SUMMARY: Cancer along with Cardiovascular disease, Diabetes, Chronic Kidney Disease and Respiratory disease, account for over 80% of all chronic disease deaths. Gouty arthritis is the most common inflammatory arthritis worldwide. Chronic inflammation may be the common denominator for chronic diseases and cancer, although other mechanisms may come into play. Patients with chronic diseases have associated lifestyle risk factors as well, which can reduce life span and increased cancer risk.
The purpose of this Prospective cohort study was to assess the independent as well as joint associations of several common chronic diseases and disease markers with cancer risk, and to explore the benefit of physical activity in reducing the cancer risk associated with chronic diseases and disease markers.
This study cohort consisted of 405,878 participants and the authors selected five common chronic diseases for evaluation, which account for most of the disease burden worldwide. They included Cardiovascular disease and associated markers such as diastolic blood pressure and systolic blood pressure, total cholesterol level, and heart rate, Diabetes and fasting blood glucose level using WHO criteria, Chronic Kidney Disease markers such as dipstick proteinuria and estimated Glomerular Filtration Rate using National Kidney Foundation criteria, Pulmonary disease markers such as Forced Expiratory Volume in one second and Forced Vital Capacity using Global Initiative for Chronic Obstructive Lung Disease (GOLD) criteria and Gouty arthritis marker such as uric acid. In this study, 48% were men and 52% were women. These participants were followed for an average of 8.7 years and the main outcome measures were cancer incidence and cancer mortality overall, as well as cancer specific incidence and mortality. The eight chronic diseases or markers included Blood Pressure, Total Cholesterol, Heart Rate, Diabetes, Proteinuria, Glomerular Filtration Rate, Pulmonary disease and Gouty arthritis marker Uric acid.
The authors observed a statistically significantly increased risk of incident cancer for the eight diseases and markers individually with the exception of Blood Pressure and Pulmonary disease. All eight diseases and markers were statistically significantly associated with risk of cancer death. Population Attributable Fraction (PAF) is the proportional reduction in population disease or mortality that would occur if exposure to a risk factor were reduced to an alternative ideal exposure scenario (eg. no tobacco use). The PAFs of cancer incidence or cancer mortality from the eight chronic diseases and markers together were comparable to those from five major lifestyle factors – ever smoking, insufficient physical activity, insufficient fruit and vegetable intake, ever alcohol consumption, and non-ideal BMI, combined (cancer incidence: 20.5% versus 24.8%; cancer mortality: 38.9% versus 39.7%). Among physically active (versus inactive) participants, the increased cancer risk associated with chronic diseases and markers was decreased by 48% for cancer incidence and 27% for cancer mortality.
It was concluded that chronic diseases contribute to more than 20% of the risk for incident cancer and more than one third of the risk for cancer death and is as important as five major lifestyle factors combined. Physical activity is associated with significant reduction in the cancer risk associated with chronic diseases. Cancer risk associated with chronic diseases and disease markers: prospective cohort study. Tu H, Wen CP, Tsai SP, et al. BMJ 2018;360:k134