Radiotherapy for breast cancer often involves some incidental exposure of the heart to ionizing radiation. The effect of this exposure on the subsequent risk of ischemic heart disease is uncertain.
...We conducted a population-based case-control study of major coronary events (i.e., myocardial infarction, coronary revascularization, or death from ischemic heart disease) in 2168 women who underwent radiotherapy for breast cancer between 1958 and 2001 in Sweden and Denmark; the study included 963 women with major coronary events and 1205 controls. Individual patient information was obtained from hospital records. For each woman, the mean radiation doses to the whole heart and to the left anterior descending coronary artery were estimated from her radiotherapy chart.
The overall average of the mean doses to the whole heart was 4.9 Gy (range, 0.03 to 27.72). Rates of major coronary events increased linearly with the mean dose to the heart by 7.4% per gray (95% confidence interval, 2.9 to 14.5; P<0.001), with no apparent threshold. The increase started within the first 5 years after radiotherapy and continued into the third decade after radiotherapy. The proportional increase in the rate of major coronary events per gray was similar in women with and women without cardiac risk factors at the time of radiotherapy.
Exposure of the heart to ionizing radiation during radiotherapy for breast cancer increases the subsequent rate of ischemic heart disease. The increase is proportional to the mean dose to the heart, begins within a few years after exposure, and continues for at least 20 years. Women with preexisting cardiac risk factors have greater absolute increases in risk from radiotherapy than other women. (Funded by Cancer Research UK and others.).
Few studies have investigated effects of air pollution on the incidence of cerebrovascular events.
We assessed the association between long-term exposure to multiple air pollutants and the incidence ...of stroke in European cohorts.
Data from 11 cohorts were collected, and occurrence of a first stroke was evaluated. Individual air pollution exposures were predicted from land-use regression models developed within the European Study of Cohorts for Air Pollution Effects (ESCAPE). The exposures were: PM2.5 particulate matter (PM) ≤ 2.5 μm in diameter, coarse PM (PM between 2.5 and 10 μm), PM10 (PM ≤ 10 μm), PM2.5 absorbance, nitrogen oxides, and two traffic indicators. Cohort-specific analyses were conducted using Cox proportional hazards models. Random-effects meta-analysis was used for pooled effect estimation.
A total of 99,446 study participants were included, 3,086 of whom developed stroke. A 5-μg/m3 increase in annual PM2.5 exposure was associated with 19% increased risk of incident stroke hazard ratio (HR) = 1.19, 95% CI: 0.88, 1.62. Similar findings were obtained for PM10. The results were robust to adjustment for an extensive list of cardiovascular risk factors and noise coexposure. The association with PM2.5 was apparent among those ≥ 60 years of age (HR = 1.40, 95% CI: 1.05, 1.87), among never-smokers (HR = 1.74, 95% CI: 1.06, 2.88), and among participants with PM2.5 exposure < 25 μg/m3 (HR = 1.33, 95% CI: 1.01, 1.77).
We found suggestive evidence of an association between fine particles and incidence of cerebrovascular events in Europe, even at lower concentrations than set by the current air quality limit value.
Midlife lipid levels are important predictors of cardiovascular diseases, yet their association with mortality in older adults is less clear. We aimed to (1) identify lipid profiles based on ...cholesterol, triglycerides, and apolipoproteins using cluster analysis, and (2) investigate how lipid profiles and lipid levels at different ages are associated with later-life all-cause and cardiovascular mortality. We used data from 98,270 individuals in the Swedish AMORIS cohort who had blood measurements between 1985-1996 and were followed until 2012. Over the follow-up (mean 18.0 years), 30,730 (31.3%) individuals died. Three lipid profiles were identified. Compared with reference profile, a high lipid profile (low ApoA-I and high total cholesterol (TC), triglycerides, ApoB, and ApoB/ApoA-I ratio) at ages 39-59 or 60-79 was associated with higher all-cause mortality. A high lipid profile at ≥ 80 years, however, did not confer higher mortality. For the specific markers, high TC (≥ 7.25 mmol/L) was associated with higher all-cause mortality in ages 39-59 but lower mortality in ages 60-79 and ≥ 80. Low ApoA-I (< 1.28 g/L) and high ApoB/ApoA-I ratio (≥ 1.18), on the other hand, were associated with higher cardiovascular mortality regardless of age at lipid measurement, highlighting their potential relevance for survival in both young and older individuals.
