Evidence that indoor dampness and mold growth are associated with respiratory health has been accumulating, but few studies have been able to examine health risks in relation to measured levels of indoor mold exposure. In particular, little is known about the contribution of indoor molds to the development of allergic sensitization.
As a part of an ongoing study examining the effects of ambient air pollutants on respiratory health and atopic diseases in German school children, we examined the relation between viable mold levels indoors and allergic sensitization in 272 children. We examined whether allergic sensitization in children is associated with higher fungal spore count in settled house dust sampled from living room floors. Adjusting for age, sex, parental education, region of residency, and parental history of atopy, we found that mold spore counts for Cladosporium and Aspergillus were associated with an increased risk of allergic sensitization. Sensitized children exposed to high levels of mold spores (> 90th percentile) were more likely to suffer from symptoms of rhinoconjunctivitis.
We conclude that elevated indoor concentrations of molds in wintertime might play a role in increasing the risk of developing atopic symptoms and allergic sensitization not only to molds but also to other common, inhaled allergens. These effects were strongest in the group of children who had lived in the same home since birth.
Mold Growth
Some molds are cryophytes (these adapt to low temperatures), some are thermo tolerant (they adapt to a wide range of temperatures) and some are thermophiles (they adapt to high temperatures). Depending on the species, these microbes will grow just about anywhere. Not even a fire in excess of 500 degrees Fahrenheit has been able to destroy some molds such as Stachybotrys. Mold requires a compatible temperature for each species. Environmental factors (temperature, nitrogen, oxygen, etc. ) are necessary compounds for indoor molds to thrive.
Mycotoxins
Mycotoxins are examples of chemical substances that molds create generally as secondary metabolites, thought to possibly play a role in either helping to prepare the substrate on which they exist for digestion, as defense mechanisms, and some have suggested that they may be produced when the organisms are under stress, which could be related to competition/defense, or simply due to inhospitable environmental conditions. The mycotoxins, which are also neurotoxins (a toxin that is determined to cause neurological damage), most commonly reach people from the air, via spores from the molds in question. They are also found in small particulates at times which may often represent mold dust, small particles of mold that has dried and turned to dust. Spores, when inhaled, can begin to colonize in the sinuses and throughout the body, including the brain, lung and gut after a period of time.
