A traditional assumption has been that chronic noncommunicable diseases are diseases of the affluent and the elderly. More recent data refute this assumption (1). Although a study of more than 100 countries did indeed demonstrate that risk factors for ischemic cardiovascular disease increase as national incomes increase from very low levels, the relationships flatten, however, and eventually decline with further increases in income. Thus Body Mass Index increases up to a national income of about I$12,500 (international dollars) per capita for women and I$17,000 for men and the inflection point of serum cholesterol is at approximately I$18,000 (Fig. 80.1) (14). These observations are consistent with studies demonstrating that in a cohort of subjects screened for cardiovascular risk factors at a mean age of 46 years in Soweto, South Africa, 78% of subjects had at least one major risk factor for cardiovascular disease, while 55% of women and 23% of men were obese (15). It also appears that within South Africa and other countries, as gross national income increases, there has been a progressive drift in risk factor prevalence
over time from those within the higher to those within the lower socioeconomic classes (16).

Accumulation of multiple risk factors within an individual also appears to be common in the developing world. For patients who attended a large cardiology unit in Soweto, 77% had more than 1 risk factor for ischemic cardiovascular disease. Of those with hypertension, for example, 38% also had hypercholesterolemia and 36% were smokers (17).

While currently ischemic cardiovascular disease in developed countries predominates in the elderly, it is projected that in South Africa for example, cardiovascular disease will impact four times more adults aged 35 to 64 than in the United States (see Fig. 80.1) (5). This will have a profound impact on the economy of developing countries (18). It has been estimated that in five countries surveyed (Brazil, India, China, South Africa, and Mexico), conservatively, cardiovascular disease will result in loss of at least 21 million years of future productive life annually (19).

Most of the current knowledge related to risk factors for ischemic cardiovascular disease is derived from populations of European origin. One important standardized case-control study examined risk factors for acute myocardial infarction in 52 countries representing every inhabited continent (the “Interheart” Study). It was observed that abnormal lipids, smoking, hypertension, diabetes, abdominal obesity, psychosocial factors, consumption of fruits, vegetable and alcohol, and lack of regular physical activity account for most of the risk of myocardial infarction worldwide, in both sexes and at all ages. It was therefore suggested that while priorities may differ between geographic regions because of variations in the prevalence of individual risk factors and economic circumstances, approaches to prevention can be based on similar principles worldwide (20).

The risk for ischemic cardiovascular disease may be modified in developing countries by a number of factors. The first is poverty and malnutrition. It is likely that maternal malnutrition may be of particular importance through its impact on the developing fetus, manifest through low birth weight. Globally, more than 20 million low–birth-weight infants are born annually. The incidence of low birth weight in developing countries is more than double (16.5%) that in the developed (7%), such that more than 95% of low–birth-weight infants are born in low- and middle-income countries (21). The impact of low birth weight on cardiovascular risk is likely to be profound and multifactorial. First, poverty and malnutrition during pregnancy may result in a low–birth-weight infant who is at risk of reduced physical and mental capacity, resulting in poverty in adulthood and the propagation of the vicious cycle of poverty (22). Second, the mismatch between fetal nutritional deprivation and later nutritional affluence may place individuals at particular risk for cardiovascular disease, via the so-called “fetal origins of disease” mechanism, as first expounded by Barker et al. (23). In a study, which examined the relationship between maternal energy consumption during pregnancy and potential cardiovascular risk in their offspring, carotid intima-media thickening (a surrogate marker of cardiovascular risk) was observed in obese 9-year olds, particularly those whose mothers had been in the lowest quartile of energy consumption during pregnancy (24). It thus appears that until nutritional affluence feeds through to improved maternal nutrition during pregnancy, at least one generation will be at particularly increased cardiovascular risk (25).

A second influence, which is likely to make an increasing contribution to cardiovascular risk in upcoming decades is HIV infection. Currently, it is estimated that there are more than 35 million people living with HIV (26). As access to highly-active retroviral therapies is increasing and HIV infection is becoming a more chronic illness, non-communicable diseases including cardiovascular disease are becoming an increasing source of morbidity (27,28). It has been estimated that HIV infection is associated with a 50% increase in the risk of an acute myocardial infarction beyond that explained by traditional risk factors (29). While as yet the pathogenic link between HIV and cardiovascular risk is unclear, it is likely to be a due to a combination of factors, including the effects of ongoing chronic inflammation, progressive immunologic dysfunction or possible the effects of the antiretroviral treatments themselves (30). It is likely that the impact will be most profound in middle- and low-income countries where more than 70% of HIV-positive patients live. It is also likely that children may be particularly susceptible because of potentially more years of life living with the condition and also possibly related to in utero exposure (31).

