The Suffering Gene: Environmental Threats to our Health

  • Roy Burdon
Zed Books: 2003. 227 pp. $59.95, £45 (hbk); $19.95, £12.99 (pbk)

In The Suffering Gene, Roy Burdon explores areas of environmental concern in which science, special interests, public opinion and regulatory requirements are frequently uncomfortable bedfellows. He addresses the extent to which environmental factors, particularly those associated with industrial activities and new technologies, can affect human health. The book also touches on the difficulties of establishing an acceptable balance between the socio-economic benefits of certain human activities and the associated risks to health.

Burdon sets about his task with obvious enthusiasm. He commences with outlines of DNA structure, function and response to damage, and subsequently covers the known or suspected health effects of different types of radiation, chemical agents and free radicals. The biological mechanisms that operate to defend against these health effects (such as DNA repair and apoptosis) also receive attention. The main emphasis of the early chapters is the risk of cancer, including heritable susceptibility, but germline mutations, developmental abnormalities and ageing are also addressed.

Later chapters cover methodologies and concerns relating to recombinant organisms and human cloning. Burdon also includes discussion of the possible consequences of global climate change and, at various points in the book, touches on topics that are somewhat peripheral to the main environmental theme, such as cancer therapy and gene therapy to treat inherited diseases.

All of these topics are dealt with in 227 pages, so this is not a book for specialist readers — many of whom will find, as I did, some deficiencies in the scientific discussions and a few errors of fact or interpretation. However, this broad coverage, together with Burdon's ability to write in a straightforward and engaging manner, should ensure that a lay audience will find it a useful scientific introduction to the effects of the environment on health.

For this target audience, a significant strength of the book is its generally balanced discussion of the health risks posed by environmental agents. For example, although Burdon emphasizes concerns about the potential risk of cancer from environmental radiation and chemicals, this is balanced by a discussion of the endogenous risk from chemical radical attack on DNA during normal cellular metabolism. Are there significant omissions or ambiguities in the book? I will address two that I thought to be important.

First, given that risks of cancer from genotoxic environmental agents generally involve low levels of exposure, I was surprised to find so little discussion of a long-standing debate concerning dose and response. There is a school of thought (E. J. Calabrese and L. A. Baldwin Nature 421, 691–692; 2003) that, at these low doses, there is an initial dose interval where cancer risk may be discounted (a threshold for risk) or where there may even be health benefits for the exposed individual (hormesis). In general, these proposals have not been viewed favourably by the national and international scientific bodies that consider risks from physical and chemical genotoxic agents. A discussion of the scientific components of the debate would have been most valuable.

My second point concerns one of the central arguments on the contribution of environmental factors to human cancer risk. Burdon emphasizes proposals that environmental factors can account for 80–90% of human cancers, and that the increasing cancer burden in the population “parallels the gradual industrialisation of the world and the widespread introduction of new synthetic chemicals into the workplace”. Although he refers to difficulties in quantifying the potential impact of environmental carcinogens and the importance of other environmental influences such as diet, I sense a degree of ambiguity in his approach. Consequently, lay readers could be forgiven for interpreting some parts of the text as reflecting scientific support for the view that involuntary exposure to environmental carcinogens is a major determining factor in human cancer risk. In my opinion, it is unlikely to be so.

In particular, although there is qualified acceptance of the view that heritable factors may account for 10–20% of cancer in Western populations, this does not imply that the remaining 80–90% of cases can be attributed to environmental carcinogens. Although exposure to carcinogens, especially tobacco smoke, is certainly important, the non-genetic component of cancer incidence in a given population incorporates a broad range of interacting elements that may be expected to vary over time with social and economic change. These include population structure and lifestyle-related factors such as diet, reproduction and certain forms of infection (R. N. Hoover N. Engl. J. Med. 343, 135–136; 2000 and Given their importance to a major theme of the book, these issues could have been discussed with greater clarity.

Overall, however, I found The Suffering Gene to be a readable and reasonably balanced introduction to DNA-related environmental issues. The discussion is a little speculative or lacking in depth in places, but given the range of issues considered, this is probably inevitable.