We aimed to investigate the association of serum pentadecanoic acid (15:0), a biomarker of dairy fat intake, with incident cardiovascular disease (CVD) and all-cause mortality in a Swedish cohort ...study. We also systematically reviewed studies of the association of dairy fat biomarkers (circulating or adipose tissue levels of 15:0, heptadecanoic acid 17:0, and trans-palmitoleic acid t16:1n-7) with CVD outcomes or all-cause mortality. We measured 15:0 in serum cholesterol esters at baseline in 4,150 Swedish adults (51% female, median age 60.5 years). During a median follow-up of 16.6 years, 578 incident CVD events and 676 deaths were identified using Swedish registers. In multivariable-adjusted models, higher 15:0 was associated with lower incident CVD risk in a linear dose-response manner (hazard ratio 0.75 per interquintile range; 95% confidence interval 0.61, 0.93, P = 0.009) and nonlinearly with all-cause mortality (P for nonlinearity = 0.03), with a nadir of mortality risk around median 15:0. In meta-analyses including our Swedish cohort and 17 cohort, case-cohort, or nested case-control studies, higher 15:0 and 17:0 but not t16:1n-7 were inversely associated with total CVD, with the relative risk of highest versus lowest tertile being 0.88 (0.78, 0.99), 0.86 (0.79, 0.93), and 1.01 (0.91, 1.12), respectively. Dairy fat biomarkers were not associated with all-cause mortality in meta-analyses, although there were less than or equal to3 studies for each biomarker. Study limitations include the inability of the biomarkers to distinguish different types of dairy foods and that most studies in the meta-analyses (including our novel cohort study) only assessed biomarkers at baseline, which may increase the risk of misclassification of exposure levels. In a meta-analysis of 18 observational studies including our new cohort study, higher levels of 15:0 and 17:0 were associated with lower CVD risk. Our findings support the need for clinical and experimental studies to elucidate the causality of these relationships and relevant biological mechanisms.
The role of cholesterol levels in the development of atrial fibrillation (AF) is still controversial. In addition, whether and to what extent apolipoproteins are associated with the risk of AF is ...rarely studied. In this study, we aimed to investigate the association between blood lipid levels in midlife and subsequent risk of new-onset AF. This population-based study included 65,136 individuals aged 45 to 60 years without overt cardiovascular diseases (CVDs) from the Swedish Apolipoprotein-Related Mortality Risk (AMORIS) cohort. Lipids were measured in 1985 to 1996, and individuals were followed until December 31, 2019 for incident AF (i.e., study outcome). Hazard ratios (HRs) with 95% confidence intervals (CIs) were estimated using Cox regression, adjusting for age, sex, and socioeconomic status. Over a mean follow-up of 24.2 years (standard deviation 7.5, range 0.2 to 35.9), 13,871 (21.3%) incident AF cases occurred. Higher levels of total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) were statistically significantly associated with a lower risk of AF during the first 5 years of follow-up (HR = 0.61, 95% CI: 0.41 to 0.99, p = 0.013; HR = 0.64, 95% CI: 0.45 to 0.92, p = 0.016), but not thereafter (HR ranging from 0.94 95% CI: 0.89 to 1.00, p = 0.038 to 0.96 95% CI: 0.77 to 1.19, p > 0.05). Lower levels of high-density lipoprotein cholesterol (HDL-C) and apolipoprotein A-I (ApoA-I) and higher triglycerides (TG)/HDL-C ratio were statistically significantly associated with a higher risk of AF during the entire follow-up (HR ranging from 1.13 95% CI: 1.07 to 1.19, p < 0.001 to 1.53 95% CI: 1.12 to 2.00, p = 0.007). Apolipoprotein B (ApoB)/ApoA-I ratio was not associated with AF risk. The observed associations were similar among those who developed incident heart failure (HF)/coronary heart disease (CHD) and those who did not. The main limitations of this study include lack of adjustments for lifestyle factors and high blood pressure leading to potential residual confounding. High TC and LDL-C in midlife was associated with a lower risk of AF, but this association was present only within 5 years from lipid measurement and not thereafter. On the contrary, low HDL-C and ApoA-I and high TG/HDL-C ratio were associated with an increased risk of AF over almost 35 years of follow-up. ApoB/ApoA-I ratio was not associated with AF risk.
To examine whether chocolate consumption is associated with a reduced risk of ischaemic heart disease, we used data from a prospective study of Swedish adults and we performed a meta-analysis of ...available prospective data.
The Swedish prospective study included 67 640 women and men from the Cohort of Swedish Men and the Swedish Mammography Cohort who had completed a food-frequency questionnaire and were free of cardiovascular disease at baseline. Myocardial infarction (MI) cases were ascertained through linkage with the Swedish National Patient and Cause of Death Registers. PubMed and EMBASE databases were searched from inception until 4 February 2016 to identify prospective studies on chocolate consumption and risk of ischaemic heart disease.
The results from eligible studies were combined using a random-effects model. During follow-up (1998-2010), 4417 MI cases were ascertained in the Swedish study. Chocolate consumption was inversely associated with MI risk. Compared with non-consumers, the multivariable relative risk for those who consumed ≥3-4 servings/week of chocolate was 0.87 (95% CI 0.77 to 0.98; p for trend =0.04). Five prospective studies on chocolate consumption and ischaemic heart disease were identified. Together with the Swedish study, the meta-analysis included six studies with a total of 6851 ischaemic heart disease cases. The overall relative risk for the highest versus lowest category of chocolate consumption was 0.90 (95% CI 0.82 to 0.97), with little heterogeneity among studies (I(2)=24.3%).
Chocolate consumption is associated with lower risk of MI and ischaemic heart disease.
