One-carbon metabolism-related micronutrients intake and risk for hepatocellular carcinoma: A prospective cohort study

Deficient intake of micronutrients involved in one-carbon metabolism (eg, choline, methionine, vitamin B₁₂ and folic acid) leads to hepatocellular carcinoma (HCC) development in rodents, but is under-investigated in humans. We investigated the association between one-carbon metabolism-related micronutrient intake and HCC risk in a prospective cohort of 494 860 participants with 16 years of follow-up in the NIH-AARP study. Dietary intakes and supplement use were ascertained at baseline using a food-frequency questionnaire. Total intake (diet plus supplements) of the following one-carbon metabolism-related micronutrients were calculated: folate, methionine and vitamins B₂ (riboflavin), B₃ (niacin), B₆ and B₁₂. These micronutrients were examined both individually and simultaneously, with adjustment for covariates. Cox proportional hazard models were used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs). Over the 16-year follow-up period, 647 incident HCC cases were diagnosed. When examined individually, higher total vitamin B₃ intake was associated with a lower HCC risk (HR_{Q5 vs Q1} = 0.60; 95% CI = 0.42-0.85; P_trend = .008), and the association remained significant when all six micronutrients were examined simultaneously (HR_{Q5 vs Q1} = 0.32; 95% CI = 0.18-0.55; P_trend < .0001). Among participants with >3 years of follow-up, higher total vitamin B₃ intake was again associated with lower risk (HR_{Q5 vs Q1} = 0.37; 95% CI = 0.20-0.68; P_trend = .001), whereas higher total vitamin B₆ intake was associated with higher risk (HR_{Q5 vs Q1} = 2.04; 95% CI = 1.02-4.07; P_trend = .04). Restricted cubic spline analyses showed a dose-response inverse association between total vitamin B₃ intake and HCC risk, and dose-response positive association between total vitamin B₆ intake and HCC risk. The study suggests that higher vitamin B₃ intake is associated with lower HCC risk, whereas higher vitamin B₆ intake is associated with increased risk.     

Intake of fatty acids and antioxidants and pancreatic cancer in a large population‐based case‐control study in the San Francisco Bay Area

There are no well‐established modifiable risk factors for pancreatic cancer except smoking. Some dietary factors have been associated with pancreatic cancer risk and require further study. We examined the associations among intake of specific fatty acids and antioxidants and risk of pancreatic cancer in a large population‐based case‐control study in the San Francisco Bay Area. Unconditional logistic regression models were used to compute odds ratios (ORs) and 95% confidence intervals (CI) as estimates of relative risk. Positive associations were observed for high levels of the 8 individual saturated fatty acids (4th vs. 1st quartile: ORs ranged from 1.6 to 2.6; all p_trend < 0.01), monounsaturated palmitoleic and oleic fatty acids [OR = 1.6 (95% CI: 1.2–2.1) and 1.4 (95% CI: 1.1–1.9); both p_trend < 0.01], and polyunsaturated linolenic acid [OR = 1.5 (95% CI: 1.1–2.0); p_trend = 0.02]. Inverse associations were observed for high levels of gadolic acid [4th vs. 1st quartile: OR = 0.68 (95% CI: 0.50–0.92); p_trend = 0.007] and omega‐3 fatty acids [≥0.85 g/day vs. 1st quartile: OR = 0.47 (95% CI: 0.25–0.90)]. An inverse association was also observed for high total intake of vitamin C [4th vs. 1st quartile: OR = 0.69 (95% CI: 0.51–0.94); p_trend = 0.004] and of vitamin E [OR = 0.67 (95% CI: 0.49–0.92); p_trend = 0.01]. Although similar decreased risks were also observed for high supplemental intake of these 2 vitamins (both p_trend < 0.01), no association was observed for intake from food alone. These results support the hypotheses that a high intake of saturated and certain monounsaturated fatty acids may increase the risk of pancreatic cancer, whereas greater intake of omega‐3 fatty acids, vitamins C and E may reduce the risk.     

