Diet Quality and Breast Cancer Recurrence and Survival: The Pathways Study

Diet quality and cardiovascular disease risk among breast cancer survivors in the Pathways Study

BACKGROUND

Women with breast cancer are at higher risk of cardiovascular disease (CVD) compared with women without breast cancer. Whether higher diet quality at breast cancer diagnosis lowers this risk remains unknown. We set out to determine if higher diet quality at breast cancer diagnosis was related to lower risk of CVD and CVD-related death.

METHODS

This analysis included 3415 participants from the Pathway Study, a prospective cohort of women diagnosed with invasive breast cancer at Kaiser Permanente Northern California between 2005 and 2013 and followed through December 31, 2021. Scores from 5 diet quality indices consistent with healthy eating were obtained at the time of breast cancer diagnosis. Scores were categorized into ascending quartiles of concordance for each diet quality index, and multivariable adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated. P values were 2-sided.

RESULTS

The Dietary Approaches to Stop Hypertension diet quality index was associated with lower risk of heart failure (HR = 0.53, 95% CI = 0.33 to 0.87; Ptrend = .03), arrhythmia (HR = 0.77, 95% CI = 0.62 to 0.94; Ptrend = .008), cardiac arrest (HR = 0.77, 95% CI = 0.61 to 0.96; Ptrend = .02), valvular heart disease (HR = 0.79, 95% CI = 0.64 to 0.98; Ptrend = .046), venous thromboembolic disease (HR = 0.75, 95% CI = 0.60 to 0.93; Ptrend = .01), and CVD-related death (HR = 0.70, 95% CI = 0.50 to 0.99; Ptrend = .04), when comparing the highest with lowest quartiles. Inverse associations were also found between the healthy plant-based dietary index and heart failure (HR = 0.60, 95% CI = 0.39 to 0.94; Ptrend = .02), as well as the alternate Mediterranean dietary index and arrhythmia (HR = 0.74, 95% CI = 0.60 to 0.93; Ptrend = .02).

CONCLUSION

Among newly diagnosed breast cancer patients, higher diet quality at diagnosis was associated with lower risk of CVD events and death.

Prevalence of loneliness and associations with health behaviours and body mass index in 5835 people living with and beyond cancer: a cross-sectional study

BACKGROUND

A cancer diagnosis and its treatment may be an especially isolating experience. Despite evidence that positive health behaviours can improve outcomes for people living with and beyond cancer (LWBC), no studies have examined associations between loneliness and different health behaviours in this population. This study aimed to describe the prevalence of loneliness in a large sample of UK adults LWBC and to explore whether loneliness was associated with multiple health behaviours.

METHODS

Participants were adults (aged ≥ 18 years) diagnosed with breast, prostate or colorectal cancer who completed the Health and Lifestyle After Cancer Survey. Loneliness was reported using the UCLA loneliness score, dichotomised into higher (≥ 6) versus lower (< 6) loneliness. Engagement in moderate-to-vigorous physical activity, dietary intake, smoking status, alcohol use, and self-reported height and weight were recorded. Behaviours were coded to reflect meeting or not meeting the World Cancer Research Fund recommendations for people LWBC. Logistic regression analyses explored associations between loneliness and health behaviours. Covariates were age, sex, ethnicity, education, marital status, living situation, cancer type, spread and treatment, time since treatment, time since diagnosis and number of comorbid conditions. Multiple imputation was used to account for missing data.

RESULTS

5835 participants, mean age 67.4 (standard deviation = 11.8) years, completed the survey. 56% were female (n = 3266) and 44% (n = 2553) male, and 48% (n = 2786) were living with or beyond breast cancer, 32% (n = 1839) prostate, and 21% (n = 1210) colorectal. Of 5485 who completed the loneliness scale, 81% (n = 4423) of participants reported lower and 19% (n = 1035) higher loneliness. After adjustment for confounders, those reporting higher levels of loneliness had lower odds of meeting the WCRF recommendations for moderate-to-vigorous physical activity (Odds Ratio [OR] 0.78, 95% Confidence Internal [CI], 0.67, 0.97, p =.028), fruit and vegetable intake (OR 0.81, CI 0.67, 1.00, p =.046), and smoking (OR 0.62, 0.46, 0.84, p =.003). No association was observed between loneliness and the other dietary behaviours, alcohol, or body mass index.

