Adherence to the World Cancer Research Fund/American Institute for Cancer Research and Korean Cancer Prevention Guidelines and cancer risk: a prospective cohort study from the Health Examinees-Gem study.

OBJECTIVES: The purpose of this study was to explore the association between adherence to 2 cancer prevention recommendations and cancer risk. METHODS: In total, 104,386 individuals aged 40-69 years old who were recruited between 2004 and 2013 in the Health Examinees-Gem study were included. Adherence scores were constructed based on 8 items from the World Cancer Research Fund/American Institute for Cancer Research (WCRF/AICR) cancer prevention recommendations, including body weight, physical activity, diet, alcohol consumption and breastfeeding, and on 6 items from the Korean cancer prevention guidelines (smoking status, eating vegetables and fruits, salty foods, alcohol intake, physical activity, and body weight). A Cox proportional hazards model was used to estimate the associations between adherence scores and the risk of total and 5 major cancers. RESULTS: The multivariable hazard ratio (HR) for total cancer with the high adherence score versus the lowest score (4.25-7.00 vs. 0.00-3.25) for the WCRF/AICR guidelines was 0.91 (95% confidence interval [CI], 0.82 to 1.00) in men. A reduced breast cancer risk was observed among women with the highest score. Men within the highest category of the Korean cancer prevention guideline score (3.25-6.00) had an HR of 0.80 (95% CI, 0.73 to 0.88) for developing total cancer compared to men within the lowest score (0.00-2.50). The higher adherence group among men showed lower risks of developing stomach, colorectal, and lung cancers. CONCLUSIONS: Adhering to guidelines for cancer prevention can help to reduce the risk of developing cancer in Korean men. The association might differ by cancer type and gender.

Dysbiotic microbiome variation in colorectal cancer patients is linked to lifestyles and metabolic diseases.

BACKGROUND: Differences in the composition and diversity of the gut microbial communities among individuals are influenced by environmental factors. However, there is limited research on factors affecting microbiome variation in colorectal cancer patients, who display lower inter-individual variations than that of healthy individuals. In this study, we examined the association between modifiable factors and the microbiome variation in colorectal cancer patients. METHODS: A total of 331 colorectal cancer patients who underwent resection surgery at the Department of Surgery, Seoul National University Hospital between October 2017 and August 2019 were included. Fecal samples from colorectal cancer patients were collected prior to the surgery. Variations in the gut microbiome among patients with different lifestyles and metabolic diseases were examined through the network analysis of inter-connected microbial abundance, the assessment of the Anna Karenina principle effect for microbial stochasticity, and the identification of the enriched bacteria using linear discrimination analysis effect size. Associations of dietary diversity with microbiome variation were investigated using the Procrustes analysis. RESULTS: We found stronger network connectivity of microbial communities in non-smokers, non-drinkers, obese individuals, hypertensive subjects, and individuals without diabetes than in their counterparts. The Anna Karenina principle effect was found for history of smoking, alcohol consumption, and diabetes (with significantly greater intra-sample similarity index), whereas obesity and hypertension showed the anti-Anna Karenina principle effect (with significantly lower intra-sample similarity index). We found certain bacterial taxa to be significantly enriched in patients of different categories of lifestyles and metabolic diseases using linear discrimination analysis. Diversity of food and nutrient intake did not shape the microbial diversity between individuals (pProcrustes>0.05). CONCLUSIONS: Our findings suggested an immune dysregulation and a reduced ability of the host and its microbiome in regulating the community composition. History of smoking, alcohol consumption, and diabetes were shown to affect partial individuals in shifting new microbial communities, whereas obesity and history of hypertension appeared to affect majority of individuals and shifted to drastic reductions in microbial compositions. Understanding the contribution of modifiable factors to microbial stochasticity may provide insights into how the microbiome regulates effects of these factors on the health outcomes of colorectal cancer patients.

Descriptive Analysis of Gastric Cancer Mortality in Korea, 2000-2020.

