Adherence to the World Cancer Research Fund/American Institute for Cancer Research recommendations and head and neck cancers risk

Prebiotics and the Risk of Upper Digestive Tract and Stomach Cancers: The PrebiotiCa Study

BACKGROUND

Fiber intake may lower digestive tract cancer risk, possibly by modulating the composition of gut microbiota. However, no data are available about the role of specific fiber fractions with prebiotic activity (e.g., inulin-type fructans (ITFs), fructo-oligosaccharides (FOSs) and galactooligosaccharides (GOSs)) on the risk lower digestive tract cancers.

OBJECTIVE

The objective was to assess the association between prebiotic intake and the risk of cancers of the upper digestive tract and stomach.

DESIGN

Within the PrebiotiCa study, data were derived from a network of Italian case-control studies conducted between 1992 and 2009. Participants' usual diet was assessed using a food frequency questionnaire. ITFs, and selected FOSs (nystose, kestose, and 1F-β-fructofuranosylnystose) and GOSs (raffinose and stachyose) were quantified in several food products via laboratory analyses. Participants' prebiotic intake was calculated by multiplying food frequency questionnaire intake by the prebiotic content of each food item.

PARTICIPANTS/SETTING

Cases were patients admitted to major hospitals with incident histologically confirmed cancers; there were 946 cases of cancer of the oral cavity/pharynx, 198 of the nasopharynx, 304 of the esophagus, 230 of the stomach. More than 4,000 patients admitted to the same hospitals for acute nonneoplastic and not diet-related conditions were selected as control subjects.

MAIN OUTCOME MEASURES

The outcomes were oral and pharyngeal, nasopharyngeal, esophageal, and stomach cancers.

STATISTICAL ANALYSES PERFORMED

The odds ratios and corresponding 95% CIs of the various cancers were derived using logistic regression models adjusted for major confounders and energy intake.

RESULTS

No association was observed between intake of prebiotics and risk of cancers of the oral cavity and pharynx, nasopharynx, and esophagus. High raffinose intake reduced stomach cancer risk (odds ratio for the third vs the first tertile 0.6, 95% CI 0.3 to 0.9); no other prebiotic was associated with stomach cancer.

CONCLUSIONS

The current study does not support a major role of prebiotic fibers on selected upper digestive tract cancers. The association between high raffinose intake and reduced stomach cancer risk needs further investigation.

Adherence to the 2018 World Cancer Research Fund (WCRF)/American Institute for Cancer Research (AICR) Cancer Prevention Recommendations and risk of 14 lifestyle-related cancers in the UK Biobank prospective cohort study

BACKGROUND

The World Cancer Research Fund (WCRF)/American Institute for Cancer Research (AICR) Cancer Prevention Recommendations are lifestyle-based recommendations which aim to reduce cancer risk. This study investigated associations between adherence, assessed using a standardised scoring system, and the risk of all cancers combined and of 14 cancers for which there is strong evidence for links with aspects of lifestyle in the UK.

METHODS

We used data from 94,778 participants (53% female, mean age 56 years) from the UK Biobank. Total adherence scores (range 0-7 points) were derived from dietary, physical activity, and anthropometric data. Associations between total score and cancer risk (all cancers combined; and prostate, breast, colorectal, lung, uterine, liver, pancreatic, stomach, oesophageal, head and neck, ovarian, kidney, bladder, and gallbladder cancer) were investigated using Cox proportional hazard models, adjusting for age, sex, deprivation index, ethnicity, and smoking status.

RESULTS

Mean total score was 3.8 (SD 1.0) points. During a median follow-up of 8 years, 7296 individuals developed cancer. Total score was inversely associated with risk of all cancers combined (HR: 0.93; 95%CI: 0.90-0.95 per 1-point increment), as well as breast (HR: 0.90; 95%CI: 0.86-0.95), colorectal (HR: 0.90; 95%CI: 0.84-0.97), kidney (HR: 0.82; 95%CI: 0.72-0.94), oesophageal (HR: 0.84; 95%CI: 0.71-0.98), ovarian (HR: 0.76; 95%CI: 0.65-0.90), liver (HR: 0.78; 95%CI: 0.63-0.97), and gallbladder (HR: 0.70; 95%CI: 0.53-0.93) cancers.

