Skip to main content

Table 1 Baseline characteristics of study participants used for the gene-specific screening for CpG sites, differentially methylated according to urinary 8-isoprostane levels

From: The associations of DNA methylation alterations in oxidative stress-related genes with cancer incidence and mortality outcomes: a population-based cohort study

Characteristics

Derivation set (n = 1000)

1st validation set (n = 548)

2nd validation set (n = 741)

P value#

Age (year, median, IQR)

62 (57–67)

62 (57–67)

62 (56–67)

0.30

Sex (n, %)

   

< 0.001

 Female

500 (50.0)

324 (61.0)

415 (56.0)

 

 Male

500 (50.0)

224 (39.0)

326 (44.0)

 

Education (n, %)

   

0.95

 < 9 years

737 (73.7)

411 (75.0)

548 (74.0)

 

 9–11 years

155 (15.5)

85 (15.5)

115 (15.5)

 

 > 12 years

108 (10.8)

52 (9.5)

78 (10.5)

 

Smoking status (n, %)

   

0.19

 Never smoker

481 (48.1)

257 (46.9)

363 (49.0)

 

 Former smoker who quitted > 20 years ago

124 (12.4)

74 (13.5)

112 (15.1)

 

 Former smoker who quitted 5 to < 20 years ago

149 (14.9)

83 (15.2)

100 (13.5)

 

 Former smoker who quitted 0 to < 5 years ago

60 (6.0)

29 (5.3)

31 (4.2)

 

 Current smoker smoking 0 to < 15 g tobacco/day

84 (8.4)

49 (8.9)

60 (8.1)

 

 Current smoker smoking 15 to < 30 g tobacco/day

97 (9.7)

49 (8.9)

60 (8.1)

 

 Current smoker smoking > 30 g tobacco/day

5 (0.5)

7 (1.3)

15 (2.0)

 

Alcohol consumption (g/day, median, IQR)

6.0 (0–14.4)

5.6 (0–12.6)

4.8 (0–13.7)

0.80

Physical activity (n, %)

   

0.17

 Inactive

204 (20.4)

114 (20.8)

157 (21.2)

 

 Sedentary

438 (43.8)

270 (49.3)

343 (46.3)

 

 Vigorously active

358 (35.8)

164 (39.9)

241 (32.5)

 

BMI (kg/m2, median, IQR)

27.4 (25.0–30.1)

27.1 (24.5–30.1)

27.2 (24.9–30.1)

0.39

Categorized BMI (n, %)

   

< 0.001

 < 25 kg/m2

251 (25.1)

167 (30.5)

195 (26.3)

 

 25 to < 30 kg/m2

483 (48.3)

235 (42.9)

350 (47.2)

 

 ≥ 30 kg/m2

266 (26.6)

146 (26.6)

196 (26.5)

 

Dietary factors (n, %)

 Fruit consumption, < once/day

391 (39.2)

192 (35.0)

287 (38.7)

0.26

 Vegetable consumption, < once/day

656 (65.6)

341 (62.2)

461 (62.2)

0.25

 Meat consumption, ≥ once/day

349 (34.9)

178 (31.5)

247 (33.3)

0.59

Leukocyte composition (mean, SD)

 CD8+ T cells

0.07 (0.05–0.10)

0.09 (0.07–0.12)

0.06 (0.04–0.09)

< 0.001

 CD4+ T cells

0.16 (0.12–0.20)

0.17 (0.13–0.20)

0.16 (0.12–0.20)

0.01

 NK cells

0.91 (0.07–0.12)

0.09 (0.07–0.12)

0.10 (0.07–0.13)

0.18

 B cells

0.06 (0.05–0.07)

0.07 (0.06–0.08)

0.06 (0.04–0.07)

< 0.001

 Monocytes

0.10 (0.09–0.11)

0.10 (0.09–0.11)

0.07 (0.06–0.08)

< 0.001

 Granulocytes

0.55 (0.48–0.60)

0.54 (0.47–0.59)

0.56 (0.50–0.62)

< 0.001

8-isoprostane (nmol/mmol creatinine, median, IQR)

0.19 (0.13–0.26)

0.21 (0.16–0.27)

0.21 (0.16–0.28)

< 0.001

Prevalent cancer cases (n, %)

75 (7.5)

32 (6.0)

57 (7.7)

0.46

Prevalent CVD cases (n, %) ^

218 (21.8)

107 (20.2)

137 (18.5)

0.24

Prevalent diabetes cases (n, %)

155 (15.5)

89 (16.8)

108 (14.6)

0.64

Prevalent asthma cases (n, %)

74 (7.4)

23 (4.3)

49 (6.6)

0.19

  1. Abbreviations: BMI body mass index, CVD cardiovascular disease, IQR interquartile range
  2. #Differences in baseline characteristics among the three groups were assessed with a Wilcoxon signed-rank test for continuous variables and a chi-square test for categorical variables
  3. The consumption of alcohol was calculated by the following equation: 1 bottle of beer = 11.88 g ethanol, 1 glass of wine = 22.0 g ethanol, 1 shot of liquor = 6.4 g ethanol
  4. Definition of inactive: < 1 h of physical activity/week. Definition of medium or high physical activity: ≥ 2 h of vigorous and ≥ 2 h of light physical activity/week. Definition of low physical activity: all other amounts of activity not categorized as “inactive” or “medium or high”
  5. Estimated by the Houseman algorithm
  6. ^Cardiovascular disease at baseline is a composite variable of either coronary heart disease or history of one or more cardiovascular event (i.e., stroke, myocardial infarction, pulmonary embolism, bypass operation, or dilatation of the coronary vessels)