PURPOSE: This study aimed to examine secular trends, age-period-cohort effects, and geographical differences in gastric cancer (GC) mortality in Korea. Materials and Methods: Using cause of death data from the Korean Statistical Information Service for GC from 2000 to 2020, we calculated average annual percentage changes (AAPCs) in the age-standardized mortality of GC in 17 cities and provinces through joinpoint regression. Decomposition of age, period, and cohort effects on GC mortality were elucidated by applying a log-linear model and an intrinsic estimate method. Spatial patterns and the degree of spatial clustering in 250 administrative regions were explored via Moran's I statistics. Stratification by sex was performed for all analyses. RESULTS: The age-standardized mortality of GC per 100,000 persons declined from 29.0 in 2000 to 7.9 in 2020 (AAPC, -6.28%). Age-period-cohort analyses of GC mortality showed a downward trend among five-year age groups from age 20-89 years across five-year periods from 2005-2020 and five-year birth cohorts from 1920-2000. Overall, the younger birth cohort showed lower mortality rates than the older cohort within the same period. In 2020, clusters of high GC mortality were observed in the central area for men (Chungcheongbuk, Jeollabuk, Gyeongsangbuk, and Gyeongsangnam) and in the eastern area for women (Gyeongsangbuk). CONCLUSION: This study identified a downward trend in GC mortality among men and women from 2000 to 2020 in Korea. This trend was mainly attributed to birth cohort rather than period effects. Spatial analysis showed high GC mortality in the Chungcheong and Gyeongsangbuk areas.

Nutrition-wide association study of microbiome diversity and composition in colorectal cancer patients.

BACKGROUND: The effects of diet on the interaction between microbes and host health have been widely studied. However, its effects on the gut microbiota of patients with colorectal cancer (CRC) have not been elucidated. This study aimed to investigate the association between diet and the overall diversity and different taxa levels of the gut microbiota in CRC patients via the nutrition-wide association approach. METHODS: This hospital-based study utilized data of 115 CRC patients who underwent CRC surgery in Department of Surgery, Seoul National University Hospital. Spearman correlation analyses were conducted for 216 dietary features and three alpha-diversity indices, Firmicutes/Bacteroidetes ratio, and relative abundance of 439 gut microbial taxonomy. To identify main enterotypes of the gut microbiota, we performed the principal coordinate analysis based on the ß-diversity index. Finally, we performed linear regression to examine the association between dietary intake and main microbiome features, and linear discriminant analysis effect size (LEfSe) to identify bacterial taxa phylogenetically enriched in the low and high diet consumption groups. RESULTS: Several bacteria were enriched in patients with higher consumption of mature pumpkin/pumpkin juice (ρ, 0.31 to 0.41) but lower intake of eggs (ρ, -0.32 to -0.26). We observed negative correlations between Bacteroides fragilis abundance and intake of pork (belly), beef soup with vegetables, animal fat, and fatty acids (ρ, -0.34 to -0.27); an inverse correlation was also observed between Clostridium symbiosum abundance and intake of some fatty acids, amines, and amino acids (ρ, -0.30 to -0.24). Furthermore, high intake of seaweed was associated with a 6% (95% CI, 2% to 11%) and 7% (95% CI, 2% to 11%) lower abundance of Rikenellaceae and Alistipes, respectively, whereas overall beverage consumption was associated with an 10% (95% CI, 2% to 18%) higher abundance of Bacteroidetes, Bacteroidia, and Bacteroidales, compared to that in the low intake group. LEfSe analysis identified phylogenetically enriched taxa associated with the intake of sugars and sweets, legumes, mushrooms, eggs, oils and fats, plant fat, carbohydrates, and monounsaturated fatty acids. CONCLUSIONS: Our data elucidates the diet-microbe interactions in CRC patients. Additional research is needed to understand the significance of these results in CRC prognosis.

Consumption of Coffee and Green Tea and the Risk of Colorectal Cancer in Korea: The Health Examinees Study.

