Table 1

General characteristics of the study population

Total populationWest Sudanese populationCentral Sudanese population
Cases (n = 112)Controls (n = 194)Cases (n = 71)Controls (n = 80)Cases (n = 41)Controls (n = 114)
Demographics
 Region, n from West Sudan (%)71 (63.4)80 (41.2)aNAbNANANA
 Age, mean (SD)57.0 (12.2)44.9 (10.9)a56.9 (11.7)48.2 (11.4)a56.9 (13.1)42.5 (10.0)a
 Gender, n males (%)86 (76.8)146 (75.3)56 (78.9)60 (75.0)29 (72.5)86 (75.4)
 Education, n illiterate (%)78 (69.6)67 (34.5)a50 (70.4)38 (47.5)a27 (67.5)29 (25.4)a
Peanut butter consumption, mean (SD)
 Average frequency (times/month)c11.3 (11.8)7.9 (9.1)a12.7 (13.6)7.2 (8.5)a9.1 (7.4)8.4 (9.5)
 Average consumption (kg/month)c0.68 (1.1)0.29 (0.6)a0.83 (1.22)0.28 (0.47)a0.44 (0.77)0.30 (0.63)
Other risk factors, n (%)
 Hepatitis B infectiond45 (41.3)14 (7.3)a31 (44.9)7 (8.8)a14 (35.0)7 (6.2)a
 Hepatitis C infectiond13 (11.9)3 (1.6)a6 (8.7)1 (1.3)a7 (17.5)2 (1.8)a
 Positive history of alcohol consumption44 (39.3)60 (30.9)29 (40.9)32 (40.0)15 (37.5)28 (24.6)
 Positive history of smoking45 (40.2)76 (39.2)27 (38.0)33 (41.3)18 (45.0)43 (37.7)
Genotype, n (%)
GSTe
  GSTM1 null47 (42.7)73 (38.8)29 (40.9)29 (38.2)17 (44.7)44 (39.3)
  GSTT1 null39 (35.8)71 (37.8)27 (38.0)29 (38.2)12 (31.6)42 (37.5)
EPHX exon 3e
  113YY68 (61.8)128 (66.3)43 (61.4)47 (59.5)25 (62.5)81 (71.1)
  113YH28 (25.5)50 (25.9)16 (22.9)24 (30.4)12 (30.0)26 (22.8)
  113HH14 (12.7)15 (7.8)11 (15.7)8 (10.1)3 (7.5)7 (6.1)
EPHX exon 4e
  139HH63 (57.3)102 (55.4)40 (57.1)37 (52.1)23 (57.5)65 (57.5)
  139HR44 (40.0)69 (37.5)28 (40.0)28 (39.4)16 (40.0)41 (36.3)
  139RR3 (2.7)13 (7.1)2 (2.9)6 (8.5)1 (2.5)7 (4.6)
EPHX exon 3 and 4 combinede
  113HH and 139HH12 (10.9)7 (3.8)a11 (15.7)3 (4.2)a1 (2.5)4 (3.5)
  • a Significantly different from cases (P < 0.05).

  • b NA, not applicable.

  • c Average frequency calculated as: [3 × freq “in season” + 9 × freq “off-season”] × Embedded Image; average consumption calculated as: [3 × freq “in season” + 9 × freq “off-season”] × portion size × Embedded Image.

  • d Information on hepatitis B and hepatitis C virus infections was available for 109 cases and 193 controls; among West Sudanese participants, 1 case and 1 control had evidence of both hepatitis B and C virus infection.

  • e Information on GSTM1 and GSTT1 genetic polymorphism was available for 109 cases and 188 controls, on EPHX exon 3 for 110 cases and 193 controls, and on EPHX exon 4 for 110 cases and 184 controls.