Moisture damage, mold at home during infancy associated with persistent childhood wheeze

Residential exposure to moisture damage and mold during infancy had a dose-dependent association with wheeze later in childhood, according to a study published in Pediatric Allergy and Immunology.

Exposures were particularly associated with persistent and recurrent wheeze, which is a risk factor for later asthma, Anne M. Karvonen, PhD, adjunct professor and chief researcher, Finnish Institute for Health and Welfare, Department of Health Security, Environmental Health Unit, and colleagues wrote.

“Asthma has several phenotypes whose risk factors are partly different,” Karvonen told Healio. “Understanding these risk factors is essential in the prevention and treatment of asthma.”

The researchers examined data from 214 rural and 228 suburban children in the LUKAS cohort born between September 2002 and May 2005 in middle and eastern Finland.

Trained civil engineers inspected their homes for moisture damage when the children were aged a mean 5.42 months, finding minor moisture damage in the child’s main living areas in 23.8% of the homes and major moisture damage or any moisture damage with visible mold in 13.4% of the homes.

“We have previously shown that moisture damage and visible mold in a child’s main living area — including the child’s bedroom, living room and kitchen — of the house are associated with an increased risk of developing asthma,” Karvonen said.

Over the following 6 years, 63.4% of the children had no or infrequent wheezing, 23.3% had transient wheezing, 3.8% had intermediate wheezing, 3.5% had late-onset wheezing and 6% had persistent wheezing.

Adjusted analyses revealed a dose-dependent association between moisture damage or mold in the child’s main living area and an increased risk for persistent wheeze, with adjusted odds ratios of 2.04 (95% CI, 0.67-6.18) for minor moisture damage, and 3.68 (95% CI, 1.04-13.05) for major damage or any moisture damage with visible mold.

Persistent wheeze also tended to be associated with minor and major moisture damage in the living room, in the child’s bedroom and in other main living areas, although confidence intervals were wide due to small numbers, but not in the bathrooms, other interior spaces or the whole house.

“According to our study, moisture damage in the main living area where children spend most of their time is particularly associated with persistent asthma, not transient asthma. Transient asthma is associated with infections in small children,” Karvonen said.

Further, the researchers found nonsignificant associations between transient wheeze and minor damage with or without mold spots (aOR = 1.59; 95% CI, 0.85-2.99) and major moisture damage or any moisture damage with visible mold (aOR = 1.75; 95% CI, 0.78-3.94), driven by exposures in the kitchen but not other living spaces.

Based on these results and their previous studies, the researchers concluded that exposure to moisture damage and mold during infancy was associated with wheeze, especially its persistent and recurrent phenotypes.

Considering these risks, which include later asthma outcomes, the researchers wrote, home environments need to be free of major moisture damage during early childhood.

“The risk of asthma is increased if the moisture damage and/or mold is located in the rooms, or if there is an air connection from damage to these rooms, where children spend most of their time,” Karvonen said.

Families can prevent this risk for asthma caused by moisture damage by keeping their homes and indoor environments in good condition, Karvonen added, noting that she and her team will continue their research.

“We’re trying to figure out what kind of microbes explain the association between moisture damage and asthma,” she said. “It is now well known what causes the adverse health effects of moisture damage.”

For more information:

Anne Karvonen, PhD, can be reached at anne.karvonen@thl.fi.