Associations of soy product intake with all-cause, cardiovascular disease and cancer mortality: Guangzhou Biobank Cohort Study and updated meta-analyses.

PURPOSE: We examined the associations of soy product intake with all-cause, cardiovascular disease (CVD), and cancer mortality and mediations through CVD risk factors based on the Guangzhou Biobank Cohort Study (GBCS), and conducted updated meta-analyses. METHODS: A total of 29,825 participants aged 50 + years were included. Causes of death were identified through record linkage. Soy product intake was assessed by food frequency questionnaire. Cox proportional hazards regression was used to analyze the associations between soy product intake and mortality, yielding hazard ratios (HRs) and 95% confidence intervals (CIs). Mediation analyses with CVD risk factors as mediators, and updated meta-analyses were conducted. RESULTS: During 454,689 person-years of follow-up, 6899 deaths occurred, including 2694 CVD and 2236 cancer. Participants who consumed soy product of 1-6 portions/week, versus no consumption, had significantly lower risks of all-cause and CVD mortality (adjusted HR (95% CI) 0.91 (0.86, 0.97) and 0.87 (0.79, 0.96), respectively). In participants who consumed soy product of ≥ 7 portions/week, the association of higher intake with lower CVD mortality was modestly mediated by total cholesterol (4.2%, 95% CI 1.0-16.6%). Updated meta-analyses showed that the highest level of soy product intake, versus the lowest, was associated with lower risks of all-cause and CVD mortality (pooled HR (95% CI) 0.92 (0.88, 0.96) and 0.92 (0.87, 0.98), respectively). CONCLUSION: Moderate and high soy product intake were associated with lower risks of all-cause and CVD mortality. Our findings provide support for current dietary guidelines recommending moderate soy product intake, and contribute additional evidence regarding the potential protective effects of high soy product intake.

Association between functional foods and cardiometabolic health in a real-life setting: a longitudinal observational study using objective diet records from an electronic purchase system.

The effects of the regular consumption of soy, barley, and green tea in a real-life setting are unclear. This longitudinal observational study showed the associations of their intake with cardiometabolic health when employees freely selected these foods in the workplace cafeteria of an industrial company in Japan. The consumption was objectively assessed by an electronic purchase system using integrated circuit chip-equipped tableware and personal identification cards. The associations between the cumulative number of servings of each food during the 12 weeks prior to a health examination and changes in cardiometabolic measurements were examined among Japanese male workers (n = 890). Higher total intake of soy products was associated with significant lower levels in low-density lipoprotein cholesterol. Higher total intake of rice with barley was marginally associated with lower levels in systolic blood pressure and glycated hemoglobin. These associations were attenuated after adjustment for the baseline values of the dependent variables. Serving soy and barley products in the workplace cafeteria possibly promotes real-life benefits to employees' cardiometabolic health.

Association between a soy-based infant diet and the onset of puberty: A systematic review and meta-analysis.

The objective of this systematic review was to evaluate the association between a soy-based infant diet and the onset of puberty. We included studies in which children were fed a soy-based diet, and we compared them with those who were not. The primary outcomes were the onset of puberty in girls (thelarche, pubarche, and menarche age), boys (pubarche, voice change, testicular and penis enlargement age), and both (risk of delayed and precocious puberty [PP]). Search strategies were performed in PubMed, Embase, LILACS, and CENTRAL databases. Two reviewers selected eligible studies, assessed the risk of bias, and extracted data from the included studies. The odds ratio (OR) and mean difference (MD) were calculated with a 95% confidence interval (CI) as a measure of the association between soy consumption and outcomes. We used a random-effects model to pool results across studies and the Grading of Recommendations Assessment, Development, and Evaluation to evaluate the certainty of evidence. We included eight studies in which 598 children consumed a soy-based diet but 2957 did not. The primary outcomes that could be plotted in the meta-analysis were the risk of PP and age at menarche. There was no statistical difference between groups for PP (OR: 0.51, 95% CI: 0.09 to 2.94, 3 studies, 206 participants, low certainty of evidence). No between-group difference was observed in menarche age (MD 0.14 years, 95% CI -0.16 to 0.45, 3 studies, 605 children, low certainty of evidence). One study presented this outcome in terms of median and interquartile range, and although the onset of menarche was marginally increased in girls who received a soy-based diet, the reported age was within the normal age range for menarche. We did not find any association between a soy-based infant diet and the onset of puberty in boys or girls. Trial Registration: PROSPERO registration: CRD42018088902.

