我沒有survivorship bias，1/10 of age >= 65 has AD in US;

that number is 1/20 in China. 2/3 of Americans with AD are women; that number is 7/26 in China. By all indicators, highly educated Chinese males are lucky ones. Having said that，我曾與高錕做過短期的同事，a very sharp and kind小個子，很不幸落入AD魔掌。家父，教授，從不鍛煉，a chain smoker, 有糖尿病，最後很衰竭但腦子清楚，活到88。身高與AD發病率有負相關，但不知是身高本身，還是與身高成正相關的幼兒腦發育期的營養狀態。老媽二戰時在教會學校學的醫，早過了90還喜歡與我爭論。她最內疚的是我小時候托紅太陽的福營養不良，至今還留有我在幼兒園的健康卡，身高體重都不達她教科書的標。