CONCLUSIONS

Loneliness is relatively common in people LWBC and may represent an unmet need. People LWBC who experience higher levels of loneliness may need additional support to improve their health behaviours.

Assessment of breast cancer chemotherapy dose reduction in an integrated healthcare delivery system

PURPOSE

Most cytotoxic drugs are dosed using body surface area (BSA), yet not all cancer patients receive the full BSA-determined dose. Prior work suggests that breast cancer patients who are obese are more likely to experience dose reduction than normal weight patients. However, the factors driving dose reduction remain unclear.

METHODS

In 452 women diagnosed with stage I-IIIA primary breast cancer at Kaiser Permanente Northern California, we evaluated the association between obesity and dose reduction, and further explored other factors in relation to dose reduction, including various sociodemographic characteristics, tumor characteristics, and comorbidities. Study participants were a part of the Pathways Study, diagnosed between 2006 and 2013 and treated with cyclophosphamide + doxorubicin, followed by paclitaxel (ACT). Dose reduction was assessed using first cycle dose proportion (FCDP) and average relative dose intensity (ARDI), a metric of dose intensity over the course of chemotherapy.

RESULTS

Overall, 8% of participants received a FCDP < 90% and 21.2% had an ARDI < 90%, with dose reduction increasing with body mass index. In adjusted logistic regression models, obese women had 4.1-fold higher odds of receiving an ARDI < 90% than normal weight women (95% CI: 1.9-8.9; p-trend = 0.0006). Increasing age was positively associated with an ADRI < 90%, as was the presence of comorbidity. Dose reduction was less common in later calendar years.

CONCLUSION

Results offer insight on factors associated with chemotherapy dosing for a common breast cancer regimen. Larger studies are required to evaluate relevance to other regimens, and further work will be needed to determine whether dose reductions impact outcomes in obese women.

Perceiving a need for dietary change in adults living with and beyond cancer: A cross-sectional study

BACKGROUND

Many people living with and beyond cancer (LWBC) do not meet dietary recommendations. To implement a healthier diet, people LWBC must perceive a need to improve their diet.

METHODS

Participants included people diagnosed with breast, prostate or colorectal cancer in the UK. Two binary logistic regression models were conducted with perceived need for dietary change as the outcome (need to improve vs. no need). Predictor variables included demographic and clinical characteristics, receipt of dietary advice, and either body mass index (BMI) or adherence to seven relevant World Cancer Research Fund (WCRF) dietary recommendations.

RESULTS

The sample included 5835 responses. Only 31% perceived a need to improve their diet. Being younger (odds ratio [OR] 0.95, 95% confidence interval [CI] = 94-0.95), female (OR = 1.33, 95% CI = 1.15-1.53), not of white ethnicity (OR = 1.8, 95% CI = 1.48-2.27), not married/cohabiting (OR = 1.32, 95% CI = 1.16-1.52) and having received dietary advice (OR = 1.36, 95% CI = 1.43-1.86) was associated with an increased odds of perceiving a need to improve diet. This association was also seen for participants with two or more comorbidities (OR = 1.31, 95% CI = 1.09-1.57), those not meeting the recommendations for fruit and vegetables (OR = 0.47, 95% CI = 0.41-0.55), fat (OR = 0.67, 95% CI = 0.58-0.77), and sugar (OR = 0.86, 95% CI = 0.75-0.98) in the dietary components model and those who had a higher BMI (OR = 1.53, 95% CI = 1.32-1.77) in the BMI model.

CONCLUSIONS

Most of this sample of people LWBC did not perceive a need to improve their diet. More research is needed to understand the reasons for this and to target these reasons in dietary interventions.

Dietary and serum advanced glycation end-products and clinical outcomes in breast cancer

One in five women with breast cancer will relapse despite ideal treatment. Body weight and physical activity are strongly associated with recurrence risk, thus lifestyle modification is an attractive strategy to improve prognosis. Trials of dietary modification in breast cancer are promising but the role of specific diets is unclear, as is whether high-quality diet without weight loss can impact prognosis. Advanced glycation end-products (AGEs) are compounds produced in the body during sugar metabolism. Exogenous AGEs, such as those found in food, combined with endogenous AGEs, make up the total body AGE load. AGEs deposit in tissues over time impacting cell signaling pathways and altering protein functions. AGEs can be measured or estimated in the diet and measured in blood through their metabolites. Studies demonstrate an association between AGEs and breast cancer risk and prognosis. Here, we review the clinical data on dietary and serum AGEs in breast cancer.

