The evaluation of bone mineral density in patients with nonalcoholic fatty liver disease

Nonalcoholic fatty liver diseases (NAFLD) are a clinical spectrum of disorders, of which nonalcoholic steatohepatitis (NASH) is the most strongly associated with inflammation. Inflammation is a known risk factor for low bone mass in the body. The primary goal of the present study was to evaluate the association between bone mineral density and liver function in patients with NASH. Consenting patients with a diagnosis of NAFLD were included in the study. Extent of fatty change was graded based on ultrasonographic appearance (Grade 1, mild; Grade 2, moderate; Grade 3, severe). Bone mineral density was measured using the dual-energy x-ray absorptiometry method. ALT and hs-CRP were considered as noninvasive marker of NASH. According to ALT levels, patients were divided into two subgroups. A total of 102 patients with NAFLD and 54 healthy controls participated in the study. None of the patients with NAFLD had an abnormal bone mineral density. Furthermore, there was no difference between groups with regard to serum vitamin D levels. A subgroup analysis revealed that female patients with elevated serum ALT level had significantly lower bone mineral densities and higher hsCRP levels than female patients with normal ALT levels. The difference in vitamin D levels and body mass indices between the same subgroups was statistically insignificant. Simple steatosis of the liver does not affect bone mineral density. However, in a subgroup of patients with NAFLD, the presence of elevated serum ALT and hs-CRP levels, which are suggestive of NASH, was associated with lower bone mineral densities. Better understanding of the biological basis and the complex interactions between NAFLD and bone mass may help guide the clinical management of bone diseases associated with inflammation of the liver.