Soy product intake and hot flashes in Japanese women: results from a community-based prospective study

The association between soy product intake and the occurrence of hot flashes was examined in a cohort of 1,106 female residents of Takayama, Gifu, JAPAN: The women were aged 35-54 years and premenopausal at their entry into the study in 1992. Diet, including intake of soy products and isoflavones, was assessed by means of a validated semiquantitative food frequency questionnaire at study entry. A follow-up mail questionnaire asking about experiences of hot flashes was sent in 1998. During the 6 years of the study period, 101 women had new moderate or severe hot flashes according to the Kupperman test of menopausal distress. After data were controlled for age, total energy intake, and menopausal status, hot flashes were significantly inversely associated with consumption of soy products in terms of both total amount (highest tertile of soy product intake (g/day) vs. lowest: hazard ratio = 0.47; 95% confidence interval: 0.28, 0.79; p for trend = 0.005) and isoflavone intake (highest tertile of isoflavone intake (mg/day) vs. lowest: hazard ratio = 0.42; 95% confidence interval: 0.25, 0.72; p for trend = 0.002). These data suggest that consumption of soy products has a protective effect against hot flashes.     

Soy isoflavone intake is not associated with the development of cedar pollinosis in adults

Although soy isoflavone has been suggested to have both immune-enhancing and immune-suppressive effects, the effects of soy isoflavone intake on allergic disorders are unclear. A cross-sectional study indicated that a high intake of soy isoflavone is associated with a decreased risk of allergic rhinitis. We aimed to prospectively examine the relationship between soy isoflavone intake and risk of cedar pollinosis, the most common seasonal allergic rhinitis in Japan. The study was conducted in a population-based cohort of Japanese men and women. Each subject's usual diet, including soy isoflavone intake, was determined with the use of a validated FFQ in 1992. In 2002, a total of 11,229 persons who were 35-69 y old and had no history of cancer or allergic diseases at the baseline responded to a follow-up questionnaire asking about 4 symptoms related to cedar pollinosis. Cox hazard regression model was used to determine the association between soy isoflavone intake and the risk of cedar pollinosis. During the 10-y follow-up, 931 of these subjects reported that they had cedar pollinosis. There was no significant association between soy isoflavone intake and risk of cedar pollinosis in men and women after controlling for covariates. For the highest compared with the lowest quartile of soy isoflavone intake, hazard ratios were 1.07 (95% CI: 0.81-1.42) in men and 0.89 (95% CI: 0.68-1.15) in women. These data did not support an association between soy isoflavone intake and risk of cedar pollinosis.     

Soy product consumption and the risk of colon cancer: a prospective study in Takayama, Japan

The relationship of the intake of soy products and the incidence of colon cancer was prospectively evaluated in a population-based cohort study in Japan. The total intake of soy products and isoflavones in a daily diet was estimated from a validated questionnaire administered at the baseline. The participation rate of the questionnaire was 92.0%. The participants were followed from 1992 to 2000, and colon cancer diagnoses were identified at the main hospitals in the study area. In the analysis, 13,894 men and 16,327 women were included. The medians for energy-adjusted soy product intake were 85.52 g/day for men and 79.60 g/day for women. During follow-up, 111 men and 102 women were diagnosed with colon cancer. A Cox-proportional hazard model was applied to assess the risk of colon cancer incidence. Among women, the risk was reduced with an increased soy product consumption; the hazard ratio in the highest tertile was 0.56 (95% CI 0.34-0.92) compared as the lowest tertile (trend: P=0.04), after adjusting for multiple potential confounders. Among men, no significant association was observed. Our results exhibited the weak benefit of soy foods only among women. Further research to confirm our results may be beneficial.     