Inflammation, Nutrition, and Clinical Outcomes in Breast Cancer Survivors: A Narrative Review

PURPOSE OF REVIEW

Breast cancer (BC) is the leading cause of death among women aged 44-55 years globally. Pro-inflammatory food can cause tissue-level inflammation, thereby creating a carcinogenic microenvironment and promoting breast cancer. The aim of this review is to provide an overview of the association between inflammation and nutrition and clinical outcomes in breast cancer survivors.

RECENT FINDINGS

Pro-inflammatory diets are associated with a higher mortality risk after diagnosis and worse prognosis after treatment. On the other hand, anti-inflammatory diets may improve tissue-level inflammation and improve the overall prognosis and quality of life of survivors. There is strong evidence that the Mediterranean diet in particular is associated with reduced recurrence risk of breast cancer and improved quality of life of survivors. This narrative review provides evidence that there is a strong association between inflammation, dietary habits, and adverse clinical outcomes in breast cancer survivors. It further discusses the current evidence for the role of dietary management in improving clinical outcomes in breast cancer survivors.

Hypothetical Interventions on Diet Quality and Lifestyle Factors to Improve Breast Cancer Survival: The Pathways Study

BACKGROUND

The number of breast cancer survivors is increasing, yet evidence to inform dietary and lifestyle guidelines is limited.

METHODS

This analysis included 3,658 participants from the Pathways Study, a prospective cohort of women diagnosed with invasive breast cancer. A healthy plant-based dietary index score (hPDI), an American Cancer Society (ACS) nutrition guidelines score, a 2015 Healthy Eating Index score (HEI), hours per week of moderate to vigorous physical activity (PA), and lifetime cumulative pack-years of cigarette smoking (SM) were each measured at diagnosis, 6, 24, and 72 months. Using g-computation, 5- and 10-year risk ratios (RR), risk differences, and 95% confidence intervals (CI) for all-cause mortality under hypothetical interventions on diet quality, PA, and SM, compared with the natural course (no intervention) were calculated.

RESULTS

Hypothetical moderate to extreme interventions on hPDI, ACS, and HEI, each in combination with PA and SM, showed 11% to 56%, 9% to 38%, and 9% to 49% decreases in 5-year risks of all-cause mortality compared with no intervention, respectively [(hPDI: RRmoderate = 0.89, 95% CI: 0.82-0.94; RRextreme = 0.44, 95% CI: 0.26-0.67), (ACS: RRmoderate = 0.91, 95% CI: 0.85-0.96; RRextreme = 0.62, 95% CI: 0.43-0.82), (HEI: RRmoderate = 0.91, 95% CI: 0.84-0.95; RRextreme = 0.51, 95% CI: 0.33-0.72)]. While 10-year relative risks were slightly attenuated, absolute risk reductions were more pronounced.

CONCLUSIONS

Interventions to improve diet quality, increase PA, or reduce SM at the time of diagnosis may improve survival among breast cancer survivors.

IMPACT

We estimate that over 10% of deaths could be delayed by even moderate adoption of these behaviors.

Survivors Overcoming and Achieving Resiliency (SOAR): Mindful Eating Practice for Breast Cancer Survivors in a Virtual Teaching Kitchen

The practice of mindful eating brings awareness to food choices, brings attention to the eating experience, and encourages selecting and preparing food that is both satisfying and nourishing. We examined mindful eating in breast cancer survivors following a 9-week, multidisciplinary virtual teaching kitchen intervention called Survivors Overcoming and Achieving Resiliency (SOAR). SOAR engaged participants through weekly cooking classes that also taught multiple domains of mindfulness. Participants (n = 102) were breast cancer survivors and completed the Mindful Eating Questionnaire (MEQ) prior to and after completion of the intervention. Linear regression analyses examined relationships between the aspects of mindful eating and body mass index (BMI). Wilcoxon (paired) rank sum tests evaluated the significance of the change in the MEQ total sum and subscales scores. A total of 102 participants completed both the pre- and post-intervention surveys. The mean change between the pre- and post-SOAR MEQ summary scores was 0.12 (sd = 0.30; Wilcoxon p-value = 0.0003). All MEQ subscale scores significantly increased with the exception of the distraction subscale. The MEQ summary scores increased for participants across both BMI stratifications. The SOAR teaching kitchen represents one of the first interventions that is tailored for breast cancer survivors and combines behavioral strategies from mindful eating training to nutritional knowledge and culinary medicine pedagogy in a virtual teaching kitchen. Further research is needed to examine whether mindful eating practices among cancer survivors result in sustainable healthy eating behaviors and food choices consistent with the cancer risk reduction guidelines.

