Rice consumption and cancer incidence in US men and women

Update of the risk assessment of inorganic arsenic in food

The European Commission asked EFSA to update its 2009 risk assessment on arsenic in food carrying out a hazard assessment of inorganic arsenic (iAs) and using the revised exposure assessment issued by EFSA in 2021. Epidemiological studies show that the chronic intake of iAs via diet and/or drinking water is associated with increased risk of several adverse outcomes including cancers of the skin, bladder and lung. The CONTAM Panel used the benchmark dose lower confidence limit based on a benchmark response (BMR) of 5% (relative increase of the background incidence after adjustment for confounders, BMDL05) of 0.06 μg iAs/kg bw per day obtained from a study on skin cancer as a Reference Point (RP). Inorganic As is a genotoxic carcinogen with additional epigenetic effects and the CONTAM Panel applied a margin of exposure (MOE) approach for the risk characterisation. In adults, the MOEs are low (range between 2 and 0.4 for mean consumers and between 0.9 and 0.2 at the 95th percentile exposure, respectively) and as such raise a health concern despite the uncertainties.

White rice consumption and risk of cardiometabolic and cancer outcomes: A systematic review and dose-response meta-analysis of prospective cohort studies

White rice is the food more than half of the world's population depends on. White rice intake can significantly increase the glycemic load of consumers and bring some adverse health effects. However, the quality of evidence implicating white rice in adverse health outcomes remains unclear. To evaluate the association between white rice consumption and the risk of cardiometabolic and cancer outcomes, a systematic review and dose-response meta-analysis of the relevant publications were performed. Twenty-three articles including 28 unique prospective cohorts with 1,527,198 participants proved eligible after a comprehensive search in four databases. For the risk of type 2 diabetes mellitus (T2DM), the pooled RR was 1.18 (16 more per 1000 persons) for comparing the highest with the lowest category of white rice intake, with moderate certainty evidence. Females presented a higher risk (23 more per 1000 persons) in subgroup analysis. And every additional 150 grams of white rice intake per day was associated with a 6% greater risk of T2DM (5 more per 1000 persons) with a linear positive trend. We found no significant associations between white rice intake and risk of cardiovascular diseases (CVD), CVD mortality, cancer, and metabolic syndrome. In conclusion, moderate certainty evidence demonstrated that white rice intake was associated with T2DM risk, with a linear positive trend. However, low to very low certainty of evidence suggested that no substantial associations were found between white rice intake and other cardiometabolic and cancer outcomes. More cohorts are needed to strength the evidence body.

Dietary Manganese Intake and Risk of Liver Cancer in Japanese Men and Women: The JACC Study

We explored the association between dietary manganese intake and the risk of liver cancer in 14,517 men and 21,583 women who participated in the Japan Collaborative Cohort Study for Cancer Risk Assessment. We assessed dietary manganese intake using a food frequency questionnaire and incident liver cancer by reviewing cancer registries. According to manganese intake, we estimated the liver cancer risk by Cox regression analyses. During the 513,657 person-year follow-ups within a median of 17.9 years of 36,100 participants, there were 239 incident cases of liver cancer. The multivariable hazard ratio (HR) (95% confidence interval [CI]; P-trend) for liver cancer risk in the highest vs. the lowest quintiles of dietary manganese intake was 0.56 (0.32-0.99; 0.04) in men and 1.16 (0.56-2.40; 0.79) in women; P-interaction = 0.06. The history of liver disease modified the observed association in men (P-interaction = 0.02), in which the multivariable HR (95%CI) of liver cancer risk comparing the highest vs. lowest quintiles of dietary manganese intake was 0.32 (0.14-0.74) in Japanese men without a history of liver disease, while it was 1.54 (0.62-3.79) in men with a history of liver disease. In conclusion, a higher dietary manganese intake was associated with a lower risk of liver cancer in men without a history of liver disease.