Coffee and green tea may affect colorectal physiology and contain many bioactive components, such as polyphenol and caffeine, which have antioxidant and anti-carcinogenic activities. However, the association between coffee and green tea consumption and the risk of colorectal cancer (CRC) has been inconclusive. This study examined the association between coffee and green tea consumption and the risk of CRC in a large-scale prospective cohort study in Korea. Data from the Health Examinees study from 2004 to 2013 were analyzed, and 114,243 participants (39,380 men and 74,863 women) aged 40-79 years were included in the final analysis. A Cox proportional hazards regression model using age at time scale was used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) of coffee and green tea consumption for the risk of CRC by sex. In both men and women, no significant association was found between coffee and green tea consumption and the risk of CRC. Among women, there was a significant increase in the risk of colon cancer (HR, 1.66; 95% CI, 1.13-2.44) in the black coffee drinker group. Our findings suggest that consumption of coffee and green tea may not be associated with the CRC incidence in Korea; instead, the association may differ depending on cancer subsites and coffee types.

Adherence to the Recommended Intake of Calcium and Colorectal Cancer Risk in the HEXA Study.

PURPOSE: Dietary calcium intake has been suggested to be protective against the development of colorectal cancer. The mean dietary calcium intake of Koreans is 490 mg/day, which is far below the recommended calcium intake of 700-800 mg/day. In this study, we explored the relationship between dietary calcium intake and colorectal cancer development in Koreans with relatively low calcium intake compared with individuals in Western countries. MATERIALS AND METHODS: The Health Examinees Study, a large-scale genomic community-based prospective cohort study, was designed to identify the general characteristics of major chronic diseases in Koreans. A total of 119,501 participants aged 40-69 years recruited between 2004 and 2013 were included in this analysis. The calcium intake level was categorized using the Dietary Reference Intakes for Koreans (KDRIs). The Cox proportional hazards regression model was used to estimate the hazard ratio (HR) and the corresponding 95% confidence intervals (CIs) for colorectal cancer risk, adjusting for potential confounders. RESULTS: In the multivariable-adjusted model, compared with the group that consumed less than the recommended amount of calcium, the group that consumed more than the recommended intake of calcium showed a significant reduction in the risk of colorectal cancer in women. (HR, 0.54; 95% CI, 0.31 to 0.95). Among men, however, no significant association was observed between dietary calcium intake and colorectal cancer risk (HR, 0.89; 95% CI, 0.54 to 1.45). CONCLUSION: Korean women who adhere to the recommended intake of calcium showed a reduced risk of colorectal cancer.

Marital status and the prevalence of obesity in a Korean population.

OBJECTIVE: Previous studies have reported on marital status and the prevalence of obesity; however, few studies have assessed the prevalence of underweight in relation to marital status. This study aimed to explore the association of obesity and abdominal obesity with marital status among Koreans aged 40-69 years. METHODS: We selected a total of 137,608 participants from the Health Examinees Gem Study for the final analysis. Multinomial logistic regression models were used to estimate odds ratios (OR) and their 95% confidence intervals (CI) for the association of obesity with marital status, with controlling for potential confounders. RESULTS: The prevalence of underweight was higher in unmarried men (OR: 1.82, 95% CI: 1.25-2.63) and women (OR: 2.16, 95% CI: 1.79-2.61) than in married individuals. Compared to married individuals, a lower prevalence of BMI≥25kg/m2 was observed for those who were unmarried (men: OR: 0.71, 95% CI: 0.62-0.81, women: OR: 0.65, 95% CI: 0.58-0.73) or divorced/separated (men: OR: 0.80, 95% CI: 0.69-0.93, women: OR: 0.90, 95% CI: 0.83-0.98). Interestingly, widowed women showed higher prevalence of BMI≥25kg/m2 (OR: 1.17, 95% CI: 1.10-1.25) and abdominal obesity (OR: 1.23, 95% CI: 1.16-1.30) compared to married women, and the association persisted only among women in their 50s and 60s. CONCLUSIONS: Married participants showed a higher prevalence of obesity and abdominal obesity than those in other marriage categories except for widowed women.

Validity of Self-reported Stroke and Myocardial Infarction in Korea: The Health Examinees (HEXA) Study.