Post-Diagnosis Dietary Patterns among Cancer Survivors in Relation to All-Cause Mortality and Cancer-Specific Mortality: A Systematic Review and Meta-Analysis of Cohort Studies

The role of overall diet on longevity among cancer survivors (CS) needs further elucidation. We performed a systematic review of the literature and a meta-analysis of related cohort studies published up to October 2022 investigating post-diagnosis a priori (diet quality indices) and a posteriori (data-driven) dietary patterns (DPs) in relation to all-cause and cancer-specific mortality. Pooled hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using random-effects meta-analyses comparing highest versus lowest categories of adherence to DPs. We assessed heterogeneity and risk of bias in the selected studies. A total of 19 cohort studies with 38,846 adult CS, some assessing various DPs, were included in the meta-analyses. Higher adherence to a priori DPs was associated with lower all-cause mortality by 22% (HR = 0.78, 95% CI: 0.73-0.83, I2 = 22.6%) among all CS, by 22% (HR = 0.78, 95% CI: 0.73-0.84, I2 = 0%) among breast CS and by 27% (HR = 0.73, 95% CI: 0.62-0.86, I2 = 41.4%) among colorectal CS. Higher adherence to a "prudent/healthy" DP was associated with lower all-cause mortality (HR = 0.79, 95% CI: 0.64-0.97 I2 = 49.3%), whereas higher adherence to a "western/unhealthy" DP was associated with increased all-cause mortality (HR = 1.48, 95% CI: 1.26-1.74, I2 = 0%) among all CS. Results for cancer-specific mortality were less clear. In conclusion, higher adherence to a "healthy" DP, either a priori or a posteriori, was inversely associated with all-cause mortality among CS. A "healthy" overall diet after cancer diagnosis could protect and promote longevity and well-being.

Association between Dietary Indices and Dietary Patterns and Mortality and Cancer Recurrence among Cancer Survivors: An Updated Systematic Review and Meta-Analysis of Cohort Studies

The number of cancer survivors is growing rapidly; however, specific lifestyle recommendations for these patients are still sparse, including dietary approaches. Thus, the aim of the present systematic review and meta-analysis was to examine the associations between adherence to diet-quality indices and dietary patterns on overall mortality, cancer-specific mortality, and cancer recurrence among cancer survivors. The literature search was conducted in PubMed and Web of Science between 18 May 2016 and 22 May 2022 with no language restrictions. Thirty-nine studies were included for quantitative analysis, providing data from 77,412 participants. Adherence to both diet-quality indices and a healthy/prudent dietary pattern was inversely associated with overall mortality (RR, 0.81; 95% CI, 0.77-0.86; RR, 0.80; 95% CI, 0.70-0.92, respectively) and with cancer-specific mortality (RR, 0.86; 95% CI, 0.79-0.94; RR, 0.79; 95% CI, 0.64-0.97, respectively). These associations could be observed following assessment of dietary patterns either pre- and/or postdiagnosis. For unhealthy/western dietary patterns, high adherence was associated with overall mortality (RR, 1.26; 95% CI, 1.08-1.47). Although the certainty of evidence was rated as low, we conclude that there are no reservations against high adherence to healthy dietary patterns or indices in cancer survivors.

Associations of Post-Diagnosis Lifestyle with Prognosis in Women with Invasive Breast Cancer

BACKGROUND

Lifestyle habits can impact breast cancer development, but its impact on breast cancer prognosis remains unclear. We investigated associations of post-diagnosis lifestyle with mortality and recurrence in 1,964 women with invasive breast cancer enrolled in the Kaiser Permanente Northern California Pathways Study shortly after diagnosis with lifestyle information at baseline (2005-2013) and the 2-year follow-up.