The possible role of arsenic and gene-arsenic interactions in susceptibility to breast cancer: a systematic review

The roles of many environmental contaminants in increasing breast cancer risk remain controversial. Arsenic (As) is a major global environmental contaminant and carcinogen. We conducted a systematic review of the role of As and gene-arsenic interactions in susceptibility to breast cancer. Following a systematic literature search using well-defined inclusion/exclusion criteria, a total of 15 epidemiologic studies (two meta-analyses, three systematic reviews, three cohort studies, two case-control studies, and five cross-sectional studies) were reviewed. In addition, several animal, in vitro, in vivo, and in silico (i.e., computer modeling) studies provided mechanistic insights into the association between As and breast cancer. Our review suggests a possible overall main effect of As on breast cancer risk. The evidence for an effect of gene-As interactions on breast cancer risk is strong. Studies that measured levels of As metabolites among participants and/or evaluated interactions between As exposure and genetic or epigenetic factors generally reported positive associations with breast cancer risk. Our analysis of the Comparative Toxicogenomics and the Ingenuity Pathway Analysis Databases provided further evidence for As-gene interactions and their effects on breast cancer-related biologic pathways. Our findings provide potential leads for future epidemiologic studies of As-associated cancer risks and interventions to reduce population exposure.

Nutrition, one-carbon metabolism and arsenic methylation

Exposure to arsenic (As) is a major public health concern globally. Inorganic As (InAs) undergoes hepatic methylation to form monomethyl (MMAs)- and dimethyl (DMAs)-arsenical species, facilitating urinary As elimination. MMAsIII is considerably more toxic than either InAsIII or DMAsV, and a higher proportion of MMAs in urine has been associated with risk for a wide range of adverse health outcomes. Efficiency of As methylation differs substantially between species, between individuals, and across populations. One-carbon metabolism (OCM) is a biochemical pathway that provides methyl groups for the methylation of As, and is influenced by folate and other micronutrients, such as vitamin B12, choline, betaine and creatine. A growing body of evidence has demonstrated that OCM-related micronutrients play a critical role in As methylation. This review will summarize observational epidemiological studies, interventions, and relevant experimental evidence examining the role that OCM-related micronutrients have on As methylation, toxicity of As, and risk for associated adverse health-related outcomes. There is fairly robust evidence supporting the impact of folate on As methylation, and some evidence from case-control studies indicating that folate nutritional status influences risk for As-induced skin lesions and bladder cancer. However, the potential for folate to be protective for other As-related health outcomes, and the potential beneficial effects of other OCM-related micronutrients on As methylation and risk for health outcomes are less well studied and warrant additional research.

The relationship between rice consumption and glioma: a case-control study in adults

Previous studies have shown the effect of refined grains on various cancers; however, data on the link between rice consumption and brain cancer are scarce. We aimed to investigate the relationship between rice consumption and glioma in Iranian adults. Current hospital-based case–control study was done in Tehran between 2009 and 2011. Cases were individuals with pathologically confirmed glioma in a maximally 1 month of the disease diagnosis (n = 128). Controls were individuals, aged between 20 and 75 years, who were hospitalized or were outpatients referred to other wards of the same hospital (n = 256). Cases and controls were frequently matched in terms of age and gender. Usual dietary intakes of participants, including rice consumption, during the preceding year were examined using a Block-format validated semi-quantitative 126-item food frequency questionnaire. Compared with participants in the lowest tertile of rice consumption (< 181 g/day), those in the highest tertile (≥ 279 g/day) had 2.47 times greater chance for having glioma (OR: 2.47, 95% CI 1.44–4.23). This relationship was also seen when potential confounders including demographic variables, energy and dietary intakes as well as body mass index were taking into account; such that individuals in the top tertile of rice consumption had 2.46 times greater odds of glioma compared with those in the bottom tertile (OR: 2.46, 95% CI 1.01–5.97). We found that rice consumption was positively associated with risk of glioma in adults. Further prospective studies are required to confirm this finding.

