Individuals' occupations may be boosting their risk of adult-onset asthma. A study conducted by researchers at the Imperial College London, the National Heart and Lung Institute in the United Kingdom and the University of London has found that certain career choices are associated with a higher risk of adult-onset asthma.

At the top of the pack are farmers. According to the Telegraph, farmers were four times more likely to develop adult-onset asthma than individuals who worked in offices. Printers had three times the risk, while hairdressers had double the risk. The group that fared the worst was job titles that dealt heavily with cleaning products; general cleaners, office cleaners, domestic helpers and laundry workers all featured on the top 18 jobs associated with adult-onset asthma.

Experts say that a person's work environment may be more responsible for the development of the condition than the occupation, per se. The study also may have been problematic in that individuals with occupations on the list may be more likely to also live in environments that would boost their risk for developing adult-onset asthma.

"Occupational asthma is widely under-recognised by employers, employees and healthcare professionals. Raising awareness that this is an almost entirely preventable disease would be a major step in reducing its incidence," Dr. Rebecca Ghosh said to the BBC.

Cleaning agents are beginning to be considered as agents that increase the risk of asthma. Other agents include flour, grain, detergents, enzymes, metals and textiles.

"This study reminds us of the many unexplored areas and gaps in our knowledge: few researchers would be able to explain the mechanisms that leave farmers, hairdressers or cleaners more susceptible to adult-onset asthma," professor Danny Atlmann said to the Telegraph. "However, learning more about these occupational exposures will clearly need to attain higher prominence."

According to the American Lung Association, asthma affects 25.9 million Americans. The condition is responsible for 14.2 million missed work days in 2008, 2.1 million emergency room visits in 2009 and 3,388 deaths in 2011.

The study was published in the journal Thorax.