Dietary vitamin D and calcium intake and premenopausal breast cancer risk in a German case-control study

Epidemiological studies and laboratory data suggest that vitamin D may protect against the development of cancer, including breast cancer. Vitamin D supply affects the bioavailability of dietary calcium, which might also have anticarcinogenic effects. However, few studies considered them jointly. We used a population-based case-control study in Germany to examine the independent and joint effects of dietary vitamin D and calcium on premenopausal breast cancer risk. Dietary information was assessed using a validated food frequency questionnaire from 278 premenopausal cases and 666 age-matched controls. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using multivariate models adjusting vitamin D models for calcium intake and vice versa. Breast cancer risk was significantly inversely associated with vitamin D intake. The OR and 95% CI for the highest intake category (> or = 5 microg/day) was 0.50 (95% CI = 0.26-0.96) compared with the lowest (< 2 microg/day; P(trend) = 0.02). Dietary calcium intake was not associated with breast cancer (OR = 0.73, 95% CI = 0.41-1.29) for the highest (> or = 1,300 mg/day) versus the lowest category (< 700 mg/day), P(trend) = 0.29). No statistically significant interaction between the 2 nutrients was observed. Our data support a protective effect of dietary vitamin D on premenopausal breast cancer risk independent of dietary calcium intake.     

Intake of Vitamins D and A and Calcium and Risk of Non-Hodgkin Lymphoma: San Francisco Bay Area Population-Based Case-Control Study

Several nutrients identified as potentially cancer protective have been inconsistently associated with non-Hodgkin lymphoma (NHL) risk. Dietary history data, including use of vitamin supplements, were collected using a semiquantitative food frequency questionnaire administered during in-person interviews with 4,133 participants (2,052 cases, 2,081 controls) in a San Francisco Bay Area population-based case-control study. Data were used to determine the association of intake levels of vitamins D and A and calcium with risk of NHL and NHL subtypes. Odds ratios (OR) and 95% confidence intervals (CI) were computed as estimates of relative risk using adjusted unconditional logistic regression. Increasing vitamin D intake from food and supplements was positively associated with NHL risk in men (5th quintile: OR = 1.6, 95% CI = 1.0–2.4, P _trend = 0.07) and with diffuse large B-cell lymphoma (DLBCL) in women and men (5th quintile: OR = 1.6, 95% CI = 1.0–2.5, P _trend = 0.02); that was largely due to the effect in men (P _trend = 0.03). These results do not support a strong role for vitamin D intake with NHL risk, with the exception of a potential association for DLBCL risk in men. Our results should be interpreted conservatively until further investigation in larger pooled studies can be conducted to better assess the role of vitamin D intake in lymphomagenesis.     

Dietary intake of soy protein and tofu in association with breast cancer risk based on a case-control study

Soy food and its constituents may protect against breast cancer, but the association between soy intake and decreased breast cancer risk is inconsistent. We evaluated the relationship between breast cancer risk and the dietary intake of soy protein as measured by total soy food and tofu intake. Histologically confirmed cases (n = 362) were matched to controls by age (within 2 yr) and menopausal status. High soy protein intake was associated with reduced breast cancer risk in analyses adjusted for potential confounders including dietary factors among premenopausal women (odds ratio [OR] = 0.39 in the highest quintile, 95% confidence interval [CI] = 0.22-0.93, P for trend = 0.03) and postmenopausal women (OR = 0.22, 95% CI = 0.06-0.88, P for trend = 0.16). We also found an inverse association between total tofu intake and breast cancer risk among premenopausal women (for total tofu intake, OR = 0.23 in the highest quintile, 95% CI = 0.11-0.48, P for trend < 0.01; for at least 1 serving of tofu as the main ingredient per day, OR = 0.26, 95% CI = 0.13-0.55, P for trend < 0.01). We concluded that increased regular soy food intake at a level equivalent to traditional Korean consumption levels may be associated with a reduced risk of breast cancer, and this effect is more pronounced in premenopausal women.     

