Table 2.
Colorectal cancer mortality by post-diagnosis physical activity quartile
| Post-diagnosis physical activity quartile (MET-hours/week) | # | Colorectal cancer-specific mortality | Overall mortality | ||||||
|---|---|---|---|---|---|---|---|---|---|
|
| |||||||||
| # of events | Univariate HR (95% CI) | Stage-stratified HR (95% CI) | Multivariate stage-stratified HRa (95% CI) | # of events | Univariate HR (95% CI) | Stage-stratified HR (95% CI) | Multivariate stage-stratified HRa (95% CI) | ||
| Male | |||||||||
| Q1 (<6.4) | 77 | 17 | 1 (referent) | 1 (referent) | 1 (referent) | 42 | 1 (referent) | 1 (referent) | 1 (referent) |
| Q2 (6.4–18.4) | 75 | 8 | 0.42 (0.18–0.98) | 0.43 (0.19–1.00) | 0.38 (0.16–0.90) | 39 | 0.87 (0.56–1.34) | 0.87 (0.56–1.36) | 0.80 (0.52–1.25 |
| Q3 (18.6–46.5) | 78 | 13 | 0.64 (0.31–1.31) | 0.61 (0.30–1.27) | 0.69 (0.33–1.44) | 31 | 0.58 (0.36–0.92) | 0.59 (0.37–0.94) | 0.66 (0.41–1.06 |
| Q4 (≥47.1) | 75 | 3 | 0.15 (0.04–0.51) | 0.16 (0.05–0.53) | 0.17 (0.05–0.57) | 30 | 0.60 (0.38–0.96) | 0.62 (0.38–0.99) | 0.63 (0.39–1.02 |
| Ptrendb | 0.0047 | 0.0051 | 0.0099 | 0.035 | 0.044 | 0.086 | |||
| Female | |||||||||
| Q1 (<2.4) | 75 | 20 | 1 (referent) | 1 (referent) | 1 (referent) | 36 | 1 (referent) | 1 (referent) | 1 (referent) |
| Q2 (2.4–7.5) | 71 | 9 | 0.44 (0.20–0.96) | 0.46 (0.21–1.01) | 0.43 (0.19–0.94) | 25 | 0.64 (0.38–1.06) | 0.63 (0.38–1.06) | 0.66 (0.39–1.10 |
| Q3 (7.7–17.7) | 80 | 10 | 0.43 (0.20–0.91) | 0.48 (0.22–1.04) | 0.48 (0.22–1.04) | 27 | 0.60 (0.36–0.99) | 0.64 (0.39–1.06) | 0.64 (0.39–1.06 |
| Q4 (≥18.3) | 74 | 9 | 0.41 (0.19–0.90) | 0.42 (0.19–0.93) | 0.40 (0.18–0.89) | 23 | 0.53 (0.31–0.89) | 0.52 (0.31–0.89) | 0.56 (0.33–0.96 |
| Ptrendb | 0.11 | 0.12 | 0.10 | 0.064 | 0.064 | 0.10 | |||
| Combined | |||||||||
| Q1 | 152 | 37 | 1 (referent) | 1 (referent) | 1 (referent) | 78 | 1 (referent) | 1 (referent) | 1 (referent) |
| Q2 | 146 | 17 | 0.43 (0.24–0.76) | 0.45 (0.25–0.79) | 0.42 (0.24–0.75) | 64 | 0.76 (0.55–1.06) | 0.77 (0.55–1.08) | 0.76 (0.54–1.06 |
| Q3 | 158 | 23 | 0.52 (0.31–0.88) | 0.52 (0.31–0.88) | 0.54 (0.32–0.91) | 58 | 0.59 (0.42–0.83) | 0.59 (0.42–0.83) | 0.62 (0.44–0.88 |
| Q4 | 149 | 12 | 0.29 (0.15–0.55) | 0.30 (0.16–0.57) | 0.29 (0.15–0.56) | 53 | 0.57 (0.40–0.80) | 0.57 (0.40–0.81) | 0.61 (0.43–0.87 |
| Ptrendb | 0.0011 | 0.0013 | 0.0006 | 0.045 | 0.057 | 0.022 | |||
| Pinteractionc | 0.58 | 0.50 | 0.47 | 0.92 | 0.88 | 0.87 | |||
The multivariate, stage-stratified Cox regression model initially included sex, age, body mass index, family history of colorectal cancer in any first degree relative, year of diagnosis, post-diagnosis aspirin use, post-diagnosis smoking status, post-diagnosis alcohol consumption, tumor location, tumor differentiation, CpG island methylator phenotype, microsatellite instability, LINE-1 methylation, and BRAF and KRAS mutations. A backward elimination with threshold of P=0.05 was used to select variables in the final models.
Tests for linear trend across categories were calculated by using the median value for each quartile of physical activity (MET-hours/week) as a continuous variable in a proportional hazards model.
P for interaction between physical activity quartile and sex/cohort.
CI, confidence interval; HR, hazard ratio; MET, metabolic equivalent task.