ians ▁of ▁European ▁descent ▁is ▁about ▁~ 1 6 % ▁in ▁individuals ▁hom o zy g ous ▁for ▁the ▁" normal " ▁AD H 1 B ▁gene ▁but ▁runs ▁to ▁~ 2 3 % ▁in ▁individuals ▁with ▁the ▁AD H 1 - Arg 4 8 H is ▁Single - n uc le ot ide ▁polym orphism ▁variant ; ▁in ▁vit ro , ▁this ▁variant ▁met abol izes ▁eth an ol ▁rapidly ▁and , ▁it ▁is ▁proposed ▁but ▁not ▁proven , ▁in ▁humans ▁forms ▁ac etal de hy de ▁at ▁levels ▁exceed ing ▁A LD H 2 ' s ▁ac etal de hy de - met abol izing ▁capacity . ▁ ▁Pres umably , ▁then , ▁ac etal de hy de ▁prov okes ▁the ▁resp ir atory ▁sympt oms ▁in ▁a ▁manner ▁similar ▁to ▁that ▁occurr ing ▁in ▁A si ans ▁with ▁the ▁gl u 4 8 7 ly s ▁A LD H 2 ▁variant . ▁ ▁In ▁studies ▁conducted ▁in ▁the ▁USA ▁and ▁pres umably ▁therefore ▁mainly ▁on ▁non - A si ans , ▁alco hol - indu ced ▁rh init is ▁and ▁ex ac erb ations ▁of ▁ast h ma ▁re actions ▁are ▁highly ▁associated ▁with ▁asp ir in - indu ced ▁ast h ma ▁re actions ; ▁more ▁than ▁half ▁of ▁individuals ▁suffering ▁from ▁the ▁asp ir in - indu ced ▁sens itivity ▁reaction ▁will ▁also ▁suffer ▁alco hol - indu ced ▁re actions . ▁ ▁It ▁seems ▁likely , ▁although ▁further ▁study ▁is ▁needed , ▁that ▁most ▁resp ir atory