The impact of body mass index and physical activity on mortality among patients with colorectal cancer in Queensland, Australia
Menée en Australie auprès de 1 825 patients atteints d’un cancer colorectal, cette étude évalue l’impact de l’indice de masse corporelle et de l’activité physique sur la survie des patients
Background:Few studies have investigated the impact of body mass index (BMI) and physical activity (PA) on mortality among colorectal cancer (CRC) patients and the results are inconsistent. We aimed to examine the impact of these lifestyle factors on all-cause and disease-specific mortality. Methods:Population-based longitudinal study followed 1825 patients diagnosed with stage I-III primary CRC 2003- 2004 in Queensland, Australia for 5 years. Socio-demographics and clinical characteristics were obtained via questionnaires and medical records. Results:Participants with some level of PA following diagnosis had 25-28% lower risk of all-cause mortality within 5 years of diagnosis than sedentary participants (Insufficiently active: Hazard ratio (HR)=0.72, [95% confidence interval=0.57-0.91]; Sufficiently active: HR=0.75[0.60-0.94]); however the differential for CRC-specific mortality was not significant. Increases in PA from 5- to 12-months post-diagnosis was associated with reduced CRC-specific mortality by 32-36% (Increase≤2hour/week: HR=0.68[0.48-0.97]; Increase>2hour/week: HR=0.64[0.44-0.93]) and 31% for all-cause mortality (Increase>2hour/week: HR=0.69[0.50-0.94]). Compared to participants with healthy BMI, significant higher mortality risk was observed in underweight patients (all-cause: HR=2.29[1.47-3.59]; CRC: HR=1.74[1.00-3.04]), while lower risk in overweight (all-cause: HR=0.75[0.61-0.94]; CRC: HR=0.75[0.59-0.97]) and no difference in obese. Excessive weight loss was associated with increased mortality risk three-fold but no difference in those gained weight. Conclusions:Protective effects of being physically active and increasing that activity underlines the importance of interventions to increase activity levels among people being diagnosed with CRC. Impact:Increased mortality risks associated with being underweight or having weight loss over time is an important indicator for which clinicians, patients and support personal can monitor.