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Table 1 Characteristics of the study population at the last questionnaire available before the date of diagnosis of cases (N = 388)

From: Application of two statistical approaches (Bayesian Kernel Machine Regression and Principal Component Regression) to assess breast cancer risk in association to exposure to mixtures of brominated flame retardants and per- and polyfluorinated alkylated substances in the E3N cohort

 

All (N = 388)

Breast cancer

Global p-value*

Control (N = 194)

Case (N = 194)

Time of follow-up (years)

12.246 (1.947)

12.257 (1.955)

12.238 (1.944)

0.060

Education

   

0.580

 ≤ BAC

39 (10.052)

22 (11.340)

17 (8.762)

 

 BAC to BAC + 2

191 (49.226)

97 (50.000)

94 (48.454)

 

 > BAC + 2

158 (40.722)

75 (38.660)

83 (42.784)

 

Physical activity (metabolic equivalent tasks (MET)-hour/week)

44.513 (36.840)

46.134 (37.878)

42.892 (35.797)

0.388

Smoking status

   

0.184

 Never

187 (48.196)

87 (44.845)

100 (51.546)

 

 Ever

201 (51.804)

107 (55.155)

94 (48.454)

 

 Body masse index at blood draw (kg/m2)

23.815 (3.553)

23.850 (3.614)

23.779 (3.500)

0.763

Family history of breast cancer

   

0.283

 None

278 (71.650)

144 (74.227)

134 (69.072)

 

 In first-degree relatives

59 (15.206)

30 (15.464)

29 (14.949)

 

 In extended relatives

51 (13.144)

20 (10.309)

31 (15.979)

 

Personal history of benign breast disease

   

0.111

 No

224 (57.732)

120 (61.856)

104 (53.608)

 

 Yes

164 (42.268)

74 (38.144)

90 (46.392)

 

 Age at menarche (year)

12.807 (1.378)

12.745 (1.446)

12.869 (1.306)

0.370

Age at menopause

   

0.437

 Menopause before age 51

189 (48.711)

98 (50.515)

91 (46.907)

 

 Menopause at age 51 or later

199 (51.289)

96 (49.485)

103 (53.093)

 

Use of oral contraceptives

   

0.420

 Never

133 (34.278)

70 (36.082)

63 (32.474)

 

 Ever

255 (65.722)

124 (63.918)

131 (67.526)

 

Current use of menopausal hormone therapy

   

0.235

 No

301 (77.577)

155 (79.897)

146 (75.258)

 

 Yes

87 (22.423)

39 (20.103)

48 (24.742)

 

Parity and age at first full-term pregnancy (FFTP)

   

0.171

 No children

55 (14.174)

22 (11.340)

33 (17.010)

 

 1 or 2 children and < 25 years old at FFTP

192 (49.485)

95 (48.969)

97 (50.000)

 

 ≥ 3 children and < 25 years old at FFTP

106 (27.320)

61 (31.443)

45 (23.196)

 

 ≥ 25 years old at FFTP

35 (9.021)

16 (8.248)

19 (9.794)

 

Total breastfeeding duration in months

   

0.343

 Never

150 (38.659)

79 (40.722)

71 (36.598)

 

 ≤ 6

162 (41.753)

83 (42.784)

79 (40.722)

 

 > 6

76 (19.588)

32 (16.494)

44 (22.680)

 

Adherence score to Prudent dietary pattern

   

0.053

  < median

193 (49.742)

87 (44.845)

106 (54.639)

 

  ≥ median

195 (50.258)

107 (55.155)

88 (45.361)

 

Adherence score to Western dietary pattern

   

0.915

 < median

193 (49.742)

96 (49.485)

97 (50.000)

 

 ≥ median

195 (50.258)

98 (50.515)

97 (50.000)

 
  1. Mean (Standart deviation) and Counts (Percentages) are presented for continuous and categorical variables respectively