Intake of Various Food Groups and Risk of Breast Cancer: A Systematic Review and Dose-Response Meta-Analysis of Prospective Studies

Despite increasing evidence for the association of food-based dietary patterns with breast cancer risk, knowledge about the shape of the relationship and the quality of meta-evidence are insufficient. We aimed to summarize the associations between food groups and risks of breast cancer. We performed a systematic literature search of the PubMed and Embase databases up to March 2020. We included cohort, case-cohort, nested case-control studies, and follow-up studies of randomized controlled trials that investigated the relationship between breast cancer risk and at least 1 of the following food groups: red meat, processed meat, fish, poultry, egg, vegetables, fruit, dairy product (overall, milk, yogurt, and cheese), grains/cereals, nuts, legumes, soy, and sugar-sweetened beverages. Summary risk ratios (RRs) and 95% CIs were estimated using a random-effects model for linear and nonlinear relationships. Inverse linear associations were observed for vegetables (RR per 100 g/d, 0.97; 95% CI, 0.95-0.99), fruit (RR per 100 g/d, 0.97; 95% CI, 0.95-0.99), cheese (RR per 30 g/d, 0.95; 95% CI, 0.91-1.00), and soy (RR per 30 g/d, 0.96; 95% CI, 0.94-0.99), while positive associations were observed for red (RR per 100 g/d, 1.10; 95% CI, 1.03-1.18) and processed meat (RR per 50 g/d, 1.18; 95% CI, 1.04-1.33). None of the other food groups were significantly associated with breast cancer risk. A nonlinear association was observed only for milk, such that the intake of >450 g/d increased the risk, while no association was observed for lower intake amounts. High intakes of vegetables, fruit, cheese, and soy products and low intakes of red and processed meat were associated with lower risks of breast cancer. However, causality cannot be inferred from these statistical correlations.

Association between rice consumption and risk of cancer incidence in the California Teachers Study

PURPOSE

We evaluated the contribution of rice intake, a source of dietary arsenic, to cancer risk in a population of women with likely low arsenic exposure from drinking water and variable rice intake who participated in the California Teachers Study.

METHODS

Rice consumption was categorized into quartiles (< 9.6, 9.7-15.6, 15.7-42.7, and ≥ 42.8 g/day). Multivariable-adjusted hazard ratios and 95% confidence intervals (95% CI) for incident cancer were estimated comparing rice consumption categories with bladder, breast, kidney, lung, and pancreatic cancer, with progressive adjustment for age, total calories, BMI, race, smoking status, physical activity, and cancer-specific covariates.

RESULTS

The number of breast, lung, pancreatic, bladder, and kidney cancer cases was 7,351; 1,100; 411; 344; and 238, respectively. The adjusted hazard ratios (95% CI) comparing the highest versus lowest rice intake quartiles were 1.07 (1.00-1.15); 0.87 (0.72-1.04); 0.95 (0.66-1.37); 1.11 (0.81-1.52) and 1.07 (0.72-1.59) for breast, lung, pancreatic, bladder, and kidney cancers, respectively. Results were consistent when rice was modeled as a continuous variable and in analyses stratified by smoking status.

CONCLUSION

Rice consumption was not associated with risk of kidney, lung or pancreatic cancer, except maybe a small excess risk for breast cancer and a small non-significant excess risk for bladder cancer, comparing the highest versus lowest quartile of rice intake. Due to lower consumption patterns in this cohort, future studies should involve populations for which rice is a staple food and use of an arsenic biomarker.

Grain and dietary fiber intake and bladder cancer risk: a pooled analysis of prospective cohort studies

BACKGROUND

Higher intakes of whole grains and dietary fiber have been associated with lower risk of insulin resistance, hyperinsulinemia, and inflammation, which are known predisposing factors for cancer.

OBJECTIVES

Because the evidence of association with bladder cancer (BC) is limited, we aimed to assess associations with BC risk for intakes of whole grains, refined grains, and dietary fiber.

METHODS

We pooled individual data from 574,726 participants in 13 cohort studies, 3214 of whom developed incident BC. HRs, with corresponding 95% CIs, were estimated using Cox regression models stratified on cohort. Dose-response relations were examined using fractional polynomial regression models.