OBJECTIVES: Self-reported disease history is often used in epidemiological studies. In this study, we acquired the hospital records of subjects who self-reported stroke or myocardial infarction (MI) and evaluated the validity of the participants' self-reported disease history. We also determined the level of agreement between specialists and non-specialists. METHODS: Among the participants in the Health Examinees study, 1488 subjects self-reported stroke or MI during 2012-2017, and medical records were acquired for the 429 subjects (28.8%) who agreed to share their medical information. Each record was independently assigned to 2 medical doctors for review. The records were classified as 'definite,' 'possible,' or 'not' stroke or MI. If the doctors did not agree, a third doctor made the final decision. The positive predictive value (PPV) of self-reporting was calculated with the doctors' review as the gold standard. Kappa statistics were used to compare the results between general doctors and neurologists or cardiologists. RESULTS: Medical records from 208 patients with self-reported stroke and 221 patients with self-reported MI were reviewed. The PPV of self-reported disease history was 51.4% for stroke and 32.6% for MI. If cases classified as 'possible' were counted as positive diagnoses, the PPV was 59.1% for stroke and 33.5% for MI. Kappa statistics showed moderate levels of agreement between specialists and non-specialists for both stroke and MI. CONCLUSIONS: The validity of self-reported disease was lower than expected, especially in those who reported having been diagnosed with MI. Proper consideration is needed when using these self-reported data in further studies.

Evaluation of gene-environment interactions for colorectal cancer susceptibility loci using case-only and case-control designs.

BACKGROUND: Genome-wide association studies (GWAS) have identified more than 40 colorectal cancer susceptibility loci, but only a small fraction of heritability was explained. To account for missing heritability, we investigated gene-environment interactions (G × Es) between GWAS-identified single-nucleotide polymorphisms (SNPs) and established risk or protective factors for colorectal cancer using both case-only and case-control study designs. METHODS: Data on 703 colorectal cancer cases and 1406 healthy controls from the National Cancer Center in Korea were used. We tested interactions between 31 GWAS-identified SNPs and 13 established risk or protective factors for colorectal cancer (family history, body mass index, history of colorectal polyps, inflammatory bowel disease, and diabetes mellitus, alcohol drinking, smoking, regular exercise, regular aspirin use, postmenopausal hormone replace therapy, red meat and processed meat intake, and dairy consumption). Logistic regression models were used to assess G × Es for colorectal cancer risk. RESULTS: The SNP rs4444235 at 14q22.2 interacted with regular exercise in colorectal cancer (pcase-only = 2.4 × 10- 3, pcase-control = 1.5 × 10- 3). The risk allele (C) of rs4444235 increased the risk of colorectal cancer in regularly exercising individuals (OR = 1.47, 95% CI = 1.02-2.10) but decreased the risk in non-exercising individuals (OR = 0.76, 95% CI = 0.62-0.94). Furthermore, the G × E between the SNP rs2423279 at 20p12.3 and regular aspirin use was statistically significant (pcase-only = 7.7 × 10- 3, pcase-control = 1.6 × 10- 3). The additive effect of the risk allele (T) of rs2423279 on colorectal cancer risk was increased among regular aspirin users (OR = 4.62, 95% CI = 1.97-10.80). CONCLUSION: Our results suggest that SNP rs4444235 at 14q22.2 and SNP rs2423279 at 20p12.3 may interact with regular exercise and aspirin use in colorectal carcinogenesis.

Association between Green Tea Consumption and Risk of Stroke in Middle-Aged and Older Korean Men: The Health Examinees (HEXA) Study.