Soy Product Consumption and the Risk of Colon Cancer: A Prospective Study in Takayama,Japan

The relationship of the intake of soy products and the incidence of colon cancer was prospectively evaluated in a population-based cohort study in Japan. The total intake of soy products and isoflavones in a daily diet was estimated from a validated questionnaire administered at the baseline. The participation rate of the questionnaire was 92.0%. The participants were followed from 1992 to 2000, and colon cancer diagnoses were identified at the main hospitals in the study area. In the analysis, 13,894 men and 16,327 women were included. The medians for energy-adjusted soy product intake were 85.52 g/day for men and 79.60 g/day for women. During follow-up, 111 men and 102 women were diagnosed with colon cancer. A Cox-proportional hazard model was applied to assess the risk of colon cancer incidence. Among women, the risk was reduced with an increased soy product consumption; the hazard ratio in the highest tertile was 0.56 (95% CI 0.34–0.92) compared as the lowest tertile (trend: P = 0.04), after adjusting for multiple potential confounders. Among men, no significant association was observed. Our results exhibited the weak benefit of soy foods only among women. Further research to confirm our results may be beneficial.     

Soy and fish oil intake and mortality in a Japanese community

The relation between intake of fish and soy products and subsequent all-cause and cause-specific mortality was examined in a cohort of 13,355 male and 15,724 female residents of Takayama, Gifu, Japan. A diet that included soy and fish intake was assessed in 1992 by using a validated semiquantitative food frequency questionnaire. Over 7 years of follow-up, 2,062 participants (1,163 men and 899 women) died. For men, the highest compared with the lowest quintile of total soy product intake was marginally significantly inversely associated with total mortality after adjustment for total energy and nondietary covariates (hazard ratio = 0.83, 95% confidence interval: 0.69, 1.01; p for trend = 0.07). After adjustment for nondietary covariates, a decreased hazard ratio for the highest compared with the lowest quintile of total soy product intake was also observed for women (hazard ratio = 0.83, 95% confidence interval: 0.68, 1.02; p for trend = 0.04). Additional adjustment for dietary factors significantly associated with total mortality did not attenuate these associations. For women but not for men, n-3 fatty acids from fish were significantly inversely associated with total mortality. Results showed that soy intake may have moderate but beneficial effects on total mortality.     

Soy product intake is inversely associated with serum homocysteine level in premenopausal Japanese women

Soybeans, which are an excellent source of folate, vitamin B-6 and minerals, may reduce serum homocysteine level. However, there is a possibility that dietary soy raises the serum homocysteine level because isoflavones, which are weak estrogens contained in soybeans, may exert antiestrogenic effects in a high estrogen environment, such as in premenopausal women. The present study examined a cross-sectional relationship between soy product intake and serum homocysteine level in 201 premenopausal Japanese women. Intakes of soy products, folate, methionine and vitamins B-6 and B-12 were estimated by a semiquantitative food frequency questionnaire. Folate status was also assessed by measuring serum folate. Soy product intake in terms of soy protein as well as soy isoflavone intake was modestly but significantly inversely associated with serum homocysteine level (r = -0.15, P = 0.04) after controlling for covariates. Soy product intake was also significantly positively correlated with serum folate (r = 0.15, P = 0.04). Although it is unclear the extent to which each component of soy, such as folate and isoflavones, is associated with the serum homocysteine concentration, this biochemical complex appears to have a favorable effect on homocysteine metabolism in premenopausal women.     

Association between Soy Food and Dietary Soy Isoflavone Intake and the Risk of Cardiovascular Disease in Women: A Prospective Cohort Study in Korea