CONCLUSIONS

Greater adherence to lifestyle-based recommendations was associated with reduced risk of all cancers combined and of breast, colorectal, kidney, oesophageal, ovarian, liver, and gallbladder cancers. Our findings support compliance with the Cancer Prevention Recommendations for cancer prevention in the UK.

Intake of prebiotic fibers and the risk of laryngeal cancer: the PrebiotiCa study

PURPOSE

To evaluate whether the intake of specific fibers with prebiotic activity, e.g., inulin-type fructans (ITFs), fructo-oligosaccharides (FOSs), and galacto-oligosaccharides (GOSs), is associated with laryngeal cancer risk.

METHODS

Within the PrebiotiCa study, we used data from a case-control study (Italy, 1992-2009) with 689 incident, histologically confirmed laryngeal cancer cases and 1605 controls. Six prebiotic molecules (ITFs, nystose [FOS], kestose [FOS], 1F-β-fructofuranosylnystose [FOS], raffinose [GOS] and stachyose [GOS]) were quantified in various foods via ad hoc conducted laboratory analyses. Subjects' prebiotic fiber intake was calculated by multiplying food frequency questionnaire intake by the prebiotic content of each food item. The odds ratios (OR) of laryngeal cancer for prebiotic fiber intake were calculated using logistic regression models, including, among others, terms for tobacco, alcohol, and total energy intake.

RESULTS

The intakes of kestose, raffinose and stachyose were inversely associated with laryngeal cancer, with ORs for the highest versus the lowest quartile of 0.70 (95% confidence interval, CI 0.50-0.99) for kestose, 0.65 (95% CI 0.45-0.93) for raffinose and 0.61 (95% CI 0.45-0.83) for stachyose. ITFs, nystose and 1F-β-fructofuranosylnystose were not associated with laryngeal cancer risk. Current smokers and heavy drinkers with medium-low intakes of such prebiotic fibers had, respectively, an over 15-fold increased risk versus never smokers with medium-high intakes and a five to sevenfold increased risk versus never/moderate drinkers with medium-high intakes.

CONCLUSION

Although disentangling the effects of the various components of fiber-rich foods is complex, our results support a favorable role of selected prebiotic fibers on laryngeal cancers risk.

Adherence to the World Cancer Research Fund/American Institute for Cancer Research recommendations and endometrial cancer risk: a multicentric case-control study

The World Cancer Research Fund/American Institute for Cancer Research (WCRF/AICR) published evidence-based recommendations for cancer prevention focusing on body weight, physical activity, and diet. Our aim is to evaluate whether adherence to the WCRF/AICR recommendations could reduce endometrial cancer risk. We used data from a multicentric, Italian hospital-based case-control study (1992-2006) including 454 endometrial cancer cases and 908 age-matched controls. Adherence to the WCRF/AICR recommendations was measured using a score (range: 0-7) based on seven components: body mass index (BMI), physical activity and five dietary items; higher scores indicated higher adherence. Odds ratios (OR) were estimated by multiple (adjusted) conditional logistic regression models including terms for major confounders and energy intake. Adherence to the WCRF/AICR recommendations was inversely related to endometrial cancer risk (OR = 0·42, 95 % confidence interval (CI) 0·30, 0·61 for the highest compared with the lowest score quartile), with a significant trend of decreasing risk with increasing adherence. An inverse association was also observed for a score including only dietary recommendations (OR = 0·67, 95 % CI 0·46, 0·96 for the highest compared with the lowest score tertile). In stratified analyses, the association was stronger among women with a normal weight, those who were older, and consequently those in post-menopause, and those with ≥ 2 children. In conclusion, high adherence to the WCRF/AICR recommendations has a favourable role in endometrial cancer risk, which is not fully explained by body weight.

The Food Environments of Fruit and Vegetable Consumption in East and Southeast Asia: A Systematic Review

Fruit and vegetable (FV) consumption benefits the health of populations. This can be especially the case in locations which have undergone significant changes in their food environments, such as East and Southeast Asian countries. This current systematic review is the first to study the food environments—facilitators, barriers, and moderators—associated with FV consumption in East and Southeast Asia. We consulted five electronic academic databases of English peer-reviewed papers published between 2010 and 2020 and found 31 studies. Results of these studies show that individuals strongly perceive FVs as being high-quality and safe, and having trust in their benefits. Food businesses with modernized systems have significantly fostered the consumption of FVs. A main barrier to FV consumption, however, is financial concerns, exacerbated by food businesses with FV unavailability and urbanization-induced FV price inflation and dietary patterns. Demographics and shopping patterns further hinder FV consumption. The fragmented and conditionalized findings of the 31 studies require standardized FV consumption measurements. Unlike the impact of FV consumption determinants and their interactions in Western countries, those in Asia, particularly countries other than China, have been substantially understudied. Therefore, as the research gaps in studies of food environments and FV consumption in East and Southeast Asia urgently demand scholarly attention, this paper proposes recommendations that favour the consumption of FVs.

