Peter Curson: The world is a health hazard

The environments in which we live and work are not always the benign and supportive settings we often believe them to be. Some are to varying degrees pathological and threatening to our health.

Yet most people remain more concerned about the epidemic of lifestyle diseases than they do about the links between environmental exposures and human health.

A recent World Health Organisation report, Preventing Disease through Healthy Environments: Towards an Estimate of the Environmental Burden of Disease, confirms what many of us have known for some time: that the environment plays a major role in our health and is a major provocateur of death and disease.

According to this report almost a quarter of all global disease and 23 per cent of all deaths are caused by preventable environmental exposures, as is 33 per cent of disease in children under 5.

And the environment in one way or another significantly affects more than 80 per cent of diseases such as heart disease, diarrhoeal diseases, lower respiratory infections, chronic pulmonary disease, cancer, road traffic and other accidents.

These environments include physical, biologic, chemical and man-made hazards that directly affect our health.

The report states that approximately 13 million deaths are due to preventable environmental factors, and most significantly almost a third of all deaths in developing countries fall into this category.

If we add infections like HIV/Aids, the death toll probably creeps closer to 20 million.

In the case of diarrhoeal diseases - responsible for almost two million deaths annually in the world - an estimated 94 per cent of such deaths are due to preventable environmental causes such as unsafe water sources and unsanitary and unhygienic living conditions.

But what about New Zealand? What role does the environment play in our health today?

Well, in the first instance, the health of Pacific Islanders more resembles the developing world than contemporary New Zealand.

For many Island communities, living and working conditions remain overcrowded, damp, cold, stressful and hazardous to health.

Life expectancy remains substantially lower than that of the Maori and European populations, age-standardised death rates are substantially higher, and environmentally triggered diseases rank as important producers of death and disease.

Such groups also suffer a much higher incidence of respiratory and childhood infections, as well as meningococcal disease.

For all New Zealanders, the workplace environment remains in many cases extremely hazardous to our health. There are probably about 1500 deaths as a result of injuries or diseases acquired in the workplace every year in New Zealand, 85 per cent of which result from occupationally acquired diseases.

More than 200,000 New Zealanders suffer non-fatal workplace-related injuries or illnesses, and "blue-collar" workers such as labourers, drivers, plant and machine operators, probably account for about three-quarters of all these cases, even though they only comprise about a third of New Zealand's workforce.

There are now far more deaths in the workplace than there are on New Zealand roads. Clearly the workplace environment needs to be accorded much higher social and political priority.

And our hospitals aren't much safer. Hospital-acquired infections are becoming a growth industry.

Probably one out of every 10 New Zealanders entering hospital for a surgical procedure will leave with a hospital-acquired infection. Possibly there are as many as 2000 deaths every year from this source.

What an irony that in these days of high technology, and high-quality medical care, that our hospitals often belie their real purpose and cause ill health and death.

The homes we live in also contribute to our health.

Asthma in particular is intimately linked to the indoor environment. The disease can be exacerbated by the way we heat and carpet our homes and dry our clothes, the propensity for our homes to be damp and closed up during the day, often supporting a variety of moulds and fungi. And our close association with domestic pets also contributes to New Zealanders having one of the highest asthma rates in the world.

Outdoor air pollution also plays its part in asthma and other respiratory diseases, while noise pollution, a growing feature of high-density living, remains largely ignored as an instigator of ill-health.

And how many road traffic accidents or falls among the elderly are caused by poor urban or housing design?

It would also appear that some of us are more vulnerable to environmental exposures than others.

The young, the old, the poor and certain ethnic minorities would seem to be particularly at risk and bear a disproportionate share of the toll in terms of injury, illness and death.

The WHO Report is a timely reminder of the important role the environment plays in our lives. Better management of our environment could prevent death, injury and disease. If only we would take heed.

* Professor Peter Curson is director of the Health Studies Programme in the Division of Environmental and Life Sciences at Macquarie University, New South Wales.