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The working environment can damage young farmers' lungs

A major follow-up study from Aarhus University shows that older farmers are not the only ones affected by agricultural work; young farmers also risk damaging their lungs. But the research results also indicate that growing up in the countryside can protect the lungs.

Working in the agricultural sector can affect your ability to use your lungs (known as pulmonary function) if you are younger than 35 years old and if you are exposed to dust and bacteria (endotoxins). The effects lead to poorer development of pulmonary function, a condition that can also lead to an increased risk of contracting lung diseases such as COPD. Statistically it also increases mortality in the long term.

This is shown by a new study from Aarhus University, which is the first major study of pulmonary function among young farmers. It has been published in the British Medical Journal’s Occupational & Environmental Medicine.

Results are shown for farmers who still work in agriculture after the 15-year follow-up, compared with farmers who stopped working in the agricultural sector during the same period, and they are especially pronounced among women.

Agricultural work and smoking have the greatest effect on young people

It is already known that older farmers can experience reduced pulmonary function over time due to the effects of their working environment. But until now there has been uncertainty about the situation for the group of farmers aged between 18-35:
This is due to a special circumstance, in that the lungs are still developing during someone’s twenties, so the question has therefore been whether exposure to dust and endotoxins during youth inhibits the development of lung capacity:

"We can now see that young farmers have a lung capacity that has developed less than you would expect, when compared with the young people who stop working as farmers, just as smoking affects farmers more than the control group," says medical doctor and PhD student Anneli C. S. Bolund from the Department of Public Health at Aarhus University. It also appears that young women’s lungs in particular are damaged.

"So in addition to yet another good argument against smoking, it’s also a good idea to protect yourself against environmental impacts already at a young age by, for example, making sure there’s good ventilation or by using water spray to bind the dust in the cowshed or pigsty," she says.

All young Danish agricultural students included

A total of nearly 2,400 young people aged 16-25 were included in the original nationwide study SUS – Sund Stald in 1992-1994, which included all the Danish agricultural students who were taking the first part of their education at that time, plus a control group of 407 young men, and form the basis of the study. The new study has followed-up on every single person's lung development over 15 years, and it is the results of this comparison which are now being published.
A total of 1,134 people were examined as part of the follow-up in 2007-2008. It accounts for 51.7 % of the original cohort which could be identified. All of them were examined using lung capacity measurements, allergy tests and bronchial hyperactivity tests. All participants also completed a number of questionnaires.

The data collected has been compared against a global ‘normal population’ to see how lung capacity could be expected to look based on age group, ethnic composition, gender and height; similarly, each part of the study has also been compared with a Danish control group.

"Even though it looks as if working as a young farmer can have a negative effect on lung capacity when compared to young farmers who have found other work, there is also some good news", says Anneli C. S. Bolund:

"Our study confirms what previous studies of allergies and the like have also shown, which is that on the other hand, growing up in the countryside protects the lungs."

  • Read the abstract from the article “The effect of occupational farming on lung function development in young adults: a 15-year follow-up study”.


  • The SUS – Sund Stald project has provided a unique insight into genetic and environmental interaction and its significance for the development of allergic and respiratory diseases in the agricultural sector. Among other things, the project identified a lower incidence of allergies and asthma among people born in the countryside. It also identified genes that have been shown to be particularly associated with an increased risk of developing asthma.
  • In the new study, researchers have in particular looked at the impact of dust and endotoxins – a substance found in certain types of bacteria, which is widespread in agricultural work, particularly work with animals.
  • The study was carried out by a team of researchers from Aarhus University in collaboration with the University of Birmingham and Aalborg University.

Further information:

MD, PhD student Anneli Clea Skjelmose Bolund
Aarhus University, Department of Public Health – Section for Environment, Occupation and Health
Mobile: (+45) 2125 5447

Associate Professor, PhD Vivi Schlünssen
Aarhus University, Department of Public Health – Section for Environment, Occupation and Health
Mobile: (+45) 2899 2499