Final answer:
The association between lung cancer and smoking was officially recognized in the 1964 U.S. Surgeon General's report, based on research conducted by scientists Richard Doll and Austin Bradford Hill starting in 1950.
Step-by-step explanation:
The association between lung cancer and smoking was officially recognized in the 1964 U.S. Surgeon General's report, which was one year after the U.S. Surgeon General initially linked cigarette smoking with diseases like lung cancer. This report was based on extensive research conducted by scientists Richard Doll and Austin Bradford Hill, who began studying the correlation between smoking and lung cancer in 1950.
They conducted large-scale, long-term observational studies and demonstrated a strong correlation between smoking and lung cancer. It took about 20 years for the decline in smoking rates among men to be reflected by a decline in lung cancer deaths in the 1970s.