Search

Background: The 5-lipoxygenase pathway has been linked to atherothrombotic disease, and a functional tandem repeat polymorphism in the arachidonate lipoxygenase-5 (ALOX-5) gene has been associated with the risk of myocardial infarction (MI). Interestingly, 2 studies have reported an interaction between dietary intakes of the ALOX-5 substrates, arachidonic acid (AA) and eicosapentaenoic acid (EPA), and genotype.Objective: We investigated whether the interactions between the ALOX-5 tandem repeat polymorphism (rs59439148) and adipose tissue AA and EPA were associated with incident MI.Methods: In the Danish Diet, Cancer and Health study, we conducted a case-cohort study including 3089 participants with incident MI identified from national registries and a randomly selected subcohort of 3000 participants. Participants were men and women with a median age of 56 y at baseline and no previous history of cancer. Adipose tissue and blood samples were collected at baseline along with comprehensive questionnaires on lifestyle and demographic data. The ALOX-5 tandem repeat polymorphism was genotyped by multititer plate sequencing. Associations were analyzed by using Cox proportional hazards models.Results: We observed a higher risk of MI for homozygous carriers of the variant alleles in the fifth quintile of AA content than for the reference group with the lowest quintile of AA and carrying the wild-type allele (HR: 3.02; 95% CI: 1.41, 6.44). In contrast, homozygotes for the variant alleles tended to have a higher risk of MI when comparing the lowest quintile of EPA content with the reference group with the highest quintile of EPA and carrying the wild-type allele (HR: 2.15; 95% CI: 0.91, 5.09; P = 0.08). Although our results suggested interactions between the polymorphism and adipose tissue AA and EPA, a quantitative evaluation of interaction by calculating the relative excess risk due to interactions was not significant.Conclusions: Adipose tissue EPA and AA and the ALOX-5 tandem repeat polymorphism did not significantly interact to affect the risk of MI. However, the results should be replicated in larger, heterogeneous populations. [ABSTRACT FROM AUTHOR]

Background Road traffic is a source of both air pollution and noise; two environmental hazards both found to increase the risk of ischemic heart disease. Given the high correlation between these pollutants, it is important to investigate combined effects, in relation to myocardial infarction (MI). Methods Among 50,744 middle-aged Danes enrolled into the Diet, Cancer and Health cohort from 1993 to 97, we identified 2403 cases of incident MI during a median follow-up of 14.5 years. Present and historical residential addresses from 1987 to 2011 were found in national registries, and traffic noise (L den ) and air pollution (NO 2 ) were modelled for all addresses. Analyses were performed using Cox proportional hazard models. Results Road traffic noise and NO 2 were both individually associated with a higher risk of MI, with hazard ratios of 1.14 (1.07–1.21) and 1.08 (1.03–1.12) per inter-quartile range higher 10-year mean of road traffic noise and NO 2 , respectively. Mutual exposure adjustment reduced the association with 10-year NO 2 exposure (1.02 (0.96–1.08)), whereas the association with road traffic noise remained: 1.12 (1.03–1.21). For fatal incident MI, the pattern was similar, but the associations for both pollutants were stronger. In analyses of tertiles across both pollutants, the strongest effects were seen for combined medium/high exposure, especially for fatal MI's. Conclusion Both road traffic noise and NO 2 were associated with a higher risk of MI in single-pollutant models. In two-pollutant models, mainly noise was associated with MI. Combined exposure to both pollutants was associated with the highest risk. [ABSTRACT FROM AUTHOR]

Background Epidemiological studies have shown that intake of drinking water with high levels of arsenic (>100 μg/L) is associated with risk for cardiovascular diseases, but studies on lower levels of arsenic show inconsistent results. Objective The aim of this study was to investigate the relationship between exposure to low level arsenic in drinking water and risk of myocardial infarction in Denmark. Methods From the Danish Diet, Cancer and Health cohort of 57,053 people aged 50–64 years at enrolment in 1993–1997, we identified 2707 cases of incident myocardial infarction from enrolment to end of follow-up in February 2012. Cohort participants were enrolled in the Copenhagen and Aarhus areas. We geocoded residential addresses of the cohort members and used a geographic information system to link addresses with water supply areas. Arsenic in tap water at each cohort members address from 1973 to 2012 was estimated for all cohort members. Poisson regression was used to estimate incidence rate ratios (IRRs) for myocardial infarction after adjustment for lifestyle factors and educational level. Results Arsenic levels in drinking water at baseline addresses ranged from 0.03 to 25.34 μg/L, with the highest concentrations in the Aarhus area. We found no overall association between 20-years average concentration of arsenic and risk of myocardial infarction. However, in the Aarhus area, fourth arsenic quartile (2.21–25.34 μg/L) was associated with an IRR of 1.48 (95% confidence interval (CI): 1.19–1.83) when compared with first quartile (0.05–1.83 μg/L). An IRR of 1.26 (95% CI: 0.89–1.79) was found for ever (versus never) having lived at an address with 10 μg/L or more arsenic in the drinking water. Conclusions This study provides some support for an association between low levels of arsenic in drinking water and the risk of myocardial infarction. [ABSTRACT FROM AUTHOR]