Understanding the Relationship between Microbiome, Diet and Cancer Risk

When it comes to the microbiome, people usually think of the gut, but there is also the breast microbiome, and its role in the health and risk of breast cancer is not fully understood. A microbiome is a collection of microorganisms that live in a specific environment in the body. Diet can affect the breast microbiome, which shows that like the gut microbiome, breast microbiomes can respond to diet. New research now shows that diet, including fish oil supplements, can alter not only the breast microbiome but also its cancerous tumors. Keywords: Cancer; Cells; Tissues; Tumors; Prevention; Prognosis; Diagnosis; Imaging; Screening, Treatment; Management

Circulating lipids and breast cancer prognosis in the Malmö diet and cancer study

Purpose Examine the association between circulating lipids and breast cancer outcomes in patients enrolled in the Malmö Diet and Cancer Study (MDCS). Patients and methods Circulating lipid levels were measured in blood sampled upon enrollment in the female MDCS cohort (N = 17,035). We identified all MDCS participants with incident invasive breast cancer diagnosed between 1991 and 2014. Follow-up time began at breast cancer diagnosis and continued until the first event of breast cancer recurrence, death, emigration, or 5 years of follow-up. We estimated the incidence rates of recurrence at 5 years and fit Cox regression models to compute crude and adjusted hazard ratios (HRs) with 95% confidence intervals (95% CI) of breast cancer recurrence as well as all-cause mortality according to cohort-specific tertiles of apolipoprotein A-1 (Apo A-1) and apolipoprotein B (Apo B). Results We enrolled 850 eligible patients. During the 5 years of follow-up, 90 invasive breast cancer recurrences were diagnosed over 3807 person-years. In multivariable analyses, high baseline levels of Apo B were associated with an increased rate of recurrence (tertile 3 vs. 1, HR = 2.30 [95% CI 1.13–4.68]). However, high baseline levels of Apo B were not associated with all-cause mortality (tertile 3 vs. 1, HR = 1.23 [95% CI 0.68–2.25]). We observed no associations between levels of Apo A-1 and recurrence (tertile 3 vs. 1, HR = 1.34 [95% CI 0.70–2.58]) or all-cause mortality (tertile 3 vs. 1, HR = 1.12 [95% CI 0.61–2.05]). Conclusion High pre-diagnostic levels of Apo B were associated with an increased risk of recurrence among breast cancer patients. Circulating Apo A-1 was not associated with breast cancer outcomes.

Leisure-time physical activities and the risk of cardiovascular mortality in the Malmö diet and Cancer study

Background The association between leisure-time physical activity and cardiovascular mortality has been previously studied, but few studies have focused on specific activities and intensities. Methods The association between different leisure-time physical activities and cardiovascular mortality was investigated among 25,876 individuals without diabetes or cardiovascular disease from the population-based Malmö Diet and Cancer Study cohort. The individuals estimated the average duration spent on 17 physical activities at baseline in 1991–1996 and after 5 years. Cardiovascular mortality was obtained from a register during a mean of 20 years of follow-up. Results A total leisure-time physical activity of 15–25 metabolic equivalent task (MET) hours/week was associated with a decreased risk of cardiovascular mortality (HR 15–25 vs < 7.5 MET-h/week =0.80, 95% CI 0.69–0.93), with no further risk reduction at higher levels. Several high-intensity activities (i.e., lawn tennis and running) and moderate-intensity activities (i.e., golf, cycling and gardening) were associated with a reduced risk. Individuals who engaged in high-intensity physical activity for an average of 2.29 MET h/week (30 min/week) had an 18% (95% CI 0.72–0.93) reduced risk of cardiovascular mortality compared with non-participants, and no further risk reductions were observed at higher levels. Decreased risk was observed among individuals who had started (HR 0.56, 95% CI 0.32–0.97) or continued (HR 0.49, 95% CI 0.36–0.66) high-intensity activities at the five-year follow-up. Conclusions Moderate- and high-intensity leisure-time physical activities reduced the risk of cardiovascular mortality. With regard to total leisure-time physical activity, the largest risk reduction was observed for 15–25 MET-h/week (equivalent to walking for approximately 5 h/week).

An umbrella review of the evidence associating diet and cancer risk at 11 anatomical sites

There is evidence that diet and nutrition are modifiable risk factors for several cancers, but associations may be flawed due to inherent biases. Nutritional epidemiology studies have largely relied on a single assessment of diet using food frequency questionnaires. We conduct an umbrella review of meta-analyses of observational studies to evaluate the strength and validity of the evidence for the association between food/nutrient intake and risk of developing or dying from 11 primary cancers. It is estimated that only few single food/nutrient and cancer associations are supported by strong or highly suggestive meta-analytic evidence, and future similar research is unlikely to change this evidence. Alcohol consumption is positively associated with risk of postmenopausal breast, colorectal, esophageal, head & neck and liver cancer. Consumption of dairy products, milk, calcium and wholegrains are inversely associated with colorectal cancer risk. Coffee consumption is inversely associated with risk of liver cancer and skin basal cell carcinoma.