Green tea consumption is known to have varying effects on health and disease. The aim of this study was to investigate the association between green tea consumption and risk of stroke in Korean adult men. Data were obtained from the Health Examinees (HEXA) Study, which included 50,439 subjects aged 40 years and older. Information regarding dietary intake was collected from semi-quantified food frequency questionnaires consisting of 106 items. Green tea consumption was categorized as none, <1 cup/d, 1 to <3 cups/d, and ≥3 cups/d. Binary logistic regression models were used to estimate odds ratios (OR) and 95% confidence intervals (CIs) to examine a possible association between green tea consumption and risk of stroke by controlling for potential confounders. Subgroup analyses by age, body mass index, hypertension, diabetes mellitus, smoking status, and alcohol consumption were also performed. Compared with green tea non-drinkers, individuals that consumed 1 to <3 cups/d or ≥3 cups/d of green tea had multivariable adjusted OR (CI) of stroke of 0.75 (0.59~0.97) and 0.62 (0.39~0.98), respectively, after adjusting for age and various confounders. In the subgroup analyses, an inverse association between green tea consumption and risk of stroke was identified among younger, non-hypertensive, and non-diabetic men. Higher consumption of green tea was inversely associated with stroke risk in middle-aged and older Korean men.

Cigarette smoking, alcohol consumption, and risk of colorectal cancer in South Korea: A case-control study.

The current case-control study comprehensively evaluated the status, quantity, and duration of smoking and alcohol drinking for both men and women, considering the subsites of colorectal cancer. A total of 925 colorectal cancer cases and 2775 controls were included in the analysis. Odds ratios (OR) and 95% confidence intervals (CI) were computed by logistic regression models adjusting for potential confounders. In men, the risk of colorectal cancer significantly increased for heavy smokers who smoked ≥40 pack-years (OR 1.74, 95% CI 1.22-2.50), ≥40 years (OR 1.50, 95% CI 1.05-2.16), or ≥40 cigarettes/day (OR 1.92, 95% CI 1.04-3.54). Men showed a significant increase in risk, especially for rectal cancer with an increasing amount or duration of smoking. In women, distal colon cancer risk increased in smokers who smoked ≥20 years (OR 3.21, 95% CI 1.27-8.14) or ≥20 cigarettes/day (OR 4.75, 95% CI 1.09-20.57). Additionally, female smokers who smoked ≥20 cigarettes/day had an increased risk of rectal cancer (OR 6.46, 95% CI 1.64-25.46). Regarding the association of cigarettes smoked per day and the risk of rectal cancer, there was no significant difference between men and women (gender interaction p value = 0.14). Compared with never-drinkers, those who consumed alcohol at ≥40 g/day in men and ≥20 g/day in women had an OR of 2.39 (95% CI 1.68-3.41) and 3.52 (95% CI 1.56-7.96), respectively. The effect of daily alcohol consumption (g of ethanol/day) on cancer risk was not significantly different among subsites. Association of alcohol consumption quantity (g of ethanol/day) and the risk of proximal and distal colon cancer were stronger in women than in men (gender interaction p value < 0.01). There was no significant interaction in the multiplicative level when alcohol consumption and cigarette smoking were combined. The duration and amount of smoking as well as the amount of alcohol consumption were associated with an elevated risk of colorectal cancer in both men and women.

The relationship between nut intake and risk of colorectal cancer: a case control study.

BACKGROUND: Nut consumption is known to reduce the risk of obesity, diabetes mellitus, and cardiovascular disease. However, in previous studies, portion sizes and categories of nut consumption have varied, and few studies have assessed the association between colorectal cancer risk and nut consumption. In this study, we investigated the relationship between nut consumption and colorectal cancer risk. METHODS: A case-control study was conducted among 923 colorectal cancer patients and 1846 controls recruited from the National Cancer Center in Korea. Information on dietary intake was collected using a semi-quantitative food frequency questionnaire with 106 items, including peanuts, pine nuts, and almonds (as 1 food item). Nut consumption was categorized as none, < 1 serving per week, 1-3 servings per week, and ≥3 servings per week. A binary logistic regression model was used to estimate odds ratios (OR) and their 95% confidence intervals (CI) for the association between nut consumption and colorectal cancer risk, and a polytomous logistic regression model was used for sub-site analyses. RESULTS: High nut consumption was strongly associated with reduced risk of colorectal cancer among women (adjusted ORs: 0.30, 95%CI: 0.15-0.60 for the ≥3 servings per week group vs. none). A similar inverse association was observed for men (adjusted ORs: 0.28, 95% CI: 0.17-0.47). In sub-site analyses, adjusted ORs (95% CIs) comparing the ≥3 servings per week group vs none were 0.25 (0.09-0.70) for proximal colon cancer, 0.39 (0.19-0.80) for distal colon cancer, and 0.23 (0.12-0.46) for rectal cancer among men. An inverse association was also found among women for distal colon cancer (OR: 0.13, 95% CI: 0.04-0.48) and rectal cancer (OR: 0.40, 95% CI: 0.17-0.95). CONCLUSIONS: We found a statistically significant association between high frequency of nut consumption and reduced risk of colorectal cancer. This association was observed for all sub-sites of the colon and rectum among both men and women, with the exception of proximal colon cancer for women.