Erythrocyte membrane fatty acids and breast cancer risk: a prospective analysis in the nurses' health study II

The roles of specific fatty acids in breast cancer etiology are unclear, particularly among premenopausal women. We examined 34 individual fatty acids, measured in blood erythrocytes collected between 1996 and 1999, and breast cancer risk in a nested case‐control study of primarily premenopausal women in the Nurses' Health Study II. Breast cancer cases diagnosed after blood collection and before June 2010 (n = 794) were matched to controls and conditional logistic regression was used to estimate OR's (95% CI's) for associations of fatty acids with breast cancer; unconditional logistic regression was used for stratified analyses. Fatty acids were not significantly associated with breast cancer risk overall; however, heterogeneity by body mass index (BMI) was observed. Among overweight/obese women (BMI ≥ 25), several odd‐chain saturated (SFA, e.g. 17:0, OR_Q4vsQ1(95% CI) =1.85 (1.18 – 2.88), p_trend=0.006 p_int<0.001), trans (TFA, e.g. 18:1, OR_Q4vsQ1(95% CI) =2.33 (1.45 – 3.77), p_trend<0.001, p_int=0.007) and dairy‐derived fatty acids (SFA 15:0 + 17:0 + TFA 16:1n‐7t; OR_Q4vsQ1(95% CI) =1.83(1.16 – 2.89), p_trend=0.005, p_int<0.001) were positively associated, and n‐3 polyunsaturated fatty acids (n‐3 PUFA, e.g. alpha‐linolenic acid; OR_Q4vsQ1(95% CI) =0.57 (0.36 – 0.89), p_trend=0.017, p_int=0.03) were inversely associated with breast cancer. Total SFA were inversely associated with breast cancer among women with BMI < 25 (OR_Q4vsQ1(95% CI) =0.68 (0.46 – 0.98), p_trend=0.05, p_int=0.01). Thus, while specific fatty acids were not associated with breast cancer overall, our findings suggest positive associations of several SFA, TFA and dairy‐derived fatty acids and inverse associations of n‐3 PUFA with breast cancer among overweight/obese women. Given these fatty acids are influenced by diet, and therefore are potentially modifiable, further investigation of these associations among overweight/obese women is warranted.     

Adolescent and mid‐life diet and subsequent risk of thyroid cancer in the NIH‐AARP diet and health study

Although thyroid cancer is suspected to have a nutritional etiology, prospective studies examining the relationship between diet and thyroid cancer are lacking. During 1996–1997, NIH‐AARP Diet and Health Study participants, ages 51–72 years, completed a 37‐item food frequency questionnaire about diet at ages 12–13 years (adolescence) and 10 years before baseline (mid‐life). Over a median 10 years of follow‐up, 325 individuals (143 men and 182 women) were diagnosed with thyroid cancer. Multivariable‐adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated for intakes of foods and food groups comparing the highest to the lowest quartiles. Adolescent intakes of chicken/turkey (HR = 1.59, 95% CI: 0.97–2.60; p_trend < 0.01) and sweet baked goods (HR = 1.59, 95% CI: 1.09–2.34; p_trend = 0.04) were positively associated with thyroid cancer risk, while intake of butter/margarine was inversely associated with risk (HR = 0.64, 95% CI: 0.44–0.91; p_trend < 0.02). Similar to adolescent diet, mid‐life intake of sweet baked goods was nonsignificantly associated with an increased risk of thyroid cancer (HR = 1.39, 95% CI: 0.96–2.00; p_trend = 0.11), but intake of butter/margarine was inversely associated with risk (HR = 0.66, 95% CI: 0.46–0.95; p_trend = 0.03). Among men, higher adolescent consumption of canned tuna was positively associated with risk of thyroid cancer (HR = 1.69, 95% CI: 1.01–2.83; p_trend = 0.03), and greater mid‐life intake of broccoli was associated with a twofold increased risk (HR = 2.13, 95% CI: 1.13–3.99; p_trend < 0.01). This large prospective study suggests that several components of the adolescent and mid‐life diet, including iodine‐rich foods and goitrogens, may influence thyroid cancer risk.     

A prospective study of serum bile acid concentrations and colorectal cancer risk in post-menopausal women on the island of Guernsey

Secondary bile acids produced by the action of the colonic microflora may increase risk of colorectal cancer. Serum bile acid concentrations reflect the faecal bile acid profile and may be of value as biomarkers of risk of colorectal cancer. In a pilot investigation we examined: (i) the reproducibility of measurements of serum bile acids in two blood samples collected several years apart; and (ii) the hypothesis that relatively high levels of secondary bile acids, particularly deoxycholic acid, would be positively associated with an increased risk of colorectal cancer in a prospective study of 3680 women in Guernsey. There was poor reproducibility between repeat measurements of absolute serum concentrations of bile acids, but there was moderately good reproducibility for the ratios of serum concentrations of deoxycholic/cholic acid, lithocholic/chenodeoxycholic and secondary/primary bile acid concentrations (duplicate blood samples were available for 30 women). There were no significant differences in ratios of serum secondary to primary bile acids or in absolute concentrations of bile acids between the 46 women who developed colorectal cancer and their matched controls, although there was a suggestion that an increased risk was associated with a high ratio of deoxycholic/cholic acid (relative risk in top third compared to lower third=3.92 (95% CI 0.91-17.0, P for trend=0.096). These findings suggest that the ratios of serum bile acid concentrations are sufficiently reproducible for epidemiological studies, but that a larger study than our own is needed to adequately test the hypothesis of their relation to cancer risk.     