Association between physical activity and digestive-system cancer: An updated systematic review and meta-analysis

BACKGROUND

Physical activity (PA) may have an impact on digestive-system cancer (DSC) by improving insulin sensitivity and anticancer immune function and by reducing the exposure of the digestive tract to carcinogens by stimulating gastrointestinal motility, thus reducing transit time. The current study aimed to determine the effect of PA on different types of DSC via a systematic review and meta-analysis.

METHODS

In accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, we searched for relevant studies in PubMed, Embase, Web of Science, Cochrane Library, and China National Knowledge Infrastructure. Using a random effects model, the relationship between PA and different types of DSC was analyzed.

RESULTS

The data used for meta-analysis were derived from 161 risk estimates in 47 studies involving 5,797,768 participants and 55,162 cases. We assessed the pooled associations between high vs. low PA levels and the risk of DSC (risk ratio (RR)  = 0.82, 95% confidence interval (95%CI): 0.79-0.85), colon cancer (RR = 0.81, 95%CI: 0.76-0.87), rectal cancer (RR = 0.88, 95%CI: 0.80-0.98), colorectal cancer (RR = 0.77, 95%CI: 0.69-0.85), gallbladder cancer (RR = 0.79, 95%CI: 0.64-0.98), gastric cancer (RR = 0.83, 95%CI: 0.76-0.91), liver cancer (RR = 0.73, 0.60-0.89), oropharyngeal cancer (RR = 0.79, 95%CI: 0.72-0.87), and pancreatic cancer (RR = 0.85, 95%CI: 0.78-0.93). The findings were comparable between case-control studies (RR = 0.73, 95%CI: 0.68-0.78) and prospective cohort studies (RR = 0.88, 95%CI: 0.80-0.91). The meta-analysis of 9 studies reporting low, moderate, and high PA levels, with 17 risk estimates, showed that compared to low PA, moderate PA may also reduce the risk of DSC (RR = 0.89, 95%CI: 0.80-1.00), while compared to moderate PA, high PA seemed to slightly increase the risk of DSC, although the results were not statistically significant (RR = 1.11, 95%CI: 0.94-1.32). In addition, limited evidence from 5 studies suggested that meeting the international PA guidelines might not significantly reduce the risk of DSC (RR = 0.96, 95%CI: 0.91-1.02).

CONCLUSION

Compared to previous research, this systematic review has provided more comprehensive information about the inverse relationship between PA and DSC risk. The updated evidence from the current meta-analysis indicates that a moderate-to-high PA level is a common protective factor that can significantly lower the overall risk of DSC. However, the reduction rate for specific cancers may vary. In addition, limited evidence suggests that meeting the international PA guidelines might not significantly reduce the risk of DSC. Thus, future studies must be conducted to determine the optimal dosage, frequency, intensity, and duration of PA required to reduce DSC risk effectively.

Adherence to the 2018 World Cancer Research Fund/American Institute for Cancer Research cancer prevention recommendations and pancreatic cancer incidence and mortality: A prospective cohort study

Background

Whether adherence to the World Cancer Research Fund/American Institute for Cancer Research (WCRF/AICR) cancer prevention recommendations is associated with a reduced risk of pancreatic cancer remains controversial. Additionally, no study has investigated this association in the US population. Hence, we investigated the association of adherence to the 2018 WCRF/AICR cancer prevention recommendations with pancreatic cancer incidence and mortality in a US population.

Methods

A population‐based cohort of 95 962 participants was identified. A score incorporating eight WCRF/AICR components was constructed to reflect adherence to the WCRF/AICR guidelines, with higher scores representing greater adherence to the guidelines. Cox and competing risk regression were used to calculate risk estimates for pancreatic cancer incidence and mortality, respectively. Restricted cubic spline functions were used to test nonlinearity.

