Association of glycated hemoglobin A1c levels with cardiovascular outcomes in the general population: results from the BiomarCaRE (Biomarker for Cardiovascular Risk Assessment in Europe) consortium.

BACKGROUND: Biomarkers may contribute to improved cardiovascular risk estimation. Glycated hemoglobin A1c (HbA1c) is used to monitor the quality of diabetes treatment. Its strength of association with cardiovascular outcomes in the general population remains uncertain. This study aims to assess the association of HbA1c with cardiovascular outcomes in the general population. METHODS: Data from six prospective population-based cohort studies across Europe comprising 36,180 participants were analyzed. HbA1c was evaluated in conjunction with classical cardiovascular risk factors (CVRFs) for association with cardiovascular mortality, cardiovascular disease (CVD) incidence, and overall mortality in subjects without diabetes (N = 32,496) and with diabetes (N = 3684). RESULTS: Kaplan-Meier curves showed higher event rates with increasing HbA1c levels (log-rank-test: p < 0.001). Cox regression analysis revealed significant associations between HbA1c (in mmol/mol) in the total study population and the examined outcomes. Thus, a hazard ratio (HR) of 1.16 (95% confidence interval (CI) 1.02-1.31, p = 0.02) for cardiovascular mortality, 1.13 (95% CI 1.03-1.24, p = 0.01) for CVD incidence, and 1.09 (95% CI 1.02-1.17, p = 0.01) for overall mortality was observed per 10 mmol/mol increase in HbA1c. The association with CVD incidence and overall mortality was also observed in study participants without diabetes with increased HbA1c levels (HR 1.12; 95% CI 1.01-1.25, p = 0.04) and HR 1.10; 95% CI 1.01-1.20, p = 0.02) respectively. HbA1c cut-off values of 39.9 mmol/mol (5.8%), 36.6 mmol/mol (5.5%), and 38.8 mmol/mol (5.7%) for cardiovascular mortality, CVD incidence, and overall mortality, showed also an increased risk. CONCLUSIONS: HbA1c is independently associated with cardiovascular mortality, overall mortality and cardiovascular disease in the general European population. A mostly monotonically increasing relationship was observed between HbA1c levels and outcomes. Elevated HbA1c levels were associated with cardiovascular disease incidence and overall mortality in participants without diabetes underlining the importance of HbA1c levels in the overall population.

Decomposing the educational gradient in allostatic load across European populations. What matters the most: differentials in exposure or in susceptibility?

BACKGROUND: We investigate whether socially disadvantaged individuals are more susceptible to the detrimental effects of smoking and alcohol intake on allostatic load (AL), a marker of physiological 'wear and tear', resulting from adaptation to chronic stress. METHODS: In a cross-sectional analysis, 27 019 men and 26 738 women aged 35-74 years were identified from 21 European cohorts in the BiomarCaRE consortium. We defined three educational classes (EDs) according to years of schooling and an AL score as the sum of z-scores of eight selected biomarkers from the cardiovascular, metabolic and inflammatory systems. We used the Oaxaca-Blinder decomposition to disentangle the ED gradient in AL score into the differential exposure (DE, attributable to different distribution of smoking and alcohol intake across EDs) and the differential susceptibility (DS, attributable to a different effect of risk factors on AL across EDs) components. RESULTS: Less-educated men (mean AL difference: 0.68, 95% CI 0.57 to 0.79) and women (1.52, 95% CI 1.40 to 1.64) had higher AL scores. DE accounted for 7% and 6% of the gradient in men and women, respectively. In men, combining smoking and alcohol intake, DS accounted for 42% of the gradient (smoking DS coefficient=0.177, 26% of the gradient; alcohol DS coefficient=0.109; 16%, not statistically significant). DS contribution increased to 69% in metabolic markers. DS estimates were consistent across age groups, irrespective of comorbidities and robust to unmeasured confounding. No DS was observed in women. CONCLUSIONS: In men, a DS mechanism substantially contributes to the educational class gradient in allostatic load.