The association between soy food and soy isoflavone intake and cardiovascular disease (CVD) risk is uncertain, especially in women. We aimed to investigate this association in Korean women. We analyzed data from the Korean Genome and Epidemiology Study, including 4713 Korean women aged 40–69 years with no CVD or cancer at baseline. Dietary information was obtained using a validated semi-quantitative food frequency questionnaire, and the incidence of CVD was assessed using biennial self-reported questionnaires on medical history. The mean follow-up time was 7.4 years, during which 82 premenopausal and 200 postmenopausal women reported CVD incidence. The highest tofu, total soy foods, and dietary soy isoflavone intake groups were significantly associated with a decreased CVD risk in premenopausal women (tofu: hazard ratio (HR) 0.39; 95% confidence interval (CI), 0.19–0.80; total soy food: HR 0.36; 95% CI, 0.18–0.70; dietary soy isoflavones: HR 0.44; 95% CI, 0.22–0.89), whereas no association was observed in postmenopausal women. Other soy foods showed no association with CVD incidence. Dietary soy isoflavones and total soy foods are associated with a decreased CVD risk in premenopausal women. Among soy foods, only tofu showed significant health benefits.     

Development of a soy food frequency questionnaire to estimate isoflavone consumption in US adults.

OBJECTIVE: To develop a dietary assessment instrument to measure soy food consumption and isoflavone intake and test it for reliability. DESIGN: A soy food frequency questionnaire, designed for use in this study, was administered twice to participants, separated by a 2-week interval. The questionnaire was tested for reproducibility of estimates of soy food consumption and isoflavone (genistein and daidzein) intake. SUBJECTS/SETTING: A convenience sample of 51 faculty, staff, and students was recruited from a naturopathic university. STATISTICAL ANALYSES PERFORMED: Intraclass correlation coefficients were used to assess reproducibility of estimates of soy food intake and genistein and daidzein intake. RESULTS: Correlation coefficients comparing mean soy food servings per month between the 2 administrations of the questionnaire ranged from 0.50 for soy yogurt to 0.89 for tempeh. Correlation coefficients for genistein and daidzein intake estimated by the 2 administrations of the questionnaire were the same: 0.89. Mean intake (+/- standard deviation) of genistein and daidzein was 7 +/- 10 and 4 +/- 6 mg/day, respectively. Fifteen soy foods contributed 95% of the total genistein and daidzein intake: tofu, soy yogurt, tempeh, soy milk, low-fat tofu, soy flour, miso, soy protein isolate, low-fat soy milk, veggie soy burger, textured vegetable protein, miso soup, cooked soybeans, soy hot dogs, and natto (fermented soy beans). APPLICATIONS: The soy food frequency questionnaire developed in this study provided highly reproducible estimates of soy food consumption and isoflavone intake. This instrument may be a useful tool in studies of the associations between isoflavone exposure and risk for chronic disease.     

Nutritional Epidemiology of Type 2 Diabetes and Depressive Symptoms

In Japan, the prevalences of type 2 diabetes and depression are increasing, but evidence linking these diseases to diet is limited. The present study reviewed the association of type 2 diabetes with intakes of rice, fish/seafood, and soy product and isoflavone, and the association of depressive symptoms with folate, vitamin D, and dietary pattern, in the Japanese population. The analysis of type 2 diabetes comprised around 55 000 men and women aged 45 to 75 years who completed a questionnaire for the Japan Public Health Center-based Prospective Study and were free of type 2 diabetes at baseline. The odds ratio of self-reported physician-diagnosed type 2 diabetes during the subsequent 5 years increased with rice intake among women and among physically inactive men but decreased with total fish/seafood intake among men. In addition, risk tended to decrease with soy product and isoflavone intake among overweight and postmenopausal women. Depressive symptoms were assessed using the Center for Epidemiologic Studies Depression Scale. The participants were approximately 530 workers aged 21 to 67 years who participated in a health survey at the time of a periodic health check. A cross-sectional and prospective inverse association between serum folate and depressive symptoms was observed. Serum 25-hydroxyvitamin D level was suggestively associated with decreased prevalence of depressive symptoms in late autumn. In addition, a healthy Japanese pattern—characterized by high intakes of vegetables, fruit, mushrooms, and soy products—was inversely associated with depressive symptoms. The findings suggest that diet has a role in the development of type 2 diabetes and depression in Japanese.Key words: depressive symptoms, diet, Japanese, type 2 diabetes     