Vitamin D decreases risk of breast cancer in premenopausal women of normal weight in subtropical taiwan

Background

Evidence for an association between vitamin D status and breast cancer is now more convincing, but is uncertain in subtropical areas like Taiwan. This hospital-based case-control study examined the relationship of breast cancer with vitamin D intake and sunlight exposure.

Methods

A total of 200 incident breast cancer cases in a Taipei hospital were matched with 200 controls by date of interview and menopausal status. Information on risk factors for breast cancer was collected in face-to-face interviews and assessed with reference to vitamin D intake (foods and nutrients) and sunlight exposure. Vitamin D intake was divided into quartiles, and threshold effect was evaluated by comparing Q2–Q4 with Q1.

Results

After controlling for age, education, parity, hormone replacement therapy, body mass index (BMI), energy intake, menopausal status, and daily sunlight exposure, the risk of breast cancer in participants with a dietary vitamin D intake greater than 5 µg per day was significantly lower (odds ratio [OR], 0.48; 95% confidence interval [CI], 0.24–0.97) than that of participants with an intake less than 2 µg per day. In analysis stratified by menopausal status and BMI, both dietary vitamin D and total vitamin D intakes were associated with a protective effect among premenopausal women. There was a significant linear trend for breast cancer risk and dietary vitamin D intake in premenopausal women (P = 0.02). In participants with a BMI lower than 24 kg/m² (ie, normal weight), dietary vitamin D intake was inversely related to breast cancer risk (P for trend = 0.002), and a threshold effect was apparent (Q2–Q4 vs Q1: OR, 0.46; 95% CI, 0.23–0.90).

Conclusions

Vitamin D had a protective effect against breast cancer in premenopausal women of normal weight in subtropical Taiwan, especially an intake greater than 5 µg per day.Key words: vitamin D, menopause, BMI, sunlight exposure, subtropical     

Dairy, calcium, and vitamin D intakes and prostate cancer risk in the National Health and Nutrition Examination Epidemiologic Follow-up Study cohort

BACKGROUND: Dairy intake may increase prostate cancer risk, but whether this is due to calcium's suppression of circulating vitamin D remains unclear. Findings on calcium and vitamin D intake and prostate cancer are inconsistent. OBJECTIVE: We examined the association of dairy, calcium, and vitamin D intake with prostate cancer. DESIGN: In a prospective study of 3612 men followed from 1982-1984 to 1992 for the first National Health and Nutrition Examination Epidemiologic Follow-up Study, 131 prostate cancer cases were identified. Dietary intake was estimated from questionnaires completed in 1982-1984. Relative risk (RR) and 95% CIs were estimated by using Cox proportional hazards models adjusted for age, race, and other covariates. RESULTS: Compared with men in the lowest tertile for dairy food intake, men in the highest tertile had a relative risk (RR) of 2.2 (95% CI: 1.2, 3.9; trend P = 0.05). Low-fat milk was associated with increased risk (RR = 1.5; 95% CI: 1.1, 2.2; third compared with first tertile; trend P = 0.02), but whole milk was not (RR = 0.8; 95% CI: 0.5, 1.3; third compared with first tertile; trend P = 0.35). Dietary calcium was also strongly associated with increased risk (RR = 2.2; 95% CI: 1.4, 3.5; third compared with first tertile; trend P = 0.001). After adjustment for calcium intake, neither vitamin D nor phosphorus was clearly associated with risk. CONCLUSIONS: Dairy consumption may increase prostate cancer risk through a calcium-related pathway. Calcium and low-fat milk have been promoted to reduce risk of osteoporosis and colon cancer. Therefore, the mechanisms by which dairy and calcium might increase prostate cancer risk should be clarified and confirmed.     

