According to an Australian study released this week, workers exposed to herbicides in their workplace are more than twice as likely to develop chronic obstructive pulmonary disease (COPD) by the time they reach middle age. For those exposed to pesticides, there is a 74 per cent increased chance of developing COPD.

The British Medical Journal study suggests that occupational exposure to pesticides and herbicides may result in a greater likelihood of developing a number of breathing problems.

For every additional decade of herbicide exposure, workers were subject to a 22 per cent increased chance of developing chronic bronchitis. In the same time frame, increased exposure to pesticides increases the risk of chronic bronchitis by 16 per cent.

“Our study looked at long-term exposure to pesticides, and it is thought that long-term exposure to pesticides increases mucus secretion and muscle contraction in the lungs, causing breathlessness, cough and wheeze,” lead study author Dr. Sheikh Alif of the University of Melbourne told Reuters.

According to the World Health Organization, more than 65 million people live with moderate to severe COPD, and the condition causes about five percent of all deaths across the globe. In most cases, COPD is caused by smoking or exposure to second-hand smoke, but exposure to certain toxic dusts, chemicals and fuels can also contribute to the development of COPD.

COPD is a disease of the lungs that develops over time and is characterized by shortness of breath and airflow obstruction. COPD is an umbrella term for a range of pulmonary disorders inclusive of emphysema, chronic bronchitis and chronic asthma.

According to the Lung Foundation Australia, one in seven Australians aged 40 or over are effected by COPD. For Australians aged 75 and over, this increases to 29 per cent.