Circulating levels of biomarkers and risk of ductal carcinoma in situ of the breast in the UK Biobank study

Observational studies have shown associations between circulating levels of various biomarkers (eg, total cholesterol [TC], low-density lipoprotein cholesterol [LDL], insulin-like growth factor-1 [IGF-1], C-reactive protein [CRP] and glycated hemoglobin-1c [HbA1c]) and the risk of invasive breast cancer (IBC). Ductal carcinoma in situ of the breast (DCIS) is a nonobligate precursor of IBC and shares several risk factors with it. However, the relationship between these biomarkers and DCIS risk remains unexplored. We studied the association between circulating levels of TC, LDL-C, high-density lipoprotein cholesterol (HDL-C), Lipoprotein (a) (Lp-(a)), IGF-1, CRP and HbA1c, with the risk of DCIS in 156801women aged 40 to 69 years and breast cancer-free at enrolment when blood samples and information on demographic and health-related factors were collected. Incident cases of DCIS were ascertained during the follow-up via linkage to the UK cancer registries Multivariable-adjusted Cox proportional hazards models were used to estimate the hazard ratios (HRs) and 95% confidence intervals (CIs) for the associations of interest. In all, 969 DCIS incident cases were diagnosed during 11.4 years of follow-up. Total cholesterol was inversely associated with the risk of DCIS (HR_{quintile(Q)5vsQ1} = 0.47, 95% CI: 0.27-0.82, P_trend = .008). Conversely, LDL-C was positively associated with DCIS risk (HR_Q3vsQ1 = 1.43, 95% CI: 1.01-2.04, HR_Q4vsQ1 = 1.60, 95% CI: 1.04-2.47, HR_Q5vsQ1 = 2.29, 95% CI: 1.36-3.88, P_trend = .004). In postmenopausal women, CRP had a weak positive association with DCIS risk, while HbA1c showed a nonlinear association with the risk. These results, in conjunction with those from previous studies on IBC, provide support for the association of several biomarkers with the risk of an early stage of breast cancer.     

Adipokines and inflammation markers and risk of differentiated thyroid carcinoma: The EPIC study

Other than the influence of ionizing radiation and benign thyroid disease, little is known about the risk factors for differentiated thyroid cancer (TC) which is an increasing common cancer worldwide. Consistent evidence shows that body mass is positively associated with TC risk. As excess weight is a state of chronic inflammation, we investigated the relationship between concentrations of leptin, adiponectin, C‐reactive protein, interleukin (IL)‐6, IL‐10 and tumor necrosis factor (TNF)‐α and the risk of TC. A case‐control study was nested within the European Prospective Investigation into Cancer and Nutrition (EPIC) study and included 475 first primary incident TC cases (399 women and 76 men) and 1,016 matched cancer‐free cohort participants. Biomarkers were measured in serum samples using validated and highly sensitive commercially available immunoassays. Odds ratios (ORs) of TC by levels of each biomarker were estimated using conditional logistic regression models, adjusting for BMI and alcohol consumption. Adiponectin was inversely associated with TC risk among women (OR_T3vs.T1 = 0.69, 95% CI: 0.49–0.98, P_trend = 0.04) but not among men (OR_T3vs.T1 = 1.36, 95% CI: 0.67–2.76, P_trend = 0.37). Increasing levels of IL‐10 were positively associated with TC risk in both genders and significantly so in women (OR_T3vs.T1 = 1.59, 95% CI: 1.13–2.25, P_trend = 0.01) but not in men (OR_T3vs.T1 = 1.78, 95% CI: 0.80–3.98, P_trend = 0.17). Leptin, CRP, IL‐6 and TNF‐α were not associated with TC risk in either gender. These results indicate a positive association of TC risk with IL‐10 and a negative association with adiponectin that is probably restricted to women. Inflammation may play a role in TC in combination with or independently of excess weight.     