Colors of vegetables and fruits and the risks of colorectal cancer.

AIM: To investigate the relationship between the colors of vegetables and fruits and the risk of colorectal cancer in Korea. METHODS: A case-control study was conducted with 923 colorectal cancer patients and 1846 controls recruited from the National Cancer Center in Korea. We classified vegetables and fruits into four groups according to the color of their edible parts (e.g., green, orange/yellow, red/purple and white). Vegetable and fruit intake level was classified by sex-specific tertile of the control group. Logistic regression models were used for estimating the odds ratios (OR) and their 95% confidence intervals (CI). RESULTS: High total intake of vegetables and fruits was strongly associated with a reduced risk of colorectal cancer in women (OR = 0.32, 95%CI: 0.21-0.48 for highest vs lowest tertile) and a similar inverse association was observed for men (OR = 0.60, 95%CI: 0.45-0.79). In the analysis of color groups, adjusted ORs (95%CI) comparing the highest to the lowest of the vegetables and fruits intake were 0.49 (0.36-0.65) for green, and 0.47 (0.35-0.63) for white vegetables and fruits in men. An inverse association was also found in women for green, red/purple and white vegetables and fruits. However, in men, orange/yellow vegetables and fruits (citrus fruits, carrot, pumpkin, peach, persimmon, ginger) intake was linked to an increased risk of colorectal cancer (OR = 1.61, 95%CI: 1.22-2.12). CONCLUSION: Vegetables and fruits intake from various color groups may protect against colorectal cancer.

Relationship between coffee consumption and stroke risk in Korean population: the Health Examinees (HEXA) Study.

BACKGROUND: Although coffee consumption is increasing rapidly, the results of previous studies regarding the association between coffee consumption and stroke risk have been conflicting. This was a multi-center cross-sectional study that aimed to evaluate the relationship between coffee consumption and stroke risk in Korean population. METHODS: Data were obtained from the Health Examinees (HEXA) Study, which involved 146,830 individuals aged 40-69 years. Coffee consumption was categorized as none, < 1 cup/day, 1 to < 3 cups/day, and ≥ 3 cups/day. We used logistic regression models to examine the association between coffee consumption and the risk of stroke while controlling for potential confounders and performed subgroup analyses. RESULTS: After adjusting for age and various possible confounders, high coffee consumption was associated with a 38% lower odds ratio for stroke in women (none vs. ≥ 3 cups/day: OR, 0.62; 95% CI 0.47-0.81; P for trend < 0.0001). No significant association was found in men (none vs. ≥ 3 cups/day: OR, 0.84; 95% CI, 0.66-1.07; P for trend = 0.1515). In analyses stratified by covariates, an inverse association between coffee consumption and stroke risk was most evident among healthy women who were younger, non-obese, non-hypertensive, non-diabetic, non-smokers, and non-alcohol drinkers. CONCLUSION: Our results suggest that higher coffee consumption may have protective benefits with regards to stroke risk in middle-aged Korean women.

Diabetes Mellitus and Site-specific Colorectal Cancer Risk in Korea: A Case-control Study.