Ultraviolet sunlight exposure during adolescence and adulthood and breast cancer risk: a population-based case-control study among Ontario women

Recent studies suggest that vitamin D may be associated with reduced breast cancer risk, but most studies have evaluated only dietary vitamin D intake. The associations among ultraviolet radiation from sunlight, factors related to cutaneous vitamin D production, and breast cancer risk were evaluated in a population-based case-control study conducted in Ontario, Canada, between 2003 and 2004 (n = 3,101 cases and n = 3,471 controls). Time spent outdoors was associated with reduced breast cancer risk during 4 periods of life (>21 vs. ≤6 hours/week age-adjusted odds ratio (OR) = 0.71, 95% confidence interval (CI): 0.60, 0.85 in the teenage years; OR = 0.64, 95% CI: 0.53, 0.76 in the 20s-30s; OR = 0.74, 95% CI: 0.61, 0.88 in the 40s-50s; and OR = 0.50, 95% CI: 0.37, 0.66 in the 60s-74 years). Sun protection practices and ultraviolet radiation were not associated with breast cancer risk. A combined solar vitamin D score, including all the variables related to vitamin D production, was significantly associated with reduced breast cancer risk. These associations were not confounded or modified by menopausal status, dietary vitamin D intake, or physical activity. This study suggests that factors suggestive of increased cutaneous production of vitamin D are associated with reduced breast cancer risk.     

The association of calcium and vitamin D with risk of colorectal adenomas

The Polyp Prevention Trial (PPT) was a multicenter randomized clinical trial designed to determine the effects of a high-fiber, high-fruit and vegetable, low-fat diet on the recurrence of adenomatous polyps in the large bowel. Detailed dietary intake and supplement use data were collected at baseline and at each of 4 annual study visits. Adenoma recurrence was ascertained by complete colonoscopy at baseline and after 1 and 4 y. Recurrence was found in 754 of the 1905 trial participants. We evaluated the association between calcium and vitamin D intake and adenomatous polyp recurrence after adjusting for intervention group, age, gender, nonsteroidal anti-inflammatory drug use, total energy intake, and the interaction of gender and intervention group. Vitamin D models were also adjusted for the location of the clinic site. Dietary variables were adjusted for total energy intake via the residual method. There were no overall significant associations between adenoma recurrence and dietary calcium intake [odds ratio (OR) for the 5th compared with the lowest quintile = 0.91; 95% CI = 0.67-1.23; P-trend = 0.68], total calcium intake (OR = 0.86; 95% CI = 0.62-1.18; P-trend = 0.20), or dietary vitamin D intake (OR = 0.93; 95% CI = 0.69-1.25; P-trend = 0.43) averaged over follow-up. Total vitamin D intake was weakly inversely associated with adenoma recurrence (OR = 0.84; 95% CI = 0.62-1.13; P-trend = 0.03). Supplemental calcium and vitamin D use during follow-up also were inversely associated with adenoma recurrence (OR for any compared with no use = 0.82; 95% CI = 0.68-0.99; and OR = 0.82; 95% CI = 0.68-0.99; for calcium and vitamin D, respectively). Slightly stronger associations were noted for the prevention of multiple recurrences. Our analyses did not suggest a significant effect modification between total calcium and total vitamin D intake (P = 0.14) on risk for adenoma recurrence. This trial cohort provides some evidence that calcium and vitamin D may be inversely associated with adenoma recurrence.     

Dietary Intakes of Retinol,Carotenes, Vitamin C,and Vitamin E and Colorectal Cancer Risk: The Fukuoka Colorectal Cancer Study

It has long been a matter of interest whether antioxidant vitamins are protective against colorectal cancer as well as human cancers in general, but epidemiological evidence is inconclusive. We investigated associations of dietary intakes of retinol and antioxidant vitamins with colorectal cancer risk in 816 incident cases of histologically confirmed colorectal cancer and 815 controls randomly selected for the Fukuoka colorectal cancer study in Japan. Dietary intakes were assessed by a PC-assisted interview regarding 148 food items. Statistical adjustment was made for body mass index, physical activity, calcium, and n-3 fatty acid intake and other factors. Retinol intake was significantly, inversely associated with colorectal cancer risk; the odds ratio for the highest vs. lowest was 0.55 (95% CI: 0.35, 0.88; P _trend = 0.01) in women, but a modest increase in the risk was observed among men with the highest intake of retinol. Liver was the major source of retinol intake and showed similar associations with colorectal cancer risk in men and women. Intake of carotenes, vitamin C, and vitamin E were not related to colorectal cancer risk in either men or women. The study did not support a hypothesis that dietary intake of antioxidant vitamins is protective in the development of colorectal cancer.     