Association of diet with the onset of menopause in Japanese women

A prospective study was conducted in Takayama, Gifu, Japan, to evaluate the association between diet and the onset of menopause. A total of 1,130 female residents aged 35-54 years who were premenopausal and completed a validated semiquantitative food frequency questionnaire in 1992 were contacted by mail with a follow-up questionnaire in 1998 to update information on menopause. Onset of menopause was defined as a woman's age at the last menstrual period prior to stopping menstruation for 12 months. During the 6-year study period, 296 women experienced natural menopause. The Cox proportional hazards model was used to estimate hazard ratios of the onset of menopause after controlling for age, total energy, body mass index, years of smoking, and age at which regular menstrual cycle began. The authors found that green and yellow vegetable intake was significantly inversely associated with the 6-year incidence of menopause (hazard ratio = 0.71, 95% confidence interval: 0.54, 0.95 for the highest vs. lowest tertile of intake, p for trend = 0.02). Association of carotene intake with the incidence of menopause was of borderline significance (hazard ratio = 0.78, 95% confidence interval: 0.59, 1.04, p for trend = 0.07).     

Validation of a soy questionnaire with repeated dietary recalls and urinary isoflavone assessments over one year

This study assessed the validity and reliability of a 12-item soy questionnaire designed for use in cancer prevention research. The questionnaire measures soy intake over the past year. Subjects were 199 healthy 35- to 46-yr-old premenopausal women participating in an ongoing soy intervention study. Soy questionnaire estimates of isoflavone intake over 1 yr were compared with individual and combined estimates from two reference measures covering the same period: three or four repeated 24-h recalls and one or two repeated urine analyses. The sensitivity and specificity of the soy questionnaire in classifying high vs. low exposure (high exposure = soy intervention group membership) were comparable with 24-h recalls and were superior to urine analyses (sensitivity = 94.8%, 97.9%, and 71.1%; specificity = 95.1%, 97.1%, and 90.3% for the soy questionnaire, 24-h recalls, and urine analyses, respectively). Soy questionnaire isoflavone estimates were highly correlated with the combination of the two reference measures for the entire study population. Its brevity, ease of administration, and good measurement properties over a 1-yr period make the soy questionnaire well suited to the needs of researchers who wish to identify high and low consumers of soy foods, especially in populations who consume traditional Asian soy foods.     

Differential influence of dietary soy intake on the risk of breast cancer recurrence related to HER2 status

The effects of soy products and isoflavone on breast cancer recurrence were compared according to receptor status including epidermal growth factor receptor-2 (HER2) with 339 Korean women. Dietary intake of soy foods was assessed using a validated food frequency questionnaire with 103 food items. Twenty-five patients experienced breast cancer recurrence, 17 patients were HER2 negative, and 8 patients were HER2 positive. Legume intake (mostly from black soybeans) was inversely associated with the risk of breast cancer recurrence in HER2 negative cancer patients (HR: 0.27, 95% CI: 0.13-0.57, P for trend < 0.01), whereas legume intake was positively associated in HER2 positive cancer patients (P for trend = 0.02). In HER2 negative cancer patients, isoflavone was inversely associated with breast cancer recurrence (HR: 0.23, 95% CI: 0.06-0.89; P for trend = 0.01). Total soy intake was not associated with an increased risk of cancer recurrence. In conclusion, overall soy food intake might not affect the risk of cancer recurrence, but high intake of soy isoflavones increased the risk of cancer recurrence in HER2-positive breast cancer patients. However, further research is needed to confirm these results due to the small number of cancer recurrence events.     

