Table 1

Distribution of 1017 cases and 951 controls by education, occupation, tobacco smoking and alcohol consumption

CovariatesCasesControls
n (%)n (%)
Distal covariates: socioeconomic status
Education
  More than 8 years207 (20.4)258 (27.1)
  4 to 8 years660 (64.9)613 (64.5)
  Less than 4 years150 (14.7)80 (8.4)
Occupation*
  Non-manual (I, II, IIIN)208 (20.5)276 (29.0)
  Manual (IIIM, IV, V)809 (79.5)675 (71.0)
Proximal covariates: lifestyle factors
Smoking (packs-year)
  Non-smokers59 (5.8)344 (36.2)
  Less than 21.8152 (14.9)240 (25.2)
  21.8 to 37.0246 (24.2)150 (15.8)
  37.1 to 57.7273 (26.9)113 (11.9)
  57.8 or more287 (28.2)104 (10.9)
Alcohol drinking (grams-year)
  Non-drinkers104 (10.2)415 (43.7)
  Less than 723.4162 (15.9)200 (21.0)
  723.4 to 2241.18221 (21.7)143 (15.0)
  2241.19 to 5562.1260 (25.6)102 (10.7)
  5562.2 or more270 (26.5)91 (9.6)
  • * Classified according to the British Registrar.10

  • Number of packs (20 cigarettes) smoked per day multiplied by the number of years of smoking.

  • Grams of ethanol consumed per day multiplied by the number of years of drinking.