The association between sodium intake and coronary and carotid atherosclerosis in the general Swedish population

Aims

A high intake of salt raises blood pressure and the risk of cardiovascular disease. Previous studies have reported on the association between salt intake and carotid stenosis, but the association with coronary atherosclerosis has not been reported. Therefore, this project aimed at studying the association between salt intake and both carotid and coronary atherosclerosis in a contemporary community-based cohort.

Methods and results

Estimated 24-h sodium excretion (est24hNa) was calculated by the Kawasaki formula for participants of two sites (Uppsala and Malmö) of the Swedish Cardiopulmonary bioImage Study, who underwent a coronary computed tomography (n = 9623) and measurement of coronary artery calcium score (CACS, n = 10 289). Carotid ultrasound was used to detect carotid plaques (n = 10 700). Ordered logistic regression was used to calculate odds ratios (OR) per 1000 mg increase in est24hNa. We also investigated potential J-formed associations using quintiles of est24hNa. Increased est24hNa was associated with increased occurrence of carotid plaques [OR: 1.09, P < 0.001, confidence interval (CI): 1.06-1.12], higher CACS (OR: 1.16, P < 0.001, CI: 1.12-1.19), and coronary artery stenosis (OR: 1.17, P < 0.001, CI: 1.13-1.20) in minimal adjusted models. Associations were abolished when adjusting for blood pressure. When adjusting for established cardiovascular risk factors (not including blood pressure), associations remained for carotid plaques but not for coronary atherosclerosis. There was no evidence of J-formed associations.

Conclusion

Higher est24hNa was associated with both coronary and carotid atherosclerosis in minimal adjusted models. The association seemed mainly mediated by blood pressure but to some degree also influenced by other established cardiovascular risk factors.

Estimated salt intake and risk of atrial fibrillation in a prospective community-based cohort

INTRODUCTION

Hypertension predisposes to atrial fibrillation (AF) - a major risk factor for ischaemic stroke. Since a high dietary salt consumption is associated with hypertension, we investigated the association between urinary sodium excretion as a marker for dietary sodium intake and risk of new-onset AF in community-dwelling adults.

METHOD

The UK Biobank includes 40- to 69-year-old British residents recruited 2006-2010. Participants were divided into sex-specific quintiles according to 24-hour sodium excretion estimated based on spot samples with the Kawasaki equation. We excluded participants with AF at baseline. Cox regression adjusted for cardiovascular risk factors was used to assess associations with risk of AF, using the third quintile as reference.

RESULTS

A total of 257 545 women and 215 535 men were included. During up to 10 years' follow-up, 2221 women and 3751 men were diagnosed with AF. There was a tendency for an increased risk of AF in the lowest and highest quintiles of estimated daily salt intake in both women and men. In the fully adjusted model, significant associations were seen amongst men in the lowest and highest quintiles of sodium excretion (hazard ratio, HR_Qv1 , 1.20; 95% CI, 1.08-1.32, P < 0.001, and HR_Qv5 1.15, 95% CI, 1.03-1.27, P = 0.011).

CONCLUSION

We found evidence for a U-shaped association between estimated daily salt intake and AF risk amongst men. A suggestive J-shaped association in women was not statistically confirmed, but analyses were likely underpowered. Our results suggest that above a certain physiological minimum level progressively higher salt intake is associated with increasing risk of AF.

Pregnancy Associated Plasma Protein-A as a Cardiovascular Risk Marker in Patients with Stable Coronary Heart Disease During 10 Years Follow-Up-A CLARICOR Trial Sub-Study

Elevated pregnancy-associated plasma protein A (PAPP-A) is associated with mortality in acute coronary syndromes. Few studies have assessed PAPP-A in stable coronary artery disease (CAD) and results are conflicting. We assessed the 10-year prognostic relevance of PAPP-A levels in stable CAD. The CLARICOR trial was a randomized controlled clinical trial including outpatients with stable CAD, randomized to clarithromycin versus placebo. The placebo group constituted our discovery cohort (n = 1.996) and the clarithromycin group the replication cohort (n = 1.975). The composite primary outcome was first occurrence of cardiovascular event or death. In the discovery cohort, incidence rates (IR) for the composite outcome were higher in those with elevated PAPP-A (IR 12.72, 95% Confidence Interval (CI) 11.0-14.7 events/100 years) compared to lower PAPP-A (IR 8.78, 8.25-9.34), with comparable results in the replication cohort. Elevated PAPP-A was associated with increased risk of the composite outcome in both cohorts (discovery Hazard Ratio (HR) 1.45, 95% CI 1.24-1.70; replication HR 1.29, 95% CI 1.10-1.52). In models adjusted for established risk factors, these trends were attenuated. Elevated PAPP-A was associated with higher all-cause mortality in both cohorts. We conclude that elevated PAPP-A levels are associated with increased long-term mortality in stable CAD, but do not improve long-term prediction of death or cardiovascular events when added to established predictors.

