Workplace link to 1 in 6 cases of adult asthma among UK baby boomers

The strongest evidence seems to be for jobs involving cleaning or cleaning agents, the research suggests.

The authors base their findings on the job histories up to the age of 42 of almost 7,500 British adults born in 1958, all of whom were taking part in the National Child Development Study, which is tracking the long term health of more than 11,000 people living in Britain.

Information about symptoms of asthma or wheezy bronchitis was collected at the ages of 7, 11, 16, 33 and 42 from 9,500 participants.

After excluding 2,000 who had these symptoms before the age of 16, the remainder were tested for sensitivity to allergens and their lung power between the ages of 42 to 45. Participants were also asked about their work history at the ages of 33 and 42.

Their exposure to compounds known to be associated with asthma was calculated using the Asthma Specific Job Exposure Matrix (ASJEM). This assigns workplace exposure to 18 different high risk antigens, environments, and respiratory irritants.

One in four were smokers by the age of 42, when the cumulative prevalence of asthma that had started in adulthood was 9%. Most (87%) were in employment at age 42, and over half (55%) had office jobs.

What is Adult-Onset Asthma?

When a doctor makes a diagnosis of asthma in people older than 20, it is known as adult-onset asthma.

Among those who may be more likely to get adult-onset asthma are:

Women who are having hormonal changes, such as those who are pregnant or who are experiencing menopause
Women who take estrogen following menopause for 10 years or longer
People who have just had certain viruses or illnesses, such as a cold or flu
People with allergies, especially to cats
People who are exposed to environmental irritants, such as tobacco smoke, mold, dust, feather beds, or perfume. Irritants that bring on asthma symptoms are called "asthma triggers." Asthma brought on by workplace triggers is called "occupational asthma."

What is the Difference Between Childhood Asthma and Adult-Onset Asthma?

Adults tend to have lower lung capacity (the volume of air you are able to take in and forcibly exhale in one second) after middle age because of changes in muscles and stiffening of chest walls. This decreased capacity may cause doctors to miss the diagnosis of adult-onset asthma.

Around one in four participants had only ever worked in a job that was zero risk, according the ASJEM. Just under one in 10 (8%) had ever been exposed to high risk agents; while a further 28% had ever been exposed to low risk agents. Around one in three (34%) had ever been exposed to both.