The United States spends more than $45 billion on percutaneous coronary interventions (32) and $20 billion on lipid-lowering drugs (33) annually. It is not likely that the economies of the developing world will be able to support these expenses. Rather, if we are to optimally address the potential epidemic of ischemic cardiovascular disease in 2030, we will need to act now, focus on prevention, and address our attention to the youth (34,35).

The key principles and objectives for a global program to address the gaps in policy and research for noncommunicable diseases (including cardiovascular disease), were outlined by the World Health Organization (36) (Table 80.4). These overarching principles include the recognition that control strategies must be closely linked to the promotion and protection of human rights, that NCDs are a major challenge to social and economic development, that there needs to be equal access of opportunity to all members of the community and a strengthening of international cooperation, advocacy, and capacity. Of particular importance to the specialist in pediatric cardiovascular disease are the recommendations that health systems must be reoriented toward prevention rather than treatment, that exposure to modifiable risk factors including smoking needs to be reduced and that if these preventive strategies are to be successful, they need to be applied against the background of a “Life-Course Approach” (see Table 80.4).

As far back as 1961, Holman suggested that atherosclerosis is a pediatric problem (37). There is increasing evidence to justify the introduction of preventive strategies in childhood. Several studies clearly demonstrate that exposure to high levels of cardiovascular risk factors in childhood shows a significant relationship with later preclinical changes in early adulthood. (38). For example, risk factor burden at 9 years predicts increased carotid intima-media thickening in adulthood (39). In high-income countries, programs of dietary interventions have begun as early as infancy (40) and given that very few people initiate smoking or become habitual smokers after their teen years, a large number of community- and school-based programs to prevent smoking have focused on children in elementary and/or middle school. (41)

There is worrying evidence of significant accumulation of modifiable risk factors for cardiovascular disease in children in developing communities. In the “Wellbeing of Adolescents in Vulnerable Environments (WAVE) Study, 32.5% of adolescents were already currently using cigarettes, 30.8% of these were consuming more than 10 per day and the average age at which children smoked their first cigarette was 14 years (42). The prevalence of childhood overweight and obesity is increasing in developing countries, in tandem with the increases in the developed world. In a study of primary school females in Zululand 9% were overweight and 3.8% obese (43). A study of 15- to 24-year olds in South Africa demonstrated that 30% of females were overweight or obese and 46% were “physically
inactive” (44). While it appears that adolescent girls in South Africa are aware of the benefits of healthy eating, they experience limited access to healthy food (45). In a further study of rural South African children, only 26% met international health guidelines of 60 minutes per day of moderately vigorous physical activity, with low levels of activity being particularly evident on those of low socioeconomic status (46).

If we are to prevent the global epidemic of acquired cardiovascular disease there is an urgent need to develop preventive programs in low- and middle-income countries. They need to be based on a life-stages approach and begin in childhood. They will need to be tailored to individual populations, so that they are evidence-based and empower local communities. The specialist in pediatric cardiovascular disease can make an important contribution to these programs.

The 20th century witnessed a dramatic reduction in the occurrence of ARF and RHD in the high-income regions of North America and Europe. As a result, apart from a number of rare, local epidemics, ARF and RHD are virtually eliminated in these regions. Although clearly, the introduction of penicillins has contributed to these reductions, it is likely that an even greater contribution was made by economic and socio-political changes in these countries. Thus, for example, it was noted that dramatic reductions in the incidence of ARF in Denmark preceded the introduction of penicillin (48).

Nonetheless ARF and RHD continue to be endemic in many middle- and low-income countries and within certain indigenous populations of higher-income countries, for example, the Aboriginal populations of Australia and the Maori population of New Zealand.

The true size of the problem of ARF and RHD remains difficult to estimate. In 2005 a report on the global burden of group A streptococcal disease, commissioned by the World Health Organization, calculated the prevalence of RHD, incidence of ARF and incidence of new cases of RHD, based on population data published between 1985 and 2005 across multiple regions. The study found an overall global burden of 471,000 annual cases of ARF, with the incidence in children aged 5 to 15 years ranging from 10 cases per 100,000 in industrialized countries to 374 cases per 100,000 in the Pacific region. There were estimated to be at least 15.6 million prevalent cases of RHD worldwide with 282,000 new cases and over 233,000 deaths per year (49). As a result, it was estimated that in the late 1990s RHD was the most common cardiovascular disease in those aged less than 25 years worldwide. A subsequent systematic review, which added more studies highlighted the wide global variation in the incidence and prevalence of ARF and RHD and suggested that the greatest burden of disease was in sub-Saharan Africa (50). The highest mortality rates from the two diseases were in the indigenous populations of Australia (23.8 per 100,000). The Global Burden of Disease Study estimated that, in 2010, there were more than 34 million people with RHD, resulting in more than 10 million disability-adjusted life years lost and 345,000 deaths (51).