Dietary folate, vitamin B6, vitamin B12 and methionine intake and the risk of breast cancer by oestrogen and progesterone receptor status

Few studies have evaluated the relationship between the consumption of dietary folate and one-carbon metabolism-related nutrients and breast cancer risk defined by oestrogen receptor (ER) and progesterone receptor (PR) status. The objective of the present study was to examine the associations between dietary folate, vitamin B6, vitamin B12, and methionine intake and the risk of breast cancer by ER and PR status among Chinese women in Guangdong. A hospital-based case-control study was conducted from June 2007 to August 2008, with 438 cases and 438 age (5-year interval)- and residence (rural/urban)-matched controls. Dietary intake information was assessed using a validated FFQ administered through a face-to-face interview. Unconditional logistic regression models were used to calculate multivariate-adjusted OR and 95 % CI. A significant inverse association was found between dietary folate and vitamin B6 intake and breast cancer risk. The adjusted OR of the highest v. the lowest quartile were 0·32 (95 % CI 0·21, 0·49; P(trend) < 0·001) for dietary folate and 0·46 (95 % CI 0·30, 0·69; P(trend) < 0·001) for vitamin B6. No associations were observed for vitamin B12 and methionine intake. A significant inverse association between dietary folate intake and breast cancer risk was observed in all subtypes of ER and PR status. These findings suggest that dietary folate and vitamin B6 intakes were inversely associated with breast cancer risk. The inverse association did not differ by ER and/or PR status.     

Dietary Intake of Soy Protein and Tofu in Association With Breast Cancer Risk Based on a Case-Control Study

Soy food and its constituents may protect against breast cancer, but the association between soy intake and decreased breast cancer risk is inconsistent. We evaluated the relationship between breast cancer risk and the dietary intake of soy protein as measured by total soy food and tofu intake. Histologically confirmed cases ( n = 362) were matched to controls by age (within 2 yr) and menopausal status. High soy protein intake was associated with reduced breast cancer risk in analyses adjusted for potential confounders including dietary factors among premenopausal women (odds ratio [OR] = 0.39 in the highest quintile, 95% confidence interval [CI] = 0.22–0.93, P for trend = 0.03) and postmenopausal women (OR = 0.22, 95% CI = 0.06–0.88, P for trend = 0.16). We also found an inverse association between total tofu intake and breast cancer risk among premenopausal women (for total tofu intake, OR = 0.23 in the highest quintile, 95% CI = 0.11–0.48, P for trend < 0.01; for at least 1 serving of tofu as the main ingredient per day, OR = 0.26, 95% CI = 0.13–0.55, P for trend < 0.01). We concluded that increased regular soy food intake at a level equivalent to traditional Korean consumption levels may be associated with a reduced risk of breast cancer, and this effect is more pronounced in premenopausal women.     

Thirty Years Ago…

Nitrate is a precursor in the endogenous formation of N-nitroso compounds, which are potent animal carcinogens, whereas antioxidant vitamins have been suggested to protect against carcinogenesis. Interestingly, nitrate and antioxidant vitamins stem from the same dietary sources. We investigated whether the intake of nitrate relative to antioxidant vitamins is associated with the risk of breast cancer. A total of 362 breast cancer cases were matched to the 362 controls by age and menopausal status. Dietary intake was assessed using a quantitative food frequency questionnaire with 121 food items by trained interviewers. The nitrate to antioxidant vitamin consumption ratio was then calculated. Conditional logistic regression analysis was used to obtain odds ratios (ORs) and corresponding 95% confidence intervals (CI). Mean intakes of nitrate for cases and controls were 421 mg/day and 424 mg/day, respectively. Intakes of nitrate, nitrate/β-carotene, nitrate/vitamin C, and nitrate/vitamin E were not associated with breast cancer risk. However, higher breast cancer risk was observed with higher intake of nitrate/folate (OR = 2.03, 95% CI = 1.16–3.54, P for trend = 0.052). Our results suggest that lowering the ratio of nitrate to folate intake may be effective in reducing breast cancer risk.     

