Consumption of Sugars, Sugary Foods, and Sugary Beverages in Relation to Cancer Risk: A Systematic Review of Longitudinal Studies.

High sugar intake may increase cancer risk by promoting insulin-glucose dysregulation, oxidative stress, inflammation, and body adiposity, but epidemiologic evidence is unclear. Associations between dietary sugars and lifestyle-related cancer risk from longitudinal studies were evaluated. We systematically searched PubMed, Embase, and CINAHL and identified 37 prospective cohort studies (1990-2017) reporting multivariable adjusted risk estimates for dietary sugars in relation to cancer. Of 15 and 14 studies on total sugar and sucrose respectively, 11 reported a null association in relation to cancer. Of 14 studies on fructose, 8 reported null associations, and 2 reported protective and 4 reported detrimental associations. In two of five studies on added sugars, a 60-95% increased cancer risk was observed with higher intakes. In 8 of 15 studies on sugary foods and beverages, a 23-200% higher cancer risk was observed with higher sugary beverage consumption. In conclusion, most studies were indicative of a null association, but suggestive detrimental associations were reported for added sugars and sugary beverages.

Consumption of whole grains and cereal fiber in relation to cancer risk: a systematic review of longitudinal studies.

CONTEXT: Evidence from previous reviews is supportive of the hypothesis that whole grains may protect against various cancers. However, the reviews did not report risk estimates for both whole grains and cereal fiber and only case-control studies were evaluated. It is unclear whether longitudinal studies support this conclusion. OBJECTIVE: To evaluate associations between whole grains and cereal fiber in relation to risk of lifestyle-related cancers data from longitudinal studies was evaluated. DATA SOURCES: The following 3 databases were systematically searched: PubMed, EMBASE, and Cochrane CENTRAL. STUDY SELECTION: A total of 43 longitudinal studies conducted in Europe and North America that reported multivariable-adjusted risk estimates for whole grains (n = 14), cereal fiber (n = 23), or both (n = 6) in relation to lifestyle-related cancers were included. DATA EXTRACTION: Information on study location, cohort name, follow-up duration, sample characteristics, dietary assessment method, risk estimates, and confounders was extracted. DATA SYNTHESIS: Of 20 studies examining whole grains and cancer, 6 studies reported a statistically significant 6%-47% reduction in risk, but 14 studies showed no association. Of 29 studies examining cereal fiber intake in relation to cancer, 8 showed a statistically significant 6%-49% reduction in risk, whereas 21 studies reported no association. CONCLUSIONS: This systematic review concludes that most studies were suggestive of a null association. Whole grains and cereal fiber may protect against gastrointestinal cancers, but these findings require confirmation in additional studies.

Treatment and outcomes in diabetic breast cancer patients.

Effective breast cancer management is more complex with diabetes present and may contribute to poor outcomes. Therefore, we conducted two simultaneous systematic reviews to address the association of diabetes with (1) treatment patterns in breast cancer patients and (2) breast cancer recurrence rates or breast cancer-specific and all-cause mortality. We searched major databases for English language peer-reviewed studies through November 2013, which addressed either of the above research questions, following the preferred reporting items for systematic reviews and meta-analyses (PRISMA) method. Analyses compared treatment patterns or health outcomes for breast cancer subjects with and without diabetes. We used STROBE quality criteria and conducted a random-effects meta-analysis of all-cause mortality. The review yielded 11 publications for question 1 and 26 for question 2, with nine overlapping. Treatment studies showed chemotherapy was less likely in patients with diabetes. Of 22 studies, 21 assessing all-cause mortality indicated a statistically significant increased overall mortality for patients with diabetes (hazard ratios: 0.33-5.40), with meta-analysis of eligible studies indicating a 52 % increased risk. Nine studies assessing breast cancer-specific mortality had inconsistent results, with five showing significantly increased risk for diabetes patients. Results were inconsistent for recurrence and metastases. The majority of studies reported detrimental associations between diabetes and optimal treatment or all-cause mortality among women with breast cancer. Divergence in variable and outcomes inclusion and definitions, potential participation bias in individual studies, and differing analytic methods make inferences difficult. This review illuminates the importance of the impact of diabetes on breast cancer patients and explicitly recognizes that co-management of conditions is necessary to prevent excess morbidity and mortality.