| 1. |
- Kaaks, Rudolf, et al.
(författare)
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Prospective study of IGF-I, IGF-binding proteins, and breast cancer risk, in Northern and Southern Sweden
- 2002
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Ingår i: Cancer Causes and Control. - 1573-7225 .- 0957-5243. ; 13:4, s. 307-316
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To examine the possible relationships of breast cancer risk to prediagnostic plasma levels of insulin; insulin-like growth factor-I (IGF-I); and IGF-binding proteins -1, -2, and -3. Methods: Within two prospective cohorts in Umea and Malmo we measured plasma concentrations of insulin, IGF-I, and IGFBPs for a total of 513 incident breast cancer cases and 987 matched controls. Results: Globally, risk was unassociated with levels of IGF-I, IGFBP-3, or IGF-I adjusted for IGFBP-3. When breaking down the analysis by subgroups of age at blood donation, an increase in risk was observed for increasing levels of IGF-I in women aged 55 or older, in the Umea cohort only (odds ratios of 1.00, 1.73, 1.76, 1.90; p(trend) = 0.05). This effect weakened, however, when the analysis was restricted to subjects who did not use exogenous hormones for the treatment of menopausal symptoms. Levels of IGF-I and IGFBP-3 were not related to risk in younger women, recruited before age 50, contrary to observations from previous studies. In a subcohort where blood samples had been collected after at least four hours of fasting, breast cancer risk showed no clear associations with levels of insulin, IGFBP-1, or IGFBP-2. Conclusions: Our results do not confirm earlier findings of an association of plasma IGF-I levels with breast cancer risk especially in young women, but suggest a possible association with postmenopausal breast cancer risk, possibly among ERT/HRT users only. Our results do not support the hypothesis that elevated plasma insulin levels, and reduced levels of IGFBP-1 and IGFBP-2, are associated with increased breast cancer risk.
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| 2. |
- Lukanova, Annekatrin, et al.
(författare)
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Circulating levels of insulin-like growth factor-I and risk of ovarian cancer.
- 2002
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Ingår i: International Journal of Cancer. - : Wiley. - 0020-7136 .- 1097-0215. ; 101:6, s. 549-554
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Tidskriftsartikel (refereegranskat)abstract
- Insulin-like growth factor (IGF)-I, a mitogenic and anti-apoptotic peptide, has been implicated in the development of several cancers. We hypothesized that high circulating IGF-I concentrations may be associated with an increased risk of ovarian cancer. A case-control study was nested within 3 prospective cohorts in New York (USA), Umeå (Sweden) and Milan (Italy). One hundred thirty-two women with primary invasive epithelial ovarian cancer diagnosed at least 1 year after blood donation were case subjects. For each case, 2 control subjects were selected, matching the case subject on cohort, menopausal status, age and date of recruitment (n = 263). Only women who did not use exogenous hormones at blood donation were included in the study. There was no association between IGF-I concentrations and ovarian cancer risk in the study group as a whole. In analyses restricted to subjects who had developed ovarian cancer at a young age (<55), circulating IGF-I was directly and strongly associated with ovarian cancer risk (OR = 4.97; 95% CI = 1.22-20.2 for the top vs. the bottom IGF-I tertile after adjustment for parity, BMI categories and smoking). There was no significant association of IGF binding protein-3 with ovarian cancer risk. We found a strong direct relationship between circulating IGF-I levels and risk of developing ovarian cancer before age 55. Additional, larger studies of this association are needed to provide more precise estimates of effect.
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| 3. |
- Lukanova, Annekatrin, et al.
(författare)
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Nonlinear relationship of insulin-like growth factor (IGF)-I and IGF-I/IGF-binding protein-3 ratio with indices of adiposity and plasma insulin concentrations (Sweden).
- 2002
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Ingår i: Cancer Causes and Control. - 0957-5243 .- 1573-7225. ; 13:6, s. 509-516
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: In this study we test the hypothesis of a nonlinear relationship of IGF-I with indices of body fat such as body mass index (BMI), insulin, and leptin.METHODS: The controls used in three case-control cancer studies nested in the Northern Sweden Health and Disease Cohort, were combined for this analysis. Measurements of plasma IGF-I, IGFBP-3, insulin, and leptin were available for 445 men and 391 women.RESULTS: In both men and women we found the highest mean IGF-I levels in subjects with BMI between 24 and 26. IGF-I concentrations decreased toward BMI < or = 20 and BMI > 30 in men; however, the results for women did not reach statistical significance. The molar ratio of IGF-I/IGFBP-3 showed a similar profile to that of IGF-I, although much less pronounced. The observed peak mean IGF-I levels in the second quintiles of insulin and leptin in men supported these findings. No significant variation of mean IGF-I levels across quintiles of insulin and leptin were observed in women.CONCLUSIONS: The results of this study provide evidence that IGF-I plasma concentrations vary substantially over a wide range of body weight and that the relationship is nonlinear.
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