CEHN Articles of the Month, May 2015 Issue
Moisture Damage and Asthma: A Birth Cohort Study
Authors: Anne M. Karvonen, Anne Hyvarinen, Matti Korppi, Ulla Haverin-Shaughnessy, Harald Renz, Petra I.Pfefferle, Sami Remes, Jon Genuneit, Juha Pekkanen
Asthma is the leading cause of absenteeism in schools, accounting for more than 14 million school days lost in the United States (US) each year. According to the Centers for Disease Control and Prevention, in 2012, 9.3% of children were diagnosed with asthma. For school-aged children, the number affected is more than 1 in 10.The most common type of asthma, allergic asthma, is triggered by inhaled allergens, such as mold, and involves the body’s immune response. Atopic individuals are those who are genetically predisposed to produce large quantities of immunoglobin E (IgE), an antibody responsible for allergic reactions. Atopic individuals are at greater risk for allergic asthma.
Excess moisture and mold are known to increase the risk of asthma in young children, whether these children are categorized as atopic or not. Past studies have shown a relationship between moisture and mold in the home and the development of asthma in young children. However, these studies were based on parent-reporting of mold and respiratory symptoms, were only done during the first 18 months of life, and did not take into account the connection to atopic children—those who are most sensitive to allergens. Respiratory symptoms during the first 18 months of life are commonly not indicative of actual development of asthma and/or chronic asthma, and thus children in a study should be followed longer in order to determine real asthma rates.
Study authors completed a thorough, expert evaluation of moisture damage and mold in children’s homes, identified atopic children, and monitored the children for longer than 18 months. The aim was to better understand the connection between asthma risk and environmental conditions, age group, and atopic sensitivity.
The study participants consisted of 398 babies born between September 2002 and May 2005, half residing in rural areas and half residing in suburban areas. A trained civil engineer inspected the home of each child for moisture and mold when the child reached 5 months of age. Respiratory symptoms were tracked in 6-month intervals by both the parents and a physician. In order to determine atopic sensitivity, blood samples were taken from the children and their parents when the child reached both one year and six years of age to measure IgE concentrations. Statistical analyses on the association between moisture and mold in the home and the presence of asthmatic symptoms were done for each child at the one-year, 1.5, 2,3,4,5, and 6-year marks.
Moisture damage and mold in the main living areas of a child’s home at the age of 5 months was associated with the development of asthma, persistent asthma, and respiratory symptoms during the first 6 years of life. The associations were strongest for moisture damage with visible mold in the child’s bedroom and in the living room. There was some evidence that atopic children may have been more susceptible to the effects of moisture damage and mold, but this evidence was not consistent. One interesting note is that parents consistently reported less moisture damage or visible mold in their homes than the inspector.
The presence of moisture damage and mold in the child’s main living areas during early infancy are associated with asthma development in early childhood. This asthma may or may not continue into later life.
Atopic children may be more susceptible than non-atopic children to asthma triggered by moisture and mold in the home.
The U.S. Department of Housing and Urban Development (HUD) has published mold guidelines with regard to public housing, and the U.S. Environmental Protection Agency (EPA) has thorough mold remediation guidelines for schools, businesses, and homes. However, no human health-based standards for mold exposure have been established, and EPA does not regulate airborne mold contamination.
According to a state policy report by the Environmental Law Institute, nearly half of all US states have child care licensing regulations addressing mold or dampness directly. Several states also have regulations pertaining to K-12 facilities.
Unfortunately, many housing, school and childcare facilities in the US experience plumbing problems, leaky roofs and poor ventilation—all of which contribute to an abnormally moist environment that encourages mold growth. Often both the enforcement of any existing state or local regulations or ordinances, and the capacity for robust public health educational campaigns are limited by insufficient funding. Increased support for prevention-oriented education and outreach campaigns, as well as for effective maintenance and repair of underlying structural problems and remediation of dampness in housing and school facilities is necessary for protecting children’s respiratory health.