Areal bone mineral density in pediatric patients with chronic hepatitis B or chronic hepatitis C

Causal associations between osteoporosis and HBV infection across Asian and European populations: evidence from Mendelian randomization and colocalization analysis

Introduction

Clinical studies have demonstrated a potential association between chronic hepatitis caused by hepatitis B virus (HBV) infection and osteoporosis. However, the causal relationship between HBV infection and osteoporosis remains to be determined.

Methods

We investigated whether HBV infection is causally associated with osteoporosis using Mendelian randomization (MR) in East Asian and European populations, respectively. The data we utilized were obtained from the genome-wide association studies (GWAS) database. Various MR methods, including inverse variance weighted (IVW), MR Egger, weighted median, simple median and simple mode were employed to estimate the association between HBV infection and osteoporosis. Heterogeneity analysis and sensitivity tests were performed to ensure the robustness of the results. Bayesian co-localization (coloc) analysis was also applied to calculate the posterior probability of causal variants and to identify common genetic variants between HBV infection and osteoporosis.

Results

MR analysis indicated that HBV infection increased the risk of osteoporosis onset in two East Asian cohort (IVW, OR = 1.058, 95% CI = 1.021 to 1.097, P = 0.002 and OR = 1.067, 95% CI = 1.029 to 1.106, P < 0.001). However, a clear effect of genetic susceptibility to HBV on the enhanced risk of osteoporosis was not observed in two European cohort (IVW, OR = 1.000, 95% CI = 0.999 to 1.001, P = 0.171 and OR = 1.003, 95% CI = 0.981 to 1.025, P = 0.780). Additional MR methods and sensitivity analyses further validated the reliability and robustness of our results. Bayesian co-localization analysis revealed co-localization of HBV infection and osteoporosis on STAT4 at rs11889341based on East Asian GWAS data.

Conclusions

Our study identified a causal relationship between HBV infection and osteoporosis in East Asian and European populations. These results provided strong evidence that HBV infection augmented the risk of developing osteoporosis in East Asian populations and provided novel therapeutic targets.

Multiple Idiopathic Cervical Root Resorptions in Patients with Hepatitis B Virus Infection

Multiple idiopathic cervical root resorptions are a rare finding. The diagnosis is perplexing, and treatment is a challenge. It is a debilitating condition that often leads to extraction of all the involved teeth. Various theories have been given for explanation of the disease entity; however, the etiology remains elusive. This report describes a case of an 18-year-old man with idiopathic cervical resorption that progressed aggressively and involved 20 teeth. The medical history of hepatitis B virus infection made this case unique in the literature. The mechanism of increased osteoclastic activity in patients with hepatitis B virus infection is discussed as a predisposing factor for the development of root resorption.

Pegylated interferon α/ribavirin therapy enhances bone mineral density in children with chronic genotype 4 HCV infection

BACKGROUND

The impact of chronic hepatitis C (CHC) on bone mineral density (BMD) has been well studied in adults with a relative paucity of data in children, especially concerning effect of treatment with pegylated interferon (PEG-IFN) plus ribavirin (RV). In the current work, we assessed prospectively changes in BMD in children with CHC before, during, and after treatment.

METHODS

Forty-six consecutive children with noncirrhotic genotype 4 CHC were subjected to dual-energy X-ray absorptiometry at baseline, 24 weeks, 48 weeks of therapy and 24 weeks after treatment. BMD, bone mineral content (BMC), and Z score of lumbar spine (L2-L4) were reported. Tanner pubertal stage, viral load, liver function tests, serum calcium, phosphorus, alkaline phosphatase, parathyroid hormone, and liver histopathology were assessed in all included children.

RESULTS

Thirty (65.2%) patients had normal BMD, 10 (21.7%) were at risk for low BMD, and 6 (13.1%) had low BMD for chronological age. Patients with low BMD were significantly older (P=0.001), with higher frequency of delayed puberty than other groups (P=0.002). Baseline densitometric parameters (BMD & BMC) were significantly positively correlated with patients' age, weight, height, body mass index and hemoglobin level; while they were insignificantly correlated with basal viral load, histopathology activity index and fibrosis score. Densitometric parameters improved significantly on PEG-IFN plus RV treatment, this improvement was found to be sustainable 24 weeks after therapy.

CONCLUSIONS

Low BMD is detectable in a proportion of CHC children. Antiviral therapy leads to a sustainable increase in BMD.

Bone health in HIV and hepatitis B or C infections

Chronic infections with human immunodeficiency virus (HIV), hepatitis B virus (HBV) or hepatitis C virus (HCV) add to age-dependent bone loss and may contribute to lower bone strength in the elderly. In this review, we report recent highlights on the epidemiology of bone fragility in chronic viral infections with HIV, HCV and HBV, its physiopathology and discuss the interference of antiviral therapies with bone metabolism. Chronic infections influence bone through the interactions between risk factors for bone fragility and falls (which are highly prevalent in infected patients), virus activity and antiviral drugs. HIV-infected patients are at increased risk of fracture and the risk is higher in cases of co-infection with HIV and untreated chronic viral hepatitis. In HIV patients, the majority of bone loss occurs during virus activity and at initiation of antiretroviral therapy (ART). However, long-term elderly HIV-infected patients on successful ART display bone microstructure alterations only partially captured by dual energy X-ray absorptiometry (DXA). Bone loss is associated with an increase of bone resorption, reflecting the upregulation of the receptor activator of nuclear factor-kappaB ligand (RANKL) and osteoprotegerin (OPG) pathways via a crosstalk between virus activity, inflammation and the immune system. The use of some antiviral drugs, such as tenofovir (controlling both HBV and HIV infections) or protease inhibitors, may be associated with higher bone toxicity. The reduction of tenofovir plasma concentrations with the implementation of tenofovir alafenamide (TAF) attenuates bone mineral density (BMD) loss but it remains unknown whether it will contribute to reducing fracture risk in long-term HIV-treated patients. Moreover, to what extent the new direct-acting agents for treatment of HCV, including nucleotide inhibitors and protease inhibitors, may affect bone health similarly as ART in HIV should be investigated.