Dietary fatty acids and colorectal cancer risk in men: A report from the Shanghai Men's Health Study and a meta‐analysis

Evidence from animal models suggests that dietary fatty acids have both anticancer and tumor‐promoting effects. Whether dietary fatty acids are associated with colorectal cancer (CRC) in humans remains inconclusive. We investigated associations between dietary fatty acids and risk of CRC among 59 986 men who participated in the Shanghai Men's Health Study (SMHS), an ongoing population‐based prospective cohort study. We identified 876 incident CRC cases in the SMHS during a mean follow‐up of 9.8 years. Associations between dietary fatty acid intake and CRC risk were evaluated by Cox proportional hazard regression analyses. Consumption of saturated fatty acids (SFA), monounsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA) was not significantly associated with CRC risk. Multivariate hazard ratios (HRs) and respective 95% confidence intervals (CIs) for Quartile 4 vs Quartile 1 were 0.92 (0.74‐1.14; P_trend = 0.47) for SFA, 0.95 (0.79‐1.16; P_trend = 0.74) for MUFA and 1.18 (0.95‐1.46; P_trend = 0.21) for PUFA. No significant associations were found for total n‐6 PUFA or total n‐3 PUFA. Additionally, we performed a meta‐analysis to summarize results from the present study and 28 reports from 26 additional cohorts, which supported the overall null association between dietary fatty acid intake and CRC risk among men. Docosahexanoic acid and eicosapentaenoic acid were associated with 11% to 12% reduced risk, and linoleic acid a 19% increased risk, of CRC in the meta‐analysis of combined sexes. In conclusion, this population‐based prospective study and meta‐analysis of cohort studies found little evidence that dietary fatty acid intake was associated with risk of CRC in men.     

A prospective evaluation of plasma polyphenol levels and colon cancer risk

Polyphenols have been shown to exert biological activity in experimental models of colon cancer; however, human data linking specific polyphenols to colon cancer is limited. We assessed the relationship between pre‐diagnostic plasma polyphenols and colon cancer risk in a case–control study nested within the European Prospective Investigation into Cancer and Nutrition study. Using high pressure liquid chromatography coupled to tandem mass spectrometry, we measured concentrations of 35 polyphenols in plasma from 809 incident colon cancer cases and 809 matched controls. We used multivariable adjusted conditional logistic regression models that included established colon cancer risk factors. The false discovery rate (q_values) was computed to control for multiple comparisons. All statistical tests were two‐sided. After false discovery rate correction and in continuous log₂‐transformed multivariable models, equol (odds ratio [OR] per log₂‐value, 0.86, 95% confidence interval [95% CI] = 0.79–0.93; q_value = 0.01) and homovanillic acid (OR per log₂‐value, 1.46, 95% CI = 1.16–1.84; q_value = 0.02) were associated with colon cancer risk. Comparing extreme fifths, equol concentrations were inversely associated with colon cancer risk (OR = 0.61, 95% CI = 0.41–0.91, p_trend = 0.003), while homovanillic acid concentrations were positively associated with colon cancer development (OR = 1.72, 95% CI = 1.17–2.53, p_trend < 0.0001). No heterogeneity for these associations was observed by sex and across other colon cancer risk factors. The remaining polyphenols were not associated with colon cancer risk. Higher equol concentrations were associated with lower risk, and higher homovanillic acid concentrations were associated with greater risk of colon cancer. These findings support a potential role for specific polyphenols in colon tumorigenesis.     

A prospective study of dairy product intake and the risk of hepatocellular carcinoma in U.S. men and women

Although increasing dairy product intake has been associated with risk of several cancers, epidemiological studies on hepatocellular carcinoma are sparse and have yielded inconsistent results. We prospectively assessed the associations of dairy products (total, milk, butter, cheese and yogurt) and their major components (calcium, vitamin D, fats and protein) with the risk of hepatocellular carcinoma development among 51,418 men and 93,427 women in the Health Professionals Follow-Up Study and the Nurses' Health Study. Diets were collected at baseline and updated every 4 years using validated food frequency questionnaires. Multivariable hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated using Cox proportional hazards regression model. During up to 32 years of follow-up, a total of 164 hepatocellular carcinoma cases were documented. After adjustment for most known hepatocellular carcinoma risk factors, higher total dairy product intake was associated with an increased risk of hepatocellular carcinoma (highest vs. lowest tertile, HR = 1.85, 95% CI: 1.19–2.88; p_trend = 0.009). For the same comparison, we observed significant positive associations of high-fat dairy (HR = 1.81, 95% CI: 1.19–2.76; p_trend = 0.008) and butter (HR = 1.58, 95% CI: 1.06–2.36; p_trend = 0.04) with hepatocellular carcinoma risk. There was a nonsignificant inverse association between yogurt intake and hepatocellular carcinoma risk (HR = 0.72, 95% CI: 0.49–1.05; p_trend = 0.26). Our data suggest that higher intake of high-fat dairy foods was associated with higher, whereas higher yogurt consumption might be associated with lower risk of developing hepatocellular carcinoma among U.S. men and women.     