METHODS

We calculated a post-diagnosis lifestyle score (range, 0-18) based on 9 diet, physical activity, and body weight recommendations from the American Cancer Society/American Society of Clinical Oncology (ACS/ASCO) using follow-up data (body weight also included baseline data); higher scores indicate greater guideline concordance. Similarly, we calculated a pre-diagnosis lifestyle score using baseline data to investigate pre- to post-diagnosis changes. We estimated hazard ratios (HR) and 95% confidence intervals (CI) using Cox proportional hazard models, with follow-up through December 2018 (observing 290 deaths and 176 recurrences).

RESULTS

The 2-year post-diagnosis lifestyle score was inversely associated with all-cause mortality (ACM; HR per 2-point increase = 0.90; 95% CI, 0.82-0.98), and breast cancer-related mortality (HR, 0.79; 95% CI, 0.67-0.95), but not recurrence. Relative to women who maintained low concordance with recommendations at both time points, women who maintained high concordance had a lower risk of ACM (HR, 0.61, 95% CI, 0.37-1.03). Improved concordance with some specific recommendations (particularly PA) may be associated with a lower hazard of ACM (HRPA, 0.52; 95% CI, 0.35-0.78).

CONCLUSIONS

Results suggest that women with breast cancer may benefit from a post-diagnosis lifestyle aligned with ACS/ASCO guidelines.

IMPACT

This information may potentially guide lifestyle recommendations for breast cancer survivors to reduce mortality risk.

Association of Mediterranean diet with survival after breast cancer diagnosis in women from nine European countries: results from the EPIC cohort study

BACKGROUND

The Mediterranean diet has been associated with lower risk of breast cancer (BC) but evidence from prospective studies on the role of Mediterranean diet on BC survival remains sparse and conflicting. We aimed to investigate whether adherence to Mediterranean diet prior to diagnosis is associated with overall and BC-specific mortality.

METHODS

A total of 13,270 incident breast cancer cases were identified from an initial sample of 318,686 women in 9 countries from the European Prospective Investigation into Cancer and Nutrition (EPIC) study. Adherence to Mediterranean diet was estimated through the adapted relative Mediterranean diet (arMED), a 16-point score that includes 8 key components of the Mediterranean diet and excludes alcohol. The degree of adherence to arMED was classified as low (score 0-5), medium (score 6-8), and high (score 9-16). Multivariable Cox proportional hazards models were used to analyze the association between the arMED score and overall mortality, and Fine-Gray competing risks models were applied for BC-specific mortality.

RESULTS

After a mean follow-up of 8.6 years from diagnosis, 2340 women died, including 1475 from breast cancer. Among all BC survivors, low compared to medium adherence to arMED score was associated with a 13% higher risk of all-cause mortality (HR 1.13, 95%CI 1.01-1.26). High compared to medium adherence to arMED showed a non-statistically significant association (HR 0.94; 95% CI 0.84-1.05). With no statistically significant departures from linearity, on a continuous scale, a 3-unit increase in the arMED score was associated with an 8% reduced risk of overall mortality (HR3-unit 0.92, 95% CI: 0.87-0.97). This result sustained when restricted to postmenopausal women and was stronger among metastatic BC cases (HR3-unit 0.81, 95% CI: 0.72-0.91).

CONCLUSIONS

Consuming a Mediterranean diet before BC diagnosis may improve long-term prognosis, particularly after menopause and in cases of metastatic breast cancer. Well-designed dietary interventions are needed to confirm these findings and define specific dietary recommendations.

Diet Quality and All-Cause Mortality in Women with Breast Cancer from the Breast Cancer Family Registry

BACKGROUND

The impact of diet on breast cancer survival remains inconclusive. We assessed associations of all-cause mortality with adherence to the four diet quality indices: Healthy Eating Index-2015 (HEI-2015), Alternative Healthy Eating Index (AHEI), Alternative Mediterranean Diet (aMED), and Dietary Approaches to Stop Hypertension (DASH).

METHODS

Dietary intake data were evaluated for 6,157 North American women enrolled in the Breast Cancer Family Registry who had been diagnosed with invasive breast cancer from 1993 to 2011 and were followed through 2018. Pre-diagnosis (n = 4,557) or post-diagnosis (n = 1,600) dietary intake was estimated through a food frequency questionnaire. During a median follow-up time of 11.3 years, 1,265 deaths occurred. Cox proportional hazards models were used to estimate multivariable-adjusted HR and 95% confidence intervals (CI).

