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Agreement between circulating IGF-I, IGFBP-1 and IGFBP-3 levels measured by current assays versus unavailable assays previously used in epidemiological studies.
Wednesday,2016-01-27 11:36 America/Los_Angeles — zdrager
| Title | Agreement between circulating IGF-I, IGFBP-1 and IGFBP-3 levels measured by current assays versus unavailable assays previously used in epidemiological studies. |
| Publication Type | Journal Article |
| Year of Publication | 2016 |
| Authors | Aneke-Nash, CS, Dominguez-Islas, C, Bůzková, P, Qi, Q, Xue, XN, Pollak, M, Strickler, HD, Kaplan, RC |
| Journal | Growth Horm IGF Res |
| Volume | 26 |
| Pagination | 11-6 |
| Date Published | 2016 Feb |
| ISSN | 1532-2238 |
| Abstract | <p><b>OBJECTIVE: </b>Levels of insulin-like growth factor (IGF) proteins are associated with the risk of cancer and mortality. IGF assays produced by Diagnostic Systems Laboratories (DSL) were widely used in epidemiological studies, were not calibrated against recommended standards and are no longer commercially available.</p><p><b>DESIGN: </b>In a split sample study among 1471 adults participating in the Cardiovascular Health Study, we compared values obtained using DSL assays with alternative assays for serum IGF-I (Immunodiagnostic Systems, IDS), IGFBP-1 (American Laboratory Products Company, ALPCO) and IGFBP-3 (IDS).</p><p><b>RESULTS: </b>Results were compared using kernel density estimation plots, quartile analysis with weighted kappa statistics and linear regression models to assess the concordance of data from the different assays. Participants had a mean age of 77years. Results between alternative assays were strongly correlated (IGF-I, r=0.93 for DSL versus IDS; log-IGFBP-1, r=0.90 for DSL versus ALPCO; IGFBP-3, r=0.92 for DSL versus IDS). Cross tabulations showed that participants were usually in the same quartile categories regardless of the assay used (overall agreement, 74% for IGF-I, 64% for IGFBP-1, 71% for IGFBP-3). Weighted kappa also showed substantial agreement between assays (kw, 0.78 for IGF-I, 0.69 for IGFBP-1, 0.76 for IGFBP-3). Regressions of levels obtained with DSL assays (denoted X) to alternative assays were, IGF-I: 0.52X+15.2ng/ml, log-IGFBP-1: 1.01X-1.73ng/ml IGFBP-3: 0.87X+791.1ng/ml. Serum values of IGF-I, IGFBP-1 and IGFBP-3 measured using alternative assays are moderately correlated.</p><p><b>CONCLUSIONS: </b>Care is needed in the interpretation of data sets involving IGF analytes if assay methodologies are not uniform.</p> |
| DOI | 10.1016/j.ghir.2015.12.007 |
| Alternate Journal | Growth Horm. IGF Res. |
| PubMed ID | 26774400 |
| PubMed Central ID | PMC4724357 |
| Grant List | AG023629 / AG / NIA NIH HHS / United States HHSN268201200036C / / PHS HHS / United States HL080295 / HL / NHLBI NIH HHS / United States K01 HL129892 / HL / NHLBI NIH HHS / United States KL2TR000088 / TR / NCATS NIH HHS / United States N01 HC55222 / HC / NHLBI NIH HHS / United States N01HC85079 / HC / NHLBI NIH HHS / United States N01HC85080 / HC / NHLBI NIH HHS / United States N01HC85081 / HC / NHLBI NIH HHS / United States N01HC85082 / HC / NHLBI NIH HHS / United States N01HC85083 / HC / NHLBI NIH HHS / United States N01HC85086 / HC / NHLBI NIH HHS / United States N01HC85239 / HC / NHLBI NIH HHS / United States P30 CA013330 / CA / NCI NIH HHS / United States P30 DK041296 / DK / NIDDK NIH HHS / United States R01 AG031890 / AG / NIA NIH HHS / United States T32 GM007288 / GM / NIGMS NIH HHS / United States T32-GM007288 / GM / NIGMS NIH HHS / United States TL1 TR001072 / TR / NCATS NIH HHS / United States TL1RR000087 / RR / NCRR NIH HHS / United States UL1TR000086 / TR / NCATS NIH HHS / United States |