Isoflavone consumption and subsequent risk of hepatocellular carcinoma in a population‐based prospective cohort of Japanese men and women

The incidence of hepatocellular carcinoma (HCC) is much higher in men than in women. Several experiment and epidemiological studies have suggested that estrogen might play an inhibitory role in the development of HCC. Because isoflavones have a similar structure as 17β‐estradiol and appear to have an anti‐estrogenic effect in women and estrogenic effect in men, we hypothesized that the effect of isoflavones on HCC differs by sex. We investigated the association between isoflavones (genistein and daidzein) and soy products and HCC in Japan in a population‐based prospective study in 19,998 Japanese (7,215 men and 12,783 women) aged 40–69 years. During 11.8 years of follow‐up, 101 subjects (69 men and 32 women) were newly diagnosed with HCC. Case patients were grouped according to consumption of isoflavones and soy products and stratified by hepatitis virus infection. Hazard ratios (HRs) and 95% confidence intervals (CIs) for HCC were calculated by Cox proportional‐hazards modeling. In women, genistein and daidzein were dose‐dependently associated with an increased risk of HCC, with multivariable HRs for the highest versus lowest tertile of 3.19 (95%CI = 1.13–9.00, p_trend = 0.03) and 3.90 (95% CI = 1.30–11.69, p_trend = 0.01), respectively. No association between isoflavones and HCC was observed in men. These results persisted when analysis was restricted to subjects positive for either or both hepatitis C and B virus. In conclusion, isoflavone consumption may be associated with an increased risk of HCC in women. Women with hepatitis virus infection may be advised to abstain from isoflavone consumption. Further studies are warranted to confirm these findings. © 2008 Wiley‐Liss, Inc.     

Inverse associations of dietary fiber and menopausal hormone therapy with colorectal cancer risk in the Multiethnic Cohort Study

In the Multiethnic Cohort Study, we previously reported that dietary fiber intake was inversely associated with colorectal cancer risk in men only. In women, the inverse relationship was weaker and appeared to be confounded by menopausal hormone therapy (MHT). We re‐examined this observation with a greatly increased power. Using Cox proportional hazards models, we analyzed data from 187,674 participants with 4,692 cases identified during a mean follow‐up period of 16 years. In multivariable‐adjusted models, dietary fiber intake was inversely associated with colorectal cancer risk in both sexes: HR = 0.73, 95% CI: 0.61–0.89 for highest vs. lowest quintile, p_trend = 0.0020 in men and HR = 0.76, 95% CI: 0.62–0.91, p_trend = 0.0067 in women. Postmenopausal women who ever used MHT had a 19% lower risk of colorectal cancer (95% CI: 0.74–0.89) compared with MHT never users. In a joint analysis of dietary fiber and MHT, dietary fiber intake was associated with a lower colorectal cancer risk in MHT never users (HR = 0.75, 95% CI: 0.59–0.95, p_trend = 0.045), but did not appear to further decrease the colorectal cancer risk of MHT ever users (p_trend = 0.11). Our results support the overall protective roles of dietary fiber and MHT against colorectal cancer and suggest that dietary fiber may not lower risk further among women who ever used MHT. If confirmed, these results would suggest that MHT and dietary fiber may share overlapping mechanisms in protecting against colorectal cancer.     

Use of isoflavone supplements is associated with reduced postmenopausal breast cancer risk

Botanical supplements are widely used and contain diverse ingredients, including isoflavones. Food‐based isoflavones have been associated with reduced breast cancer risk. However, no study has comprehensively evaluated supplements identified by isoflavone content and breast cancer risk. Associations between ever use of 28 isoflavone supplements and breast cancer risk in Ontario, Canada were evaluated using cases (n = 3,101) identified in 2002–2003 from the Ontario Cancer Registry and controls (n = 3,471) identified through random digit dialing methods. Multivariate logistic regression was used to estimate age‐adjusted odds ratio (AOR) and 95% confidence intervals (CI). Several individual supplements were associated with reduced breast cancer risk (e.g., Natural HRT; AOR = 0.39; 95% CI: 0.22, 0.69; n_users = 58). Use of any isoflavone supplements was associated with reduced risk when ≥3 were ever used (AOR = 0.68; 95% CI: 0.54, 0.86; n_users = 332; p_trend = 0.008) or any was taken >5 years (AOR = 0.75; 95% CI: 0.60, 0.94; n_users = 325; p_trend = 0.01); high content supplements were consistently associated with reduced risk. Risk reduction was confined to postmenopausal breast cancer for both individual and combined supplements, and was strongest in the latter among high content users who ever took ≥3 supplements (AOR = 0.55; 95% CI: 0.38, 0.81; n_users = 118; p_trend = 0.04) or any >5 years (AOR = 0.47; 95% CI: 0.27, 0.81; n_users = 60; p_trend = 0.03). Associations did not differ by estrogen‐progesterone tumor receptor status. In conclusion, isoflavone supplements were associated with decreased postmenopausal breast cancer risk. Further research to examine these novel findings is warranted, given the low supplement use and potential limitations of our results.     

