Three studies have found a statistically significant inverse relationship between consumption of raw milk and asthma and allergies. However, all of these studies have been performed in children living on farms and living a farming lifestyle, rather than comparing urban children living typical urban lifestyles and with typical urban exposures on the basis of consumption or nonconsumption of raw milk. Aspects of the overall urban vs. farming environment lifestyle have been suggested as having a role in these differences, and for this reason, the overall phenomenon has been named the "farm effect". A recent scientific review concluded that "most studies alluding to a possible protective effect of raw milk consumption do not contain any objective confirmation of the raw milk's status or a direct comparison with heat-treated milk. Moreover, it seems that the observed increased resistance seems to be rather related to the exposure to a farm environment or to animals than to raw milk consumption." For example, in the largest of these studies, exposure to cows and straw as well as raw milk were associated with lower rates of asthma, and exposure to animal feed storage rooms and manure with lower rates of atopic dermatitis; "the effect on hay fever and atopic sensitization could not be completely explained by the questionnaire items themselves or their diversity."