‘The area I’m mostly interested in is trying to prevent diseases from happening, although some of our research has application in terms of improved treatment as well,’ he says. ‘The bulk of the work I do is a combination of traditional epidemiology and biomedical research. One of the things that makes this type of research unusual is that these areas tend to be separated, particularly in New Zealand. In the last ten to twenty years, I’ve been trying to bring public health and biomedical research close together, because I think that if we are to find solutions then a combined effort will be most effective.’

Professor Douwes’ approach is multifaceted, involving questionnaires; blood, urine and airway samples; and lung function and skin prick testing. ‘It’s trying to combine traditional epidemiology using questionnaire-based approaches with clinical and laboratory-based approaches. We’ve got our own lab where we analyse all those biological samples. This combination gives a much more complete picture.’

Establishing the specific risk factors that contribute towards childhood asthma development and the underlying immunological mechanisms is a key area in which Professor Douwes is involved, but a solution is elusive. ‘In some cases, we struggle to find out what it is in the environment that causes children to develop asthma. Is it allergens, or irritants or other things? We’ve been doing this type of research for several decades now and we’re still a long way away from knowing what causes asthma.’

On the other hand, much more is known about the causes of occupational disease, another of Professor Douwes’ key research areas. ‘Deaths from occupational disease are higher than road fatalities, and we put in a lot of time and effort to try and reduce the road toll. This is another area where we can make an immediate impact in terms of both mortality and morbidity.’

In 2017, Professor Douwes and colleagues won a grant from the Health Research Council to carry out a series of three occupational intervention studies. Based on the knowledge Professor Douwes has gained about specific workplace exposures that may cause respiratory disease, cancer, motor neurone disease or cognitive deficits, the project aims to find ways to reduce those exposures, and as a result reduce the incidence of these conditions. ‘We’re moving from traditional risk factor research to now also trying to make a real impact by taking what we have discovered over many years in to better practice.’

The research is focusing on three occupational exposures. One is solvents, which can cause cancer and a range of other conditions, including neurocognitive deficits. Focusing on collision repair workers, the research will involve both finding technical solutions to reducing exposures and better informing workers about how to protect themselves. ‘Encouragingly, our previous research has shown that if people try and avoid solvent exposure, they have a considerably lower risk of having adverse outcomes.’

Another part of the study involves looking at pesticide exposure in agricultural occupations. Pesticide exposure is associated with cancer and reduced cognitive or neuropsychological performance. ‘We know that people get exposed through the skin, so personal protective equipment is one area that we’d be looking at, but also looking at whether there are different methods of spraying that would be less conducive to personal exposures,’ Professor Douwes explains.

The third intervention study is with construction workers who are exposed to crystalline silica, which can cause lung cancer. Again, the study will be looking at ways to better understand when the highest exposures occur, and effective interventions.

‘One of the nice things about public health is that on the one hand we can do the really advanced stuff in the laboratory or complicated analyses, but at the same time some of the interventions can be relatively simple and straightforward. We will be working intensely with workers and management to come up with solutions that actually work. What we hope in the end is that we will provide the industry and the workers with something that is really practicable, and can be used. Ultimately, the reason we’re doing this is to try to improve health, and this is why I’m very enthusiastic about this work. Being able to move from generating knowledge to translating that into something that is actually useful for people is a wonderful thing to be involved in.’