Table 2

Antibiotic use at age 20–39 and risk of colorectal adenoma, Nurses’ Health Study 2004–2010

Antibiotic use at age 20–39
None1–14 days15 days to 2 months2 months+ptrend
Total adenoma
 No. of cases (n=1195)141653296105
 Age-adjusted* OR (95% CI)1 (referent)1.13 (0.93–1.37)1.40 (1.13–1.74)1.36 (1.04–1.79)0.001
 Multivariable† OR (95% CI)1 (referent)1.12 (0.92–1.36)1.41 (1.13–1.75)1.36 (1.03–1.79)0.002
High risk‡
 No. of cases (n=436)5125110034
 Age-adjusted* OR (95% CI)1 (referent)1.25 (0.92–1.71)1.40 (0.99–2.00)1.35 (0.86–2.11)0.22
 Multivariable† OR (95% CI)1 (referent)1.23 (0.90–1.68)1.43 (1.00–2.05)1.37 (0.86–2.16)0.14
Low risk
 No. of cases (n=630)7333116759
 Age-adjusted* OR (95% CI)1 (referent)1.08 (0.83–1.40)1.47 (1.10–1.96)1.40 (0.97–2.00)0.002
 Multivariable† OR (95% CI)1 (referent)1.08 (0.82–1.41)1.47 (1.09–1.97)1.42 (0.98–2.05)0.002
Proximal
 No. of cases (n=709)8239117660
 Age-adjusted* OR (95% CI)1 (referent)1.18 (0.92–1.51)1.46 (1.11–1.92)1.36 (0.96–1.93)0.02
 Multivariable† OR (95% CI)1 (referent)1.17 (0.91–1.51)1.46 (1.10–1.93)1.43 (1.00–2.04)0.01
Distal
 No. of cases (n=509)6727112843
 Age-adjusted* OR (95% CI)1 (referent)0.99 (0.75–1.30)1.29 (0.94–1.76)1.20 (0.81–1.79)0.04
 Multivariable† OR (95% CI)1 (referent)0.98 (0.74–1.30)1.31 (0.96–1.81)1.18 (0.78–1.78)0.04
Rectal
 No. of cases (n=163)13964014
 Age-adjusted* OR (95% CI)1 (referent)1.88 (1.03–3.43)2.21 (1.15–4.24)2.16 (0.99–4.71)0.12
 Multivariable† OR (95% CI)1 (referent)1.84 (1.00–3.38)2.23 (1.16–4.30)1.95 (0.87–4.37)0.17
  • *Adjusted for age, time period of colonoscopy, number of reported endoscopies, time since most recent endoscopy and reason for current colonoscopy.

  • †Additionally adjusted for family history of colorectal cancer, history of diabetes, menopausal status and postmenopausal hormone use, body mass index, height, regular use of aspirin, current use of multivitamin, alcohol intake, smoking, total calorie, folate, calcium intake, red and processed meat intake and Alternate Healthy Eating Index 2010.

  • ‡High-risk adenomas include adenoma ≥1 cm, or with tubulovillous/villous histology, or ≥3 adenomas.