Pre-diagnosis and early post-diagnosis dietary soy isoflavone intake and survival outcomes: A prospective cohort study of early stage breast cancer survivors.

BACKGROUND: There is concern that the estrogen-like effects of soy isoflavones may stimulate mammary tumor growth and interfere with the efficacy of breast cancer treatment. This study aimed to examine prospectively the associations of dietary soy isoflavone intake with all-cause mortality and breast cancer (BC) specific mortality and recurrence among BC survivors. DESIGN: The study included 1460 Chinese women with early-stage incident BC. Pre-diagnosis and early post-diagnosis soy food intakes were assessed at study entry, and at 18-month follow-up using validated soy food frequency questionnaire. Associations of soy isoflavone intake with prognostic outcomes within 48 months were examined using multivariable adjusted Cox proportional hazards models. RESULTS: We observed increasing pre-diagnosis and early post-diagnosis soy isoflavone intakes up to the third quartile (Q3) were associated with reductions for adverse prognostic outcomes. Relative to the lowest quartile (Q1), the hazard ratios (HRs) for all-cause mortality for pre-diagnosis and post-diagnosis Q3 intake were respectively 0.34 (95% CI, 0.16-0.74), and 0.44 (95% CI, 0.22-0.89). A similar risk reduction was observed for pre- and post-diagnosis intakes and BC-specific mortality when comparing Q3 versus Q1 with the respective HRs 0.36 (95% CI, 0.16-0.82), and 0.49 (95% CI, 0.23-1.01). Subgroup analyses showed more favourable prognostic outcomes in association with moderate soy intake among premenopausal women, those with triple negative cancer and recipients of tamoxifen treatment. CONCLUSION: Moderate soy isoflavone intake was associated with favourable prognostic outcomes in Chinese early stage BC survivors.

Fermented and nonfermented soy foods and the risk of breast cancer in a Japanese population-based cohort study.

BACKGROUND: Although preclinical studies suggest that fermented soy foods may have a protective effect against breast cancer, no prospective cohort studies have examined this association. OBJECTIVE: Our study examined the association between fermented and nonfermented soy food intake and breast cancer risk using a population-based prospective cohort study in Japan. METHODS: We included a total of 47,614 women aged 45-74 years in an analysis of the Japan Public Health Center-based Prospective Study (JPHC Study). A validated food frequency questionnaire (FFQ) was used for the assessment of dietary intake. Breast cancer incidence was analyzed by multivariate Cox proportional hazards regression models. RESULTS: During an average of 15.5 years of follow-up, 825 breast cancer cases were newly identified. We found no association of intake of soy foods with breast cancer risk, regardless of fermentation, with multivariate hazard ratios (HRs) and 95% confidence intervals (CIs) for the highest quartiles of fermented and nonfermented soy food intake of 0.94 (0.67, 1.32) and 1.15 (0.85, 1.57) compared with the lowest quartile (p for trend = 0.305 and 0.393). Unlike nonfermented soy, higher intake of fermented soy foods was associated with a significant decrease in the risk of nonlocalized breast cancer. The HR and 95% CI in the highest compared to lowest intake category of fermented soy foods was 0.53 (0.28, 0.99) versus nonfermented soy foods 0.85 (0.51, 1.42) (p for trend = 0.026 and 0.797). CONCLUSIONS: Our analyses showed that fermented soy foods had no association with overall breast cancer but may be associated with decreased risk of nonlocalized breast cancer.

Tofu intake is inversely associated with risk of breast cancer: A meta-analysis of observational studies.

