcy, MMA, folate, and MCA were measured in matched controls (n = 66) and patients (n = 71) using validated liquid chromatography-tandem mass spectrometry techniques and protocols in the United Arab Emirates (UAE). Results: The median B12 concentration in patients (177 pmol\/L) was significantly lower (p &lt; 0.001) than in the controls (334.7 pmol\/L). The tHcy and MMA levels were significantly increased (p &lt; 0.001 and p = 0.011, respectively) and folate levels were significantly decreased (p = 0.001) in the LSG patients compared to the controls. Interestingly, no significant difference in MCA levels were observed between the two groups. The levels of tHcy and MMA were concomitantly increased with the decreased folate levels in postoperative LSG patients when compared with the controls. The Hb levels were significantly lower in males and females in the patient group compared with those in the control group, respectively (p = 0.005 and p = 0.043). Conclusions: This is the first report of serum levels of B12 and its functional biomarkers in postoperative LSG patients among a local population from the UAE. Our findings revealed significant alterations of the B12 biomarkers, total B12, MMA, and tHcy in one-year postoperative LSG patients.<\/jats:p>","DOI":"10.3390\/medicina56030142","type":"journal-article","created":{"date-parts":[[2020,3,20]],"date-time":"2020-03-20T11:42:11Z","timestamp":1584704531000},"page":"142","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":4,"title":["Role of Functional Biomarkers to Identify Early Vitamin B12 Deficiency in Patients with Sleeve Gastrectomy: A Cross-Sectional Study"],"prefix":"10.3390","volume":"56","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-4045-9647","authenticated-orcid":false,"given":"Osama Y.","family":"Al-Dirbashi","sequence":"first","affiliation":[{"name":"Department of Pediatrics, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain 17666, UAE"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Charu","family":"Sharma","sequence":"additional","affiliation":[{"name":"Department of Internal Medicine, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain 17666, UAE"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Nahid","family":"Al Dahouri","sequence":"additional","affiliation":[{"name":"Department of Pediatrics, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain 17666, UAE"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Anas","family":"Al Aidaros","sequence":"additional","affiliation":[{"name":"Department of Pediatrics, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain 17666, UAE"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Shamma","family":"Al-Muhairi","sequence":"additional","affiliation":[{"name":"Ambulatory Medicine (Dep) - Medical Affairs, Tawam Hospital (S.A.M.), Al Ain 17666, UAE"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Rami","family":"Beiram","sequence":"additional","affiliation":[{"name":"Department of Pharmacology, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain 17666, UAE"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Salah","family":"Gariballa","sequence":"additional","affiliation":[{"name":"Department of Internal Medicine, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain 17666, UAE"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2477-0408","authenticated-orcid":false,"given":"Juma","family":"Al Kaabi","sequence":"additional","affiliation":[{"name":"Department of Internal Medicine, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain 17666, UAE"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2020,3,20]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"88","DOI":"10.1186\/s13098-017-0287-0","article-title":"Prevalence of overweight and obesity in United Arab Emirates Expatriates: The UAE National Diabetes and Lifestyle Study","volume":"9","author":"Sulaiman","year":"2017","journal-title":"Diabetol Metab Syndr."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"1724","DOI":"10.1001\/jama.292.14.1724","article-title":"Bariatric surgery: A systematic review and meta-analysis","volume":"292","author":"Buchwald","year":"2004","journal-title":"JAMA"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"547","DOI":"10.7326\/0003-4819-142-7-200504050-00013","article-title":"Meta-analysis: Surgical treatment of obesity","volume":"142","author":"Maggard","year":"2005","journal-title":"Ann. Intern. Med."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"1171","DOI":"10.1007\/s11695-010-0145-8","article-title":"A review of laparoscopic sleeve gastrectomy for morbid obesity","volume":"20","author":"Shi","year":"2010","journal-title":"Obes. Surg."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"189","DOI":"10.1016\/j.soard.2006.10.013","article-title":"Laparoscopic sleeve gastrectomy for morbid obesity: A review","volume":"3","author":"Aggarwal","year":"2007","journal-title":"Surg. Obes. Relat. Dis."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"271","DOI":"10.1007\/s11695-009-0038-x","article-title":"Laparoscopic sleeve gastrectomy as a single-stage bariatric procedure","volume":"20","author":"Sammour","year":"2010","journal-title":"Obes. Surg."