Seven studies [10, 12, 18, 27, 35, 37, 50] assessed whether the patient was a current, former, or never smoker (as separate categories), 15 [13, 15, 17, 21, 32, 40,41,42,43,44, 46, 47, 51, 52, 54] studies assessed whether the patient was a current smoker, 24 [8, 9, 11, 14, 16, 19, 20, 22,23,24,25,26, 28,29,30, 33, 34, 36, 38, 39, 45, 48, 49, 53] studies assessed whether the patient had a history of smoking (current and former)
16 Statins, which lower cholesterol levels by inhibiting the function of HMGCR, are primarily used to treat atherosclerosis and have been found to possess anti-inflammatory properties in respiratory diseases, 7,8 reducing the incidence and mortality of COPD
cMRTP aerosols with significantly reduced effects on both key mechanisms involved in cancer causation hypothesized by Balkwill and Mantovani ( genetic damage and inflammation ) [24] would be reasonably expected to also reduce the risk of lung cancer compared with cigarette smoking
In the analysis, the domain option in SAS was used to control for subgroups with full clusters in reducing the dataset of interest