Observational studies on the association between tofu intake and breast cancer incidence have reported inconsistent results. We reviewed the current evidence and quantitatively assessed this association by conducting a dose-response meta-analysis. The electronic databases PubMed and EMBASE were searched for relevant studies published up to August, 2018. We included epidemiological studies that reported relative risks (RRs) or odds ratios (ORs) with 95% confidence intervals (CIs) for the association between tofu intake and breast cancer risk. A total of 14 studies (2 cohort studies, 12 case-control studies) were included in the meta-analysis. The overall OR of breast cancer for highest vs lowest intake of tofu was 0.78 (95% CI 0.69-0.88), with moderate heterogeneity (P = 0.011, I2 = 49.7%). Dose-response analysis based on 5 case-control studies revealed that each 10 g/d increase in tofu intake was associated with 10% reduction in the risk of breast cancer (95% CI 7%-13%, P = 0.037, I2 = 40.8%). In summary, our findings suggest an inverse dose-response association between tofu intake and risk of breast cancer. However, owing to the limitations of case-control studies, more properly designed prospective studies are warranted to confirm this association.

Association of soy and fermented soy product intake with total and cause specific mortality: prospective cohort study.

OBJECTIVE: To investigate the association between several types of soy products and all cause and cause specific mortality. DESIGN: Population based cohort study. SETTING: Japan Public Health Centre-based Prospective Study, which includes 11 public health centre areas in Japan. PARTICIPANTS: 92 915 participants (42 750 men and 50 165 women) aged 45 to 74 years. EXPOSURES: Intake of total soy products, fermented soy products (natto and miso), non-fermented soy products, and tofu from a five year survey questionnaire. MAIN OUTCOME MEASURES: All cause and cause specific mortality (cancer, total cardiovascular disease, heart disease, cerebrovascular disease, respiratory disease, and injury) obtained from residential registries and death certificates. RESULTS: During 14.8 years of follow-up, 13 303 deaths were identified. In the multivariable adjusted models, intake of total soy products was not significantly associated with total mortality. Compared with the lowest fifth of total soy product intake, the hazard ratios in the highest fifth were 0.98 (95% confidence interval 0.91 to 1.06, Ptrend=0.43) in men and 0.98 (0.89 to 1.08, Ptrend=0.46) in women. Intake of fermented soy products was inversely associated with all cause mortality in both sexes (highest versus lowest fifth: 0.90 (0.83 to 0.97), Ptrend=0.05 in men, and 0.89 (0.80 to 0.98), Ptrend=0.01 in women). Natto showed significant and inverse associations with total cardiovascular disease related mortality in both sexes. CONCLUSIONS: In this study a higher intake of fermented soy was associated with a lower risk of mortality. A significant association between intake of total soy products and all cause mortality was not, however, observed. The findings should be interpreted with caution because the significant association of fermented soy products might be attenuated by unadjusted residual confounding.

Dairy, soy, and calcium consumption and risk of cognitive impairment: the Singapore Chinese Health Study.

PURPOSE: It is unclear if midlife consumption of dairy and soy food intake, and their components of calcium and isoflavones (in soy), is related to cognitive impairment in elderly. METHODS: We used baseline data on lifestyle and habitual diet of 16,948 participants collected during their recruitment into the Singapore Chinese Health Study from 1993 to 1998, and data on their cognitive function, measured using a 30-item Singapore modified Mini-Mental State Examination, during follow-up interviews from 2014 to 2016. We used multivariable logistic regression models to estimate the odds ratios (ORs) and 95% confidence intervals (CIs) for developing cognitive impairment. RESULTS: Higher dairy intake was associated with a lower risk of cognitive impairment in a dose-dependent manner (P for trend = 0.009). Compared to the lowest quartile of dairy intake, ORs (95% CIs) were 0.93 (0.81-1.07) for the second, 0.88 (0.76-1.01) for the third, and 0.82 (0.72-0.94) for the fourth quartiles of intake. Similar results were found for dairy calcium intake (P for trend = 0.008). However, there was no statistically significant association for intake of soy (OR comparing extreme quartiles 0.99, 95% CI 0.87-1.14, P for trend = 0.92), isoflavones (OR 1.01, 95% CI 0.88-1.15, P for trend = 0.90) or non-dairy calcium (OR 1.06, 95% CI 0.86-1.30, P for trend = 0.81) with risk of cognitive impairment. CONCLUSIONS: Dairy intake at midlife could have a protective association against cognitive impairment that may not be attributed to its calcium content alone, while soy or isoflavone intake was not associated with the cognition of elderly in our study.

High soy isoflavone or soy-based food intake during infancy and in adulthood is associated with an increased risk of uterine fibroids in premenopausal women: a meta-analysis.