RESULTS

We found that higher intake of total whole grain was associated with lower risk of BC (comparing highest with lowest intake tertile: HR: 0.87; 95% CI: 0.77, 0.98; HR per 1-SD increment: 0.95; 95% CI: 0.91, 0.99; P for trend: 0.023). No association was observed for intake of total refined grain. Intake of total dietary fiber was also inversely associated with BC risk (comparing highest with lowest intake tertile: HR: 0.86; 95% CI: 0.76, 0.98; HR per 1-SD increment: 0.91; 95% CI: 0.82, 0.98; P for trend: 0.021). In addition, dose-response analyses gave estimated HRs of 0.97 (95% CI: 0.95, 0.99) for intake of total whole grain and 0.96 (95% CI: 0.94, 0.98) for intake of total dietary fiber per 5-g daily increment. When considered jointly, highest intake of whole grains with the highest intake of dietary fiber showed 28% reduced risk (95% CI: 0.54, 0.93; P for trend: 0.031) of BC compared with the lowest intakes, suggesting potential synergism.

CONCLUSIONS

Higher intakes of total whole grain and total dietary fiber are associated with reduced risk of BC individually and jointly. Further studies are needed to clarify the underlying mechanisms for these findings.

Arsenic Exposure and Breast Cancer Risk: A Re-Evaluation of the Literature

Arsenic is a widespread environmental contaminant and recognized carcinogen for the skin, bladder and lungs. In recent years, there has been an increasing number of studies that have investigated the effects of arsenic exposure and cancer risk at other sites, including the breast. However, to date, the association between arsenic exposure and breast cancer risk remains unclear. This article will provide an overview of arsenic metabolism, the clinically important biomarkers commonly used to assess arsenic exposure, and review the epidemiologic studies examining the role of arsenic exposure on breast cancer risk. Given the large burden of disease associated with breast cancer, it is of the upmost importance to identify risk factors and preventative strategies that could reduce cancer incidence. Limiting exposure to endemic environmental toxins, such as arsenic, represents one such strategy. More studies are required to better ascertain this relationship and to develop the public policy necessary to significantly reduce breast cancer incidence.

Rice Intake and Emerging Concerns on Arsenic in Rice: a Review of the Human Evidence and Methodologic Challenges

PURPOSE OF REVIEW

Rice is a major staple food worldwide and a dietary source of arsenic. We therefore summarized the state of the epidemiologic evidence on whether rice consumption relates to health outcomes associated with arsenic exposure.

RECENT FINDINGS

While epidemiologic studies have reported that higher rice consumption may increase the risk of certain chronic conditions, i.e., type 2 diabetes, most did not consider specific constituents of rice or other sources of arsenic exposure. Studies that examined rice intake stratified by water concentrations of arsenic found evidence of increasing trends in cardiovascular disease risk, skin lesions, and squamous cell skin cancers and bladder cancer associated with higher rice consumption. Further studies are needed to understand the health impacts of arsenic exposure from rice consumption taking into account all sources of rice intake and potential confounding by other dietary constituents or contaminants and arsenic exposure from sources such as water.

Development of a colorectal cancer diagnostic model and dietary risk assessment through gut microbiome analysis

Colorectal cancer (CRC) is the third most common form of cancer and poses a critical public health threat due to the global spread of westernized diets high in meat, cholesterol, and fat. Although the link between diet and colorectal cancer has been well established, the mediating role of the gut microbiota remains elusive. In this study, we sought to elucidate the connection between the gut microbiota, diet, and CRC through metagenomic analysis of bacteria isolated from the stool of CRC (n = 89) and healthy (n = 161) subjects. This analysis yielded a dozen genera that were significantly altered in CRC patients, including increased Bacteroides, Fusobacterium, Dorea, and Porphyromonas prevalence and diminished Pseudomonas, Prevotella, Acinetobacter, and Catenibacterium carriage. Based on these altered genera, we developed two novel CRC diagnostic models through stepwise selection and a simplified model using two increased and two decreased genera. As both models yielded strong AUC values above 0.8, the simplified model was applied to assess diet-based CRC risk in mice. Mice fed a westernized high-fat diet (HFD) showed greater CRC risk than mice fed a regular chow diet. Furthermore, we found that nonglutinous rice, glutinous rice, and sorghum consumption reduced CRC risk in HFD-fed mice. Collectively, these findings support the critical mediating role of the gut microbiota in diet-induced CRC risk as well as the potential of dietary grain intake to reduce microbiota-associated CRC risk. Further study is required to validate the diagnostic prediction models developed in this study as well as the preventive potential of grain consumption to reduce CRC risk.

