Table 4.

Colorectal cancer subsites by time since last OC among 88,691 NHSI and 93,080 NHSII participants

Time since last OC use (years)Never≤4>4 to <10≥10 to <1515+
N cases
HR (95% CI)aPtrend
NHSI
Colorectal1,11267184245156
ref.1.14 (0.88–1.47)0.98 (0.83–1.15)1.08 (0.93–1.25)0.96 (0.81–1.15)0.89
 Colon87249139191134
ref.1.09 (0.81–1.47)0.96 (0.80–1.16)1.10 (0.93–1.30)1.07 (0.89–1.29)0.30
  Proximal colon508319410981
ref.1.28 (0.88–1.86)1.19 (0.94–1.49)1.14 (0.92–1.41)1.15 (0.90–1.46)0.13
  Distal colon33816447350
ref.0.82 (0.49–1.38)0.72 (0.52–0.99)1.00 (0.77–1.31)1.00 (0.73–1.35)0.82
 Rectum24018455422
ref.1.31 (0.79–2.17)1.02 (0.73–1.42)1.00 (0.73–1.37)0.59 (0.38–0.93)0.10
NHSII
Colorectal45131418116
ref.1.00 (0.53–1.86)0.62 (0.33–1.14)1.04 (0.59–1.81)0.95 (0.65–1.39)0.86
 Colon349111174
ref.0.92 (0.44–1.92)0.62 (0.31–1.23)0.82 (0.41–1.63)0.81 (0.52–1.25)0.56
  Proximal colon2047334
ref.0.64 (0.22–1.90)0.67 (0.28–1.59)0.38 (0.11–1.29)0.64 (0.35–1.16)0.29
  Distal colon1454838
ref.1.35 (0.48–3.78)0.55 (0.18–1.69)1.46 (0.61–3.51)0.99 (0.52–1.89)0.97
 Rectum1143742
ref.1.24 (0.39–3.95)0.59 (0.16–2.13)1.76 (0.68–4.58)1.42 (0.71–2.83)0.23
  • aAdjusted for age, BMI, height, physical activity, smoking, processed and red meat, folate, calcium, total energy, aspirin use, alcohol, age at first birth, parity, HT use, family history, and previous endoscopy screening.