Speaker Abstracts: 5.12.14 – Diet, lifestyle and cardiovascular risk

Dr Martin O’Flaherty

Senior Lecturer in Epidemiology, Department of Public Health and Policy, University of Liverpool.

The massive decline in cardiovascular disease mortality in Western populations in the 20^th century and continuing in the 21^st is one of the most important epidemiological phenomena in history. What drives these trends has been a research question that attracted significant attention, and over the decades the role of medical treatments and risk factors was better understood. Diet and Smoking have emerged as major drivers of these trends and are at the centre of the policy debate to reduce the impact of cardiovascular disease in populations.

Crucially changes in diet when happening at a population level can deliver fast, massive and equitable reductions in CVD mortality, and these gains might extends to other non-communicable disease.   In this talk, Dr O’Flaherty will review the evidence on what are the drivers of recent cardiovascular disease mortality trends and explore the potential health gains achievable by targeting diet and lifestyle factors to reduce CVD burden with a range of policy alternatives.

Emerging ethnic differences in cardiovascular risk in childhood – implications for early prevention

Professor Peter Whincup

Population Health Research Institute, St George’s, University of London

In the UK, there are marked ethnic differences in the risks of coronary heart disease, stroke and type 2 diabetes in adult life; UK South Asians have high risks of all three conditions, while UK blacks of African origin have high risks of stroke and type 2 diabetes. This presentation will present evidence, particularly from the recent Child Heart and Health Study in England (CHASE), that ethnic differences in risk markers for chronic disease risk (particularly in insulin resistance, glycaemia, LDL-cholesterol and body fatness) are apparent in children. It will also examine the roles of childhood socioeconomic factors, diet and physical activity, in emerging ethnic differences in chronic disease risk. Overall the results suggest that population-wide policies for chronic disease prevention need to include children as well as adults, and include a special emphasis on chronic disease prevention in UK ethnic minority populations.

Alcohol consumed ‘with a meal’ or ‘without a meal’ is differently associated with risk of coronary heart disease in a UK prospective population study.

Lentjes MAH, Khawaja AP, Mulligan AA, Luben RN, Bhaniani A, Wareham NJ and Khaw KT.

University of Cambridge, Department of Public Health & Primary Care, Strangeways Research Laboratories, Worts Causeway, CAMBRIDGE CB1 8RN, United Kingdom.

Background: Moderate alcohol intake has been observed to reduce the risk of coronary heart disease (CHD) in many –but not all– population-based studies (1,2). The context of alcohol consumption might be of importance(3).

Aim: Assess how ‘with meal’ and ‘without meal’ alcohol consumption is associated with CHD incidence.

Subjects and Methods: Prospective cohort study, the Norfolk-based European Prospective Investigation into Cancer (EPIC-Norfolk). 30445 participants were recruited from 35 general practices in Norfolk, East-Anglia (UK). 25639 men and women, aged 39-79 years at baseline, attended a health examination between 1993 and 1998. Participants who returned a completed 7-day diet diary, without a history of stroke, myocardial infarction, or cancer at baseline and complete covariable data were included in analyses (n=20229). Linkage with national and hospital records over a median of 12.9 years accumulated 2506 incident CHD events. Study approval was obtained from the Norfolk District Health Authority Ethics Committee. All participants completed a written informed consent.

Results: The association between alcohol consumption and CHD was examined using multivariable Cox regression. Participants not drinking alcohol had a higher CHD risk compared to non-drinkers (HR 1.18; 95%CI 1.07,1.29). Alcohol intake was partitioned into ‘with meal’ when consumed with: meat, fish, eggs, potatoes, vegetables, soup, or cereals; otherwise, as ‘without meal’. Among alcohol drinkers, ’with meal’ alcohol was associated with lower CHD risk, HR adjusted for sex, age, socioeconomic and lifestyle factors of 14-28 units/week compared to 0‑14 units/week was 0.82 (95%CI 0.70,0.96); whereas >28 units of ‘without meal’ alcohol per week compared to 0-14 units/week was 1.27 (95%CI 1.02,1.57). After adjustment for frequency of consumption, the associations for ‘with meal’ alcohol attenuated, whereas the association strengthened for ‘without meal’ alcohol (HR 1.41; 95%CI 1.12,1.77). Findings were consistent for type of alcoholic beverage.

Conclusions: In this UK cohort, among drinkers, lower CHD risk was only observed for moderate alcohol consumption ‘with meals’ but not for alcohol consumption ‘without meals’. This finding might explain the heterogeneity found across populations in the alcohol‑CHD association and has implications for current public health recommendations.

1. Ronksley PE, Brien SE, Turner BJ, Mukamal KJ, Ghali WA. Association of alcohol consumption with selected cardiovascular disease outcomes: a systematic review and meta-analysis. BMJ. 2011 Jan;342:d671.
2. Leong DP, Smyth A, Teo KK, McKee M, Rangarajan S, Pais P, et al. Patterns of alcohol consumption and myocardial infarction risk: observations from 52 countries in the INTERHEART case-control study. Circulation. 2014 Jul 29;130(5):390–8.
3. Trevisan M, Schisterman E, Mennotti A, Farchi G, Conti S. Drinking pattern and mortality: the Italian Risk Factor and Life Expectancy pooling project. Ann Epidemiol. 2001 Jul;11(5):312–9.

Dietary nitrate and cardiovascular disease

Professor Amrita Ahluwalia

William Harvey Research Institute, Queen Mary’s University of London.

Fruit and vegetable-rich diets reduce blood pressure and risk of ischaemic stroke and ischemic heart disease. Whilst the cardioprotective effects of a fruit and vegetable-rich diet are unequivocal, the exact mechanisms of this effect have remained uncertain. Recent evidence has highlighted the possibility that dietary nitrate, an inorganic anion found in large quantities in vegetables (particularly green leafy vegetables), may have a role to play.

The beneficial activity of nitrate lies in the processing in vivo of nitrate to nitrite and then nitrite to the pleiotropic molecule nitric oxide (NO). NO in turn exerts a range of beneficial effects on the cardiovascular system including lowering of blood pressure, suppression of inflammation and prevention/retardation of atherosclerosis.

The processing of nitrate in humans is a multi-step pathway often dubbed the enterosalivary circuit of inorganic nitrate that relies on the nitrate reducing activity of oral commensal bacteria.   Importantly recent evidence form the Ahluwalia Lab suggests that provision of dietary nitrate exerts a range of beneficial effects most notably blood pressure lowering in hypertensive patients and that deficiencies in the nitrate-reducing oral bacteria exert important negative effects on the cardiovascular system.

Prof Ahluwalia will describe the enterosalivary circuit of nitrate and give an update on recent evidence supporting the view that dietary nitrate might be useful cardiovascular-based therapeutics.