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Press releases Saturday 26 January 2008

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(1) Climate change poses a huge threat to human health
(2) Can condoms prevent sexually transmitted infections other than HIV?

(1) Climate change poses a huge threat to human health
(Global environmental change and health: impacts, inequalities, and the health sector)
http://www.bmj.com/cgi/content/short/336/7637/191

Climate change will have a huge impact on human health and bold environmental policy decisions are needed now to protect the world's population, according to the author of an article published in the BMJ today.

The threat to human health is of a more fundamental kind than is the threat to the world's economic system, says Professor McMichael, a Professor of public health from the Australian National University. "Climate change is beginning to damage our natural life-support system," he says.

The risks to health are many, and include the impact of heat waves, floods and wildfires, changes in infectious disease patterns, the effect of worsening food yields and loss of livelihoods.

The World Health Organisation estimates that a quarter of the world's disease burden is due to the contamination of air, water, soil and food – particularly from respiratory infections and diarrhoeal disease.

Climate change, says Professor McMichael, will make these and other diseases worse. While it is unlikely to cause entirely new diseases it will alter the incidence, range and seasonality of many existing health disorders. So, for example, by 2080 between 20 and 70 million more people could be living in malarial regions due to climate change.

The adverse health impacts will be much greater in low-income countries and vulnerable sub-populations than in richer nations.

Professor McMichael says:
"Poverty cannot be eliminated while environmental degradation exacerbates malnutrition, disease and injury. Food supplies need continuing soil fertility, climatic stability, freshwater supplies and ecological support (such as pollination). Infectious diseases cannot be stabilised in circumstances of climatic instability, refugee flows and impoverishment."

The relationship between the environment and health is complex. For example, as India modernises it expects the health of its population to improve, yet industrialisation also means a rapidly increased level of coal-burning and greater global emissions. This in turn leads to climate change, the impact of which is felt most by vulnerable populations.

Professor McMichael concludes that the global changes we are seeing now are unprecedented in their scale, and healthcare systems should develop strategies to deal with the resulting growing burden of disease and injury. More bold and far-sighted policy decisions need to be taken at national and international level to arrest the process and health professionals "have both the opportunity and responsibility to contribute to resolving this momentous issue."

Contact:
Anthony McMichael, National Centre for Epidemiology and Population Health, the Australian National University, Canberra, Australia
Email: tony.mcmichael@anu.edu.au

(2) Can condoms prevent sexually transmitted infections other than HIV?
(Head to Head: Are condoms the answer to rising rates of non-HIV sexually transmitted infection?)
Yes: http://www.bmj.com/cgi/content/short/336/7637/184
No: http://www.bmj.com/cgi/content/short/336/7637/185

Consistent condom use can reduce the spread of HIV, but are they the answer to rising rates of other sexually transmitted infections?

Researchers debate the issue in this week's BMJ.

For people who are sexually active, condoms remain our best solution to reducing risks of acquiring sexually transmitted infections (if uninfected) or transmitting these infections (if infected), say Markus Steiner and Willard Cates of Family Health International.

Despite some inconsistencies in the evidence, studies show that condoms are an effective physical barrier against passage of even the smallest sexually transmitted pathogens, they write.

For example, a recent review provides strong evidence that condoms reduce the risk of gonorrhoea and chlamydia in both men and women. Studies have also shown consistent and correct use of condoms can reduce genital herpes and human papillomavirus infection.

However, the promotion of condoms remains controversial in many countries, including the United States. Another concern is that condom promotion could lead to risk compensation, although the authors point to a recent review of condom related prevention approaches which concluded that sexual risk reduction interventions do not increase unsafe sexual behaviour.

Like any prevention tool (such as seat belts or airbags) condoms are not 100% effective, they say. Accurate messages about condoms must build on a wide range of risk avoidance and risk reduction approaches, such as the ABC strategy: abstinence, be faithful to one partner, and use condoms.

They suggest that clinicians reassure people who are sexually active that condom use reduces the risk of most infections, while emphasising the importance of consistent and correct use for optimal risk reduction.

But Stephen Genuis from the University of Alberta argues that a more comprehensive approach is needed.

Condoms cannot be the definitive answer to sexually transmitted infection, he writes, because they provide insufficient protection against many common diseases. Intercourse generally involves skin to skin contact in the external genital area not covered by a condom.

But the main problem with condoms, he says, is that average people, particularly teenagers and young adults, do not use them consistently, regardless of knowledge or education.

He points to numerous large studies where concerted efforts to promote use of condoms has consistently failed to control rates of sexually transmitted infection – even in countries with advanced sex education programmes like Canada, Sweden, and Switzerland.

Data also suggest that changes in sexual behaviour (fewer partners, less casual sex, and less use of sex workers) rather than widespread condom use is reducing infections in countries such as Thailand and Cambodia.

The World Health Organisation estimates that two thirds of sexually transmitted infections worldwide occur in teenagers and young adults. Yet innumerable adolescents saturated with condom focused sex education end up contracting sexually transmitted infections, he argues.

Although factual information should be included in any discussion of sexually transmitted infections, narrow condom focused initiatives should be replaced with comprehensive evidence-based programmes, he concludes.

Contacts:
Willard Cates, President, Family Health International, NC, USA
Email: wcates@fhi.org 

Stephen Genuis, Associate Clinical Professor, University of Alberta, Edmonton, Canada
mail: sgenuis@ualberta.ca 

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