RESULTS

Women in the highest versus lowest quartile of adherence to the HEI-2015, AHEI, aMED, and DASH indices had a lower risk of all-cause mortality. HR (95% CI) were 0.88 (0.74-1.04; Ptrend = 0.12) for HEI-2015; 0.82 (0.69-0.97; Ptrend = 0.02) for AHEI; 0.73 (0.59-0.92; Ptrend = 0.02) for aMED; and 0.78 (0.65-0.94; Ptrend = 0.006) for DASH. In subgroup analyses, the associations with higher adherence to the four indices were similar for pre- or post-diagnosis dietary intake and were confined to women with a body mass index <25 kg/m2 and women with hormone receptor positive tumors.

CONCLUSIONS

Higher adherence to the HEI-2015, AHEI, aMED, and DASH indices was associated with lower mortality among women with breast cancer.

IMPACT

Adherence to a healthy diet may improve survival of women with breast cancer.

The Role of the Mediterranean Diet in Breast Cancer Survivorship: A Systematic Review and Meta-Analysis of Observational Studies and Randomised Controlled Trials

Female breast cancer is the most frequently diagnosed cancer. The long-term survival rates for this disease have increased; however, the unique demand for high-quality healthcare to improve breast-cancer survivorship are commonly unmet. The Mediterranean diet (MD) is associated with reduced breast-cancer risk and various health-related benefits in the general population, but its effect on breast-cancer survivors remains uncertain. The objective of this systematic review and meta-analysis was to assess current evidence from randomised controlled trials (RCTs) and observational studies (cohort, cross-sectional and case-control) regarding the effect of the MD on survival, quality of life (QoL) and health-related outcomes in female breast-cancer survivors. MEDLINE, EMBASE, Web of Science and the Cochrane library were searched for studies published before and including April 2022. Two reviewers independently screened the literature and completed the data extraction and risk-of-bias assessment. Eleven studies (fifteen reports) were included, including two RCTs, four cohort and five cross-sectional studies. The meta-analysis of the cohort studies showed strong evidence of an inverse association between high adherence to the MD and all-cause mortality (hazard ratio (HR) 0.78, 95% confidence interval (CI) 0.66-0.93, I²: 0%, Grading of Recommendations Assessment, Development and Evaluation (GRADE) = low certainty of evidence) and non-breast-cancer mortality (HR 0.67, 95% CI 0.50-0.90, I²: 0%, GRADE = very low certainty of evidence). The associations between high adherence to the MD and QoL and health-related parameters were not consistent. These findings highlight the potential of adherence to the MD to reduce the risk of mortality. Future research with better study designs, as well as more consistent measurements of QoL and MD adherence, taking into account changes in MD adherence over time and population subgroups, is needed to provide more robust evidence on the survival, QoL and health-related outcomes in BC survivors.

Postdiagnosis dietary factors, supplement use and breast cancer prognosis: Global Cancer Update Programme (CUP Global) systematic literature review and meta-analysis

Little is known about how diet might influence breast cancer prognosis. The current systematic reviews and meta-analyses summarise the evidence on postdiagnosis dietary factors and breast cancer outcomes from randomised controlled trials and longitudinal observational studies. PubMed and Embase were searched through 31st October 2021. Random-effects linear dose-response meta-analysis was conducted when at least three studies with sufficient information were available. The quality of the evidence was evaluated by an independent Expert Panel. We identified 108 publications. No meta-analysis was conducted for dietary patterns, vegetables, wholegrains, fish, meat, and supplements due to few studies, often with insufficient data. Meta-analysis was only possible for all-cause mortality with dairy, isoflavone, carbohydrate, dietary fibre, alcohol intake and serum 25-hydroxyvitamin D (25(OH)D), and for breast cancer-specific mortality with fruit, dairy, carbohydrate, protein, dietary fat, fibre, alcohol intake and serum 25(OH)D. The results, with few exceptions, were generally null. There was limited-suggestive evidence that predefined dietary patterns may reduce the risk of all-cause and other causes of death; that isoflavone intake reduces the risk of all-cause mortality (relative risk (RR) per 2 mg/day: 0.96, 95% confidence interval (CI): 0.92-1.02), breast cancer-specific mortality (RR for high vs low: 0.83, 95% CI: 0.64-1.07), and recurrence (RR for high vs low: 0.75, 95% CI: 0.61-0.92); that dietary fibre intake decreases all-cause mortality (RR per 10 g/day: 0.87, 95% CI: 0.80-0.94); and that serum 25(OH)D is inversely associated with all-cause and breast cancer-specific mortality (RR per 10 nmol/L: 0.93, 95% CI: 0.89-0.97 and 0.94, 95% CI: 0.90-0.99, respectively). The remaining associations were graded as limited-no conclusion.