Blood arsenic levels and the risk of familial breast cancer in Poland

Arsenic is recognized as a potent carcinogen at high concentrations, but the relationship between environmental arsenic and breast cancer risk has not well been studied. Most research has focused on the effect of arsenic in populations with high endemic exposure, and not in populations with arsenic levels within normal limits. We sought to determine if blood arsenic levels predict the risk of breast and other cancers risk among women in northern Poland. The cohort consisted of 1,702 healthy women, aged 40 and above, identified between 2010 and 2017. Blood arsenic level was determined by inductively coupled plasma mass spectrometry. After an average of 4.5 years of follow‐up (range 0.7–7.3 years), there were 110 incident cases of cancer diagnosed in the cohort, including 68 cases of breast cancer. Women in the highest quartile of arsenic had a highly significant 13‐fold increased risk of developing breast cancer, compared to women in the lowest quartile (hazard ratio [HR] = 13.2; 95% confidence interval [CI] 4.02–43.0). Results were similar for arsenic and all incident cancers (HR quartile 4 vs. quartile 1 = 13.3; 95% CI 4.78–37.0). If confirmed, our study suggests that the blood arsenic level may be a useful predictive marker of cancer risk in women.

What's new?

Arsenic has long been recognized as a potent carcinogen at high concentrations. But can it affect cancer risk at “normal,” environmental concentrations? In this Polish study, the authors found that women whose blood levels of arsenic were in the highest quartile had a 13‐fold increased risk of developing breast cancer, compared to women in the lowest quartile. If confirmed in further studies, these results suggests that blood arsenic level may be a useful predictive marker of cancer risk in women.

miRNA-182-5p, via HIF2α, contributes to arsenic carcinogenesis: evidence from human renal epithelial cells

Chronic exposure to high levels of arsenic has been associated with high risks for many cancers, including renal cell carcinoma (RCC). However the underlying mechanisms are not clear. In the present study, chronic arsenite exposure (2 μM or 5 μM, 30 weeks) induced malignant transformation of HK-2 human renal epithelial cells as indicated by elevated colony formation (6.2- and 5.4-fold increase, respectively), secreted MMP-9 activity (10.1- and 11.3-fold increase, respectively) and proliferation rate (1.2- and 1.3-fold increase in 72 h, respectively). Lipid accumulation, typical of clear cell RCC, was observed in arsenic-transformed (As-TM) cells. Overexpression of hypoxia-inducible factor 2α (HIF2α) and suppression of carnitine palmitoyltransferase 1A (CPT1A) were found at the level of mRNA (1.5- and 0.49-fold of control, respectively) and protein (4.0- and 0.28-fold of control, respectively) after exposure to 2 μM arsenite for 20 weeks. Silencing of HIF2α significantly attenuated arsenite-induced malignant phenotypes and lipid accumulation. Inactivation of Von Hippel-Lindau (VHL) and impaired protein degradation of HIF2α were not found in As-TM cells. Expression of miR-182-5p and miR-802 in As-TM cells was 42.4% and 54.0% of control, respectively (p < 0.05). The levels of mRNA and protein of HIF2α were increased 2.4 folds and 1.6 folds of negative control in response to the miR-182-5p inhibitor, respectively, but decreased to 58.1% and 50.1% of negative control in response to miR-182-5p mimics, respectively. No significant alteration was observed in HIF2α expression when miR-802 was silenced. Our data provide further evidence for the carcinogenic role of arsenic in the kidney. Moreover, the miR-182-5p/HIF2α pathway is indicated to be involved in malignant transformation of human renal epithelial cells under arsenite exposure.