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"330","DOI":"10.1007\/s11695-011-0501-3","article-title":"Laparoscopic sleeve gastrectomy feasible for bariatric revision surgery","volume":"22","author":"Berende","year":"2012","journal-title":"Obes. Surg."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"1202","DOI":"10.1016\/j.soard.2014.08.007","article-title":"Self-report of gastrointestinal side effects after bariatric surgery","volume":"10","author":"Kalarchian","year":"2014","journal-title":"Surg. Obes. Relat. Dis."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"727","DOI":"10.1016\/j.soard.2016.12.018","article-title":"American Society for Metabolic and Bariatric Surgery Integrated Health Nutritional Guidelines for the Surgical Weight Loss Patient 2016 Update: Micronutrients","volume":"13","author":"Parrott","year":"2017","journal-title":"Surg. Obes. Relat. Dis."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"906","DOI":"10.1016\/j.clnu.2018.02.007","article-title":"Early changes in vitamin B12 uptake and biomarker status following Roux-en-Y gastric bypass and sleeve gastrectomy","volume":"38","author":"Kornerup","year":"2019","journal-title":"Clin. Nutr."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"447","DOI":"10.1007\/s11695-009-0068-4","article-title":"Fewer nutrient deficiencies after laparoscopic sleeve gastrectomy (LSG) than after laparoscopic Roux-Y-gastric bypass (LRYGB)-a prospective study","volume":"20","author":"Gehrer","year":"2010","journal-title":"Obes. Surg."},{"key":"ref_12","first-page":"109","article-title":"Prevalence of symptoms and risk of sleep apnea in Dubai, UAE","volume":"6","author":"Mahboub","year":"2013","journal-title":"Int. J. Gen. Med."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"569","DOI":"10.1097\/00075197-200409000-00010","article-title":"Nutrient deficiencies secondary to bariatric surgery","volume":"7","year":"2004","journal-title":"Curr. Opin. Clin. Nutr. Metab. Care"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"299","DOI":"10.3390\/nu2030299","article-title":"Vitamin B12 in Health and Disease","volume":"2","author":"Samman","year":"2010","journal-title":"Nutrients"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"673","DOI":"10.1002\/jimd.12009","article-title":"Vitamin B12, folate, and the methionine remethylation cycle-biochemistry, pathways, and regulation","volume":"42","author":"Froese","year":"2019","journal-title":"J. Inherit. Metab. Dis."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"1057","DOI":"10.1111\/j.1532-5415.2012.03998.x","article-title":"Relationship between vitamin B12 and sensory and motor peripheral nerve function in older adults","volume":"60","author":"Leishear","year":"2012","journal-title":"J. Am. Geriatr. Soc."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"469","DOI":"10.7326\/0003-4819-124-5-199603010-00002","article-title":"Elevated methylmalonic acid and total homocysteine levels show high prevalence of vitamin B12 deficiency after gastric surgery","volume":"124","author":"Sumner","year":"1996","journal-title":"Ann. Intern. Med."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"501","DOI":"10.7326\/0003-4819-101-4-501","article-title":"Vitamin B12 deficiency after gastric bypass surgery for obesity","volume":"101","author":"Schilling","year":"1984","journal-title":"Ann. Intern. Med."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"582","DOI":"10.1111\/apt.12872","article-title":"Review article: The nutritional and pharmacological consequences of obesity surgery","volume":"40","author":"Stein","year":"2014","journal-title":"Aliment. Pharm. Ther."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"S73","DOI":"10.1016\/j.soard.2008.03.002","article-title":"ASMBS Allied Health Nutritional Guidelines for the Surgical Weight Loss Patient","volume":"4","author":"Aills","year":"2008","journal-title":"Surg. Obes. Relat. Dis."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"345","DOI":"10.1038\/nrgastro.2012.76","article-title":"Vitamin B12 transport from food to the body\u2019s cells\u2014A sophisticated, multistep pathway","volume":"9","author":"Nielsen","year":"2012","journal-title":"Nat. Rev. Gastroenterol. Hepatol."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"27","DOI":"10.3389\/fmolb.2016.00027","article-title":"Biomarkers and Algorithms for the Diagnosis of Vitamin B12 Deficiency","volume":"3","author":"Hannibal","year":"2016","journal-title":"Front. Mol. Biosci."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"65","DOI":"10.1007\/8904_2014_321","article-title":"Analysis of Methylcitrate in Dried Blood Spots by Liquid Chromatography-Tandem Mass Spectrometry","volume":"Volume 16","author":"McIntosh","year":"2014","journal-title":"JIMD Report"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"215","DOI":"10.1016\/S1570-0232(02)00293-3","article-title":"Validated capillary gas chromatographic-mass spectrometric assay to determine 2-methylcitric acid I and II levels in human serum by using a pulsed splitless injection procedure","volume":"775","author":"Busch","year":"2002","journal-title":"J. Chromatogr. B Anal. Technol. Biomed. Life Sci."