406 PAHO BULLETIN l vol. 18, no. 4, 1984
impossible to determine whether malnutrition is definitely getting better or worse; only an ap- proximation of trends can be seen.
When data from the Americas, excluding the temperate countries (Canada and the United States of America, Chile, Argentina, the Falk- land Islands, and Uruguay), were averaged by age group, each group showed a trend toward improvement; in other words, proportionately fewer children were found to be malnourished (as defined by low weight-for-age) between
1973 and 1983 than between 1963 and 1973. The same could be said for Africa. However, while there may have been some improvement in decreasing “absolute” numbers of mal- nourished children in the Americas, Africa’s population increases caused the numbers to re- main approximately the same in this time-span. In Oceania, the country surveyed during the period 1963-1973 is not sufficiently representa- tive to permit a general statement about prevail- ing trends. When the data for Asia (weighted for India and excluding the USSR and the North- east Asian countries of China, Hong Kong, Japan, Macao, Mongolia, and the Republic of Korea) were averaged, no percentage improve- ment appeared; and in fact the data suggest the situation may have worsened.
Overall, even though the percentage of mal- nourished children in developing areas indicated by weight-for-age data does not appear to be
increasing, the growth in population over the past 20 years appears to have caused the number of malnourished children under five years of age to be somewhat larger than it was 10 years ago.
Gross estimates of the numbers of malnour- ished children in these regions, based on weight- ed one-year age groups and the 1963-1973 and
1973-1983 surveys, yield totals of 126 and 145 million malnourished children, respectively. However, there are probably individual coun- tries in each region which were able to decrease the number of malnourished children during this same time period, while others may have experi- enced a dramatic worsening of the situation.
Furthermore, these numbers only give very gross trend estimates and do not tell how many children are wasted or stunted, and how many are currently or previously malnourished. In the future, it may be possible to make a better esti- mate of trends and to shed more light on specific types of malnutrition by using the more specific indicators of weight-for-height and height-for- age; in the meantime, however, the information presented here at least gives a retrospective view of this global problem and may be of use in trying to find solutions.
Source. World Health Organ~zatmn, Weekly Epm’emrolog~ca/Rec- ord 59.189-192, 1984 A hst of references for this rep-! IS awlable upon request from the Umt of Nutrmon. Dw~sion of Famly Health, World Health Organm~m, 121 I Geneva 27, Swmerland.
HUMAN GENETICS AND PREVENTION OF CORONARY HEART DISEASE
Since the beginning of this century, dramatic progress has been made in the treatment and pre- vention of diseases that are largely determined by environmental factors or by specific genetic defects. One consequence of this progress is that many of the most important residual causes of morbidity and mortality in developed societies are diseases of complex etiology-such as
cancer, heart disease, mental illness, and birth defects-in which both genetic and environmen- tal factors may play an important role.
l ABSTRACTS AND REPORTS 407
genetic markers have been identified that influ- ence either risk factor levels or the risk of coro- nary heart disease itself.
Further progress in the understanding and pri- mary prevention of cardiovascular disease will require a joint approach by geneticists and epide- miologists to design studies that are capable of revealing individual as well as population differ- ences in genetic and environmental risk factors. Once these differences have been recognized, it should be possible to develop individualized in- tervention strategies, as a supplement to commu- nity-wide efforts, to identify and change modifi- able environmental (including dietary) risk fac- tors .
The recognition of heterogeneity, which has been the dominant theme of research in medical genetics during the past 25 years, has important implications for therapy. Although the phenom- enon does not exclude the possibility that some treatments would be generally effective, it is likely that certain therapies would be more effec- tive in some individuals than in others. Sufficient knowledge is already available to predict that most if not all forms of monogenic hypercholes- terolemia resulting from Iow-density-lipoprotein- receptor abnormalities are likely to be less re- sponsive to dietary control than other hyper- cholesterolemias. For the former, more radical forms of surgical or pharmacologic intervention might well be appropriate. Further examples of heterogeneity in treatment response will undoubt- edly emerge as more is learned about the genetic
and molecular basis for the individual differ- ences that are reflected by specific cardiovascu- lar risk factors. It is essential that future epide- miologic studies of cardiovascular disease be de- signed to provide information about the genetic component of cardiovascular risk and its recog- nized determinants, as well as about individual variation in response to environmental risk fac- tors and therapeutic or preventive interventions.
The need to exploit the many new advances
‘See Report of a WHO Consultation on Genetic Ap- proaches to the Prevention of Coronary Heart Disease, un- published WHO document HMGICons183.4, copies of which may be obtained upon request from the Hereditary Diseases Program, Division of Noncommunicable Diseases,
WorldHealthOrganization, 1211 Geneva27, Switzerland.
that implicate genetic susceptibility and resis- tance factors in many common diseases was em- phasized by a WHO advisory group on hereditary diseases in 1982 which identified atherosclerosis as an area of particular importance. Following this, a meeting of a WHO consultation group’ was convened in Geneva in May 1983 (a) to review current epidemiologic, clinical, and genetic knowledge about individuals at risk for coronary heart disease and the current status of protective interventions applied to communities at large and to high-risk families and individuals; (b) to consider the relationship between genetic epidemiologic approaches and community-wide intervention strategies; and (c) to recommend priorities for international collaboration in this area.
The major recommendations of the group in- cluded the following:
1) Having discussed the genetic knowledge, expertise, methods, and research strategies avail- able, the meeting suggested that genetic epide- miologic approaches should be incorporated into efforts to combat coronary heart disease and other atherosclerotic diseases, and that standard- ized protocols and analytical methodologies should be developed in order to make such studies efficient and economical and their results comparable between nations.
2) A multicenter retrospective study of first- degree reIatives of patients with premature coro- nary heart disease should be initiated to describe the genetic risk-factor distribution in such families, and to detect any differences in re- sponse to intervention in persons of different genotypes.
3) Although several retrospective studies have linked different genetic factors with coro- nary heart disease, there is a need to evaluate the predictive value of individual genetic risk factors, or combinations of genetic and environ- mental risk factors, in a collaborative prospec- tive study of genetic risk factors in suitable popu- lations (40-50-year-old males or 50-60-year-old females).