Global burden of cancer and coronary heart disease resulting from dietary exposure to arsenic, 2015

Arsenic is a ubiquitous, naturally occurring metalloid that poses a significant risk for human cancer and non-cancer diseases. It is now evident that arsenic contamination in food, especially rice and grains, presents a significant exposure to hundreds of millions of individuals worldwide. However, the disease risk from chronic exposure to the low amounts of arsenic found in food remains to be established. Thus, this research estimates the global burdens of disease expressed as Disability-Adjusted Life Years (DALYs) for lung, skin and bladder cancers, as well as coronary heart disease (CHD) attributable to inorganic arsenic in food. To determine foodborne inorganic arsenic exposures worldwide, we used the World Health Organization (WHO) estimates of food consumption in 17 country clusters, in conjunction with the reported measurements of total and inorganic arsenic in different foods. We estimated cancer potency factors for arsenic related bladder and lung cancers, and from US Environmental Protection Agency risk estimates for skin cancer to calculate the cancer incidence in males and females within each of the WHO member states. Summary relative risk estimates and population attributable fractions were developed to estimate the YLD, YLL, and DALYs for arsenic-induced CHD. The findings indicate that, globally, each year the combined DALYs for all cancers attributable to inorganic arsenic in food are approximately 1.4 million with variation in global distribution based on population and food consumption patterns. The global burden of CHD attributable to foodborne inorganic arsenic also varied with WHO region and may contribute as much as 49 million DALYs. However, in contrast to cancer burden, there is a threshold effect for arsenic-associated CHD with no increased risk of heart disease at the expected lower bound of arsenic consumption in food. These estimates indicate that foodborne arsenic exposure causes a significant yet avoidable global burden of human disease.

Association between whole grain intake and breast cancer risk: a systematic review and meta-analysis of observational studies

Background

Epidemiological studies have found that high whole grain intake may be associated with a reduced risk of breast cancer. However, the evidence has not been consistent. We conducted a meta-analysis to quantitatively assess the association between whole grain intake and breast cancer risk.

Methods

Relevant observational studies were identified by searching PubMed, Embase, Cochrane library databases, and Google Scholar through April 2017. Summary relative risk (RR) estimates were calculated using random-effects meta-analysis.

Results

A total of 11 studies, including 4 cohort and 7 case-control studies and involving 131,151 participants and 11,589 breast cancer cases, were included in the current meta-analysis. The pooled RR of breast cancer for those with high versus low whole grain intake was 0.84 (95% confidence interval [CI]: 0.74 to 0.96, p = 0.009; I² = 63.8%, p_{for heterogeneity} = 0.002). Subgroup analysis by study design found a significant inverse association in the case-control studies (RR: 0.69; 95% CI: 0.56 to 0.87, p = 0.001; I² = 58.2%, p _{for heterogeneity} = 0.026), but not in the cohort studies (RR, 0.96; 95% CI: 0.82 to 1.14, p = 0.69; I² = 66.7%, p for heterogeneity = 0.029). In addition, stratified analysis suggested that sample size could be a potential source of heterogeneity.

Conclusions

Results of the current meta-analysis suggest that high intake of whole grains might be inversely associated with a reduced risk of breast cancer, and the inverse association was only observed in case-control but not cohort studies. More large-scale cohort studies are needed to confirm the inverse association observed.

Electronic supplementary material

The online version of this article (10.1186/s12937-018-0394-2) contains supplementary material, which is available to authorized users.

Opportunities and Challenges for Dietary Arsenic Intervention

The diet is emerging as the dominant source of arsenic exposure for most of the U.S. population. Despite this, limited regulatory efforts have been aimed at mitigating exposure, and the role of diet in arsenic exposure and disease processes remains understudied. In this brief, we discuss the evidence linking dietary arsenic intake to human disease and discuss challenges associated with exposure characterization and efforts to quantify risks. In light of these challenges, and in recognition of the potential longer-term process of establishing regulation, we introduce a framework for shorter-term interventions that employs a field-to-plate food supply chain model to identify monitoring, intervention, and communication opportunities as part of a multisector, multiagency, science-informed, public health systems approach to mitigation of dietary arsenic exposure. Such an approach is dependent on coordination across commodity producers, the food industry, nongovernmental organizations, health professionals, researchers, and the regulatory community. https://doi.org/10.1289/EHP3997.