Reproductive factors, hormonal contraception, and risk of uterine leiomyomata in African-American women: a prospective study

The authors assessed the risk of uterine leiomyomata in relation to reproductive factors and hormonal contraception in a prospective cohort study of US Black women. From March 1997 through March 2001, the authors followed 22,895 premenopausal women with intact uteri and no prior self-reported diagnosis of uterine leiomyomata. The authors used age- and time-stratified Cox regression models to estimate incidence rate ratios for self-reported uterine leiomyomata, confirmed by ultrasound or hysterectomy, in association with selected reproductive and hormonal factors. During 76,711 person-years of follow-up, 2,279 new cases of ultrasound- or hysterectomy-confirmed uterine leiomyomata were self-reported. After adjustment for age, body mass index, smoking, alcohol intake, and other reproductive covariates, the risk of ultrasound- or hysterectomy-confirmed leiomyomata was inversely associated with age at menarche, parity, and age at first birth and positively associated with years since last birth. Overweight or obesity appeared to attenuate the inverse association between parity and uterine leiomyomata. Current use of progestin-only injectables was inversely associated with risk. No consistent patterns were observed for other forms of hormonal contraception. Reproductive history is an important determinant of leiomyomata risk in premenopausal US Black women. Progestin-only injectables may reduce risk.     

Intake of animal products and stroke mortality in the Hiroshima/Nagasaki Life Span Study

BACKGROUND: To determine whether intake of animal products was associated with a reduced risk of stroke mortality in a large-scale population-based cohort in Japan. METHODS: A self-administered questionnaire, including questions on dietary habits, was mailed to the members of the Life Span Study, a cohort of people exposed and non-exposed to atomic bomb radiation, who were alive as of 1 September 1979. Animal products included frequency intake of beef/pork, chicken, ham/sausage, milk, dairy products, eggs, fish, and broiled fish. Responses were obtained from 40 349 people (72%): 15 350 men (mean age 54 years) and 24 999 women (mean age 58 years). The subjects were followed for 16 years, and deaths were ascertained by linkage to the nationwide family registration system of Japan. The associations between diet and stroke mortality were examined using a Cox proportional hazard model. RESULTS: During the follow-up period, 1462 stroke deaths occurred. Four animal products comprising eggs, dairy products, fish, and broiled fish were independently associated with a decreased risk of stroke mortality; while beef/pork, chicken, ham/ sausage, and milk consumption were not associated with stroke death. A composite measure of eggs, dairy products, fish, and broiled fish intake was calculated, and the highest tertile was significantly inversely associated with total stroke mortality (Hazards Ratio [HR] = 0.80, 95% CI: 0.68, 0.93) compared with the lowest tertile. The protective effect of animal product intake on total stroke death was largely confined to intracerebral haemorrhage death; the RH of intracerebral haemorrhage death for the highest tertile of consumption was 0.72 (95% CI: 0.53-0.98) compared with the lowest tertile; animal products intake was not related to cerebral infarction mortality (HR = 0.84; 95% CI: 0.67-1.06). CONCLUSIONS: Intake of animal products such as eggs, dairy products, and fish may be protective against intracerebral haemorrhage, but is not related to cerebral infarction mortality.     

Validation of a soy food-frequency questionnaire and evaluation of correlates of plasma isoflavone concentrations in postmenopausal women

BACKGROUND: Soy foods may have various health benefits, but little is known about the patterns and correlates of soy consumption among postmenopausal women in the United States. OBJECTIVE: We assessed the reliability and validity of a soy food-frequency questionnaire (FFQ) and examined demographic, lifestyle, and dietary correlates of plasma isoflavone concentrations in postmenopausal women. DESIGN: In this cross-sectional study, soy isoflavone intake and plasma isoflavone concentration were analyzed in 96 postmenopausal women aged 50-79 y; the data were obtained at 2 visits that were 1 wk apart. Intake was determined with a 20-item soy FFQ and a comprehensive FFQ that included questions about tofu and soymilk. Fasting plasma daidzein and genistein concentrations were determined with liquid chromatography-mass spectrometry. RESULTS: Intraclass correlations between week 1 and week 2 values were >0.98 for both the soy and comprehensive FFQs. Median reported isoflavone intake was <2 mg/d. Pearson's product-moment correlation coefficients relating isoflavone intakes with plasma isoflavone concentrations ranged from 0.35 to 0.43. Plasma isoflavone concentrations were positively associated with age, fiber consumption, servings of fruit and vegetables, and dietary supplement use and were inversely associated with caffeine consumption; no associations with body mass index, education, dietary beliefs, activity level, alcohol intake, or fat intake were observed. CONCLUSIONS: Within a population with low soy consumption, the soy FFQ and comprehensive FFQ showed good reliability and moderate validity. Associations of plasma isoflavone concentrations with other dietary behaviors suggest that these compounds may serve as biomarkers of health behaviors in populations with low soy consumption.     