The effect of exposure to long working hours on ischaemic heart disease: A systematic review and meta-analysis from the WHO/ILO Joint Estimates of the Work-related Burden of Disease and Injury.

BACKGROUND: The World Health Organization (WHO) and the International Labour Organization (ILO) are developing Joint Estimates of the work-related burden of disease and injury (WHO/ILO Joint Estimates), with contributions from a large network of experts. Evidence from mechanistic data suggests that exposure to long working hours may cause ischaemic heart disease (IHD). In this paper, we present a systematic review and meta-analysis of parameters for estimating the number of deaths and disability-adjusted life years from IHD that are attributable to exposure to long working hours, for the development of the WHO/ILO Joint Estimates. OBJECTIVES: We aimed to systematically review and meta-analyse estimates of the effect of exposure to long working hours (three categories: 41-48, 49-54 and ≥55 h/week), compared with exposure to standard working hours (35-40 h/week), on IHD (three outcomes: prevalence, incidence and mortality). DATA SOURCES: We developed and published a protocol, applying the Navigation Guide as an organizing systematic review framework where feasible. We searched electronic databases for potentially relevant records from published and unpublished studies, including MEDLINE, Scopus, Web of Science, CISDOC, PsycINFO, and WHO ICTRP. We also searched grey literature databases, Internet search engines and organizational websites; hand-searched reference lists of previous systematic reviews; and consulted additional experts. STUDY ELIGIBILITY AND CRITERIA: We included working-age (≥15 years) workers in the formal and informal economy in any WHO and/or ILO Member State but excluded children (aged < 15 years) and unpaid domestic workers. We included randomized controlled trials, cohort studies, case-control studies and other non-randomized intervention studies which contained an estimate of the effect of exposure to long working hours (41-48, 49-54 and ≥55 h/week), compared with exposure to standard working hours (35-40 h/week), on IHD (prevalence, incidence or mortality). STUDY APPRAISAL AND SYNTHESIS METHODS: At least two review authors independently screened titles and abstracts against the eligibility criteria at a first stage and full texts of potentially eligible records at a second stage, followed by extraction of data from qualifying studies. Missing data were requested from principal study authors. We combined relative risks using random-effect meta-analysis. Two or more review authors assessed the risk of bias, quality of evidence and strength of evidence, using Navigation Guide and GRADE tools and approaches adapted to this project. RESULTS: Thirty-seven studies (26 prospective cohort studies and 11 case-control studies) met the inclusion criteria, comprising a total of 768,751 participants (310,954 females) in 13 countries in three WHO regions (Americas, Europe and Western Pacific). The exposure was measured using self-reports in all studies, and the outcome was assessed with administrative health records (30 studies) or self-reported physician diagnosis (7 studies). The outcome was defined as incident non-fatal IHD event in 19 studies (8 cohort studies, 11 case-control studies), incident fatal IHD event in two studies (both cohort studies), and incident non-fatal or fatal ("mixed") event in 16 studies (all cohort studies). Because we judged cohort studies to have a relatively lower risk of bias, we prioritized evidence from these studies and treated evidence from case-control studies as supporting evidence. For the bodies of evidence for both outcomes with any eligible studies (i.e. IHD incidence and mortality), we did not have serious concerns for risk of bias (at least for the cohort studies). No eligible study was found on the effect of long working hours on IHD prevalence. Compared with working 35-40 h/week, we are uncertain about the effect on acquiring (or incidence of) IHD of working 41-48 h/week (relative risk (RR) 0.98, 95% confidence interval (CI) 0.91 to 1.07, 20 studies, 312,209 participants, I2 0%, low quality of evidence) and 49-54 h/week (RR 1.05, 95% CI 0.94 to 1.17, 18 studies, 308,405 participants, I2 0%, low quality of evidence). Compared with working 35-40 h/week, working ≥55 h/week may have led to a moderately, clinically meaningful increase in the risk of acquiring IHD, when followed up between one year and 20 years (RR 1.13, 95% CI 1.02 to 1.26, 22 studies, 339,680 participants, I2 5%, moderate quality of evidence). Compared with working 35-40 h/week, we are very uncertain about the effect on dying (mortality) from IHD of working 41-48 h/week (RR 0.99, 95% CI 0.88 to 1.12, 13 studies, 288,278 participants, I2 8%, low quality of evidence) and 49-54 h/week (RR 1.01, 95% CI 0.82 to 1.25, 11 studies, 284,474 participants, I2 13%, low quality of evidence). Compared with working 35-40 h/week, working ≥55 h/week may have led to a moderate, clinically meaningful increase in the risk of dying from IHD when followed up between eight and 30 years (RR 1.17, 95% CI 1.05 to 1.31, 16 studies, 726,803 participants, I2 0%, moderate quality of evidence). Subgroup analyses found no evidence for differences by WHO region and sex, but RRs were higher among persons with lower SES. Sensitivity analyses found no differences by outcome definition (exclusively non-fatal or fatal versus "mixed"), outcome measurement (health records versus self-reports) and risk of bias ("high"/"probably high" ratings in any domain versus "low"/"probably low" in all domains). CONCLUSIONS: We judged the existing bodies of evidence for human evidence as "inadequate evidence for harmfulness" for the exposure categories 41-48 and 49-54 h/week for IHD prevalence, incidence and mortality, and for the exposure category ≥55 h/week for IHD prevalence. Evidence on exposure to working ≥55 h/week was judged as "sufficient evidence of harmfulness" for IHD incidence and mortality. Producing estimates for the burden of IHD attributable to exposure to working ≥55 h/week appears evidence-based, and the pooled effect estimates presented in this systematic review could be used as input data for the WHO/ILO Joint Estimates.