OBJECTIVES: Previous large-scale cohort studies conducted in Korea have found a positive association between diabetes mellitus (DM) and colorectal cancer (CRC) in men only, in contrast to studies of other populations that have found significant associations in both men and women. METHODS: A total of 1070 CRC cases and 2775 controls were recruited from the National Cancer Center, Korea between August 2010 and June 2013. Self-reported DM history and the duration of DM were compared between cases and controls. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated by binary and polytomous logistic regression models. RESULTS: DM was associated with an elevated risk of CRC in both men (OR, 1.47; 95% CI, 1.13 to 1.90) and women (OR, 1.92; 95% CI, 1.24 to 2.98). This association remained when we controlled for age, body mass index, alcohol consumption, and physical activity level. In sub-site analyses, DM was associated with distal colon cancer risk in both men (multivariate OR, 2.04; 95% CI, 1.39 to 3.00) and women (multivariate ORs, 1.99; 95% CI, 1.05 to 3.79), while DM was only associated with rectal cancer risk in women (multivariate OR, 2.05; 95% CI, 1.10 to 3.82). No significant association was found between DM and proximal colon cancer risk in either men (multivariate OR, 1.45; 95% CI, 0.88 to 2.41) or women (multivariate OR, 1.79; 95% CI, 0.78 to 4.08). CONCLUSIONS: Overall, DM was associated with an increased risk of CRC in Koreans. However, potential over-estimation of the ORs should be considered due to potential biases from the case-control design.

Dietary calcium intake and the risk of colorectal cancer: a case control study.

BACKGROUND: High intake of dietary calcium has been thought to be a protective factor against colorectal cancer. To explore the dose-response relationship in the associations between dietary calcium intake and colorectal cancer risk by cancer location, we conducted a case-control study among Korean population, whose dietary calcium intake levels are relatively low. METHODS: The colorectal cancer cases and controls were recruited from the National Cancer Center in Korea between August 2010 and August 2013. Information on dietary calcium intake was assessed using a semi-quantitative food frequency questionnaire and locations of the colorectal cancers were classified as proximal colon cancer, distal colon cancer, and rectal cancer. Binary and polytomous logistic regression models were used to evaluate the association between dietary calcium intake and risk of colorectal cancer. RESULTS: A total of 922 colorectal cancer cases and 2766 controls were included in the final analysis. Compared with the lowest calcium intake quartile, the highest quartile group showed a significantly reduced risk of colorectal cancer in both men and women. (Odds ratio (OR): 0.16, 95% confidence interval (CI): 0.11-0.24 for men; OR: 0.16, 95% CI: 0.09-0.29 for women). Among the highest calcium intake groups, decrease in cancer risk was observed across all sub-sites of colorectum in both men and women. CONCLUSION: In conclusion, calcium consumption was inversely related to colorectal cancer risk in Korean population where national average calcium intake level is relatively lower than Western countries. A decreased risk of colorectal cancer by calcium intake was observed in all sub-sites in men and women.

Isoflavone and Soyfood Intake and Colorectal Cancer Risk: A Case-Control Study in Korea.

We aimed to assess the relationship between dietary soyfood and isoflavone intake and colorectal cancer risk in a case-control study. A total of 901 colorectal cancer cases and 2669 controls were recruited at the National Cancer Center, Korea. A semi-quantitative food frequency questionnaire was used to assess the usual dietary habits, and the isoflavone intake level was estimated from five soyfood items. A high intake of total soy products, legumes, and sprouts was associated with a reduced risk for colorectal cancer in men and women, although the middle quartiles of intake of total soy products were associated with an elevated risk. In contrast, a high intake of fermented soy paste was associated with an elevated risk for colorectal cancer in men. The groups with the highest intake quartiles of isoflavones showed a decreased risk for colorectal cancer compared to their counterparts with the lowest intake quartiles in men (odds ratio (OR): 0.67, 95% confidence interval (CI): 0.51-0.89) and women (OR: 0.65, 95% CI: 0.43-0.99). The reduced risk for the highest intake groups persisted for distal colon cancer in men and rectal cancer in women. The association between soyfood intake and colorectal cancer risk was more prominent among post-menopausal women than pre-menopausal women. In conclusion, a high intake of total soy products or dietary isoflavones was associated with a reduced risk for overall colorectal cancer, and the association may be more relevant to distal colon or rectal cancers.