atopy, finding that "...trauma may be a particularly robust potentiator of the cascade of biological events that increase vulnerability to atopy and may help explain the increased risk found in low-income urban populations." Environmental factors are also thought to play a role in the development of atopy, and the 'hygiene hypothesis' is one of the models that may explain the steep rise in the incidence of atopic diseases, though this hypothesis is incomplete and in some cases, contradictory to findings. This hypothesis proposes that excess 'cleanliness' in an infant's or child's environment can lead to a decline in the number of infectious stimuli that are necessary for the proper development of the immune system. The decrease in exposure to infectious stimuli may result in an imbalance between the infectious-response ("protective") elements and the allergic-response ("false alarm") elements within the immune system. Some studies also suggest that the maternal diet during pregnancy may be a causal factor in atopic diseases (including asthma) in offspring, suggesting that consumption of antioxidants, certain lipids, and/or a Mediterranean diet may help to prevent atopic diseases. A Swedish research study titled "Atopy In Children Of Families With An Anthroposophic Lifestyle" comparing the rate of bronchial asthma, allergies, dermatitis, and other atopic diseases among Steiner school pupils and pupils in public schools originally appeared in the May 1, 1999, edition of the British medical journal The Lancet. The findings indicated that Steiner school pupils were "at a significantly lower risk of atopy" than children attending public schools. The researchers investigated a variety of factors in the lives of the Steiner school pupils that might have contributed to this lower rate of atopy, which included breastfeeding, reduced immunization, avoidance of antibiotics and medications that reduce fevers, consumption of bio-dynamic and organic foods, and other physical aspects of the children's lives. The multicenter PARSIFAL study in 2006, involving 6,630 children age 5 to 13 in 5 European countries, suggested that reduced use of antibiotics and antipyretics is associated with a reduced risk of allergic disease in children. Genetics There is a strong genetic predisposition toward atopic allergies, especially on the maternal side. Because of the strong familial evidence, investigators have tried to map susceptibility genes for atopy. Genes for atopy (C11orf30, STAT6, SLC25A46, HLA-DQB1, IL1RL1/IL18R1, TLR1/TLR6/TLR10, LPP, MYC/PVT1, IL2/ADAD1, HLA-B/MICA) tend to be involved in allergic responses or other components of the immune system. The gene C11orf30 seems to