Numerous studies have examined the association of soy isoflavones or soy-based food intake with the risk of uterine fibroids (UF), but the results are inconsistent. The purpose of this meta-analysis was to quantitatively assess whether high soy isoflavones intake is associated with an increased risk of UF. PUBMED and EMBASE databases were reviewed to screen for relevant published studies up to December 2018. Using key words of uterine fibroid and isoflavone, we identified 4 studies focusing on infancy intake and 7 studies evaluating intake during adulthood. The pooled odds ratio (OR) and corresponding 95% confidence interval (95% CI) were calculated using a random-effect model. In addition, subgroup analyses and 2-stage random-effect dose-response were also performed. When comparing high vs low intake of soy isoflavones, we found that there were positive associations of UF among patients being fed soy formula during infancy (OR, 1.19; 95% CI, 0.99-1.43; P = .06) and with high consumption of soy-based foods in adulthood (OR, 2.50; 95% CI, 1.09-5.74; P = .03), respectively. Additionally, dose-response analysis showed the pooled ORs (95% CIs) of UF risk for low, moderate, and high intake of soy isoflavones were 1.00 (0.87-1.14), 1.08 (0.94-1.24), and 1.23 (0.99-1.53) when compared to occasional intake, respectively. Our findings suggest that high soy isoflavones or soy-based food intake during infancy and in adulthood is associated with an increased risk of uterine fibroids in premenopausal women. There is a need for large-scale prospective cohort studies using more accurate measurements of soy isoflavones to further ascertain our study findings.

Soy intake and vasomotor menopausal symptoms among midlife women: a pooled analysis of five studies from the InterLACE consortium.

BACKGROUND/OBJECTIVES: Phytoestrogen rich-foods such as soy may be associated with less frequent/severe vasomotor menopausal symptoms (VMS), although evidence is limited. We thus investigated the associations between the consumption of soy products and soy milk and the frequency/severity of VMS. SUBJECTS/METHODS: We pooled data from 19,351 middle-aged women from five observational studies in Australia, UK, USA, and Japan that contribute to the International Collaboration for a Life course Approach to reproductive health and Chronic disease Events (InterLACE). Information on soy consumption, VMS and covariates were collected by self-report. We included 11,006 women who had complete data on soy consumption, VMS and covariates at baseline for the cross-sectional analysis. For the prospective analysis, 4522 women who were free of VMS at baseline and had complete data on VMS at follow-up were considered. Multinomial logistic regression and binary logistic regression models were used. RESULTS: No statistically significant evidence of an association was found between soy products (relative risk ratio (RRR): 0.92, 95% CI: 0.76-1.11) or soy milk (RRR: 1.24, 95% CI: 0.93-1.65) and the likelihood of reporting frequent or severe VMS cross-sectionally. Prospective results indicated that frequent consumption of soy products (odds ratio (OR): 0.63, 95% CI: 0.45-0.89) but not soy milk (OR: 1.11, 95% CI: 0.85-1.45) was associated with lower likelihood of reporting subsequent VMS, after adjustment for socio-demographic and reproductive factors. CONCLUSIONS: These are the first ever findings from pooled observational data of association between consumption of soy products and VMS.

Acceptability and consumption of tofu as a meat alternative among secondary school boarders in Enugu State, Nigeria: Implications for nutritional counseling and education.

Tofu, a food made of condensed soymilk that originated in China, has both nutritional and health benefits. The main objective of this study was to determine the acceptability and consumption of tofu as a meat alternative among students in boarding secondary schools in Enugu State, Nigeria.In this study, the authors adopted a cross-sectional analytic design. A representative sample of 603 adolescents in the boarding secondary schools took part in the study. Power analysis was conducted to estimate the appropriate sample size for the current study. Correlations analysis, moderation analysis, χ, analysis of variance (ANOVA), and t tests were employed for the analysis of the data.Students' acceptance of the 3 cooking options of tofu (steamed, boiled, and fried) did not significantly differ by gender. It was found that 94.5% of the respondents recognized the benefits of tofu; there is no significant difference between the male and female students on the extent to which they would eat tofu in school; the recognition of benefits of tofu is not significantly associated with acceptance of steamed, boiled, and fried tofu among the students; and the recognition of benefits of tofu is not significantly associated with consumption of tofu among the students. The finding further revealed that gender did not significantly moderate the association between recognition of benefits of tofu and students' acceptability of tofu. Also, it was found that gender did not significantly moderate the association between recognition of benefits of tofu and consumption of tofu among students.Further research is needed to identify the level of tofu acceptability and consumption among adolescents in boarding secondary schools in other states of Nigeria. Further research on factors influencing how recognition of benefits of tofu is associated with its acceptability among the Nigerian student population can have implications for nutritional counseling and regional health.

