Serum Vitamin D Concentrations and Unexplained Elevation in ALT Among US Adults.
Dig Dis Sci. 2011 Apr 19.
Liangpunsakul S, Chalasani N.
Division of Gastroenterology and Hepatology, Department of Medicine, Indiana University School of Medicine, 550 N. University Blvd, UH 4100, Indianapolis, IN, 46202-5124, USA, sliangpu at iupui.edu.
Low serum levels of vitamin D are associated with metabolic syndrome. Participants in NHANES III with unexplained elevation in ALT levels have high prevalence of metabolic syndrome. We hypothesized that the serum concentrations of vitamin D were inversely associated with unexplained elevation in ALT.
A total of 6,826 fasting subjects underwent morning physical examination and met the inclusion and exclusion criteria.
From these participants, we have constructed cases with unexplained elevation in ALT (n = 308) and compared their serum vitamin D concentrations to matched controls with normal ALT (N = 979).
We examined the prevalence of unexplained elevation in ALT level across different quartiles of vitamin D levels.
Participants with unexplained elevation in ALT had significantly lower serum vitamin D levels compared to controls (61.8 ± 26.0 nmol/l vs. 66.8 ± 27.1 nmol/l, P < 0.01). The unadjusted prevalence of unexplained elevation in ALT in patients with highest to lowest quartiles of serum vitamin D levels were 21.4, 21.4, 25.6, and 31.5%, respectively. Compared to lowest quartile, patients with top two quartiles of serum vitamin D levels had significantly lower prevalence of unexplained elevation in ALT (OR, 95% CI for highest quartile 0.62 [0.43-0.89] and for third quartile 0.61 [0.42-0.86]). This relationship persisted even after controlling for metabolic syndrome, insulin resistance, and serum triglycerides.
This study suggests a significant inverse relationship between serum vitamin D levels and unexplained elevation in ALT.
Further studies are needed to confirm this observation and to understand the basis for and implications of this observation.
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From the web
Alanine transaminase (ALT) is an enzyme found in the highest amounts in the liver.
Injury to the liver results in release of the substance into the blood.