Fatty Liver: Vitamin D Deficiency Is Common Comorbidity – MedPage Today
HONOLULU — Patients with non-alcoholic fatty liver disease have more than double the risk of vitamin D deficiency, a retrospective case-control study found.
Among 33,217 patients with non-alcoholic fatty liver disease included in a national database, the unadjusted odds ratio for vitamin D deficiency was 3.160 (95% CI 2.546-3.922), reported Alexander Potashinsky, MD, of Long Island Jewish Medical Center, North Shore-LIJ Health System in Manhasset, N.Y.
And after adjustment for age, sex, race, smoking, obesity, hypertension, dyslipidemia, and metabolic syndrome, the odds ratio for vitamin D deficiency was 2.218 (95% CI 1.789-2.797), Potashinsky reported in a poster session at the annual meeting of the American College of Gastroenterology.
Non-alcoholic fatty liver disease is the deposition of fat in the liver in the absence of other recognized causes of fatty liver. This condition has increased markedly in the past 20 years, and is now estimated to be present in one-quarter of the U.S. population.
“Vitamin D is involved in the regulation of inflammation, and is probably important in the pathogenesis of fatty liver disease,” Potashinsky told MedPage Today.
“Considering how prevalent fatty liver is, if we were able to do something as easy as measure vitamin D and treat the deficiency, it would be one less hurdle for patients,” he said.
There has been much interest recently in linking vitamin D with diseases that are mediated by inflammation.
“Vitamin D has been implicated in the regulation of immunity, inflammation, and apoptosis, mechanisms that are key to regulating fibrosis and that are crucial in the progression of nonalcoholic fatty liver disease,” he explained.
In addition, both non-alcoholic fatty liver disease and vitamin D deficiency are associated with considerable patient morbidity, and with the development of insulin resistance, diabetes, and cardiovascular disease.
Therefore, to examine the possibility that patients with the liver condition might be at increased risk of vitamin D deficiency, he and his colleagues compared cases and controls from the 2009 Nationwide Inpatient Sample, which was maintained by the Healthcare Cost and Utilization Project of the Agency for Healthcare Research and Quality.
Cases were adults who had been hospitalized with a primary or secondary diagnosis of non-alcoholic fatty liver disease.
The overall prevalence of vitamin D deficiency among the 33,217 patients was 1.03%, which was lower than expected and probably reflects an underdiagnosis because of the hospital setting of the database.
Among the equivalent number of controls, the prevalence of vitamin D deficiency was 0.33%. A similar proportion of cases and controls were women (57% versus 58%). Among the cases, 43% were younger than 50, as were 47% of controls. The mean Elixhauser comorbidity index was 3.20 for cases and 2.66 for controls.
Among cases, 71% were white, 9% were black, 14% were Hispanic, and slightly over 6% were classified as “other.” Among controls, the corresponding numbers were 66%, 14%, 13%, and 7%.
Among cases, the primary payer was Medicare in 32% of cases and Medicaid in 13%.
Cases were more likely than controls to be obese, to have diabetes, dyslipidemia, hypertension, and metabolic syndrome, and to be smokers.
A recent meta-analysis that included 17 studies found that patients were 1.26 times more likely to be vitamin D deficient (OR 1.26, 95% CI 1.17-1.35). The authors of the meta-analysis concluded that “vitamin D deficiency is prevalent” in patients with non-alcoholic fatty liver disease, and that “supplementation may proved to be beneficial.”
“Our study showed an even stronger association,” Potashinsky said.
However, more research will be needed to assess causality, he noted. “Further studies also will be required to determine if correcting deficiencies in vitamin D can halt and possibly reverse the progression of nonalcoholic fatty liver disease,” he concluded.
“Based on our data, we recommend that all patients with nonalcoholic fatty liver disease be screened for micronutrient deficiencies, including vitamin D.”
“The literature suggests that vitamin D deficiency is associated with so many other conditions that checking it will probably be standard of care in liver disease,” he added.
The authors reported no financial conflicts.
Henry A. Solomon, MD, FACP, FACC Clinical Associate Professor, Weill Cornell Medical College