The MONICA Project
MONICA is the acronym for “monitoring trends and determinants in cardiovascular disease,” and is a WHO-coordinated international CVD surveillance research program that began in the early 1980s (Tunstall-Pedoe et al. 1999). Like the Minnesota Heart Survey (MHS), which got underway in 1979, MONICA was designed to answer questions that arose at the Conference on the Decline of Coronary Heart Disease Mortality convened in 1978 at the National Heart, Lung, and Blood Institute in Bethesda: Was the apparent decline in CVD death rates, witnessed since the 1960s, genuine? If so, was improved survival or declining coronary event rates the primary contributor to the decline? What were the relative roles in the mortality trends of medical care and public health innovations?
MONICA assessed trends in community rates of hospitalized CVD events and their case fatality, along with trends in acute cardiovascular care, and carried out parallel population-based surveys of risk factors in 21 countries across four continents (ibid.) Inclusion criteria required advanced medical services for coronary heart disease, including stroke diagnostic imaging, thus restricting the study to developed countries (Tuomilehto, Pisa, Tunstall-Pedoe, 2003). No populations were surveyed from South America or Africa, and few from Asia.
Coronary Heart Disease
Ten-year results from 37 of the populations participating in MONICA indicated that the decline in CHD was genuine. Among men, deaths due to CHD declined in 25 of the 37 (68 per cent) of the populations studied (Tunstall-Pedoe et al., 1999). The average annual change in CHD death rates for men across populations was –2.1 per cent. A similar trend was found among women with CHD death rates declining in approximately 60 per cent of the populations studied over the ten-year period, with an average annual change of -2.7 per cent (ibid.).
Among men, the number of incident CHD cases decreased in 28 of the 37 (76 per cent) populations studied and increased in 9 (24 per cent) (ibid.). Case fatality in men decreased in 25 (68 per cent) populations and increased in 12 (32 per cent). A similar trend was found among women, with coronary-event rates decreasing in 22 of the 35 (63 per cent) populations that studied events in women and increasing in 13 (37 per cent). Case fatality also decreased in 22 (63 per cent) populations and increased in 13 (37 per cent).
The largest decrease in coronary-event rates in men occurred in two northern European populations in Finland, North Karelia and Kuopio Province, where rates had been very high and where an active health promotion campaign was carried out (ibid.). Populations that experienced increases in coronary-event rates were mainly eastern (central and eastern Europe and Asia). Those with little improvement in case-fatality were populations that historically belonged to the eastern bloc.
The key contributor to the international decline in CHD death rates was investigated by partitioning the relative contribution of event rates and of case fatality to the mortality change. Ten-year results during this particular period showed a greater contribution from the decline in coronary-event rates than from improved case fatality (Tunstall-Pedoe et al., 1999). These results were interpreted to have important implications for more effective strategies of primary prevention and medical care (ibid.). [American studies found that the relative contribution of health promotion and medical care appeared to shift toward proportionately greater effect of cardiac care in the mid-1980s.]
Trends in Developing Countries
Although cardiovascular disease among developing countries has received less research and public attention compared to that in developed countries, the burden of CVD among these populations is high and is expected to increase (Reddy & Yusuf, 1998). Presently the developing countries contribute a greater share to the absolute burden of CVD than the developed countries. It is projected that CVD mortality rates will rise in the developing countries over the next two to three decades (Pearson et al., 1993) due to an increase in life expectancy and to lifestyle changes (Reddy, 2004).
As a population ages due to a decline in infant deaths and improvements in public health, it has longer exposure to cardiovascular risk factors. Lifestyle changes, such as Westernized diet, diminished physical activity of work, and increased smoking rates result in increased levels of risk factors (Reddy, 2004).
Based on demographic shifts alone, it is projected that mortality attributable to “circulatory system diseases” in India will rise by 103 per cent in men and 90 per cent in women during the period 1985 to 2015 (Bulattao & Stephens, 1992). The ratio of deaths from circulatory diseases to deaths from infectious diseases is likely to rise from 0.60 to 2.75 in Asia and from 1.1 to 4.75 in Latin America during the period 1985 to 2015 (Bulattao & Stephens, 1992; Pearson et al., 1993). If lifestyle change contributes to increased risk factor levels in these populations, the observed rise in CVD mortality will be larger than these estimates, which are based solely on anticipated demographic shifts (Reddy & Yusuf, 1998).
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Sarti, C., Stegmayr, B., Tolenen, H., Mahonen, M, Tuomilehto, J, Asplund, K. (2003). Are Changes in Mortality From Stroke Caused by Changes in Stroke Events or Case Fatality?: Results from the WHO MONICA Project. Stroke, 34, 1833-1841.
Tunstall-Pedoe, H., Kuulasmaa, K., Mahonen, M., Tolenen, H., Ruokokoski, Eamouyel, P. (1999). Contribution of trends in survival and coronary-event rates to changes in coronary heart disease mortality: 10-year results from 37 WHO MONICA Project populations. Lancet, 353, 1547-1557.
Tuomilehto, J., Pisa, Z., Tunstall-Pedoe, H. (2003). Recruitment of Populations. In H. Tunstall-Pedoe (Ed.). MONICA: Monograph and Multimedia Sourcebook. Geneva, Switzerland: World Health Organization.