Dietary patterns and breast cancer risk, prognosis, and quality of life: A systematic review

Background

Statistics indicate that the morbidity of breast cancer is increasing globally, and its (overall figures) incidence has now surpassed that of lung cancer for the first time. The relation between a whole dietary pattern, rather than of a single food or nutrient, and breast cancer (BC) should be examined for findings to capture the complexities of diet and the potential for synergism between dietary components. Hence, the effects of dietary patterns on breast cancer have recently attracted increasing attention.

Objective

To systematically review the effects of dietary patterns on breast cancer risk, prognosis, and quality of life in survivors.

Methods

This systematic review was conducted following PRISMA guidelines and was registered in PROSPERO. Data from Ovid, China Biomedical Literature Database, Wanfang Data Knowledge Service Platform, CNKI, PubMed, Weipu, The Cochrane Library, Duxiu Data, ProQuest, Embase, Web of Science, and Scopus Database were retrieved and evaluated.

Results

A total of 47 studies that investigated the association between eating patterns and breast cancer were identified. Ten studies evaluated the effect of the model on treatment outcome and prognosis of breast cancer and two cross-sectional studies examined the influence of dietary patterns on quality of life. The resulting favorable dietary patterns were shown to regulate metabolic biomarkers, antioxidants, anti-inflammatory agents, and protective genes, and inhibit cell proliferation and invasion.

Conclusion

Numerous studies have examined the effects of healthy eating, plant-based, anti-inflammation, low-fat, and other favorable dietary patterns in relation to breast cancer. However, few studies reported significant associations and the studies had limitations, suggesting that the current findings should be interpreted with caution.

Systematic review registration

https://www.crd.york.ac.uk/prospero/, CRD4202 2350171.

Adherence to the Dietary Approaches to Stop Hypertension diet reduces the risk of breast cancer: A systematic review and meta-analysis

Background

Despite increasing evidence for the association of adherence to the Dietary approaches to stop hypertension (DASH) diet with breast cancer risk, the results remain inconclusive. The purpose of the current systematic review was to summarize the evidence from previous observational studies and explore the potential association between DASH diet and breast cancer risk using meta-analysis.

Methods

A comprehensive literature search was conducted using the databases of PubMed, Web of Science, CNKI and Wanfang Data to identify the relevant publications from inception up to July 2022. The pooled relative risks (RRs) and 95% confidence intervals (CIs) were calculated for the highest versus the lowest categories of DASH score in relation to breast cancer risk, using a random-effects model. The Cochran's Q test and I-squared (I ²) statistic were used to detect the sources of heterogeneity among the included studies.

Results

Overall, eleven studies, involving 23,254 breast cancer cases and 449,273 participants, were included in this systematic review and meta-analysis. Combining 16 effect sizes from 11 studies, a significant inverse association between adherence to the DASH diet and risk of breast cancer was observed (RR = 0.79; 95% CI: 0.70, 0.90, P < 0.0001). Stratified analysis showed a significant association between adherence to the DASH diet and risk of breast cancer in case-control studies (RR = 0.49; 95% CI: 0.27-0.89, P = 0.019), and a marginally significant association in prospective cohort studies (RR = 0.92; 95% CI: 0.86-0.98, P = 0.014), respectively. Besides, a more significant association between DASH score and reduced risk of breast cancer was observed in Asian countries (RR = 0.50; 95% CI: 0.31-0.81, P = 0.005) than in the United States (RR = 0.93; 95% CI: 0.89-0.99, P = 0.012). Similarly, when we conducted analyses separately by menopausal status, we found a significant inverse association between DASH diet and breast cancer risk in postmenopausal women (RR = 0.58; 95% CI: 0.39-0.87, P = 0.008).

Conclusion

The results of this systematic review and meta-analysis indicate a significant inverse association between adherence to the DASH diet and risk of breast cancer. Further large prospective studies and randomized controlled trials are required to confirm our findings.