Inverse association of soy product intake with serum androgen and estrogen concentrations in Japanese men

The cross-sectional relationships of soy product intake and serum testosterone, estrone, estradiol, sex hormone-binding globulin, and dihydrotestosterone were examined in 69 Japanese men. Soy product intake was estimated from a semiquantitative food frequency questionnaire. Serum estradiol concentration was significantly inversely correlated with soy product intake (r = -0.32, p = 0.009), and serum estrone concentration was nonsignificantly inversely correlated with soy product intake (r = -0.24, p = 0.05) after controlling for age, body mass index, smoking status, and ethanol intake. Total and free testosterone concentrations were inversely correlated with soy product intake after controlling for the covariates, but these correlations were of border line significance (r = -0.25, p = 0.05 and r = -0.25, p = 0.06, respectively). Similar correlations were observed for these hormones with isoflavone intake from soy products. The data suggest that soy product intake may be associated with the endogenous hormone levels in Japanese men.     

Three measures show high compliance in a soy intervention among premenopausal women

OBJECTIVE: To evaluate adherence to a soy-based diet among premenopausal women. DESIGN: First year of a 2-year, randomized dietary intervention. SUBJECTS: 220 healthy premenopausal women who reported low baseline soy intake. INTERVENTION: 5 counseling visits, 7 follow-up phone calls, and 12 group meetings. Main outcome measures Self-reported soy intake logs; food frequency questionnaires; repeated, randomly timed 24-hour recalls; and analysis of urinary isoflavone excretion by high-pressure liquid chromatography. Statistical analyses Frequency distributions, means, t tests, and mixed effects models. RESULTS: At baseline, the 2 groups did not differ in dietary soy intake (P=.51) or urinary isoflavone excretion (P=.16). According to the 24-hour recalls and the food frequency questionnaires, the intervention group's estimated isoflavone intake increased more than 10 times compared with baseline and with the control group (P<.0001). During follow-up, urinary isoflavone excretion results showed no change in the control group, but a 6-fold increase for intervention subjects (P<.0001). Intake logs showed a strong preference for soymilk and tofu over the other foods and indicated that intervention participants consumed at least 12 servings of soy foods per week during 84 out of 100 follow-up contacts. CONCLUSIONS: These data indicate a high level of compliance with the study regimen, which we attribute to the following strategies: repeated contact with the study subjects, personal relationships with the dietitians, wide choice of soy foods, easy access to soy foods at no cost, and recipes that allowed substitution of previously eaten foods with soy products.     

Dietary soy and fats in relation to serum insulin-like growth factor-1 and insulin-like growth factor-binding protein-3 levels in premenopausal Japanese women

Circulating levels of insulin-like growth factor-1 (IGF-1) and insulin-like growth factor-binding protein-3 (IGFBP-3) have each been associated with premenopausal breast cancer risks. We analyzed data from a cross-sectional study of 261 premenopausal Japanese women aged 20-54 yr with adequate nutritional status to evaluate the relationships between concentrations of IGF-1 and IGFBP-3 in serum and dietary intakes of soy, fats and other nutrients. Diet was assessed by a semiquantitative food frequency questionnaire. There was no significant correlation between soy product as well as soy isoflavone intake and serum IGF-1 or IGFBP-3 levels after controlling for age, total energy, percent body fat, and education level. Total fat intake was significantly inversely correlated with serum IGFBP-3 level (r = -0.13, P = 0.04). The correlations of saturated and monounsaturated fats with serum IGFBP-3 were of borderline significance (r = -0.12, P = 0.06 and r = -0.11, P = 0.07, respectively).     

