Liver fat and SHBG affect insulin resistance in midlife women: The Study of Women's Health Across the Nation (SWAN)12. (20th June 2013)

• Record Type: Journal Article
• Authors: Kavanagh, Kylie; Espeland, Mark A.; Sutton‐Tyrrell, Kim; Barinas‐Mitchell, Emma; Khoudary, Samar R. El; Wildman, Rachel P.
• Is Part Of: Obesity. Volume 21:Number 5(2013:May)
• Page Start: 1031
• Page End: 1038
• Publication Date: 2013-06-20
• Subjects: Obesity -- Periodicals; 616.398005
• DOI: 10.1002/oby.20077
• Languages: English
• ISSNs: 1930-7381

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <sec id="abs1-1" sec-type="section"> <title>Objective:</title> <p>The liver is an insulin‐responsive organ that contributes significantly to both whole body insulin sensitivity and availability of sex steroids through the production of sex hormone binding globulin (SHBG). Our objective was to explore whether lower SHBG was associated with ectopic liver fat and mediated its effect on insulin resistance in The Study of Women's Health Across the Nation (SWAN).</p> </sec> <sec id="abs1-2" sec-type="section"> <title>Design and Methods:</title> <p>A subset of midlife African American and Caucasian women from SWAN (<italic>n</italic> = 208; 50.9 ± 0.18 yrs; 71% Caucasian) had computed tomography scans to quantify visceral, subcutaneous and liver fat. Blood samples were collected and assayed for hormonal and metabolic markers.</p> </sec> <sec id="abs1-3" sec-type="section"> <title>Results:</title> <p>The cohort, while overweight, was generally healthy, and both liver fat and SHBG were unaffected by menopausal stage or race. Both higher liver fat and lower SHBG levels were significantly associated with higher insulin concentrations after adjustment for adiposity (<italic>r</italic> = −0.25, <italic>P</italic> < 0.001 and <italic>r</italic> = −0.18, <italic>P</italic> = 0.01). SHBG and liver fat had additive effects on insulin concentrations such that women with the lowest SHBG and the highest fat levels had the highest values (interaction <italic>P</italic> = 0.09). The association between SHBG and insulin was more apparent among women with fattier livers. SHBG and liver fat appear to have independent effects on insulin levels as adjustment for each other did not diminish the strength of either association (<italic>P</italic> = 0.023 and 0.001 respectively).</p> </sec> <sec id="abs1-4" sec-type="section"> <title>Conclusion:</title> <p>These results confirmed the strong independent associations between increased liver fat and decreased SHBG with increased metabolic risk in midlife women. Further these data underscore the need for additional research into the role of liver fat in modifying SHBG's influence on insulin levels.</p> </sec> </abstract>