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Background: Circadian rhythms regulate key biological processes influencing metabolic pathways. Disregulation is associated with type 2 diabetes (T2D) and cardiovascular diseases (CVD). Circadian rhythms are generated by a transcriptional autoregulatory feedback loop involving core clock genes. CLOCK (circadian locomotor output cycles protein kaput), one of those core genes, is known to regulate glucose metabolism in rodent models. Cross-sectional studies in humans have reported associations between this locus and obesity, plasma glucose, hypertension and T2D prevalence, supporting its role in cardiovascular risk. However, no longitudinal study has investigated the association between CLOCK gene variation and T2D or CVD incidence. Moreover, although in a previous work we detected a gene-diet interaction between the CLOCK-rs4580704 (C > G) single nucleotide polymorphism (SNP) and monounsaturated (MUFA) intake on insulin resistance, no interventional study has analyzed gene-diet interactions on T2D or CVD outcomes. Methods: We analyzed the association between the CLOCK-rs4580704 SNP and incidence of T2D and CVD longitudinally in 7098 PREDIMED trial (ISRCTN35739639) participants after a median 4.8-year follow-up. We also examined modulation by Mediterranean diet (MedDiet) intervention (high in MUFA) on these associations. Results: We observed a significant association between the CLOCK-rs4580704 SNP and T2D incidence in n = 3671 non-T2D PREDIMED participants, with variant allele (G) carriers showing decreased incidence (dominant model) compared with CC homozygotes (HR: 0.69; 95 % CI 0.54-0.87; P = 0.002). This protection was more significant in the MedDiet intervention group (HR: 0.58; 95 % CI 0.43-0.78; P < 0.001) than in the control group (HR: 0.95; 95 % CI 0.63-1.44; P = 0.818). Moreover, we detected a statistically significant interaction (P = 0.018) between CLOCK-rs4580704 SNP and T2D status on stroke. Thus, only in T2D subjects was CLOCK-rs4580704 SNP associated with stroke risk, G-carriers having decreased risk (HR: 0.61; 95 % CI 0.40-0.94; P = 0.024 versus CC) in the multivariable-adjusted model. Conclusions: In agreement with our previous results showing a protective effect of the G-allele against hyperglycemia, we extended our findings by reporting a novel association with lower T2D incidence and also suggesting a dietary modulation. Moreover, we report for the first time an association between a CLOCK polymorphism and stroke in T2D subjects, suggesting that core clock genes may significantly contribute to increased CVD risk in T2D., This study was funded, by the Spanish Ministry of Health (Instituto de Salud Carlos III) and the Ministerio de Economia y Competitividad (Projects PI051839, PI070240, PI1001407, G03/140, CIBER 06/03, RD06/0045 PI07-0954, CNIC-06, PI11/02505, SAF2009-12304, AGL2010-22319-C03-03 and PRX14/00527), Fondo Europeo de Desarrollo Regional, by the University Jaume I (Project P1-1B2013-54) and by the Generalitat Valenciana (AP111/10, AP-042/11, BEST/2015/087, GVACOMP2011-151, ACOMP/2011/145, ACOMP/2012/190 and ACOMP/2013/159). This material is based upon work supported by the U.S. Department of Agriculture-Agricultural Research Service (ARS), under Agreement No. 58-1950-4-003.

[Background] Whilst it is well known that psychosocial determinants may contribute to cardiovascular diseases (CVD), data from specific groups are scarce. The present study aims to determine the contribution of psychosocial determinants in increasing the risk of cardiovascular events (myocardial infarction and stroke), and death from CVD, in a high risk adult population., [Methods] Longitudinal prospective study of 7263 patients (57.5% women), mean age 67.0 (SD 6.2) free from CVD but at high risk, with a median follow-up of 4.8 years (from October 2003 to December 2010). The Hazard Ratios (HRs) of cardiovascular events (myocardial infarction, stroke, and death from cardiovascular causes) related to educational attainment, diagnosed depression (based on medical records), and low social support (number of people living in the household) were estimated by multivariate Cox regression models., [Results] Stroke incidence was associated with low educational level in the whole population (HR: 1.83, 95% CI: 1.09–3.09), and especially in men (HR: 2.11, 95% CI 1.09–4.06). Myocardial infarction and CVD mortality were not associated with any of the psychosocial factors considered., [Conclusion] Adults with low educational level had a higher risk of stroke. Depression and low social support were not associated with CVD incidence., [Trial registration] Clinical trial registration information unique identifier: ISRCTN35739639., Instituto de Salud Carlos III, and Centro de Investigación Biomédica en Red de Fisiopatología de la Obesidad y Nutrición, and Centro Nacional de Investigaciones Cardiovasculares, Fondo de Investigación Sanitaria–Fondo Europeo de Desarrollo Regional, Ministerio de Ciencia e Innovación, Fundación Mapfre 2010, Consejería de Salud de la Junta de Andalucía, Public Health Division of the Department of Health of the Autonomous Government of Catalonia, Generalitat Valenciana, and the Regional Government of Navarra. None of the institutions described above have influenced the design, collection, analysis, and interpretation of data; the writing of the manuscript; and the decision to submit the manuscript for publication.

Background Several epidemiological studies have observed an increased risk of type 2 diabetes mellitus (T2DM) among subjects with a higher consumption of red and processed meat. Heme iron intake has been directly associated with a higher risk of T2DM in healthy adult Chinese and U.S populations. The objective of the present study was to evaluate the association between heme iron intake and the incidence of T2DM in a Mediterranean population at high cardiovascular risk. Methods We assessed a subset of participants in the PREDIMED trial as an observational cohort, followed up for a maximum of eight years. We initially included 1073 non-diabetic subjects (57.1% women) aged 67.3 ± 6.0 years, at high cardiovascular risk. Diet was assessed at the study baseline using a validated, semi-quantitative food frequency questionnaire. Results During the follow-up period 131 diabetics were newly diagnosed. The risk of developing T2DM was assessed using baseline heme iron intake and proportional hazard models, first unadjusted, then adjusted for energy, and finally adjusted for dietary, anthropometric, socio-demographic and lifestyle variables. Significant direct associations with the incidence of T2DM were found for heme iron (Hazard Ratio [HR] 1.30, 95% confidence interval [CI], 1.02 to 1.66). Secondarily, we have also observed that coffee (HR:0.93, 95% CI, 0.89 to 0.98) and alcoholic beverages (HR: 1.02, 95% CI, 1.01 to 1.04) were also found to reduce and increase the risk of T2DM, respectively. Conclusion High dietary intake of heme iron was associated with an increased risk of developing T2DM in a Mediterranean population at high cardiovascular risk. Trial registration Identifier: ISRCTN35739639.