Patients with insufficient or deficient levels of 25-hydroxyvitamin D are at increased risk of developing non-alcoholic fatty liver disease, according to recent results.
Researchers evaluated serum 25-hydroxyvitamin D (25[OH]D) levels collected between Jan. 1999 and Dec. 2009 in 607 patients with NAFLD, along with 607 matched controls. Liver ultrasonography was also performed in all cases, within 3 to 15 months of 25(OH)D measurement.
Patients with NAFLD had significantly lower 25(OH)D levels than controls (75 ± 17 nmol/L, 30 ± 7 ng/mL compared with 85 ± 20 nmol/L, 34 ± 8 ng/mL, P<.001). Both 25(OH)D insufficiency (between 37 and 75 nmol/L, 5-30 ng/mL] and deficiency (below 37 nmol/L, below 15 ng/mL) were more common among participants with NAFLD (60.79% vs. 53.71%, P=.001 for insufficiency and 15.65% vs. 10.71%, P=.015 for deficiency). Both insufficient (adjusted OR=2.40, 0.90-6.34) and deficient (aOR=2.56, 1.27-5.19) levels of 25(OH)D were associated with increased risk for NAFLD compared to those with sufficient levels.
Analysis of log10 25(OH)D as a continuous variable indicated an inverse association between 25(OH)D and NAFLD after adjustment for BMI, diabetes history and renal, peripheral vascular and liver disease (aOR=0.43, 0.20-0.93 per each log10 increase). This association was maintained after further adjustment for hypertension (aOR=0.25, 0.064-0.96), and after excluding patients with liver disease (aOR=0.21, 0.04-0.96) (95% CI for all).
“While the present study cannot draw any firm conclusions regarding causality, the association of lower serum 25(OH)D levels with NAFLD independent of numerous confounding factors suggest that inadequate 25(OH)D status might play a role in the development and/or progression of NAFLD,” the researchers wrote. “… Future studies are needed to prospectively determine if vitamin D supplementation reduces the development and progression of NAFLD, as well as the physiological mechanisms mediating any effects.”