Results

In the fully adjusted model, higher overall WCRF/AICR scores were shown to be associated with lower risks of developing pancreatic cancer (hazard ratio_{tertile 3 vs 1}:0.67; 95% confidence interval: 0.49, 0.90; P_trend = .0099) and mortality due to this cancer (subdistribution hazard ratio_{tertile 3 vs 1} 0.65; 95% confidence interval: 0.47, 0.89; P_trend = .0108) in a linear dose–response manner (all P_nonlinearity > .05). The component “be physically active” was shown to be a key contributor to the observed associations. No association of the diet‐specific WCRF/AICR score with pancreatic incidence and mortality was found.

Conclusions

Adherence to the 2018 WCRF/AICR guidelines, especially “be physically active,” confers reduced risks of pancreatic cancer incidence and mortality in the US population; however, adherence to dietary components alone does not confer such beneficial effects.

Nutrition and cancer: evidence gaps and opportunities for improving knowledge

The Nutrition Society's 1st Annual Nutrition and Cancer Networking Conference brought together scientists from the fields of Nutrition, Epidemiology, Public Health, Medical Oncology and Surgery with representatives of the public, cancer survivors and cancer charities. Speakers representing these different groups presented the challenges to collaboration, how the needs of patients and the public can be met, and the most promising routes for future research. The conference programme promoted debate on these issues to highlight current gaps in understanding and barriers to generating and implementing evidence-based nutrition advice. The main conclusions were that the fundamental biology of how nutrition influences the complex cancer risk profiles of diverse populations needs to be better understood. Individual and population level genetics interact with the environment over a lifespan to dictate cancer risk. Large charities and government have a role to play in diminishing our current potently obesogenic environment and exploiting nutrition to reduce cancer deaths. Understanding how best to communicate, advise and support individuals wishing to make dietary and lifestyle changes, can reduce cancer risk, enhance recovery and improve the lives of those living with and beyond cancer.

Compliance with the 2018 World Cancer Research Fund/American Institute for Cancer Research Cancer Prevention Recommendations and Prostate Cancer

The etiology of prostate cancer (PCa) remains largely unknown. Compliance with the 2018 World Cancer Research Fund/American Institute for Cancer Research (WCRC/AICR) cancer prevention recommendations and its relationship to PCa was evaluated. A total of 398 incident PCa cases and 302 controls were included. The selection criteria for both cases and controls were: (i) age between 40-80 years; and (ii) residence in the coverage area of the reference hospitals for 6 months or more prior to recruitment. A score to measure the compliance with the recommendations of 2018 WCRC/AICR criteria was built. The level of compliance was used as a continuous variable and categorized in terciles. The aggressiveness of PCa was determined according to the ISUP classification. Adjusted odds ratios (aOR) and their 95% confidence intervals (95% CI) were estimated using multivariable logistic regression models. A slight protective tendency was observed between the level of compliance with the preventive recommendations and PCa risk, aOR = 0.81 (95% CI 0.69-0.96) for the total cases of PCa. This association also was observed when the aggressiveness was considered. In addition, limiting consumption of "fast foods", sugar-sweetened drinks, and alcohol were independently associated with lower risk of PCa.

Adherence to the World Cancer Research Fund/American Institute for Cancer Research Recommendations and the Risk of Breast Cancer

The World Cancer Research Fund/American Institute for Cancer Research (WCRF/AICR) introduced in 2007, and updated in 2018, nutrition-related recommendations for cancer prevention. Previous studies generally reported inverse associations of breast cancer with the 2007 recommendations, while no study has yet evaluated the association with the 2018 guidelines. We investigated the association between adherence to the 2018 WCRF/AICR recommendations and breast cancer risk in a case–control study from Italy and Switzerland (1991–2008) including 3034 incident histologically-confirmed breast cancer cases and 3392 hospital controls. Adherence to the 2018 guidelines was summarized through a score incorporating eight recommendations (body fatness, physical activity, consumption of wholegrains/vegetables/fruit/beans, “fast foods” and other processed foods high in fat, starches, or sugars, red/processed meat, sugar-sweetened drinks, alcohol, breastfeeding), with higher scores indicating higher adherence. Odds ratios (OR) were estimated using multiple logistic regression models. We also conducted a meta-analysis including 15 additional studies using random-effects models. In our case–control study, adherence to the 2018 WCRF/AICR guidelines was inversely associated with breast cancer, with ORs of 0.60 (95% confidence interval (CI), 0.51–0.70) for a score ≥5.5 vs. ≤4.25, and of 0.83 (95% CI, 0.79–0.88) for a 1-point increment. In our study, 25% of breast cancers were attributable to low-to-moderate guideline adherence. In the meta-analysis, the pooled relative risks (RRs) were 0.73 (95% CI, 0.65–0.82, p heterogeneity among studies < 0.001) for the highest vs. the lowest WCRF/AICR score category, and 0.91 (95% CI, 0.88–0.94, p heterogeneity < 0.001) for a 1-point increment. This work provides quantitative evidence that higher adherence to the WCRF/AICR recommendations reduces the risk of breast cancer, thus opening perspectives for prevention.