Antioxidants, carotenoids, and risk of rectal cancer

Numerous properties suggest that antioxidants and carotenoids may be valuable chemopreventive agents. A population-based case-control study of 952 rectal cancer cases and 1,205 controls from Northern California and Utah was conducted between September 1997 and February 2002. Detailed diet history, medical history, and lifestyle factors interviews were conducted. Dietary antioxidants were not associated with rectal cancer risk in men. For women, relative to the highest level of intake, low intake of dietary lycopene (odds ratio (OR) = 1.7, 95% confidence interval (CI): 1.0, 2.8) or vitamin E (OR = 2.2, 95% CI: 1.1, 4.3) was associated with an increased risk of rectal cancer. Alpha-, beta-, and gamma-tocopherol were associated with an approximate twofold increased risk of rectal cancer in women. Associations were stronger for women aged > or = 60 years for vitamin E and tocopherols (alpha-tocopherol OR = 3.6, 95% CI: 1.4, 9.4; gamma-tocopherol OR = 5.3, 95% CI: 2.1, 13.2; delta-tocopherol OR = 1.9, 95% CI: 0.9, 4.0), except for beta-tocopherol, for which risk increased twofold for all women. Associations differed by estrogen status for beta-carotene, lycopene, and vitamin E. These results suggest that vitamin E and lycopene may modestly reduce the risk of rectal cancer in women.     

Dietary Iron Intake and Risk of Endometrial Cancer: A Population-Based Case-Control Study in Shanghai,China

Dietary red meat and animal fat have been linked to endometrial cancer (EC) risk, but the impact of bioavailable iron in animal-derived foods has been less well studied. Our objective was to investigate the effects of iron and fats on the risk of EC in a large, population-based, case-control study. The Shanghai Endometrial Cancer Study enrolled 1,204 EC cases and 1,212 controls who completed in-person interviews, including a food frequency questionnaire. Animal-derived iron and fat intakes were calculated from dietary intakes and food composition tables. Logistic regression models were used to evaluate independent and joint effects of iron and fat on EC risk. Animal-derived iron intake was positively associated with EC risk [adjusted OR = 1.9; 95% CI = 1.4–2.7, P _trend < 0.01, highest vs. lowest quartile], predominantly after menopause (OR = 2.2; 95%CI = 1.4–3.4, P _trend < 0.01) and in women with BMI ≥ 25 kg/m ² (OR = 3.2; 95% CI = 1.4–7.5 in postmenopausal obese women, P _trend < 0.01). Animal-derived fat was also associated with postmenopausal EC risk (OR = 1.7; 95% CI = 1.2–2.5, P _trend < 0.01). Multiplicative interactions between animal-derived iron and BMI or animal-derived fat intake were not observed. Animal-derived iron intake is associated with increased risk of EC after menopause and among obese women. Avoidance of animal-derived (heme) iron may reduce the risk of EC in these women.     