Determinants of social inequalities in stroke incidence across Europe: a collaborative analysis of 126 635 individuals from 48 cohort studies.

BACKGROUND: Knowledge on the origins of the social gradient in stroke incidence in different populations is limited. This study aims to estimate the burden of educational class inequalities in stroke incidence and to assess the contribution of risk factors in determining these inequalities across Europe. MATERIALS AND METHODS: The MORGAM (MOnica Risk, Genetics, Archiving and Monograph) Study comprises 48 cohorts recruited mostly in the 1980s and 1990s in four European regions using standardised procedures for baseline risk factor assessment and fatal and non-fatal stroke ascertainment and adjudication during follow-up. Among the 126 635 middle-aged participants, initially free of cardiovascular diseases, generating 3788 first stroke events during a median follow-up of 10 years, we estimated differences in stroke rates and HRs for the least versus the most educated individuals. RESULTS: Compared with their most educated counterparts, the overall age-adjusted excess hazard for stroke was 1.54 (95% CI 1.25 to 1.91) and 1.41 (95% CI 1.16 to 1.71) in least educated men and women, respectively, with little heterogeneity across populations. Educational class inequalities accounted for 86-413 and 78-156 additional stroke events per 100 000 person-years in the least compared with most educated men and women, respectively. The additional events were equivalent to 47%-130% and 40%-89% of the average incidence rates. Inequalities in risk factors accounted for 45%-70% of the social gap in incidence in the Nordic countries, the UK and Lithuania-Kaunas (men), but for no more than 17% in Central and South Europe. The major contributors were cigarette smoking, alcohol intake and body mass index. CONCLUSIONS: Social inequalities in stroke incidence contribute substantially to the disease rates in Europe. Healthier lifestyles in the most disadvantaged individuals should have a prominent impact in reducing both inequalities and the stroke burden.

Combined use of short-term and long-term cardiovascular risk scores in primary prevention: an assessment of clinical utility.

