Ingrid Hein

September 12, 2017

MILAN — The risk for chronic obstructive pulmonary disease (COPD) is higher in those who use disinfectants at least once a week than in those who do not, a preliminary observational study of a large cohort of female nurses in the United States reveals.

"We're not really surprised by the results," said Orianne Dumas, PhD, from INSERM in Villejuif, France. "Occupational exposures are thought to cause 15% of COPD cases," she said here at the European Respiratory Society (ERS) International Congress 2017.

In fact, COPD was linked to occupational exposures in 22 of 25 population-based studies, according to one literature review (Scand J Work Environ Health. 2014;40:19-35).

The onsite nurse at the conference, Isaura Crisci, who normally works in the emergency department at San Paolo Hospital in Milan, had a wide-eyed reaction to the study results. "I won't clean anymore; I refuse to clean," she quipped.

But she quickly followed that with a less alarmist reaction: "At the moment, we must use the products; we have no other solution to kill the germs."

She expressed surprise that hydrogen peroxide was on the list of possibly dangerous disinfectants. "We know that glutaraldehyde is bad but we still use it. I didn't know we had to worry about hydrogen peroxide," she said.

The paramedic by her side at the ERS medical center chimed in, asking, "What about us?"

8 Years of Data on Disinfectant Exposure

For their study, Dr Dumas and her colleagues analyzed data from the Nurses' Health Study II.

From 2009 to 2017, participants completed a survey every 2 years. The women were asked whether they worked in education or administration, an outpatient environment, an inpatient emergency room, or an operating room, and about their exposure to disinfectants (none, at least weekly surface cleaning, at least weekly surgical instrument cleaning).

The women were also asked about their COPD status, whether they had physician-diagnosed chronic bronchitis or emphysema, the time of diagnosis, smoking status, and age.

Dr Dumas and her colleagues used Cox proportional hazard models — adjusted for age, smoking status, pack-years, race, ethnicity, and body mass index — to assess time of exposure. And they used the job-task exposure matrix to evaluate seven major disinfectants: formaldehyde, glutaraldehyde, hypochlorite bleach, hydrogen peroxide, alcohol, quaternary ammonium compounds (or quats), and enzymatic cleaners.

In the cohort of 55,185 women who were nursing in 2009, 663 reported incident physician-diagnosed COPD during the follow-up period.

The team found an association between incident COPD and high-level exposure to glutaraldehyde, bleach, hydrogen peroxide, alcohol, and quats (odds ratio range, 1.24 - 1.32; P < .05 for all).

Of the nurses diagnosed with COPD, 37% reported the weekly use of disinfectants to clean surfaces, and 19% reported weekly use to clean instruments. Regression models demonstrated that the risk for COPD was 22% higher for nurses who cleaned instruments, and 32% higher for nurses who cleaned surfaces.

Replication Needed

"These results need to be replicated before we can be sure of a causal link, but if nurses have respiratory problems, they should see occupational health physicians who can evaluate the products they are using that might make their health worse," Dr Dumas said.

We've been aware of the association between disinfectants and asthma for some time, she told Medscape Medical News. "And we know that breathing in fumes from a product can trigger symptoms in the next few hours for people with respiratory disorders."

But COPD is something that might be related to "longer exposure," she added, pointing out that the link is less obvious from an individual perspective.

There's no easy solution, Dr Dumas acknowledged. "Protection from infection is important, but so is the health of workers." Green products might be one solution, "but we're not sure of their effect on health either. Just because they're natural, doesn't mean they're safe; they can have allergens."

Another solution could be ultraviolet light, as previously reported by Medscape Medical News.

Disinfectants and the Pathology of COPD

This was a "well-performed study," said Lidwien Smit, PhD, from the University of Utrecht in the Netherlands. "I just wonder about the pathology, and how it influences the microbiome."

"Disinfectants are meant to kill off bacteria, but if you're exposed to large concentrations, you're also inhaling them, which could affect your airway microbes," she explained.

In fact, disinfectants could play a role in killing off bacterial communities in the airways that are responsible for "immune homeostasis" and keep users healthy, she added.

If that immune balance gets disturbed, it might have an influence on a person's reaction to pathogens or inflammation. "This is all part of the COPD pathology — that could be another interesting hypothesis to study," Dr Smit told Medscape Medical News.

Dr Dumas is clear that this is preliminary observational research and more studies are needed. Determining which agents are most harmful "would help define guidelines to protect workers," she noted.

The current findings do not show that the disinfectants are a direct cause of COPD, but they do draw an association between some disinfectants and development of the disease. "I hope this study will help open the discussion for better guidelines," Dr Dumas said.

Dr Dumas, Ms Crisci, and Dr Smit have disclosed no relevant financial relationships.

European Respiratory Society (ERS) International Congress 2017: Abstract OA1774. Presented September 11, 2017.

Follow Medscape Pulmonary Medicine on Twitter @MedscapeLung and Ingrid Hein @ingridhein


Comments on Medscape are moderated and should be professional in tone and on topic. You must declare any conflicts of interest related to your comments and responses. Please see our Commenting Guide for further information. We reserve the right to remove posts at our sole discretion.