Erythrocyte membrane fatty acid composition, serum lipids, and non-Hodgkin’s lymphoma risk in a nested case–control study: the multiethnic cohort

Purpose

Composition of dietary fatty acid intake, which influences cytokine production, may contribute to the development of non-Hodgkin’s lymphoma (NHL). Serum lipid levels may serve as biomarkers of inflammation associated with NHL risk.

Methods

We conducted a case–control analysis (275 cases and 549 controls) nested within the Multiethnic Cohort Study (whites, Japanese Americans, Latinos, African Americans, and Native Hawaiians) to examine the association of prediagnostic, erythrocyte membrane phospholipid fatty acid composition, and serum cholesterol and triglyceride (TG) concentrations with the risk of NHL. Conditional logistic regression was used to calculate odds ratios (OR) and 95?% confidence intervals (CI) by tertiles of biomarker concentrations.

Results

Higher total saturated fatty acids (SFA) were associated with an increase in NHL risk (OR_{T3 vs. T1}?=?1.57 [95?% CI: 1.03–2.39]; p _trend?=?0.01), whereas no associations were detected for total n?3 or n?6 polyunsaturated fatty acids. Inverse associations were observed for total cholesterol (TC; OR _{T3 vs. T1}?=?0.51 [95?% CI: 0.35–0.74]; p _trend ?T3 vs. T1?=?0.47 [95?% CI: 0.31–0.71]; p _trend ?=?0.0001) but not for low-density lipoprotein cholesterol or TG. Adjustment for the use of lipid-lowering medication did not modify the results substantially.

Conclusions

This prospective biomarker investigation offers supportive evidence for an adverse effect of higher erythrocyte membrane SFA levels on NHL risk, but preclinical effects cannot be excluded. Inverse relations between prediagnostic, circulating TC and HDL-C and NHL risk may be due to reverse causation or a result of protective actions of these lipids and lipoproteins.     

Association of plasma concentrations of branched-chain amino acids with risk of colorectal adenoma in a large Japanese population

BackgroundAvailable evidence from animal studies suggests that branched-chain amino acids (BCAAs) may have a protective effect against colorectal carcinogenesis. However, a possible effect of BCAAs against colorectal neoplasia has not been evaluated in humans. Here, we aimed to evaluate whether plasma concentrations of BCAA are associated with the risk of colorectal adenoma (CRA), a precursor lesion of colorectal cancer.Patients and methodsCRA cases and controls were identified from examinees who underwent total colonoscopy as part of a cancer screening program between 2004 and 2005 and responded to self-administered dietary and lifestyle questionnaires. We measured plasma concentrations of leucine, isoleucine and valine in 629 patients with adenoma and 584 controls. Unconditional logistic regression models were used to estimate odds ratio (OR) and 95% confidence interval (CI) for the association between BCAA and CRA risk after adjustment for potential confounders.ResultsHigh plasma concentrations of leucine, valine and total BCAA were inversely associated with CRA risk after adjustment of potential confounders. The multivariate-adjusted ORs for the highest versus lowest quartiles were 0.60 (95% CI 0.42–0.87,P_trend = 0.006) for leucine, 0.68 (95% CI 0.48–0.97,P_trend = 0.09) for valine and 0.68 (95% CI 0.48–0.98,P_trend = 0.10) for total BCAA. Further analysis by gender revealed that this inverse association was clearly evident in men, but not in women: the corresponding OR for leucine, valine and total BCAA was 0.50 (95% CI 0.32–0.80,P_trend = 0.003), 0.60 (95% CI 0.38–0.95,P_trend = 0.01) and 0.58 (95% CI 0.37–0.93,P_trend = 0.04), respectively, in men and 0.78 (95% CI 0.42–1.45,P_trend = 0.44), 0.77 (95% CI 0.41–1.43,P_trend = 0.85) and 0.84 (95% CI 0.45–1.57,P_trend = 0.81), respectively, in women.ConclusionOur finding suggests that BCAAs may have a beneficial influence against the process of colorectal carcinogenesis, at least in the early stage. The mechanisms underlying this potential association between BCAA and colorectal carcinogenesis warrant further investigation.     