Dietary diversity, diet quality, and oxidative stress in older adults

This cross-sectional study aimed to explore the relationship between diet quality, dietary diversity, and oxidative stress levels in older adults in parts of the Ningxia Hui Autonomous Region in northwestern China. A total of 335 participants voluntarily participated in the study from April to July 2021. Laboratory tests and questionnaires were used to obtain general characteristics, dietary conditions, and indicators of oxidative stress. The dietary diversity scores of the participants were 5.20±1.39, the diet quality indices were 56.91±11.14, and most had poor diet quality. The levels of the oxidative stress markers malondialdehyde, superoxide dismutase, 8-iso-prostaglandin F2α, and total antioxidant capacity were 4.77±1.77, 40.33±9.85, 763.10±245.41, and 1.02±0.14, respectively. The results showed that the diet quality scores of participants were related to dietary diversity and whether the scores passed or not was significantly related to total antioxidant capacity.

Healthy Eating and Mortality among Breast Cancer Survivors: A Systematic Review and Meta-Analysis of Cohort Studies

This systematic review examined the effect of diet quality, defined as adherence to healthy dietary recommendations, on all-cause and breast cancer-specific mortality. Web of Science, Medline, CINAHL, and PsycINFO databases were searched to identify eligible studies published by May 2021. We used a random-effects model meta-analysis in two different approaches to estimate pooled hazard ratio (HR) and 95% confidence interval (CI) for highest and lowest categories of diet quality: (1) each dietary quality index as the unit of analysis and (2) cohort as the unit of analysis. Heterogeneity was examined using Cochran’s Q test and inconsistency I² statistics. The risk of bias was assessed by the Newcastle–Ottawa Scale for cohort studies, and the quality of evidence was investigated by the GRADE tool. The analysis included 11 publications from eight cohorts, including data from 27,346 survivors and seven dietary indices. Both approaches yielded a similar effect size, but cohort-based analysis had a wider CI. Pre-diagnosis diet quality was not associated with both outcomes. However, better post-diagnosis diet quality significantly reduced all-cause mortality by 21% (HR = 0.79, 95% CI = 0.70, 0.89, I² = 16.83%, n = 7) and marginally reduced breast cancer-specific mortality by 15% (HR = 0.85, 95% CI = 0.62, 1.18, I² = 57.4%, n = 7). Subgroup analysis showed that adhering to the Diet Approaches to Stop Hypertension and Chinese Food Pagoda guidelines could reduce breast cancer-specific mortality. Such reduction could be larger for older people, physically fit individuals, and women with estrogen receptor-positive, progesterone receptor-negative, or human epidermal growth factor receptor 2-positive tumors. The risk of bias in the selected studies was low, and the quality of evidence for the identified associations was low or very low due to imprecision of effect estimation, inconsistent results, and publication bias. More research is needed to precisely estimate the effect of diet quality on mortality. Healthcare providers can encourage breast cancer survivors to comply with healthy dietary recommendations to improve overall health. (Funding: University of Central Florida Office of Undergraduate Research, Registration: PROSPERO-CRD42021260135).

Plant-Based Dietary Patterns and Breast Cancer Recurrence and Survival in the Pathways Study

Plant-based diets are recommended for cancer survivors, but their relationship with breast cancer outcomes has not been examined. We evaluated whether long-term concordance with plant-based diets reduced the risk of recurrence and mortality among a prospective cohort of 3646 women diagnosed with breast cancer from 2005 to 2013. Participants completed food frequency questionnaires at diagnosis and 6-, 25-, and 72-month follow-up, from which we derived plant-based diet indices, including overall (PDI), healthful (hPDI), and unhealthful (uPDI). We observed 461 recurrences and 653 deaths over a median follow-up of 9.51 years. Using multivariable-adjusted Cox proportional hazards models, we estimated hazard ratios (HR) and 95% confidence intervals for breast cancer recurrence and all-cause, breast-cancer-specific, and non-breast-cancer mortality. Increased concordance with hPDI was associated with a reduced hazard of all-cause (HR 0.93, 95% CI: 0.83–1.05) and non-breast-cancer mortality (HR 0.83, 95% CI: 0.71–0.98), whereas increased concordance with uPDI was associated with increased hazards (HR 1.07, 95% CI: 0.96–1.2 and HR 1.20, 95% CI: 1.02–1.41, respectively). No associations with recurrence or breast-cancer-specific mortality were observed. In conclusion, healthful vs. unhealthful plant-based dietary patterns had differing associations with mortality. To enhance overall survival, dietary recommendations for breast cancer patients should emphasize healthful plant foods.