Three new publications

Since the last update, I’ve been co-authoring three new papers.

Association of Dietary Vitamin K and Risk of Coronary Heart Disease in Middle-Age Adults: The Hordaland Health Study Cohort.

This study, by first author Theresa Risan Haugsgjerd, was published in BMJ Open, check it out here:

Abstract

Objective: The role of vitamin K in the regulation of vascular calcification is established. However, the association of dietary vitamins K1 and K2 with risk of coronary heart disease (CHD) is inconclusive.

Design: Prospective cohort study.

Setting: We followed participants in the community-based Hordaland Health Study from 1997 - 1999 through 2009 to evaluate associations between intake of vitamin K and incident (new onset) CHD. Baseline diet was assessed by a past-year food frequency questionnaire. Energy-adjusted residuals of vitamin K1 and vitamin K2 intakes were categorised into quartiles.

Participants: 2987 Norwegian men and women, age 46-49 years.

Methods: Information on incident CHD events was obtained from the nationwide Cardiovascular Disease in Norway (CVDNOR) Project. Multivariable Cox regression estimated HRs and 95% CIs with test for linear trends across quartiles. Analyses were adjusted for age, sex, total energy intake, physical activity, smoking and education. A third model further adjusted K1 intake for energy-adjusted fibre and folate, while K2 intake was adjusted for energy-adjusted saturated fatty acids and calcium.

Results: During a median follow-up time of 11 years, we documented 112 incident CHD cases. In the adjusted analyses, there was no association between intake of vitamin K1 and CHD (HRQ4vsQ1 = 0.92 (95% CI 0.54 to 1.57), p for trend 0.64), while there was a lower risk of CHD associated with higher intake of energy-adjusted vitamin K2 (HRQ4vsQ1 = 0.52 (0.29 to 0.94), p for trend 0.03). Further adjustment for potential dietary confounders did not materially change the association for K1, while the association for K2 was slightly attenuated (HRQ4vsQ1 = 0.58 (0.28 to 1.19)).

Conclusions: A higher intake of vitamin K2 was associated with lower risk of CHD, while there was no association between intake of vitamin K1 and CHD.

Transsulfuration metabolites and the association with incident atrial fibrillation - An observational cohort study among Norwegian patients with stable angina pectoris.

This study, led by Mads Malm Svenningsson, was published in the International Journal of Cardiology. Check it out here:

Abstract

Background/aim: Plasma total homocysteine (tHcy) is elevated in patients with persistent vs. paroxysmal atrial fibrillation (AF), and has been related to increased risk of new-onset AF. Homocysteine is degraded to cystathionine (Cysta) and cysteine (Cys). All three metabolites have been linked to potential proarrhythmic traits such as inflammation and atrial fibrosis. We evaluated the prospective association between these metabolites and new-onset AF among patients with suspected stable angina pectoris.

Methods: Information regarding AF was obtained by linking patient data to national health registries. Risk associations were explored by Cox regression and potential improvements in risk reclassification were calculated by the continuous net reclassification index (NRI ˃ 0).

Results: At baseline, 3535 patients without any prior history of AF were included. During median follow-up of 7.4 years, 392 patients (10.2%) were registered with incident AF. Higher plasma tHcy and tCys were associated with increased risk of incident AF [age and gender adjusted HRs (95% CI) per 1 log transformed SD 1.23 (1.12-1.35) and 1.23 (1.11-1.38)]; multivariate adjustment yielded similar results. Plasma tHcy and tCys also improved reclassification of patients (NRI ˃ 0 (95% CI)) for tHcy 0.118 (0.02-0.22) and tCys 0.107 (0.002-0.21). No association was seen between plasma Cysta and incident AF.

Conclusion: Plasma tHcy and tCys, but not Cysta, were associated with, and improved risk classification of, new-onset AF among patients with stable angina pectoris. Our results motivate further studies to explore the relationship between homocysteine metabolism and cardiac arrhythmias.

Lipid parameters and vitamin A modify cardiovascular risk prediction by plasma neopterin.

Indu Dhar led this work, which was published in Heart. Check it out here:

Abstract

Objectives: Oxidised cholesterol metabolites are linked to increased production of the active vitamin A (Vit-A) form and monocyte/macrophage activation, which may be reflected by neopterin, a marker of both interferon-γ-mediated immune activation and coronary artery disease risk. We examined the influence of serum lipid parameters and Vit-A on the risk association between neopterin and incident acute myocardial infarction (AMI).

Methods: We included 4130 patients with suspected stable angina pectoris (SAP), of whom 80% received lipid-lowering treatment with statins. Risk associations between plasma neopterin and AMI are given as HRs per SD increase in log-transformed neopterin.

Results: During a median follow-up of 7.5 years, 530 (12.8%) patients experienced an AMI. In age-adjusted and sex-adjusted analysis, plasma neopterin was positively associated with incident AMI (HR (95% CI) per SD: 1.26 (1.17 to 1.35)). However, the estimates were most pronounced in patients with serum low-density lipoprotein cholesterol (LDL-C) or apolipoprotein (apo) B100 below-median (HR (95% CI) per SD: 1.35 (1.24 to 1.48) and 1.42 (1.27 to 1.58), respectively; both pinteraction ≤0.03). We also observed a particularly strong risk association in those with above-median Vit-A (HR (95% CI) per SD: 1.32 (1.21 to 1.44); pinteraction=0.03). The estimates were slightly modified after multivariable adjustment.

Conclusions: In patients with suspected SAP, the majority of whom receiving statin therapy, high plasma neopterin was associated with increased risk of AMI particularly among those with low LDL-C and apoB100 or high Vit-A levels. The particularly strong relationship of plasma neopterin with residual cardiovascular risk in patients with low lipid levels should be further investigated.

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Vegard Lysne
Postdoctoral researcher

Clinical Dietitian and postdoctoral researcher. See more about Vegard.

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