cultivation in Southern China with the spread of the allele. The reasons for this positive selection are unknown, but the hypothesis that elevated concentrations of acetaldehyde may have conferred protection against certain parasitic infections, such as Entamoeba histolytica have been suggested. The same SNP allele of ALDH2, also termed glu487lys, and the abnormal accumulation of acetaldehyde following the drinking of alcohol, is associated with the alcohol-induced respiratory reactions of rhinitis and asthma that occur in Eastern Asian populations. Alcohol and Native Americans Compared with the United States population in general, the Native American population is much more susceptible to alcohol use disorder and related diseases and deaths. From 2006 to 2010, alcohol-attributed deaths accounted for 11.7 percent of all Native American deaths, more than twice the rates of the general U.S. population. The median alcohol-attributed death rate for Native Americans (60.6 per 100,000) was twice as high as the rate for any other racial or ethnic group. Males are affected disproportionately more by alcohol-related conditions than females. Native American and Native Alaskan youth are far more likely to experiment with alcohol at a younger age than non-Native youth. Low self-esteem and transgenerational trauma have been associated with substance use disorders among Native American teens in the U.S. and Canada. Native American populations exhibit genetic differences in the alcohol-metabolizing enzymes alcohol dehydrogenase and ALDH, although evidence that these genetic factors are more prevalent in Native Americans than other ethnic groups has been a subject of debate. According to one 2013 review of academic literature on the issue, there is a "substantial genetic component in Native Americans" and that "most Native Americans lack protective variants seen in other populations." Many scientists have provided evidence of the genetic component of alcohol use disorder by the biopsychosocial model of alcohol use disorder. Molecular genetics research currently has not found one specific gene that is responsible for the rates of alcohol use disorder among Native Americans, implying the phenomenon may be due to an interplay of multiple genes and environmental factors. Research on alcohol use disorder in families suggests that learned behavior augments genetic factors in increasing the probability that children of people with alcohol use disorder will themselves have problems with alcohol misuse. Genetics and amount of consumption Having a particular genetic variant (A-allele of ADH1B rs1229984) is associated with non-drinking and lower alcohol consumption. This variant is also associated with favorable cardiovascular profile