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- Ballantyne, C., et al.
(författare)
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Collaborative meta-analysis of individual participant data from observational studies of Lp-PLA(2) and cardiovascular diseases
- 2007
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Ingår i: European Journal of Cardiovascular Prevention & Rehabilitation. - 1741-8275. ; 14:1, s. 41344-41344
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Forskningsöversikt (refereegranskat)abstract
- Background A large number of observational epidemiological studies have reported generally positive associations' between circulating mass and activity levels of lipoprotein-associated phospholipase A(2) (Lp-PLA(2)) and the risk of cardiovascular diseases. Few studies have been large enough to provide reliable estimates in different circumstances, such as in different subgroups (e.g., by age group, sex, or smoking status) or at different Lp-PLA2 levels. Moreover, most published studies have related disease risk only to baseline values of Lp-PLA(2) markers (which can lead to substantial underestimation of any risk relationships because of within-person variability over time) and have used different approaches to adjustment for possible confounding factors. Objectives By combination of data from individual participants from all relevant observational studies in a systematic,meta-analysis, with correction for regression dilution (using available data on serial measurements of Lp-PLA(2)), the Lp-PLA(2) Studies Collaboration will aim to characterize more precisely than has previously been possible the strength and shape of the age and sex-specific associations of plasma Lp-PLA(2) with coronary heart disease (and, where data are sufficient with other vascular diseases, such as ischaemic stroke). It will also help to determine to what extent such associations are independent of possible confounding factors and to explore potential sources of heterogeneity among studies, such as those related to assay methods and study design. It is anticipated that the present collaboration will serve as a framework to investigate related questions on Lp-PLA(2) and cardiovascular outcomes. Methods A central database is being established containing data on circulating Lp-PLA(2) values, sex and other potential confounding factors, age at baseline Lp-PLA(2) Measurement, age at event or at last follow-up, major vascular morbidity and cause-specific mortality. Information about any repeat measurements of Lp-PLA2 and potential confounding factors has been sought to allow adjustment for possible confounding and correction for regression dilution. The analyses will involve age-specific regression models. Synthesis of the available observational studies of Lp-PLA(2) will yield information on a total of about 15 000 cardiovascular disease endpoints.
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| 2. |
- McKay, James D., et al.
(författare)
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Vitamin D Receptor Polymorphisms and Breast Cancer Risk: Results from the National Cancer Institute Breast and Prostate Cancer Cohort Consortium
- 2009
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Ingår i: Cancer Epidemiology Biomarkers & Prevention. - 1538-7755. ; 18:1, s. 297-305
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Tidskriftsartikel (refereegranskat)abstract
- Background: Vitamin D is hypothesized to lower the risk of breast cancer by inhibiting cell proliferation via the nuclear vitamin D receptor (VDR). Two common single nucleotide polymorphisms (SNP) in the VDR gene (VDR), rs154441.0 (BsmI), and rs2228570 (FokI), have been inconsistently associated with breast cancer risk. Increased risk has been reported for the FokIff genotype, which encodes a less transcriptionally active isoform of VDR, and reduced risk has been reported for the BsmI BB genotype, a SNP in strong linkage disequilibrium with a 3'-untranslated region, which may influence VDR mRNA stability. Methods: We pooled data from 6 prospective studies in the National Cancer Institute Breast and Prostate Cancer Cohort Consortium to examine associations between these SNPs and breast cancer among >6,300 cases and 8,100 controls for each SNP using conditional logistic regression. Results: The odds ratio (OR) for the rs2228570 (FokI) ff versus FF genotype in the overall population was statistically significantly elevated [OR, 1-1.6; 95% confidence interval (95% CI), 1.04-1.28] but was weaker once data from the cohort with previously published positive findings were removed (OR, 1.1.0; 95% CI, 0.981.24). No association was noted between rs1544410 (Bsm I) BB and breast cancer risk overall (OR, 0.98; 95% CI, 0.89-1.09), but the BB genotype was associated with a significantly lower risk of advanced breast cancer (OR, 0.74; 95% CI, 0.60-0.92). Conclusions: Although the evidence for independent contributions of these variants to breast cancer susceptibility remains equivocal, future large studies should integrate genetic variation in VDR with biomarkers of vitamin D status. (Cancer Epidemiol Biomarkers Prev 2009;18(1):297-305)
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| 3. |
- Ulmert, David, et al.
