Document 5bqrm3ZgLDNDnj3jwbXpBJNQR

1 . when we talked about smoking. The more packs per day Page 3488 2 you smoke, the higher the risk of lung cancer. 3 That is a very good criteria to determine . 4 whether there is a causal relationship or not. If 5 indeed chemical X causes disease Y, the more X you 6 have, the higher the Y. 7 Q Okay. And then what is the final one? 8 A The final one is what we call the time 9 sequence. 10 If we look at all of these criteria, a 11 substance satisfies the first four, then we look at 12 the latency because when we talk about chronic disease 13 such as cancer, cancer takes about, depending on what 14 substance we are talking about, for example, smoking 15 and lung cancer, it takes about 20 years to develop. 16 If I start smoking today, I am not going to 17 get lung cancer tomorrow or next year or the year 18 after that. 19 I would most likely get lung cancer 20 years 20 down the road, and that is one of the major problems 21 to try to stop people from smoking.