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Table 1 The baseline characteristics of study population

From: The mediation effect of serum metabolites on the relationship between long-term smoking exposure and esophageal squamous cell carcinoma

Variable Controls Cases Total P-value
N 257 207 464  
Age, year 52.7 (7.5) 58.8 (7.4) 55.4 (8.1) < 0.001
Males, n (%) 91 (35.4) 89 (43.0) 180 (38.8) 0.116
BMI, kg/m2 24.9 (3.3) 24.1 (3.4) 24.5 (3.3) 0.016
Ever Smoker, n (%) 43 (16.7) 65 (31.4) 108 (23.3) < 0.001
Smoking Index*, cigarette-years 560.4 (293.7) 743.1 (509.6) 670.4 (444.2) 0.033
Alcohol Drinker, n (%) 55 (21.4) 60 (29.0) 115 (24.8) 0.076
  1. The continuous and categorical variables are presented as mean and percentages, respectively
  2. BMI, body mass index
  3. Smoking index = the number of cigarettes smoked per day × the number of years of smoking
  4. *: just for ever smokers