In “Smoking, smoking cessation, and lung cancer in the UK since 1950: combination of national statistics with two case-control studies,” they state that "by 1950 lung cancer rates among men in the United Kingdom had already been rising steeply for many years, but the relevance of smoking was largely unsuspected” (Peto et al., 2000, pp. 323). This proves that part of the reason smoking had a relaxed perception was because the fact that smoking could cause lung cancer was not well known until a few decades after the 1950s.