Downloaded from http://jramc.bmj.com/ on November 7, 2017 - Published by group.bmj.com

Review

The Hearts of Heroes: the epidemiology of cardiac disease in the UK Armed Forces Andrew T Cox,1,2 CJ Boos,3 S Sharma2 1

Royal Centre for Defence Medicine, Birmingham, UK 2 Department for Clinical Sciences, St George’s University of London, London, UK 3 Department of Cardiology, Poole Hospital NHS Foundation Trust, Poole, UK Correspondence to Maj Andrew T Cox, Royal Centre for Defence Medicine, Birmingham, B15 2SQ, UK; [email protected] Received 26 June 2015 Accepted 27 June 2015 Published Online First 4 August 2015

ABSTRACT When the general public look from the outside at the armed services, their impression is often one of earnest young men and women who are the pinnacle of physical fitness and health, and put their lives on the line for their country. There is usually sadness and respect for those killed on active operations, having put themselves in harm’s way. Therefore, when the public discover that more than 1 in 10 deaths in the UK Armed Forces are due to cardiovascular disease, the air of sadness is invariably replaced with surprise and disbelief. These figures, while lower than those due to deaths in accidents, are approaching the numbers of those due to suicide in the armed services; yet deaths from cardiac disease are barely recognised by society, in spite of many of them being avoidable. This article reviews the epidemiology of cardiac disease in the UK Armed Forces, both in terms of morbidity and mortality. It outlines current understanding and gaps in the knowledge regarding the burden of cardiovascular disease in the military population. The particular demographics of the Armed Forces and its influence on cardiac disease burden are discussed. The role of inherited and congenital diseases in younger servicemen and women is highlighted, as is the trend that with increasing age, the burden of disease shifts to ischaemic heart disease, which becomes the dominant cause of both death and disability.

INTRODUCTION Cardiovascular disease (CVD) is the leading cause of death worldwide, and accounts for 29.6% of deaths.1 The cardiovascular mortality rates for the UK were 205.2 per 100 000 in 2010, and this represented an impressive fall of 51% over the previous decade, led primarily by improved outcomes in coronary artery disease (CAD) from better control of acquired risk factors,2 improvement in the acute care of coronary syndromes and advances in secondary prevention. Conversely, as mortality has decreased, morbidity has gradually risen with an increase in hospital admissions due to acute coronary syndromes as great as the decrease in mortality. These statistics relating to the general population are important starting blocks in examining the military population. Those factors affecting society as a whole may also affect the Armed Forces; it is after all from the general population that the Armed Forces are recruited.

THE INFLUENCE OF DEMOGRAPHICS To cite: Cox AT, Boos CJ, Sharma S. J R Army Med Corps 2015;161:169–172.

Clearly, there are important differences between the general and military populations. First, entry to the UK Armed Forces begins at the earliest in late

Key messages ▸ Cardiovascular disease is a leading cause of death or discharge on medical grounds in the UK Armed Forces. ▸ Inherited cardiac diseases such as cardiomyopathies and primary electrical disease are frequent causes of death in younger servicemen and women. ▸ Deaths from coronary artery disease increase with age, and are the most common cause of death. ▸ There are gaps in the knowledge of the epidemiology of many cardiovascular conditions, including hypertension and dyslipidaemia. ▸ Understanding the epidemiology of cardiovascular disease in the UK Armed Forces is key to develop measures that can reduce the risk of death or significant morbidity in this population.

adolescence, and is truncated at a younger age than the population as a whole—approximately 70% of servicemen and women are under the age of 35 years, and fewer than 3% are older than 50 years.3 This means children and young adolescents, with particularly high-risk conditions such as the primary arrhythmic syndromes,4 may succumb prior to the age they can enlist. It also means that deaths from CAD should be under-represented relative to the general population, as the incidence of CAD increases exponentially after the age of 35 years.5 More severe congenital heart diseases should also be under-represented due to their associated physical limitations that effectively prevent military service; however, congenital conditions that do not produce overt symptoms might occur in similar proportions to the equivalent UK civilian population where the prevalence is approximately 1%–2%. Physical training and fitness is an integral part of military life, and any benefits of exercise on general health should be observed in terms of primary prevention of CAD in particular. While the benefits of regular exercise on long-term physical and mental health are well known,6 sudden cardiac deaths (SCDs) in young athletes most commonly occur during, or immediately following, intensive exercise and sports involving intermittent explosive power, such as football, rugby or basketball, rather than in those participating in endurance running or cycling.7 Athletes in Italy were observed to have an

Cox AT, et al. J R Army Med Corps 2015;161:169–172. doi:10.1136/jramc-2015-000498

169

Downloaded from http://jramc.bmj.com/ on November 7, 2017 - Published by group.bmj.com

Review increased risk of SCD 2.8 times greater than sedentary controls.8 This is in contrast to the general population where SCD primarily occurs in those at rest.9 10 Males account for 90% of athletic deaths in the general population, and the UK Armed Forces are male dominated, with a male-to-female ratio of approximately 9:1; so, conditions primarily affecting men are likely to be emphasised in any statistics. Finally, ethnicity appears to play a role in SCD in the young with black athletes 2.6 times more likely to die compared with Caucasians11; blacks and other ethnic minorities constitute 7.1% of the UK Regular Armed Forces.

CARDIAC DISEASE IN POPULATIONS COMPARABLE WITH THE UK ARMED FORCES In general, the hearts of both young athletic individuals and the military ‘Hearts of Heroes’ are healthy. This article relates not to these, but to the small minority of servicemen and women who harbour unidentified inherited or congenital diseases or that suffer from risk factors or lifestyle choices that put them at increased risk of death. Although excellent data relating specifically to the UK Armed Forces is available, the most extensive research has involved other similar populations. Deaths in athletes younger than 35 years of age are rare events, given the large numbers participating in sport. The exact prevalence is difficult to quantify, and frequently, studies of SCD incidence are methodologically biased and likely to underrepresent the mortality rate, that is, reviewing media coverage of SCDs in order to derive the SCD rate.12 Consequently, estimates range between 1 per 23 000 and 1 per 300 000 person years.13 The studies with some of the most rigorous methodology are US military figures where the entire subject population was reliably observed. The reported SCD rate in US military recruits was approximately 13 per 100 000 recruit years14—the highest rates reported in a cohort of the young and apparently well (at least at the point of enlistment). The leading autopsy findings were anomalous coronary artery origins (31.0%), structurally normal hearts (also known as the sudden arrhythmic death syndrome (SADS)) (34.9%), myocarditis (10.3%) and hypertrophic cardiomyopathy (HCM) (6.3%). A second study by the same authors15 quantified deaths throughout the US Armed Forces (not exclusively in recruits), and demonstrated an overall mortality rate of 5.9 per 100 000 service years and a higher rate in males compared with females (6.7 compared with 1.4 per 100 000 service years, p

The Hearts of Heroes: the epidemiology of cardiac disease in the UK Armed Forces.

When the general public look from the outside at the armed services, their impression is often one of earnest young men and women who are the pinnacle...
277KB Sizes 4 Downloads 9 Views