Dairy Products,Dietary Calcium and Vitamin D Intake as Risk Factors for Prostate Cancer: A Meta-Analysis of 26,769 Cases From 45 Observational Studies

In this study, we examined the available evidence and sources of heterogeneity for studies of dairy products, calcium, and vitamin D intake and the risk of prostate cancer. We pooled data from 45 observational studies using a general variance-based, meta-analytic method employing CIs. Summary relative risks (RRs) were calculated for specific dairy products such as milk and dairy micronutrients. Sensitivity analyses were performed to test the robustness of these summary measures of effect. Cohort studies showed no evidence of an association between dairy [RR = 1.06; 95% confidence interval (CI) = 0.92–1.22] or milk intake (RR = 1.06; 95% CI = 0.91–1.23) and risk of prostate cancer. This was supported by pooled results of case-control analyses (RR = 1.14; 95% CI = 1.00–1.29), although studies using milk as the exposure of interest were heterogeneous and could not be combined. Calcium data from cohort studies were heterogeneous. Case-control analyses using calcium as the exposure of interest demonstrated no association with increased risk of prostate cancer (RR = 1.04; 95% CI = 0.90–1.15). Dietary intake of vitamin D also was not related to prostate cancer risk (RR = 1.16; 95% CI = 0.98–1.38). The data from observational studies do not support an association between dairy product use and an increased risk of prostate cancer.     

Dietary Fat,Cooking Fat,and Breast Cancer Risk in a Multiethnic Population

Our objective was to examine the association between dietary fat intake, cooking fat usage, and breast cancer risk in a population-based, multiethnic, case-control study conducted in the San Francisco Bay area. Intake of total fat and types of fat were assessed with a food frequency questionnaire among 1,703 breast cancer cases diagnosed between 1995 and 1999 and 2,045 controls. In addition, preferred use of fat for cooking was assessed. Unconditional logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs). High fat intake was associated with increased risk of breast cancer (highest vs. lowest quartile, adjusted OR = 1.35, 95% CI = 1.10–1.65, P _trend < 0.01). A positive association was found for oleic acid (OR = 1.55, 95% CI = 1.14–2.10, P _trend < 0.01) but not for linoleic acid or saturated fat. Risk was increased for women cooking with hydrogenated fats (OR = 1.58, 95% CI = 1.20–2.10) or vegetable/corn oil (rich in linoleic acid; OR = 1.30, 95% CI = 1.06–1.58) compared to women using olive/canola oil (rich in oleic acid). Our results suggest that a low-fat diet may play a role in breast cancer prevention. We speculate that monounsaturated trans fats may have driven the discrepant associations between types of fat and breast cancer.     

Intake of specific carotenoids and essential fatty acids and breast cancer risk in Montreal, Canada

BACKGROUND: Evidence from previous investigations into the possible role of dietary and serum carotenoid concentrations in the etiology of breast cancer is inconsistent. No study has examined the combined effect of carotenoids and essential fatty acids on the risk of breast cancer. OBJECTIVE: The objective was to assess the possible association between specific and total carotenoids and breast cancer risk and to evaluate the effect modification by diet-related fatty acids and lifestyle factors in the development of breast cancer. DESIGN: A population-based case-control study involving 414 incident cases and 429 controls was conducted in French Canadians in Montreal. Dietary intake was estimated with the use of a validated food-frequency questionnaire in face-to-face interviews. RESULTS: No significant association was apparent between any of the individual or total carotenoids and the risk of breast cancer after adjustment for major underlying determinants of breast cancer. In premenopausal women who ever smoked, an increased risk was related to alpha-carotene [odds ratio (OR) for the upper relative to the lowest quartiles of intake: 2.40; 95% CI: 0.90, 6.41; P for trend = 0.046]. Conversely, a reduced risk was related to beta-carotene (OR: 0.57; 95% CI: 0.26, 1.24; P for trend = 0.05) in women who never used hormone replacement therapy. In postmenopausal women, total carotenoids were positively associated with breast cancer risk in those with a high arachidonic acid intake (OR: 1.92; 95% CI: 0.93, 3.94; P = 0.028 for trend) and inversely associated in those with a high docosahexaenoic acid intake (OR: 0.52; 95% CI: 0.25, 1.07; P for trend = 0.054). CONCLUSION: These findings suggest that the combined high intake of total carotenoids and docosahexaenoic acid may reduce the risk of breast cancer.     