A J-shaped association between soy food intake and depressive symptoms in Chinese adults.

BACKGROUND & AIMS: Soy food has been proven to have multiple positive effects on human health, however, no study has yet investigated the association between habitual intake of soy food and depressive symptoms in general population. The objective of this study was to examine this association. METHODS: In a cross-sectional analysis, we studied a sample of 13,760 adults (mean age 43.5 years) in Tianjin, China. The Self-Rating Depression Scale (SDS) was used to assess depressive symptoms, with four cut-off points (SDS ≥40, 45, 48 or 50) indicating increased level of depressive symptoms. Food Frequency Questionnaire (FFQ) was used to assess dietary intake. RESULTS: In the total population, the prevalence of increased depressive symptoms was 7.2% (SDS ≥50). Comparing to the group with lowest intake frequency of soy food (

Association between consumption of soy and risk of cardiovascular disease: A meta-analysis of observational studies.

Background The relationships between dietary intake of soy foods and risk of cardiovascular disease are uncertain. The aims of this study were to evaluate and summarize the evidence on the association between consumption of soy and risk of cardiovascular disease (including stroke and coronary heart disease). Methods We systematically searched the MEDLINE and EMBASE databases from their inception up to 22 February 2016. We included only observational studies, and used random-effects models to calculate summary relative risks (SRRs) and 95% confidence intervals (CIs). Results A total of 10 prospective cohort and seven case-control studies met the inclusion criteria. There were a total of 17,269 cardiovascular disease events, including 6265 stroke events, 10,806 coronary heart disease events, and 198 other cardiovascular disease events. A significant negative association was shown between soy intake and risk of cardiovascular disease (SRR = 0.84 95% CI: 0.75-0.94; pheterogeneity<0.001, I2 = 71.4%). Subgroup meta-analyses indicated that a statistically significant protective effect was primarily observed in case-control studies and in Asian populations. There was a borderline significant association between intake of tofu and the risk of cardiovascular disease (SRR = 0.80, 95% CI: 0.64-1.00). A significant negative association was shown for the association between soy intake and risk of stroke (SRR = 0.82, 95% CI: 0.68-0.99) and coronary heart disease (SRR = 0.83, 95% CI: 0.72-0.95). There were no associations between soy isoflavones consumption and risk of cardiovascular disease, stroke, and coronary heart disease. Conclusion Overall evidence indicated that consumption of soy was negatively associated with the risk of cardiovascular disease, stroke, and coronary heart disease risk.

Soy-based Infant Formula Feeding and Heavy Menstrual Bleeding Among Young African American Women.

BACKGROUND: Phytoestrogen exposure from soy formula feeding during infancy may disrupt reproductive system development, resulting in altered menstrual bleeding in adulthood. METHODS: We investigated this relationship in a cohort of 1,696 young African American women using enrollment data from the Study of Environment, Lifestyle, & Fibroids (2010-2012). Questionnaire data on soy formula feeding were available for 1,553 participants, 89% based on mother's report. Menstrual bleeding outcomes including those indicative of heavy menstrual bleeding were ascertained by interview. We estimated relative risks (RRs) and 95% confidence intervals (CI) for associations between soy formula feeding and menstrual bleeding outcomes using log-binomial regression and log-multinomial regression, comparing participants ever fed and never fed soy formula. RESULTS: We observed associations between soy formula feeding and variables indicating a history of heavy menstrual bleeding, including ever experiencing heavy, gushing-type bleeding (RR: 1.2, 95% CI: 1.0, 1.4), ever use of nonsteroidal anti-inflammatory drugs for heavy bleeding (RR: 1.3, 95% CI: 1.0, 1.6), and ever use of a contraceptive method for heavy bleeding (RR: 1.2, 95% CI, 0.9, 1.6). Among the subset of participants with menses in the past year who did not use medication that may alter menstrual flow (n = 762), our data suggested that soy formula feeding was associated with heavier flow and the adverse impact of menstrual bleeding on quality of life, but CIs were wide. CONCLUSIONS: Our data suggested that soy formula feeding is associated with heavy menstrual bleeding. Our results support the idea that infancy is a susceptible developmental window for female reproductive function.