Circulating 25-hydroxyvitamin D,vitamin D binding protein and risk of advanced and lethal prostate cancer

We previously found that higher total 25-hydroxyvitamin D [25(OH)D] levels were associated with lower risk of lethal prostate cancer. However, the relationships of bioavailable 25(OH)D and vitamin D binding protein (VDBP) with risk of advanced and lethal prostate cancer are unclear. In a prospective case–control study of 156 pairs of advanced prostate cancer cases and controls, we directly measured prediagnostic circulating 25(OH)D and VDBP and calculated bioavailable 25(OH)D using a validated formula. We examined the association of bioavailable 25(OH)D and VDBP levels with risk of advanced and lethal prostate cancer and whether total 25(OH)D levels interacted with VDBP levels to affect the risk. Conditional logistic models were used to calculate odds ratios (ORs) and 95% confidence intervals (CIs). Compared to total 25(OH)D (p_trend = 0.02), bioavailable 25(OH)D levels were not more strongly associated with risk of advanced prostate cancer (p_trend = 0.14). Although VDBP levels were not associated with risk of advanced prostate cancer (p_trend = 0.16), we observed an interaction between total 25(OH)D levels and VDBP levels in relation to risk of advanced prostate cancer (p_interaction = 0.03). Compared to those with total 25(OH)D levels below the median and VDBP levels above the median (at highest risk), men with both levels above the median had a multivariable-adjusted OR of 0.31 (95% CI, 0.15–0.65) for advanced prostate cancer. We observed similar results when we restricted the analyses to 116 lethal prostate cancer cases and their controls. Our data suggest that VDBP levels may modify the association between total 25(OH)D levels and risk of advanced and lethal prostate cancer.     

Prediagnostic plasma IGFBP‐1, IGF‐1 and risk of prostate cancer

Insulin‐like growth factor (IGF)?1 is associated with a higher risk of prostate cancer. IGF‐binding protein (IGFBP)?1, a marker for insulin activity, also binds IGF‐1 and inhibits its action. Data on IGFBP‐1 and prostate cancer risk are sparse and whether the IGF and insulin axes interact to affect prostate cancer carcinogenesis is unknown. We evaluated the independent and joint influence of prediagnostic plasma levels of IGFBP‐1 (fasting) and IGF‐1 on risk of prostate cancer among 957 cases and 1,021 controls with fasting levels of IGFBP‐1 and 1,709 cases and 1,778 controls with IGF‐1 nested within the Health Professionals Follow‐up Study. Unconditional logistic regression adjusting for matching factors was used to estimate the odds ratio (OR) and 95% confidence interval (CI). Higher prediagnostic fasting IGFBP‐1 levels were associated with lower risk of prostate cancer (highest vs. lowest quartile OR = 0.67, 95% CI 0.52–0.86, p_trend = 0.003), which remained similar after adjusting for IGF‐1. Prediagnostic IGF‐1 was associated with increased risk of prostate cancer (highest vs. lowest quartile OR = 1.28, 95% CI = 1.05–1.56, p_trend = 0.01). The associations with each marker were primarily driven by lower‐grade and non‐advanced prostate cancer. Being low in IGFBP‐1 and high in IGF‐1 did not confer appreciable additional risk (p_interaction = 0.42). In summary, prediagnostic fasting IGFBP‐1 may influence prostate cancer carcinogenesis. Being low in IGFBP‐1 or high in IGF‐1 is sufficient to elevate the risk of prostate cancer.     

Endogenous sex hormones and colorectal cancer survival among men and women

Although previous studies have suggested a potential role of sex hormones in the etiology of colorectal cancer (CRC), no study has yet examined the associations between circulating sex hormones and survival among CRC patients. We prospectively assessed the associations of prediagnostic plasma concentrations of estrone, estradiol, free estradiol, testosterone, free testosterone and sex hormone-binding globulin (SHBG) with CRC-specific and overall mortality among 609 CRC patients (370 men and 239 postmenopausal women not taking hormone therapy at blood collection) from four U.S. cohorts. Multivariable hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using Cox proportional hazard regression. We identified 174 deaths (83 CRC-specific deaths) in men and 106 deaths (70 CRC-specific deaths) in women. In men, higher circulating level of free testosterone was associated with lower risk of overall (the highest vs. lowest tertiles, HR = 0.66, 95% CI, 0.45–0.99, p_trend = 0.04) and possibly CRC-specific mortality (HR = 0.73, 95% CI, 0.41–1.29, p_trend = 0.27). We generally observed nonsignificant inverse associations for other sex steroids, and a positive association for SHBG with CRC-specific mortality among male patients. In women, however, we found a suggestive positive association of estrone with overall (HR = 1.54, 95% CI, 0.92–2.60, p_trend = 0.11) and CRC-specific mortality (HR = 1.96, 95% CI, 1.01–3.84, p_trend = 0.06). Total estradiol, free estradiol and free testosterone were generally suggestively associated with higher risk of mortality among female patients, although not statistically significant. These findings implicated a potential role of endogenous sex hormones in CRC prognosis, which warrant further investigation.     