A systematic review and meta-analysis of the 2007 WCRF/AICR score in relation to cancer-related health outcomes

BACKGROUND

We conducted a systematic literature review and meta-analysis of observational studies investigating adherence to the 2007 World Cancer Research Fund/American Institute for Cancer Research (WCRF/AICR) lifestyle recommendations for cancer prevention and health outcomes.

PATIENTS AND METHODS

We searched PubMed and the in-house database of the WCRF Continuous Update Project for publications up to June 2019. Cross-sectional studies were only narratively reviewed given their heterogeneity while findings of cohort/case-control studies were synthesized in umbrella reviews and meta-analyses. Summary relative risks (RRs) and 95% confidence intervals (CI) were estimated using a random-effects model when at least two studies reported results on a specific outcome.

RESULTS

Thirty-eight articles (17 prospective, 8 case-control, and 13 cross-sectional studies) were included. The summary RR per each point increment in the 2007 WCRF/AICR score was 0.90 (95% CI: 0.87-0.93, n = 11) for breast cancer, regardless of hormone receptor and menopausal status, 0.86 (95% CI: 0.82-0.89, n = 10) for colorectal cancer, and 0.93 (95% CI: 0.89-0.96, n = 2) for lung cancer risk. No statistically significant associations were reported for prostate (n = 6) and pancreatic cancers (n = 2). Adherence to the recommendations was associated with lower overall mortality (RR = 0.90, 95% CI 0.84-0.96, n = 3) and cancer-specific mortality (RR = 0.91, 95% CI 0.89-0.92; n = 3) in healthy populations, as well as with higher survival in cancer patients (n = 2). In cross-sectional studies, a healthier plasma marker profile and lower cancer risk factors in the general population and a better health status and quality of life in cancer patients/survivors were reported.

CONCLUSIONS

Adhering to the 2007 WCRF/AICR recommendations is associated with lower risks of cancer incidence, namely breast and colorectal cancers, and mortality. Primary prevention of cancer should emphasize modification of multiple lifestyle factors. Upcoming studies examining the recently updated 2018 guidelines will further clarify such associations.

Physical activity and laryngeal cancer

Although an active lifestyle physical has been convincingly associated with a decreased risk of developing many forms of cancers, including neck and head malignancies, uncertainty surrounds the relationship between physical activity (PA) and laryngeal carcinogenesis. Epidemiologic evidence, garnered from some well-conducted cross-sectional, prospective and retrospective studies, seemingly attests that the impact of PA may be not so straightforward in lowering laryngeal cancer risk as for other malignancies. Reasonable consensus has been reached that moderate-intensity PA may generate the larger potential benefits, whilst the effect of high-intensity PA appears more controversial and even contradictory. This is mainly attributable to the fact that moderate PA may have more favorable effects than high-intensity exercise in decreasing the impact of some risk factors of laryngeal cancer such as metabolic syndrome, cigarette smoking, inflammation, and gastroesophageal reflux disease. Significant biological and psychological benefits from moderate-intensity exercise have also been described in patients surviving from primary laryngeal cancers. This would hence lead us to conclude that promotion of an active lifestyle, characterized by performance of moderate-intensity PA (e.g., between 3 and 6 metabolic equivalents, equaling short distance running), may be beneficial for lowering the risk of developing laryngeal cancer and for improving the quality of life of larynx cancer survivors.