Understanding why individuals with severe mental illness (Schizophrenia, Bipolar Disorder and Major Depressive Disorder) have increased risk of cardiometabolic disease (including obesity, type 2 ...diabetes and cardiovascular disease), and identifying those at highest risk of cardiometabolic disease are important priority areas for researchers. For individuals with European ancestry we explored whether genetic variation could identify sub-groups with different metabolic profiles. Loci associated with schizophrenia, bipolar disorder and major depressive disorder from previous genome-wide association studies and loci that were also implicated in cardiometabolic processes and diseases were selected. In the IMPROVE study (a high cardiovascular risk sample) and UK Biobank (general population sample) multidimensional scaling was applied to genetic variants implicated in both psychiatric and cardiometabolic disorders. Visual inspection of the resulting plots used to identify distinct clusters. Differences between these clusters were assessed using chi-squared and Kruskall-Wallis tests. In IMPROVE, genetic loci associated with both schizophrenia and cardiometabolic disease (but not bipolar disorder or major depressive disorder) identified three groups of individuals with distinct metabolic profiles. This grouping was replicated within UK Biobank, with somewhat less distinction between metabolic profiles. This work focused on individuals of European ancestry and is unlikely to apply to more genetically diverse populations. Overall, this study provides proof of concept that common biology underlying mental and physical illness may help to stratify subsets of individuals with different cardiometabolic profiles.
We aimed to investigate whether different measures of obesity could similarly predict atrial fibrillation, and whether the atrial fibrillation risk associated with obesity is dependent on presence of ...metabolic syndrome.
We performed our study in a population-based longitudinal cardiovascular study, comprising 1 924 men and 2 097 women, aged 60 years, from Stockholm. Body mass index, waist circumference, sagittal abdominal diameter and components of metabolic syndrome (systolic- and diastolic blood pressure, fasting glucose, triglycerides, high-density lipoprotein-cholesterol) were recorded at baseline. Participants were classified by their body mass index (normal weight, overweight or obese), waist circumference (normal, semi-elevated or elevated), and according to presence of metabolic syndrome. Atrial fibrillation risk was estimated by Cox proportional hazards regression models, adjusted for common atrial fibrillation risk factors, expressed as HR and 95% CI.
During a mean follow-up of 13.6 years, 285 incident atrial fibrillation cases were recorded. One standard deviation increment of each obesity measure was associated with increased atrial fibrillation risk as: body mass index 1.25 (1.12 - 1.40), waist circumference 1.35 (1.19 - 1.54) and sagittal abdominal diameter 1.28 (1.14 - 1.44). Compared to normal weight subjects without metabolic syndrome, increased atrial fibrillation risk was noted for overweight subjects with metabolic syndrome, 1.67 (1.16 - 2.41), obese subjects without metabolic syndrome, 1.75 (1.11 - 2.74) and obese subjects with metabolic syndrome, 1.92 (1.34 - 2.74). Compared to subjects with normal waist circumference without metabolic syndrome, subjects with elevated waist circumference and metabolic syndrome suffered increased atrial fibrillation risk, 2.03 (1.44 - 2.87).
Body mass index, waist circumference and sagittal abdominal diameter could similarly predict atrial fibrillation. Obesity was associated with an increased atrial fibrillation risk regardless of metabolic syndrome, whereas overweight and elevated waist circumference was associated with increased atrial fibrillation risk only if metabolic syndrome was present.
Abstract
Background
Pro-inflammatory processes underlie ischemic stroke, albeit it is largely unknown if they selectively associate with the risk of atherothrombotic or cardioembolic ischemic stroke. ...Here we analyze whether pro-inflammatory interleukin (IL) 6 trans-signaling, is associated with the risk of ischemic stroke and underlying atrial fibrillation (AF).
Methods
During a 20-year follow-up, 203 incident ischemic strokes were recorded from national registers in the cohort of 60-year-old men and women from Stockholm (n = 4232). The risk of ischemic stroke associated with circulating IL6 trans-signaling, assessed by a ratio between the pro-inflammatory binary IL6:sIL6R complex and the inactive ternary IL6:sIL6R:sgp130 complex (B/T ratio), was estimated by Cox regression and expressed as hazard ratio (HR) with a 95% confidence interval (CI) in the presence or absence of AF. Risk estimates were adjusted for cardiovascular risk factors and anticoagulant treatment. In a secondary analysis, the association of IL6 trans-signaling with the risk of incident AF (n = 279) was analyzed.
Results
B/T ratio > median was associated with increased risk of ischemic stroke in study participants without AF (adjusted HR 1.49; 95% CI 1.08–2.06), while an association could not be demonstrated in the presence of AF. Moreover, the B/T ratio was not associated with the risk of AF (HR 0.96; 95% CI 0.75–1.24).
Conclusions
Pro-inflammatory IL6 trans-signaling, estimated by the B/T ratio, is associated with ischemic stroke in individuals without AF. These findings suggest that the B/T ratio could be used to assess the risk of non-AF associated ischemic stroke.
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