Circulating anti‐Müllerian hormone and breast cancer risk: A study in ten prospective cohorts

A strong positive association has been observed between circulating anti‐Müllerian hormone (AMH), a biomarker of ovarian reserve, and breast cancer risk in three prospective studies. Confirming this association is important because of the paucity of biomarkers of breast cancer risk in premenopausal women. We conducted a consortium study including ten prospective cohorts that had collected blood from premenopausal women. A nested case–control design was implemented within each cohort. A total of 2,835 invasive (80%) and in situ (20%) breast cancer cases were individually matched to controls (n = 3,122) on age at blood donation. AMH was measured using a high sensitivity enzyme‐linked immunoabsorbent assay. Conditional logistic regression was applied to the aggregated dataset. There was a statistically significant trend of increasing breast cancer risk with increasing AMH concentration (p_trend across quartiles <0.0001) after adjusting for breast cancer risk factors. The odds ratio (OR) for breast cancer in the top vs. bottom quartile of AMH was 1.60 (95% CI = 1.31–1.94). Though the test for interaction was not statistically significant (p_interaction = 0.15), the trend was statistically significant only for tumors positive for both estrogen receptor (ER) and progesterone receptor (PR): ER+/PR+: OR_Q4–Q1 = 1.96, 95% CI = 1.46–2.64, p_trend <0.0001; ER+/PR?: OR_Q4–Q1 = 0.82, 95% CI = 0.40–1.68, p_trend = 0.51; ER?/PR+: OR_Q4–Q1 = 3.23, 95% CI = 0.48–21.9, p_trend = 0.26; ER?/PR?: OR_Q4–Q1 = 1.15, 95% CI = 0.63–2.09, p_trend = 0.60. The association was observed for both pre‐ (OR_Q4–Q1= 1.35, 95% CI = 1.05–1.73) and post‐menopausal (OR_Q4–Q1 = 1.61, 95% CI = 1.03–2.53) breast cancer (p_interaction = 0.34). In this large consortium study, we confirmed that AMH is associated with breast cancer risk, with a 60% increase in risk for women in the top vs. bottom quartile of AMH.     

Higher diet-dependent acid load is associated with risk of breast cancer: Findings from the sister study

Dietary factors that contribute to chronic low-grade metabolic acidosis have been linked to breast cancer risk, but to date no epidemiologic study has examined diet-dependent acid load and breast cancer. We used data from 43,570 Sister Study participants who completed a validated food frequency questionnaire at enrollment (2003–2009) and satisfied eligibility criteria. The Potential Renal Acid Load (PRAL) score was used to estimate diet-dependent acid load. Higher scores reflect greater consumption of protein and phosphorus, and lower consumption of potassium, calcium and magnesium. The association between PRAL and breast cancer was evaluated using multivariable Cox proportional hazards regression. We identified 1,614 invasive breast cancers diagnosed at least 1 year after enrollment (mean follow-up, 7.6 years). The highest PRAL quartile, reflecting greater acid-forming potential, was associated with increased risk of breast cancer (HR_{highest vs. lowest quartile}: 1.21 [95% CI, 1.04–1.41], p_trend = 0.04). The association was more pronounced for estrogen receptor (ER)-negative (HR_{highest vs. lowest quartile}: 1.67 [95% CI, 1.07–2.61], p_trend = 0.03) and triple-negative breast cancer (HR_{highest vs. lowest quartile}: 2.20 [95% CI, 1.23–3.95], p_trend = 0.02). Negative PRAL scores, representing consumption of alkaline diets, were associated with decreased risk of ER-negative and triple-negative breast cancer, compared to a PRAL score of 0 representing neutral pH. Higher diet-dependent acid load may be a risk factor for breast cancer while alkaline diets may be protective. Since PRAL scores are positively correlated with meat consumption and negatively correlated with fruit and vegetable intake, results also suggest that diets high in fruits and vegetables and low in meat may be protective against hormone receptor negative breast cancer.