Cathepsin B and S as markers for cardiovascular risk and all-cause mortality in patients with stable coronary heart disease during 10 years: a CLARICOR trial sub-study

BACKGROUND AND AIMS

The lysosomal cysteine proteases cathepsin B and S have been implicated in the atherosclerotic process. The present paper investigates the association between serum levels of cathepsin B and S and cardiovascular events and mortality in patients with stable coronary heart disease.

METHODS

The CLARICOR trial is a randomised, placebo-controlled trial investigating the effect of clarithromycin versus placebo in patients with stable coronary heart disease. The outcome was time to either a cardiovascular event or all-cause mortality. The placebo group was used as discovery sample and the clarithromycin group as replication sample: n = 1998, n = 1979; mean age (years) 65, 65; 31%, 30% women; follow-up for 10 years; number of composite outcomes n = 1204, n = 1220; respectively. We used a pre-defined multivariable Cox regression model adjusting for inflammation, established cardiovascular risk factors, kidney function, and use of cardiovascular drugs.

RESULTS

Cathepsin B was associated with an increased risk of the composite outcome in both samples after multivariable adjustment (discovery: multivariable ratio (HR) per standard deviation increase 1.12, 95% confidence interval (CI) 1.05-1.19, p < 0.001, replication; HR 1.14, 95% CI 1.07-1.21, p < 0.001). There was no significant association between cathepsin S and the composite outcome in either the discovery or replication sample after multivariable adjustment (p>0.45). Secondary analyses suggest that cathepsin B was predominantly associated with mortality rather than specific cardiovascular events.

CONCLUSIONS

Cathepsin B, but not serum cathepsin S, was associated with an increased risk of cardiovascular events in patients with stable coronary heart disease. The clinical implications of our findings remain to be established.

The association between circulating endostatin and a disturbed circadian blood pressure pattern in patients with type 2 diabetes

BACKGROUND

Endostatin, cleaved from collagen XVIII in the extracellular matrix, is a promising circulating biomarker for cardiovascular damage. It possesses anti-angiogenic and anti-fibrotic functions and has even been suggested to be involved in blood pressure regulation. Less is known if endostatin levels relate to circadian blood pressure patterns. In the present paper we studied the association between circulating levels of endostatin and nocturnal dipping in blood pressure.

METHODS

We used the CARDIPP-study, a cohort of middle aged, type 2 diabetics (n = 593, 32% women), with data on both 24-hour and office blood pressure, serum-endostatin, cardiovascular risk factors, and incident major cardiovascular events. Nocturnal dipping was defined as a >10% difference between day- and night-time blood pressures.

RESULTS

Two-hundred four participants (34%) were classified as non-dippers. The mean endostatin levels were significantly higher in non-dippers compared to dippers (mean ± standard deviation: 62.6 ± 1.8 µg/l vs. 58.7 ± 1.6 µg/l, respectively, p = .007). Higher serum levels of endostatin were associated with a diminished decline in nocturnal blood pressure adjusted for age, sex, HbA1c, mean systolic day blood pressure, hypertension treatment, glomerular filtration rate, and prevalent cardiovascular disease (regression coefficient per SD increase of endostatin -0.01, 95% CI, -0.02-(-0.001), p = .03). Structural equation modelling analyses suggest that endostatin mediates 7% of the association between non-dipping and major cardiovascular events.

CONCLUSION

We found an independent association between higher circulating levels of endostatin and a reduced difference between day- and night-time systolic blood pressure in patients with type 2 diabetes. Yet endostatin mediated only a small portion of the association between non-dipping and cardiovascular events arguing against a clinical utility of our findings.

[Severe ketoacidosis in breastfeeding woman with low energy and carbohydrate intake]

Ketoacidosis is a life threatening condition usually caused by diabetes mellitus or alcohol. In this case report we present a lactating woman who developed a severe ketoacidosis a few weeks post partum. Her nutritional status was inadequate due to illness and a diet low on carbohydrates. Five case reports regarding ketoacidosis in lactating women have previously been described in the literature. This case report highlights the importance of nutrition during periods of breast feeding.