Table 3.

Colorectal cancer mortality by postdiagnosis physical activity quartile, stratified by PTGS2 (COX-2) status

Postdiagnosis physical activity quartileNo.Colorectal cancer–specific mortalityOverall mortality
No. of eventsUnivariate HR (95% CI)Stage-stratified HR (95% CI)Multivariate stage-stratified HRa (95% CI)No. of eventsUnivariate HR (95% CI)Stage-stratified HR (95% CI)Multivariate stage-stratified HRa (95% CI)
PTGS2 (COX-2) (−)
 Q16181 (referent)1 (referent)1 (referent)281 (referent)1 (referent)1 (referent)
 Q25870.87 (0.32–2.41)0.96 (0.34–2.68)0.89 (0.32–2.51)240.83 (0.48–1.43)0.86 (0.49–1.49)0.87 (0.50–1.52)
 Q35681.07 (0.40–2.85)1.10 (0.41–2.94)1.14 (0.42–3.08)170.65 (0.36–1.20)0.67 (0.37–1.23)0.68 (0.37–1.26)
 Q44850.74 (0.24–2.27)0.82 (0.26–2.55)0.85 (0.27–2.67)130.52 (0.27–1.00)0.54 (0.28–1.05)0.65 (0.33–1.29)
Ptrendb0.670.830.840.180.270.40
PTGS2 (COX-2) (+)
 Q191291 (referent)1 (referent)1 (referent)501 (referent)1 (referent)1 (referent)
 Q288100.31 (0.15–0.63)0.29 (0.14–0.60)0.30 (0.14–0.62)400.72 (0.47–1.09)0.71 (0.46–1.08)0.70 (0.46–1.06)
 Q3102150.38 (0.20–0.71)0.36 (0.19–0.67)0.38 (0.20–0.71)410.54 (0.36–0.82)0.54 (0.36–0.82)0.60 (0.39–0.91)
 Q410170.18 (0.08–0.41)0.18 (0.08–0.41)0.18 (0.08–0.41)400.57 (0.37–0.86)0.57 (0.37–0.86)0.57 (0.38–0.88)
Ptrendb0.00040.00040.00020.0950.100.030
Pinteractionc0.0400.0300.0240.770.840.82
  • aThe multivariate, stage-stratified Cox regression model included the same set of covariates selected as in Table 2.

  • bTests for linear trend across categories were calculated by using the median value for each quartile of physical activity (MET-h/wk) as a continuous variable in a proportional hazards model.

  • cPinteraction between physical activity quartile and tumor PTGS2 status.