Table 1.

Characteristics and distribution of study subjects and ORs (and 95% CIs) for EPL according to sociodemographic features, lifestyle, and eating habits

Cases (n = 667)Controls (n = 10,851)Crude OR (95% CI)PAdjusted OR (95% CI)aPAge-adjusted OR (95% CI)bP
n (%)n (%)
Gender
 Male306 (45.9)4,125 (38.0)1.00 (reference)1.00 (reference)1.00 (reference)
 Female361 (54.1)6,726 (62.0)0.72 (0.62–0.85)<0.0010.77 (0.62–0.94)0.0110.82 (0.70–0.96)0.014
Age at baselinePtrend<0.001Ptrend<0.001
 <5175 (11.2)3,294 (30.4)1.00 (reference)-1.00 (reference)
 51-216 (32.4)4,153 (38.3)2.28 (1.75–2.98)<0.0012.17 (1.66–2.85)<0.001
 61-376 (56.4)3,404 (31.4)4.85 (3.77–6.25)<0.0014.44 (3.41–5.79)<0.001
Educationc
 Illiterate313 (46.9)4,247 (39.1)1.00 (reference)1.00 (reference)1.00 (reference)
 Educated354 (53.1)6,604 (60.9)0.73 (0.62–0.85)<0.0010.86 (0.71–1.04)0.1130.94 (0.77–1.13)0.493
Annual income per capita (RMB)Ptrend0.054Ptrend0.5900.429
 ≤5,000185 (27.7)2,511 (23.1)1.00 (reference)1.00 (reference)1.00 (reference)
 5,001-317 (47.5)5,384 (49.6)0.80 (0.66–0.96)0.0190.89 (0.74–1.08)0.2420.86 (0.71–1.04)0.120
 10,001-106 (15.9)1,891 (17.4)0.76 (0.60–0.97)0.0290.86 (0.67–1.10)0.2320.86 (0.67–1.10)0.229
 15,001-59 (8.8)1,065 (9.8)0.75 (0.56–1.02)0.0640.94 (0.69–1.28)0.6840.94 (0.69–1.27)0.669
Source of drinking waterdPtrend<0.001Ptrend<0.001<0.001
 Tap water282 (42.3)3,999 (36.9)1.00 (reference)1.00 (reference)1.00 (reference)
 Deep well water361 (54.1)6,742 (62.1)0.76 (0.65–0.89)0.0010.75 (0.63–0.89)0.0010.74 (0.63–0.87)<0.001
 Shallow wells and surface water24 (3.6)110 (1.0)3.09 (1.96–4.89)<0.0013.35 (2.08–5.39)<0.0012.37 (1.32–4.27)0.004
Regularity of diet
 Regular diet623 (93.4)10383 (95.5)1.00 (reference)-1.00 (reference)-1.00 (reference)-
 Irregular diet44 (6.6)468 (4.5)1.57 (1.14–2.16)0.0061.81 (1.30–2.51)<0.0011.87 (1.35–2.59)<0.001
  • aAdjusted for gender, age, BMI, education level, annual income, number of cigarettes per day and alcohol units consumed per day, except the specific variable itself.

  • bAdjusted for age only.

  • cAverage ages of illiterate and educated subjects were 58.6 and 53.9 years old respectively (P < 0.001, Student t test).

  • dAverage annual incomes per capita (RMB) of subjects who consume tap water, deep water and shallow wells and surface water were 10,942, 8,469, and 7,576, respectively (P < 0.05, Student t test).