Comparative analysis of speciation and bioaccessibility of arsenic in rice grains and complementary medicines

In many countries, rice grains and complementary medicines are important sources of arsenic (As) consumption. The objective of this study was to compare the speciation and bioaccessibility of As in selected rice grains and complementary medicines. A number of rice grain samples, and a range of herbal and ayurvedic medicines were analyzed for total As, speciation of As using sequential fractionation and extended x-ray absorption fine structure (EXAFS) techniques, and bioaccessibility of As using an in vitro extraction test. The daily intake of As through the uptake of these As sources was compared with the safety guidelines for As. The results demonstrated higher levels of As in ayurvedic medicines compared to herbal medicines and rice grains. The sequential fractionation showed the dominance of organic-bound As species in rice grains and herbal medicines, however, inorganic-bound As species dominated the ayurvedic medicines. This implies that As is derived from plant uptake in herbal medicines and rice grains, and from inorganic mineral input in ayurvedic medicines. Arsenic bioaccessibility was higher in ayurvedic than herbal medicines and rice grains, suggesting that inorganic As added as a mineral therapeutic input is more bioaccessible than organic As species derived from plant uptake. This study also showed a positive relationship between soluble As fractions and bioaccessibility indicating that solubility is an important factor controlling bioaccessibility. The daily intake values for As as estimated by total As content are likely to exceed the safe threshold level in rice grains that are enriched with As.

Blood cadmium by race/hispanic origin: The role of smoking

BACKGROUND

There have been increasing concerns over health effects of low level exposure to cadmium, especially those on bones and kidneys.

OBJECTIVE

To explore how age-adjusted geometric means of blood cadmium in adults varied by race/Hispanic origin, sex, and smoking status among U.S. adults and the extent to which the difference in blood cadmium by race/Hispanic origin and sex may be explained by intensity of smoking, a known major source of cadmium exposure.

METHODS

Our sample included 7,368 adults from National Health and Nutrition Examination Survey (NHANES) 2011-2014. With direct age adjustment, geometric means of blood cadmium and number of cigarettes smoked per day were estimated for subgroups defined by race/Hispanic origin, smoking status, and sex using interval regression, which allows mean estimation in the presence of left- and right-censoring.

RESULTS

Among never and former smoking men and women, blood cadmium tended to be higher for non-Hispanic Asian adults than adults of other race/Hispanic origin. Among current smokers, who generally had higher blood cadmium than never and former smokers, non-Hispanic white, black, and Asian adults had similarly elevated blood cadmium compared to Hispanic adults. A separate analysis revealed that non-Hispanic white adults tended to have the highest smoking intensity regardless of sex, than adults of the other race/Hispanic origin groups.

CONCLUSIONS

The observed pattern provided evidence for smoking as a major source of cadmium exposure, yet factors other than smoking also appeared to contribute to higher blood cadmium of non-Hispanic Asian adults.

