Alcohol consumption is a social activity, and as such can be strongly influenced by cultural and social forces. In Japan, where the risk of alcohol-related esophageal cancer in ALDH2 heterozygotes has been most well documented, going out drinking after work with colleagues is an essential element of Japanese business society, and the idea of group harmony is particularly powerful. The percentage of heavy drinking men who are low-activity ALDH2 heterozygotes has risen substantially in the last few decades, in parallel with the proliferation of business society in Japan and increases in per capita alcohol consumption. Harada et al. [23] first reported that the frequency of inactive ALDH2 was very low (only 2%) in Japanese alcoholics in 1982. In a later study using archival DNA samples, Higuchi et al. [24] determined that in 1979, 3% of Japanese alcoholics were ALDH2 heterozygotes, compared with 8% in 1986 and 13% in 1992. In a more recent study, approximately 26% of heavy drinking (consuming more than about 400 g of ethanol per week) men in Tokyo were ALDH2 Lys487 heterozygotes [35]. In other East
