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A Life Course Approach to Chronic Disease Epidemiology

Ed Diana Kuh, Yoav Ben-Shlomo 
 
Oxford University Press, £45, pp 317 
 
ISBN 0 19 2627821 
 
The 20th century has seen a remarkable shift in the health of populations in industrialised countries. For example, life expectancy in England and Wales has risen from 48.5 years in men and 52.4 years in women in 1901 to 74.4 and 79.6 years respectively in 1996. The main causes of death in 1901 were bronchitis, pulmonary tuberculosis, and pneumonia; in 1996 they were ischaemic heart disease, cerebrovascular disease, and pneumonia. 
 
Changes of this size imply that different factors influence health today from at the start of the century. They also impact on what we think is important. And yet some of the key scientific questions seem to remain the same. Is nature or nurture more important? Are the patterns we observe in our society a function of socioeconomic environment or do they simply reflect the survival of the fittest? However, perhaps we fool ourselves by formulating the questions in such a “simple” way. 
 
Recent developments in genetics and a growing body of research on disordered developmental programming in the fetus have again focused epidemiological attention on the earliest stages of life. They have led people to raise again questions about nature versus nurture. In A Life Course Approach to Chronic Disease Epidemiology the authors systematically review the evidence used to support the emphasis on prenatal exposure as opposed to exposure in infancy. They show that how we think about health, and in particular how we view the wider world, influences and is influenced by the methods that we use. This is apparent from the classifications epidemiologists use to characterise causes of death and social groups. It is also evident from research design. 
 
Recent research, both on effects of prenatal exposures and early life influences, draws on the interrelation of information collected about individuals at different stages of their lives. A growing body of data on large population samples has been used to conduct complex analyses, integrating information before and after critical periods in different parts of the population and at different times. The authors’ careful analysis of the evidence in relation to diseases such as cardiovascular disease, cancer, diabetes, respiratory disease, and allergies supports a life course approach. The argument is further strengthened by discussion of different biological and social processes and patterns in different social and geographical groups and over time. 
 
The book’s conclusion, that biological and social chains of risk can be broken at several stages of life and that treatment for people at high risk should be targeted to those times when change is most likely, will be supported by most chronic disease epidemiologists. The conclusion is of major importance to public health policy. It reinforces the need for a life course strategy, with attention being paid to the mother, baby, child, adolescent, adult, and elderly person.