Large inter-individual variation in isoflavone plasma concentration limits use of isoflavone intake data for risk assessment.

BACKGROUND/OBJECTIVES: Isoflavones are present in soy foods and soy-based supplements. Despite low plasma isoflavone concentrations in the general Western population, concentrations in supplement users exceed those suggested to be beneficial for health in Asian populations, raising concerns for adverse effects. To aid risk assessment, quantification of the relation between isoflavone intake and plasma concentrations is essential. SUBJECTS/METHODS: Plasma samples were collected from postmenopausal women in three placebo-controlled crossover studies with 8-week periods for supplements (two studies, ~100 mg isoflavones/day, n=88) or 4-week periods for soy foods (one study, ~48 mg isoflavones/day, n=15). Plasma isoflavone concentrations (daidzein, equol, genistein and glycitein) were quantified using high-performance liquid chromatography and electrochemical detection. The association between plasma concentrations and isoflavone intake, equol producer status, intake-producer interaction and background dietary intake was assessed based on the assumption of a log-linear relation. RESULTS: Median plasma total isoflavone concentrations after the soy food and supplement interventions were respectively 2.16 and 3.47 µmol/l for equol producers and 1.30 and 2.39 µmol/l for non-producers. Regression analysis showed that doubling isoflavone intake increased plasma concentrations by 55-62% (±s.e. 1-2%, R(2)>0.87) for daidzein, genistein, equol (only for producers) and total isoflavones; for glycitein the association was weaker (15±1%, R(2)=0.48). Adjustments for energy, carbohydrate and fat intake did not affect these estimates. Inter-individual variation, estimated based on repeated measures in one of the studies, was 30-96%. CONCLUSIONS: Although the relation between isoflavone intake and plasma concentrations was adequately quantified, the use of isoflavone intake data for risk assessment needs caution due to large inter-individual variation in plasma concentrations.

Dispelling myths about a new healthful food can be more motivating than promoting nutritional benefits: the case of Tofu.

OBJECTIVE: This study examines what factors impact the adoption of certain types of healthy foods, such as Tofu, by future nutritional gatekeepers. DESIGN: Information on perceived facilitators and barriers to the utilization of barriers would be obtained via interviews and surveys. SETTING: In-depth laddering interviews and an online survey during 2012 were utilized. SUBJECTS: The in-depth laddering interviews were conducted with 83 young women and new mothers (non-vegetarians and non-Asians) who were enthusiastic lovers of Tofu. 502 women from the target demographic (between 20 and 35, non-Asian) were recruited from a national panel and surveyed online in 2012. RESULTS: Based on the interviews, 21 primary reasons for trying Tofu (facilitators) and 10 reasons that might be preventative (barriers) were identified. A key finding was that facilitators were not motivating factors for why women adopted Tofu into their diets. Instead, barriers explained more than 44% of the variance for not adopting tofu. CONCLUSIONS: When encouraging nutritional gatekeepers to add Tofu to their household diets, it may be more effective to focus on changing the barriers. This study suggests that nutritionists and health practitioners may be more successful in encouraging the adoption of healthy new foods by dispelling their misconceptions rather than focusing on their nutritional benefits.

Soy food consumption and breast cancer.

Breast cancer is the most frequently diagnosed cancer in female worldwide and occurs as an interaction of genes and diet. As regards diet numerous studies all over the world have associated the disease with many foods and nutrients including soy and its compounds. Soy food and soy products are rich in phytoestrogens, naturally occurring hormone-like compounds with weak estrogenic effects. Despite inconsistencies in the available data, an inverse association between soy food consumption and breast cancer is likely. However, it seems that this correlation is more obvious in Asian rather than Western populations, where the consumption of soy is already higher. Moreover, the vast majority of studies that demonstrate this inverse association are case-control studies, a fact that should be taken into account. In this review, the current scientific evidence relating breast cancer and soy consumption is reported through a systematic way.

Intake of soy products and other foods and gastric cancer risk: a prospective study.

