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Table 4 Effect of lifetime chest X-ray exposure (any exposure) on breast cancer risk according to the number of exposures, the age at first exposure, and the first full-term pregnancy

From: Diagnostic chest X-rays and breast cancer risk among women with a hereditary predisposition to breast cancer unexplained by a BRCA1 or BRCA2 mutation

 

Number of

  

Multiple Imputation

Cases

Controls

ORa

95% CI

ORa

95% CI

Chest X-ray exposureb

 Never

208

239

1

 

1

 

 Ever

1304

1104

2.05

1.55–2.73

2.05

1.54–2.72

Number of exposures

 0

208

239

1

 

1

 

 1–3

392

390

1.70

1.23–2.34

1.62

1.18–2.23

 4–9

251

200

2.52

1.76–3.61

2.29

1.65–3.16

 ≥10

263

215

2.37

1.64–3.43

2.70

1.89–3.87

 Continuous

  

1.03

1.01–1.04

1.03

1.02–1.05

Age at first exposure, yearsc

 No exposure

208

239

0.55

0.40–0.76

0.58

0.42–0.80

 ≥20

485

490

1

 

1

 

 15–19

288

222

1.02

0.75–1.37

1.01

0.75–1.36

 <15

290

219

1.11

0.83–1.50

1.08

0.80–1.45

 Continuous

  

1.00

0.99–1.01

1.01

0.99–1.02

According to first full-term pregnancy (FFTP)c

 Only after FFTPd

268

232

1

 

1

 

 Before (incl. no FTP)

825

725

0.81

0.61–1.08

0.85

0.64–1.12

According to first FFTP and number of exposures

 Only after and ≤5d

186

178

1

 

1

 

 Only after and >5d

56

43

1.77

0.98–3.18

1.68

0.99–2.85

 Before and ≤5 (incl. no FTP)

442

412

0.95

0.67–1.36

0.89

0.63–1.25

 Before and >5 (incl. no FTP)

272

215

1.12

0.77–1.61

1.33

0.96–1.85

  1. Abbreviations: OR (95%CI) odds ratio (95% confidence interval)
  2. aAdjusted for age at censoring, birth cohort (≤1945; 1946–1959; ≥1960), number of full-term pregnancies (>2; 1–2; 0), mammography use (never; ever), educational level (intermediate/high; basic; not graduated), BMI (18.5–24.9; <18.5; ≥25 and <30; ≥30), smoking (no; current; past), and breast cancer family history (0;1st degree; 2nd degree)
  3. bChest X-ray exposure includes pulmonary radiological examinations in the field of preventive/occupational medicine or for lung disease, preoperative radiological examinations, and radiological examinations of heart and thoracic vessels for all the reported procedures
  4. cAdjusted as in a plus number of exposures (≤5;>5)
  5. dAfter = also includes chest X-ray exposure that occurred during the same year of first full-term pregnancy