Traffic pollution and breast cancer

Joseph Grech is to be congratulated for his excellent article on prevention of breast cancer (Weighing the risk of breast cancer... where do you stand, 10 October) As he says, the essence of prevention lies in maintaining a healthy body weight, healthy diet, doing plenty of exercise, limiting alcohol intake and avoidance of smoking. Since it is Pink October further comment is in place.

First of all, the message on exercise needs to be reinforced.

It is now clear that a physically active lifestyle protects against a great many diseases which lead to disability or early death. The major benefits of exercise were recently re-emphasised in a report aptly titled ‘Exercise, the Miracle Cure’ published by the UK Academy of Medicine (2015). Here it was stated that exercise reduces the chances of developing heart disease by over 40%; the risk of stroke by 30%; the risk of developing dementia by 30%; the risk of breast cancer by 25% and the of risk bowel cancer by 45%.

Sedentary lifestyles with accompanying adiposity and diabetes have increased in parallel with incomes and car ownership. As in some other Western countries, typically the UK and USA, private car use is predominant in Malta and this contributes to high obesity rates and street-level pollution – both risk factors for breast cancer.

A worldwide survey has shown Malta to be the least physically active country in the world. Maltese children are also the least physically active children in the EU. Part of the explanation for this must lie in Malta’s car-dependence for mobility and the number of hours per day spent watching television by Maltese children – also the highest in the EU.

Unfortunately promotion of physical activity on a national basis remains a major challenge in most countries. Malta’s deteriorating urban environment and dysfunctional transport situation tends to further reduce physical activity at every opportunity.

Our streets are becoming less pedestrian-friendly; they have ceased to be ‘people spaces’ and are fast becoming traffic spaces. Pavements are being narrowed to create more space for cars.

Over-development continues to degrade our urban environment, add to our traffic congestion and our government remains hell-bent on encouraging car use by its preoccupation with creation of centrally situated urban car parks so that people might use their car more and need to walk even less.

So much for exercise; it now remains to draw attention (again) to a disturbing aspect of streetlevel traffic pollution which is of pivotal relevance to breast cancer: A component of traffic pollutants responsible for increases in breast cancer is a group of compounds known as “polycylic aromatic hydrocarbons” or PAHs.

Traffic sources are responsible for 90% of ambient PAHs. These are also present in particulates emitted by traffic – especially from diesel engines.

Detailed research on epidemiological data conducted at McGill University Health Centre re-confirmed the link between breast cancer and exposure to traffic pollutants.

Besides contributing to cases of lung and other cancers, exposure to PAHs from traffic has another worrying aspect. In addition to the long time lag, measured in years or even decades, between critical exposure to PAHs and adverse health outcomes, there is evidence which suggests that the damage from PAHs can be “trans-generational” in the case of breast cancer. This means that the adverse effects of exposure to PAHs can skip a generation and be passed on to children of people by parents who were exposed to traffic pollution.

This raises the spectre of “silent environmental heritage” passed from parent to child. These findings were reaffirmed by the EU in its State of the Environment report, Environment and Health and the Quality of Life (2007),

The World Health Organisation and the UK Committee on the Medical Effects of Air Pollutants now endorse that exposure to traffic-related particulate air pollution is one of the most important environmental risk factors for excess mortality from cardiopulmonary disease and lung and other cancers.

To that is added the causative role in breast cancer of exposure to PAHs across generations.

All the forgoing stresses the tremendous importance of taking steps to reduce traffic pollution.

The government has shown little concern and remains indifferent to the degree of traffic pollution in densely urbanised areas; no attempt is made to limit pollution by taking steps to discourage urban traffic and rendering streets pedestrian-friendly.

Neither is our Health Department involved in decisions on street planning as the creation of urban car parks.

This continuing inaction can be expected to result in significant delayed health impacts, including breast cancer, which will become apparent over the coming years by virtue of cumulation of effect in generations currently exposed and their children.

The solution does not lie entirely with our government – every one of us who drives a motor vehicle is part of the problem. It is also up to you.

George Debono