BACKGROUND: Gastric cancer, the most common cancer in the world, is affected by some foods or food groups. We examined the relationship between dietary intake and stomach cancer risk in the Korean Multi-Center Cancer Cohort (KMCC). METHODS: The KMCC included 19 688 Korean men and women who were enrolled from 1993 to 2004. Of those subjects, 9724 completed a brief 14-food frequency questionnaire at baseline. Through record linkage with the Korean Central Cancer Registry and National Death Certificate databases, we documented 166 gastric cancer cases as of December 31, 2008. Cox proportional hazard models were used to estimate relative risks (RRs) and 95% CIs. RESULTS: Frequent intake of soybean/tofu was significantly associated with reduced risk of gastric cancer, after adjustment for age, sex, cigarette smoking, body mass index, alcohol consumption, and area of residence (P for trend = 0.036). We found a significant inverse association between soybean/tofu intake and gastric cancer risk among women (RR = 0.41, 95% CI: 0.22-0.78). Men with a high soybean/tofu intake had a lower risk of gastric cancer, but the reduction was not statistically significant (RR = 0.77, 95% CI: 0.52-1.13). There was no interaction between soybean/tofu intake and cigarette smoking in relation to gastric cancer risk (P for interaction = 0.268). CONCLUSIONS: Frequent soybean/tofu intake was associated with lower risk of gastric cancer.

Prediagnosis soy food consumption and lung cancer survival in women.

PURPOSE: We recently reported an inverse association between soy food intake and lung cancer risk among nonsmoking women. The effect size for aggressive lung cancers was larger than that observed for other types of lung cancer. Therefore, we hypothesized that soy consumption may favorably affect the overall survival of patients with lung cancer. PATIENTS AND METHODS: This analysis included 444 women with incident lung cancer identified from the Shanghai Women's Health Study. Prediagnosis soy food intake was assessed at enrollment and reassessed 2 years later. Proportional hazards models were used to evaluate the association between soy food intake and overall survival. RESULTS: Of the 444 patients with lung cancer, 318 died during follow-up. Initial analyses including all patients showed that higher intake of soy food was associated with better overall survival after adjusting for demographic and lifestyle characteristics and other nonclinical factors. Larger effect sizes for the association were found after additional adjustment for tumor stage and treatment in analyses including 301 patients with data available on these clinical factors. Compared with the median intake of soy food, fully adjusted hazard ratios for total mortality associated with the 10th, 30th, 70th, and 90th percentiles of intake were 1.81 (95% CI, 1.26 to 2.59), 1.25 (95% CI, 1.09 to 1.42), 0.88 (95% CI, 0.80 to 0.97), and 0.89 (95% CI, 0.68 to 1.16), respectively. Similar inverse associations were observed for dietary isoflavone intake. CONCLUSION: This study suggests, to the best of our knowledge for the first time, that, among women with lung cancer, prediagnosis intake of soy food is associated with better overall survival.

Soy food intake and risk of lung cancer: evidence from the Shanghai Women's Health Study and a meta-analysis.

The authors prospectively evaluated the association of soy food intake with lung cancer risk, overall and by tumor aggressiveness, and performed a meta-analysis of published data. Included in the analysis were 71,550 women recruited into the Shanghai Women's Health Study (Shanghai, China) in 1997-2000. Usual soy food intake was assessed at baseline and reassessed during follow-up through in-person interviews. During a mean follow-up period of 9.1 years, 370 incident lung cancer cases were identified; 340 patients were lifetime never smokers. After adjustment for potential confounders, soy food intake was inversely associated with subsequent risk of lung cancer (P(trend) = 0.004); the hazard ratio for the highest quintile of intake compared with the lowest was 0.63 (95% confidence interval: 0.44, 0.90). This inverse association appeared predominately among women with later age at menopause (P(interaction) = 0.01) and for aggressive lung cancer as defined by length of survival (<12 months vs. ≥12 months; P(heterogeneity) = 0.057). Meta-analysis of 7 studies conducted among nonsmokers found a summary relative risk of 0.59 (95% confidence interval: 0.49, 0.71) for the highest categories of soy or isoflavone intake versus the lowest. This study suggests that soy food consumption may reduce lung cancer risk in nonsmoking women, particularly for aggressive tumors, and its effect may be modified by endogenous estrogens.