IGF1 and lung cancer: Among those who smoked for 1–39 pack-years, those carrying the IGF1 (CA)19/(CA)19 and (CA)19/X genotypes (OR = 3.78, 95% CI = 1.79–8.01) and IGF1 X/X genotype (OR = 4.51, 95% CI = 1.99–10.22) had significantly increased risks of lung cancer.