title: The association of liver fat content and serum alanine aminotransferase with bone mineral density in middle-aged and elderly Chinese men and postmenopausal women.
abstract: BACKGROUND
  Recent studies have linked non-alcoholic fatty liver disease (NAFLD) to a reduced bone mineral density (BMD). We aimed to detect the quantitative association of liver fat content (LFC) and serum alanine aminotransferase (ALT) with BMD in a middle-aged and elderly Chinese population.
  
  
  METHODS
  The lumbar spine, hip and whole body BMDs were measured using dual-energy x-ray absorptiometry (Lunar iDXA, GE Healthcare) in 1659 Chinese (755 men and 1028 postmenopausal women) from Shanghai Changfeng community. Liver fat content was quantified via an ultrasound quantitative method. Multivariate linear regression analyses were carried out to determine the independent association of LFC and serum ALT with BMD and bone metabolic biomarkers. We also attempted to investigate the synergistic association between LFC and ALT as risk factors for bone mineral loss in Chinese.
  
  
  RESULTS
  Subjects with higher LFC had significantly lower BMD at all skeletal sites. Univariate correlation analysis showed that both LFC and ALT were inversely associated with BMD at the spine (r = -0.116, P < 0.001 and r = -0.102, P = 0.005), hip (r = -0.095, P = 0.014 and r = -0.075, P = 0.041) and whole body sites (r = -0.134, P < 0.001 and r = -0.164, P < 0.001) in men. After confounders were controlled for, LFC and ALT remained associated with BMD and bone formation biomarkers in men, but not postmenopausal women. When both NAFLD and elevation of ALT were present, there was a significant synergistic worsening of the BMDs at all bone sites.
  
  
  CONCLUSIONS
  Liver fat content and serum ALT were inversely correlated with BMD in middle-aged and elderly men. The underlying mechanism might relate to a reduction in osteoblast activity. Elevation of the hepatotoxic biomarker ALT may indicate high risk for osteoporosis in patients with NAFLD.
authors.affiliation: Department of Endocrinology and Metabolism, Zhongshan Hospital, Fudan University, Shanghai, China. dr_xiamingfeng@163.com.|Institute of Chronic Metabolic Diseases, Fudan University, Shanghai, China. dr_xiamingfeng@163.com.
authors.forename: Ming-Feng
authors.initials: MF
authors.lastname: Xia
authors.affiliation: Department of Endocrinology and Metabolism, Zhongshan Hospital, Fudan University, Shanghai, China. lin.huandong@zs-hospital.sh.cn.|Institute of Chronic Metabolic Diseases, Fudan University, Shanghai, China. lin.huandong@zs-hospital.sh.cn.
authors.forename: Huan-Dong
authors.initials: HD
authors.lastname: Lin
authors.affiliation: Department of Endocrinology and Metabolism, Zhongshan Hospital, Fudan University, Shanghai, China. yan.hongmei@zs-hospital.sh.cn.|Institute of Chronic Metabolic Diseases, Fudan University, Shanghai, China. yan.hongmei@zs-hospital.sh.cn.
authors.forename: Hong-Mei
authors.initials: HM
authors.lastname: Yan
authors.affiliation: Department of Endocrinology and Metabolism, Zhongshan Hospital, Fudan University, Shanghai, China. bian.hua@zs-hospital.sh.cn.|Institute of Chronic Metabolic Diseases, Fudan University, Shanghai, China. bian.hua@zs-hospital.sh.cn.
authors.forename: Hua
authors.initials: H
authors.lastname: Bian
authors.affiliation: Department of Endocrinology and Metabolism, Zhongshan Hospital, Fudan University, Shanghai, China. chang.xinxia@zs-hospital.sh.cn.|Institute of Chronic Metabolic Diseases, Fudan University, Shanghai, China. chang.xinxia@zs-hospital.sh.cn.
authors.forename: Xin-Xia
authors.initials: XX
authors.lastname: Chang
authors.affiliation: Department of Endocrinology and Metabolism, Zhongshan Hospital, Fudan University, Shanghai, China. zhang.linshan@zs-hospital.sh.cn.|Institute of Chronic Metabolic Diseases, Fudan University, Shanghai, China. zhang.linshan@zs-hospital.sh.cn.
authors.forename: Lin-Shan
authors.initials: LS
authors.lastname: Zhang
authors.affiliation: Department of Ultrasonography, Zhongshan Hospital, Fudan University, Shanghai, China. he.wanyuan@zs-hospital.sh.cn.
authors.forename: Wan-Yuan
authors.initials: WY
authors.lastname: He
authors.affiliation: Department of Endocrinology and Metabolism, Zhongshan Hospital, Fudan University, Shanghai, China. zhongshan_endo@126.com.|Institute of Chronic Metabolic Diseases, Fudan University, Shanghai, China. zhongshan_endo@126.com.
authors.forename: Xin
authors.initials: X
authors.lastname: Gao
mesh_terms: D050154:Adiposity; D000368:Aged; D000369:Aged, 80 and over; D000410:Alanine Transaminase / Q000097:blood*; D044466:Asian People; D015415:Biomarkers / Q000097:blood; D015519:Bone Density; D002681:China; D003710:Demography; D005260:Female; D006801:Humans; D016014:Linear Models; D008099:Liver / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D017698:Postmenopause / Q000097:blood*; D012307:Risk Factors
chemical_list: D015415:Biomarkers; D000410:Alanine Transaminase