(författare)
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Long-term prediction of prostate cancer: Prostate-specific antigen (PSA) velocity is predictive but does not improve the predictive accuracy of a single PSA measurement 15 years or more before cancer diagnosis in a large, representative, unscreened population
- 2008
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Ingår i: Journal of Clinical Oncology. - 1527-7755. ; 26:6, s. 835-841
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Tidskriftsartikel (refereegranskat)abstract
- Purpose We tested whether total prostate-specific antigen velocity (tPSAv) improves accuracy of a model using PSA level to predict long-term risk of prostate cancer diagnosis. Methods During 1974 to 1986 in a preventive medicine study in Sweden, 5,722 men aged <= 50 gave two blood samples about 6 years apart. We measured free (fPSA) and total PSA (tPSA) in archived plasma samples from 4,907 participants. Prostate cancer was subsequently diagnosed in 443 (9%) men. Cox proportional hazards regression was used to evaluate tPSA and tPSAv as predictors of prostate cancer. Predictive accuracy was assessed by the concordance index. Results The median time from second blood draw to cancer diagnosis was 16 years; median follow-up for men without prostate cancer was 21 years. In univariate models, tPSA level at second assessment and tPSAv between first and second assessments were associated with prostate cancer (both P < .001). tPSAv was highly correlated with tPSA level (r = 0.93). Twenty-year probabilities of cancer for men at 50th, 90th, and 95th percentile of tPSA and tPSAv were 10.6%, 17.1%, and 21.2% for tPSA, and 9.1%, 11.8%, and 14.1% for tPSAv, respectively. The concordance index for tPSA level was 0.771. Adding tPSAv, fPSA, % fPSA or velocities of fPSA and % fPSA did not importantly increase accuracy of tPSA to predict prostate cancer. Results were unchanged if the analysis was restricted to patients with advanced cancer at diagnosis. Conclusion Although PSA velocity is significantly increased in men with prostate cancer up to two decades before diagnosis, it does not aid long-term prediction of prostate cancer.
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| 4. |
- Ulmert, David, et al.
(författare)
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Prostate-specific antigen at or before age 50 as a predictor of advanced prostate cancer diagnosed up to 25 years later: A case-control study
- 2008
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Ingår i: BMC Medicine. - : Springer Science and Business Media LLC. - 1741-7015. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- Background: Based on a large, representative unscreened cohort from Malmo, Sweden, we have recently reported that a single prostate-specific antigen (PSA) measurement at or before age 50 is a strong predictor of prostate cancer occurring up to 25 years subsequently. We aimed to determine whether this association holds for advanced cancers, defined as clinical stage T3 or higher, or skeletal metastasis at the time of the cancer diagnosis. Methods: In 1974-1986 blood samples were obtained from a cohort of 21,277 men aged up to 50. Through 1999, 498 men were diagnosed with prostate cancer, and of these 161 had locally advanced or metastatic prostate cancers. Three controls, matched for age and date of venipuncture, were selected for each case. Conditional logistic regression was used to test associations between molecular markers and advanced cancer. Results: Median time from venipuncture to diagnosis was 17 years. Levels of all PSA forms and hK2 were associated with case status. Total PSA was a strong and statistically significant predictor of subsequent advanced cancer ( area under the curve 0.791; p < 0.0005). Two-thirds of the advanced cancer cases occurred in men with the top 20% of PSA levels (0.9 ng/ml or higher). Conclusion: A single PSA test taken at or before age 50 is a very strong predictor of advanced prostate cancer diagnosed up to 25 years later. This suggests the possibility of using an early PSA test to risk-stratify patients so that men at highest risk are the focus of the most intensive screening efforts.
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| 5. |
- Vickers, Andrew J., et al.
(författare)
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The predictive value of prostate cancer biomarkers depends on age and time to diagnosis: Towards a biologically-based screening strategy
- 2007
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Ingår i: International Journal of Cancer. - : Wiley. - 0020-7136 .- 1097-0215. ; 121:10, s. 2212-2217
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Tidskriftsartikel (refereegranskat)abstract
- Both benign and malignant prostate diseases elevate total prostate-specific antigen (tPSA), and the incidence of benign disease increases markedly with age. There is evidence, however, that free-to-total PSA ratio (%fPSA) and human kallikrein 2 (hK2) more closely reflect the malignant process. We tested the hypothesis that tPSA levels are more strongly predictive of cancer in younger when compared to older men, whereas %fPSA and hK2 are more strongly predictive in men tested closer to diagnosis. The study included 13,676 men age >= 44 in Sweden, where PSA screening was uncommon during the study period. fPSA, tPSA and hK2 were measured in archived plasma collected during 1974-1986 in 501 men subsequently diagnosed with prostate cancer up to 1999 and in 1,292 matched controls. The predictive value of tPSA was lower in older men (p = 0.003) but was not strongly affected by time to diagnosis (p = 0.3); the predictive value of hK2 was higher closer to diagnosis (p < 0.0005) but was not modified by age (p = 0.7). A model including tPSA, fPSA and hK2 was superior (p = 0.02) to tPSA alone in older (AUC 0.819 vs. 0.794), but not in younger men (0.758 vs. 0.759). Total PSA can be used as a single marker at early middle age to predict long-term risk of prostate cancer and thus to determine intensity of subsequent screening. In contrast, %fPSA and hK2 add important predictive value in older men and much closer to diagnosis. Strategies for prostate cancer screening should be based on thorough understanding of the interaction of kallikreinrelated biomarkers with prostate pathobiology.
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