| 1. |
- Ekblom, Kim, et al.
(författare)
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Iron Biomarkers in Plasma, HFE Genotypes, and the Risk for Colorectal Cancer in a Prospective Setting
- 2012
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Ingår i: Diseases of the Colon & Rectum. - 0012-3706. ; 55:3, s. 337-344
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: High iron levels can increase the formation of noxious oxygen radicals, which are thought to promote carcinogenesis. OBJECTIVE: The aim of this prospective study was to determine whether iron biomarkers and HFE genotypes, which influence iron regulation, constitute risk factors for colorectal cancer. DESIGN: This is a prospective nested case-referent study. SETTINGS: The study was performed within the population-based Northern Sweden Health and Disease Study. PATIENTS: The study included 226 cases of colorectal cancer and 437 matched referents. MAIN OUTCOME MEASURES: Conditional regression analysis was performed. Adjustments for smoking, smoking and BMI, and HFE C282Y and H63D were performed. RESULTS: The highest quintile of total iron-binding capacity showed significantly higher risk for colorectal cancer, unadjusted OR 2.35 (95% CI 1.38-4.02). When stratified by sex, the findings were only present in women (OR 3.34 (95% CI 1.59-7.02)). Ferritin was associated with reduced risk throughout quintiles 2 to 5 both in univariate and multivariate models. LIMITATIONS: Colorectal cancer may influence iron markers because of occult bleeding. Homozygotes for HFE C282Y were too few to make conclusions for this group. The relatively short follow-up time might be insufficient to detect risk of iron biomarkers. CONCLUSIONS: High iron levels do not increase the risk of colorectal cancer. HFE genotypes influencing iron uptake had no effect on colorectal cancer risk.
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| 2. |
- Van Guelpen, Bethany, et al.
(författare)
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Folate, vitamin B12, and risk of ischemic and hemorrhagic stroke: a prospective, nested case-referent study of plasma concentrations and dietary intake.
- 2005
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Ingår i: Stroke; a journal of cerebral circulation. - 1524-4628. ; 36:7, s. 1426-31
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND AND PURPOSE: Folate metabolism has been implicated in stroke. However, the possibility of a role for folate and vitamin B12, independent of their effects on homocysteine status, remains to be explored. The aim of this prospective, nested case-referent study was to relate plasma and dietary intake levels of folate and vitamin B12 to risk of stroke, taking into consideration plasma homocysteine concentrations and methylenetetrahydrofolate reductase polymorphisms. METHODS: Subjects were 334 ischemic and 62 hemorrhagic stroke cases and matched double referents from the population-based Northern Sweden Health and Disease Cohort. RESULTS: Plasma folate was statistically significantly associated with risk of hemorrhagic stroke in an inverse linear manner, both in univariate analysis and after adjustment for conventional risk factors including hypertension (odds ratio [OR] for highest versus lowest quartile 0.21 (95% confidence interval [CI], 0.06 to 0.71; P for trend=0.008)). Risk estimates were attenuated by inclusion of homocysteine in the model (OR, 0.34; 95% CI, 0.08 to 1.40; P for trend=0.088). A similar pattern was observed for increasing folate intake (multivariate OR, 0.07; 95% CI, 0.01 to 0.55; P for trend=0.031 without homocysteine, and OR, 0.16, 95% CI, 0.02 to 1.23; P for trend=0.118 with homocysteine in the analysis). We found little evidence of an association between plasma or dietary folate and risk of ischemic stroke. Neither plasma nor dietary vitamin B12 was associated with risk of either stroke subtype. CONCLUSIONS: The results of this study suggest a protective role for folate, possibly in addition to its effects on homocysteine status, in hemorrhagic but not ischemic stroke.
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| 3. |
- Van Guelpen, Bethany, et al.
(författare)
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Plasma folate and total homocysteine levels are associated with the risk of myocardial infarction, independently of each other and of renal function.
- 2009
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Ingår i: Journal of internal medicine. - 1365-2796. ; 266:2, s. 182-95
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: To investigate the relationship between plasma folate, vitamin B12 and total homocysteine concentrations, dietary intake of folate and vitamins B12, B6 and B2, and the risk of first acute myocardial infarction (MI). DESIGN: Nested case-referent study with up to 13 years of follow-up. SETTING: The population-based Northern Sweden Health and Disease Study, with 73 879 participants at the time of case ascertainment. SUBJECTS: A total of 571 MI cases (406 men) and 1569 matched referents. Of the cases, 530 had plasma samples available, and 247 had dietary B-vitamin intake data. RESULTS: Plasma concentrations of folate were inversely associated, and total homocysteine positively associated, with the risk of MI, independently of each other and of a number of established and novel cardiovascular risk factors, including renal function [multivariate odds ratio for highest vs. lowest quintile of folate 0.52 (95% CI 0.31-0.84), P for trend = 0.036, and homocysteine 1.92 (95% CI 1.20-3.09), P for trend = 0.006]. For plasma vitamin B12 concentrations, and vitamin B12, B6 and B2 intake, no clear risk relationship was apparent. Though not statistically significant, the results for folate intake were consistent with those for plasma concentrations. CONCLUSIONS: In this large prospective study of a population without mandatory folic acid fortification, both folate and homocysteine were strongly associated with the risk of myocardial infarction, independently of each other and of renal function. Although randomized trials of folic acid supplementation are needed to determine causality, our findings highlight the potential importance of folate, or sources of folate, in incident cardiovascular disease.
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