Dietary patterns and oral and pharyngeal cancer using latent class analysis

The methods traditionally used to identify a posteriori dietary patterns are principal components, factor and cluster analysis. The aim of our study is to assess the relationship between dietary patterns derived with latent class analysis (LCA) and oral/pharyngeal cancer risk (OPC), highlighting the strengths of this method compared to traditional ones. We analyzed data from an Italian multicentric case-control study on OPC including 946 cases and 2,492 hospital controls. Dietary patterns were derived using LCA on 25 food groups. A multiple logistic regression model was used to derive odds ratios (ORs) and corresponding 95% confidence intervals (CIs) for OPC according to the dietary patterns identified. We identified four dietary patterns. The first one was characterized by a high intake of leafy and fruiting vegetable and fruits (Prudent pattern), the second one showed a high intake of red meat and low intake of selected fruits and vegetables (Western pattern). The last two patterns showed a combination-type of diet. We labeled "Lower consumers-combination pattern" the cluster that showed a low intake of the majority of foods, and "Higher consumers-combination pattern" the one characterized by a high intake of various foods. Compared to the "Prudent pattern", the "Western" and the "Lower consumers-combination" ones were positively related to the risk of OPC (OR = 2.56, 95% CI: 1.90-3.45 and OR = 2.23, 95% CI: 1.64-3.02). No difference in risk emerged for the "Higher consumers-combination pattern" (OR = 1.28, 95% CI: 0.92-1.77).

Lifestyle and cancer incidence and mortality risk depending on family history of cancer in two prospective cohorts

The extent to which a favorable lifestyle may lower cancer risk in subjects with a family history of cancer is unknown. We conducted a prospective study in two Swedish cohorts, the Malmö Diet and Cancer Study (MDCS; n = 25,604) and the Malmö Preventive Project (MPP; n = 16,216). The association between a favorable lifestyle (based on nonsmoking, normal weight, absence of excessive drinking, regular physical activity and healthy diet) and cancer incidence and mortality risk was assessed using Cox regression stratified by family history of cancer (all types). A favorable lifestyle was associated with a 22% (95% confidence interval [CI]: 18-26%) and 40% (95% CI: 36-44%) lower risk of cancer incidence and mortality, respectively, compared to an unfavorable lifestyle. No significant effect modification by family history was observed but there was a null association between lifestyle and cancer incidence among subjects with two or more affected first-degree relatives. The observed relative risk estimates comparing an unfavorable with a favorable lifestyle corresponded to standardized 10-year cancer incidence rates of 11.2 vs. 9.5% in the MDCS, and 4.4 vs. 3.2% in the MPP, and a reduction in 20-year cancer mortality rate from 11.7% to 7.4% in the MDCS and 6.7% to 3.9% in the MPP. Improved adherence to cancer prevention recommendations may reduce cancer incidence and mortality risk in the general population, however, further studies are needed to assess the impact of lifestyle on cancer incidence among subjects with strong familial or polygenic risk for specific cancers.

Index-Based Dietary Patterns and the Risk of Prostate Cancer

Prostate cancer is the second leading cause for cancer incidence in male. Although this high incidence is due to prostate specific antigen screening, other risk-factors, such as diet, might also be involved. The results of previous studies on the association between prostate cancer risk and individual dietary components have been conflicting. Thus, evaluation by dietary pattern analysis rather than individual dietary factors is suggested. The purpose of this study was to review the association of prostate cancer with a priori dietary indices, which are less studied and reviewed to date compared to a posteriori indices. Studies reviewed in this research were published from January 1997 to March 2017. Seventeen studies with nine indices were selected. In Mediterranean Diet Score (MDS), all four studies were non-significant. In Dietary Inflammatory Index (DII), 3 out of 4 studies significantly increased risk by 1.33-2.39 times, suggesting that a higher pro-inflammatory diet may be a possible prostate cancer risk factor. In Oxidative Balance Score (OBS), 2 out of 5 studies had decreased risk by 0.28 and 0.34 times, whereas 1 study had increased risk by 1.17 times. Among other indices, Healthy Eating Index (HEI) and prostate cancer dietary index were associated with decreased risk, while the results from 2 studies of Low Carbohydrate, High Protein Diet (LCHP) score were conflicting. In conclusion, we observed that it is insufficient to support the association between a priori indices and prostate cancer risk, except for MDS and DII, which had relatively constant results among studies. Therefore, further studies are required to identify consistent criteria for each a priori index, and should be conducted actively in various populations.