Interaction of nitrate and folate on the risk of breast cancer among postmenopausal women

Ingested nitrate can be endogenously reduced to nitrite, which may form N-nitroso compounds, known potent carcinogens. However, some studies have reported no or inverse associations between dietary nitrate intake and cancer risk. These associations may be confounded by a protective effect of folate, which plays a vital role in DNA repair. We evaluated the interaction of dietary and water nitrate intake with total folate intake on breast cancer risk in the Iowa Women's Health Study. Dietary intake was assessed at study baseline. Nitrate intake from public water was assessed using a historical database on Iowa municipal water supplies. After baseline exclusions, 34,388 postmenopausal women and 2,875 incident breast cancers were included. Overall, neither dietary nor water nitrate was associated with breast cancer risk. Among those with folate intake ≥400 μg/day, breast cancer risk was significantly increased in public water users with the highest nitrate quintile (HR = 1.40, 95% CI = 1.05-1.87) and private well users (HR = 1.38, 95% CI = 1.05-1.82) compared to public water users with the lowest nitrate quintile; in contrast, there was no association among those with lower folate intake. Our findings do not support a previous report of increased risk of breast cancer among individuals with high dietary nitrate but low folate intake.     

Dietary carbohydrates, fiber, and breast cancer risk

Dietary fiber, fiber fractions, carbohydrate, glycemic index, and glycemic load were prospectively assessed five times over 18 years with a validated food frequency questionnaire in relation to breast cancer risk among 88,678 women (aged 34-59 years at baseline) in the Nurses' Health Study. Incident breast cancer occurred in 4,092 of these women between 1980 and 1998. The authors observed no material association between carbohydrate intake, glycemic index and glycemic load, total dietary fiber intake, and breast cancer risk. The relative risks for the highest versus the lowest quintile of intake were 0.97 (95% confidence interval (CI): 0.87, 1.08) for carbohydrates, 1.08 (95% CI: 0.97, 1.19) for glycemic index, 0.99 (95% CI: 0.89, 1.10) for glycemic load, and 0.98 (95% CI: 0.87, 1.11) for fiber. The relative risk comparing those in the highest 0.7% of fiber intake (>30 g/day) with those in the lowest 10% of fiber intake (< or =10 g/day) was 0.68 (95% CI: 0.43, 1.06). Analyses stratified by menopausal status and body mass index also showed no clear risk pattern. In this cohort of middle-aged women, no overall association was found for dietary carbohydrates, glycemic index and glycemic load, and breast cancer risk. This study also confirmed the lack of an overall association between intake of fiber and fiber types and breast cancer risk observed in other prospective studies.     

Dietary Polyamines Intake and Risk of Colorectal Cancer: A Case-Control Study

Polyamines (including putrescine, spermidine, and spermine) are small, cationic molecules that are necessary for cell proliferation and differentiation. Few studies have examined the association of dietary polyamines intake with colorectal cancer risk. The aim of this study was to evaluate total polyamines, putrescine, spermidine, and spermine intake in relation to colorectal cancer risk in China. In total, 2502 colorectal cancer cases and 2538 age-(5-year interval) and sex-matched controls were recruited from July 2010 to April 2019. Odds ratios (ORs) and 95% confidence intervals (CI) were calculated by multivariable unconditional logistic regression after adjustment for various potential confounding factors. Higher intake of total polyamine, putrescine and spermidine was significantly associated with reduced risk of colorectal cancer. The adjusted ORs for the highest compared with the lowest quartile of intake were 0.60 (95% CI 0.50, 0.72; P_trend < 0.001) for total polyamines, 0.35 (95% CI 0.29, 0.43; P_trend < 0.001) for putrescine and 0.79 (95% CI 0.66, 0.95; P_trend = 0.001) for spermidine, respectively. However, higher intake of spermine was associated with increased risk of colorectal cancer, with an adjusted OR of 1.58 (95% CI 1.29, 1.93; P_trend < 0.001). This data indicate that higher intake of total polyamines, putrescine and spermidine, as well as lower intake of spermine, is associated with a decreased risk of colorectal cancer.