Isoflavone intake in persons at high risk of cardiovascular events: implications for vascular endothelial function and the carotid atherosclerotic burden

BACKGROUND: Epidemiologic studies have suggested that a high phytoestrogen intake is inversely associated with cardiovascular disease risk factors and the incidence of cardiovascular events. However, the relation between the intake of isoflavone, a major component of phytoestrogen, and vascular endothelial function and the atherosclerotic burden remains unclear. OBJECTIVE: We aimed to investigate the effects of various dietary soy isoflavone intakes on brachial artery flow-mediated dilation and mean maximum carotid intima-media thickness. DESIGN: We studied 126 consecutive patients (x +/- SD age: 66.5 +/- 11.1 y; 69% male) at high risk of cardiovascular events (94% had documented coronary artery disease or stroke; 44% had diabetes). A validated food-frequency questionnaire was used to estimate their dietary intake after they achieved stable dietary patterns for 3 mo. RESULTS: The median intakes of isoflavone and soy protein were 5.5 (range: 2.2-13.3) mg/d and 1.2 (range: 0.4-2.8) g/d, respectively. Persons in the 4th quartile of daily isoflavone intake had significantly (P < 0.05) greater flow-mediated dilation-but not mean maximum carotid intima-media thickness-than did those in the lower quartiles. After adjustment for potential confounders, a higher isoflavone intake in the 4th than in the 1st quartile (>13.3 mg/d), but not a higher intake of soy protein, predicted an absolute 2.71% increase in flow-mediated dilation (relative increase: 103%; P = 0.02) and a 0.17-mm decrease in mean maximum carotid intima-media thickness (relative decrease: 14.5%; P = 0.04). CONCLUSION: In persons at high risk of cardiovascular events, a greater isoflavone intake is associated with better vascular endothelial function and lower carotid atherosclerotic burden.     

大豆食品摄入与乳腺癌发病关系的Meta分析

目的探讨大豆食品摄入与乳腺癌发病的关系。方法检索1991年到2011年4月公开发表的关于大豆食品摄入与乳腺癌关系的流行病学研究进行Meta分析,结果报告合并比值比(OR)及95%可信区间(95%CI)。结果 28个研究纳入Meta分析,其中有23个病例对照研究,5个队列研究。总体分析,大豆食品摄入对乳腺癌具有保护作用(合并OR=0.86,95%CI 0.78～0.94),但按设计类型分层后,只有病例对照研究的结果显示大豆食品对乳腺癌具有保护作用(合并OR=0.86,95%CI 0.77～0.95)。在不同国家和地区人群中开展的研究结果显示,在亚洲地区人群中,合并OR=0.76(95%CI 0.67～0.87),而欧美地区人群的研究合并OR=1.01(95%CI 0.93～1.09)。对在亚洲地区人群中开展的病例对照研究和队列研究分别进行合并分析,结果显示大豆食品摄入对乳腺癌均具有保护作用,合并OR分别为0.76(95%CI 0.65～0.89)和0.81(95%CI 0.70～0.92)。但在欧美地区人群中开展的两类研究均未发现大豆食品摄入对乳腺癌有保护作用。根据绝经前后的亚组分析结果显示,仅在绝经后女性中大豆食品摄入对乳腺癌起保护作用。结论根据亚洲地区人群中开展的研究,尤其是病例对照研究结果的合并分析,提示大豆食品摄入对亚洲地区女性乳腺癌具有保护作用。