AIMS: To evaluate the clinical utility of cardiovascular disease (CVD) risk stratification based on a combined use of short-term and long-term risk scores in the primary prevention setting. METHODS: CVD-free participants 40-65 years old initially to seven population-based cohorts enrolled in northern and central Italy were stratified as 'low' (ESC-SCORE ≤ 1%), 'intermediate' (SCORE 1-4%) and 'moderate/high' short-term CVD risk (SCORE ≥ 4% or diabetes). The long-term CVD risk was estimated using the CAMUNI-MATISS model, validated for the Italian population. Participants were followed up for a median time of 16 years to ascertain the first major CVD event, fatal or nonfatal. To compare the 'combined' (SCORE + CAMUNI-MATISS) with the 'current' (SCORE alone) stratification, we estimated the difference in Net Benefit between the two strategies. RESULTS: Study sample included 3935 men (468 CVD events) and 4393 women (210 events). Under the 'current' stratification, 76% of men and 21% of women were at 'intermediate' risk and eligible to treatment. Only 40% of them had elevated predicted long-term risk and could have received indication to treatment under the 'combined' strategy. The latter would have saved 3 and 3.5 unnecessary treatments per every CVD case in men and women, respectively, and the Net Benefit significantly increased [men: 4.1, 95% confidence interval (CI): 2.7-5.6; women: 4.4, 95% CI: 1.7-6.9].Similarly, among the 74% of women not receiving indication for prevention because at 'low' short-term risk, the 'combined' stratification significantly increased the Net Benefit (1.4, 95% CI: 0.6-2.1) and reduced from 40 to 10% the proportion of events occurring among women not eligible to any preventive action. CONCLUSION: In the Italian population, a combination of validated short-term and long-term CVD risk scores has the potential to select for prevention women whose risk is currently not fully addressed and to reduce unnecessary costly treatment.

Educational class inequalities in the incidence of coronary heart disease in Europe.

OBJECTIVE: To estimate the burden of social inequalities in coronary heart disease (CHD) and to identify their major determinants in 15 European populations. METHODS: The MORGAM (MOnica Risk, Genetics, Archiving and Monograph) study comprised 49 cohorts of middle-aged European adults free of CHD (110 928 individuals) recruited mostly in the mid-1980s and 1990s, with comparable assessment of baseline risk and follow-up procedures. We derived three educational classes accounting for birth cohorts and used regression-based inequality measures of absolute differences in CHD rates and HRs (ie, Relative Index of Inequality, RII) for the least versus the most educated individuals. RESULTS: N=6522 first CHD events occurred during a median follow-up of 12 years. Educational class inequalities accounted for 343 and 170 additional CHD events per 100 000 person-years in the least educated men and women compared with the most educated, respectively. These figures corresponded to 48% and 71% of the average event rates in each gender group. Inequalities in CHD mortality were mainly driven by incidence in the Nordic countries, Scotland and Lithuania, and by 28-day case-fatality in the remaining central/South European populations. The pooled RIIs were 1.6 (95% CI 1.4 to 1.8) in men and 2.0 (1.7 to 2.4) in women, consistently across population. Risk factors accounted for a third of inequalities in CHD incidence; smoking was the major mediator in men, and High-Density-Lipoprotein (HDL) cholesterol in women. CONCLUSIONS: Social inequalities in CHD are still widespread in Europe. Since the major determinants of inequalities followed geographical and gender-specific patterns, European-level interventions should be tailored across different European regions.

Validity of a long-term cardiovascular disease risk prediction equation for low-incidence populations: the CAMUNI-MATISS Cohorts Collaboration study.

BACKGROUND: Before introducing long-term cardiovascular disease (CVD) risk models in clinical practice, their external validity should be investigated. We assessed the validity of the CArdiovascular Monitoring Unit in Northern Italy (CAMUNI) 20-year risk score, developed in Northern Italy, and published previously, when applied to a population with different risk factors distribution and event incidence. METHODS: The validation sample consisted of 5307 35-69 year-old subjects (2418 men) enrolled in Central Italy during the 1980s (Malattia ATerosclerotica Istituto Superiore di Sanità (MATISS) study). Baseline risk factor assessment and follow-up procedures, including MONICA definition of acute events, followed a shared protocol with the derivation cohorts. We estimated model calibration and discrimination (area under the ROC curve, AUC) in the validation set; as well as the net benefit of using the CAMUNI risk score as second-level screening in subjects at different levels of short-term risk. RESULTS: The 20-year risk of event was 14% in men and 7% in women. Model calibration was satisfactory, and the strength of the association between predictors and the endpoint was the same as in the derivation population. The AUC was 0.734 (men) and 0.802 (women). The net benefit of the CAMUNI score was 3.9 (95% confidence interval: 2.1-5.7) and 2.9 (1.7-4.3) in men and women at low 10-year risk, respectively. Among subjects at high short-term risk, a significant net benefit of 9.8 was observed in men only. A pooled CAMUNI-MATISS risk score is provided. CONCLUSIONS: In this low-incidence European population, long-term CVD prediction through the CAMUNI risk score is accurate and it has the potential to improve current primary prevention strategies based on short-term risk scores alone.