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"30","DOI":"10.1159\/000052767","article-title":"Long-term effects of vitamin B(12), folate, and vitamin B(6) supplements in elderly people with normal serum vitamin B(12) concentrations","volume":"47","author":"Henning","year":"2001","journal-title":"Gerontology"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"1304","DOI":"10.1007\/s12325-019-00955-0","article-title":"Clinical Application of LC-MS\/MS in the Follow-Up for Treatment of Children with Methylmalonic Aciduria","volume":"36","author":"Wang","year":"2019","journal-title":"Adv. Ther."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"978","DOI":"10.1016\/0026-0495(93)90010-L","article-title":"Elevation of 2-methylcitric acid I and II levels in serum, urine, and cerebrospinal fluid of patients with cobalamin deficiency","volume":"42","author":"Allen","year":"1993","journal-title":"Metabolism"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"66","DOI":"10.1111\/j.1532-5415.2004.52012.x","article-title":"Metabolic markers of cobalamin deficiency and cognitive function in normal older adults","volume":"52","author":"Garcia","year":"2004","journal-title":"J. Am. Geriatr. Soc."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"41","DOI":"10.1016\/j.cca.2018.09.017","article-title":"Quantification of methylcitrate in dried urine spots by liquid chromatography tandem mass spectrometry for the diagnosis of propionic and methylmalonic acidemias","volume":"487","author":"Langhans","year":"2018","journal-title":"Clin. Chim. Acta"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"12366","DOI":"10.1038\/s41598-019-48885-9","article-title":"Assessment of methylcitrate and methylcitrate to citrate ratio in dried blood spots as biomarkers for inborn errors of propionate metabolism","volume":"9","author":"Alfadhel","year":"2019","journal-title":"Sci. Rep."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"47","DOI":"10.1016\/j.cca.2013.04.002","article-title":"Biochemical markers of vitamin B12 deficiency combined in one diagnostic parameter: The age-dependence and association with cognitive function and blood hemoglobin","volume":"422","author":"Fedosov","year":"2013","journal-title":"Clin. Chim. Acta"},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"53","DOI":"10.3389\/fmolb.2017.00053","article-title":"Corrigendum: Biomarkers and Algorithms for the Diagnosis of Vitamin B12 Deficiency","volume":"4","author":"Hannibal","year":"2017","journal-title":"Front. Mol. Biosci."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"405","DOI":"10.1097\/01.med.0000244220.53163.85","article-title":"Micronutrient deficiencies and bariatric surgery","volume":"13","author":"Kushner","year":"2006","journal-title":"Curr Opin Endocrinol Diabetes"},{"key":"ref_34","first-page":"979","article-title":"Vitamin B12 deficiency","volume":"67","author":"Oh","year":"2003","journal-title":"Am. Fam. Physician"},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"69","DOI":"10.1381\/096089291765561493","article-title":"Folate Status Following Gastric Bypass Surgery (The Great Folate Mystery)","volume":"1","author":"Mallory","year":"1991","journal-title":"Obes. Surg."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"702S","DOI":"10.3945\/ajcn.2008.26947C","article-title":"Folate-vitamin B-12 interaction in relation to cognitive impairment, anemia, and biochemical indicators of vitamin B-12 deficiency","volume":"89","author":"Selhub","year":"2009","journal-title":"Am. J. Clin. Nutr."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"1700","DOI":"10.1016\/j.clnu.2017.07.008","article-title":"Folate and vitamin B12 status is associated with insulin resistance and metabolic syndrome in morbid obesity","volume":"37","author":"Li","year":"2018","journal-title":"Clin. Nutr."},{"key":"ref_38","doi-asserted-by":"crossref","unstructured":"Ciob\u00e2rc\u0103, D.C.A., Cop\u0103escu, C., and Miere, D.G.C. (2020). Bariatric Surgery in Obesity: Effects on Gut Microbiota and Micronutrient Status. Nutrients, 12.","DOI":"10.3390\/nu12010235"},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"391","DOI":"10.1016\/j.nut.2011.07.012","article-title":"Daily vitamin supplementation and hypovitaminosis after obesity surgery","volume":"28","author":"Donadelli","year":"2012","journal-title":"Nutrition"}],"container-title":["Medicina"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1648-9144\/56\/3\/142\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T09:10:12Z","timestamp":1760173812000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1648-9144\/56\/3\/142"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2020,3,20]]},"references-count":39,"journal-issue":{"issue":"3","published-online":{"date-parts":[[2020,3]]}},"alternative-id":["medicina56030142"],"URL":"https:\/\/doi.org\/10.3390\/medicina56030142","relation":{},"ISSN":["1648-9144"],"issn-type":[{"value":"1648-9144","type":"electronic"}],"subject":[],"published":{"date-parts":[[2020,3,20]]}}}