The contribution of major risk factors and job strain to occupational class differences in coronary heart disease incidence: the MONICA Brianza and PAMELA population-based cohorts.

OBJECTIVES: We investigated the contribution of major coronary heart disease (CHD) risk factors and job strain to occupational class differences in CHD incidence in a pooled-cohort prospective study in northern Italy. METHODS: 2964 men aged 25-74 from four northern Italian population-based cohorts were investigated at baseline and followed for first fatal or non-fatal CHD event (171 events). Standardised procedures were used for baseline risk factor measurements, follow-up and validation of CHD events. Four occupational classes were derived from the Erikson-Goldthorpe-Portocarero social class scheme: higher and lower professionals and administrators, non-manual workers, skilled and unskilled manual workers, and the self-employed. HRs were estimated with Cox models. RESULTS: Among CHD-free subjects, with non-manual workers as the reference group, age-adjusted excess risks were found for professionals and administrators (+84%, p=0.02), the self-employed (+72%, p=0.04) and manual workers (+63%, p=0.04). The relationship was consistent across different CHD diagnostic categories. Adjusting for major risk factors only slightly reduced the reported excess risks. In a sub-sample of currently employed subjects, adjusting for major risk factors, sport physical activity and job strain reduced the excess risk for manual workers (relative change = -71.4%) but did not substantially modify the excess risks of professionals and administrators and the self-employed. CONCLUSIONS: In our study, we found higher CHD incidence rates for manual workers, professionals and administrators, and the self-employed, compared to non-manual workers. When the entire spectrum of job categories is considered, the job strain model helped explain the CHD excess risk for manual workers but not for other occupational classes.

Social status and cardiovascular disease: a Mediterranean case. Results from the Italian Progetto CUORE cohort study.

BACKGROUND: Social factors could offer useful information for planning prevention strategy for cardiovascular diseases. This analysis aims to explore the relationship between education, marital status and major cardiovascular risk factors and to evaluate the role of social status indicators in predicting cardiovascular events and deaths in several Italian cohorts. METHODS: The population is representative of Italy, where the incidence of the disease is low. Data from the Progetto CUORE, a prospective study of cohorts enrolled between 1983-1997, were used; 7520 men and 13127 women aged 35-69 years free of previous cardiovascular events and followed for an average of 11 years. Educational level and marital status were used as the main indicators of social status. RESULTS: About 70% of the studied population had a low or medium level of education (less than high school) and more than 80% was married or cohabitating. There was an inverse relationship between educational level and major cardiovascular risk factors in both genders. Significantly higher major cardiovascular risk factors were detected in married or cohabitating women, with the exception of smoking. Cardiovascular risk score was lower in married or cohabitating men. No relationship between incidence of cardiac events and the two social status indicators was observed. Cardiovascular case-fatality was significantly higher in men who were not married and not cohabitating (HR 3.20, 95%CI: 2.21-4.64). The higher cardiovascular risk observed in those with a low level of education deserves careful attention even if during the follow-up it did not seem to determine an increase of cardiac events. CONCLUSIONS: Preventive interventions on cardiovascular risk should be addressed mostly to people with less education. Cardiovascular risk score and case-fatality resulted higher in men living alone while cardiovascular factors were higher in women married or cohabitating. Such gender differences seem peculiar of our population and require further research on unexpected cultural and behavioural influences.