Lifetime grain consumption and breast cancer risk

We evaluated individual grain-containing foods and whole and refined grain intake during adolescence, early adulthood, and premenopausal years in relation to breast cancer risk in the Nurses' Health Study II. Grain-containing food intakes were reported on a baseline dietary questionnaire (1991) and every 4 years thereafter. Among 90,516 premenopausal women aged 27-44 years, we prospectively identified 3235 invasive breast cancer cases during follow-up to 2013. 44,263 women reported their diet during high school, and from 1998 to 2013, 1347 breast cancer cases were identified among these women. Cox proportional hazards regression was used to estimate relative risks (RR) and 95 % confidence intervals (95 % CI) of breast cancer for individual, whole and refined grain foods. After adjusting for known breast cancer risk factors, adult intake of whole grain foods was associated with lower premenopausal breast cancer risk (highest vs. lowest quintile: RR 0.82; 95 % CI 0.70-0.97; P trend = 0.03), but not postmenopausal breast cancer. This association was no longer significant after further adjustment for fiber intake. The average of adolescent and early adulthood whole grain food intake was suggestively associated with lower premenopausal breast cancer risk (highest vs lowest quintile: RR 0.74; 95 % CI 0.56-0.99; P trend = 0.09). Total refined grain food intake was not associated with risk of breast cancer. Most individual grain-containing foods were not associated with breast cancer risk. The exceptions were adult brown rice which was associated with lower risk of overall and premenopausal breast cancer (for each 2 servings/week: RR 0.94; 95 % CI 0.89-0.99 and RR 0.91; 95 % CI 0.85-0.99, respectively) and adult white bread intake which was associated with increased overall breast cancer risk (for each 2 servings/week: RR 1.02; 95 % CI 1.01-1.04), as well as breast cancer before and after menopause. Further, pasta intake was inversely associated with overall breast cancer risk. Our results suggest that high whole grain food intake may be associated with lower breast cancer risk before menopause. Fiber in whole grain foods may mediate the association with whole grains.

Whole grain consumption and risk of cardiovascular disease, cancer, and all cause and cause specific mortality: systematic review and dose-response meta-analysis of prospective studies

OBJECTIVE

 To quantify the dose-response relation between consumption of whole grain and specific types of grains and the risk of cardiovascular disease, total cancer, and all cause and cause specific mortality.

DATA SOURCES

 PubMed and Embase searched up to 3 April 2016.

STUDY SELECTION

 Prospective studies reporting adjusted relative risk estimates for the association between intake of whole grains or specific types of grains and cardiovascular disease, total cancer, all cause or cause specific mortality.

DATA SYNTHESIS

 Summary relative risks and 95% confidence intervals calculated with a random effects model.

RESULTS

 45 studies (64 publications) were included. The summary relative risks per 90 g/day increase in whole grain intake (90 g is equivalent to three servings-for example, two slices of bread and one bowl of cereal or one and a half pieces of pita bread made from whole grains) was 0.81 (95% confidence interval 0.75 to 0.87; I(2)=9%, n=7 studies) for coronary heart disease, 0.88 (0.75 to 1.03; I(2)=56%, n=6) for stroke, and 0.78 (0.73 to 0.85; I(2)=40%, n=10) for cardiovascular disease, with similar results when studies were stratified by whether the outcome was incidence or mortality. The relative risks for morality were 0.85 (0.80 to 0.91; I(2)=37%, n=6) for total cancer, 0.83 (0.77 to 0.90; I(2)=83%, n=11) for all causes, 0.78 (0.70 to 0.87; I(2)=0%, n=4) for respiratory disease, 0.49 (0.23 to 1.05; I(2)=85%, n=4) for diabetes, 0.74 (0.56 to 0.96; I(2)=0%, n=3) for infectious diseases, 1.15 (0.66 to 2.02; I(2)=79%, n=2) for diseases of the nervous system disease, and 0.78 (0.75 to 0.82; I(2)=0%, n=5) for all non-cardiovascular, non-cancer causes. Reductions in risk were observed up to an intake of 210-225 g/day (seven to seven and a half servings per day) for most of the outcomes. Intakes of specific types of whole grains including whole grain bread, whole grain breakfast cereals, and added bran, as well as total bread and total breakfast cereals were also associated with reduced risks of cardiovascular disease and/or all cause mortality, but there was little evidence of an association with refined grains, white rice, total rice, or total grains.

CONCLUSIONS

 This meta-analysis provides further evidence that whole grain intake is associated with a reduced risk of coronary heart disease, cardiovascular disease, and total cancer, and mortality from all causes, respiratory diseases, infectious diseases, diabetes, and all non-cardiovascular, non-cancer causes. These findings support dietary guidelines that recommend increased intake of whole grain to reduce the risk of chronic diseases and premature mortality.

Considerations when using longitudinal cohort studies to assess dietary exposure to inorganic arsenic and chronic health outcomes

Dietary arsenic exposure and chronic health outcomes are of interest, due in part to increased awareness and data available on inorganic arsenic levels in some foods. Recent concerns regarding levels of inorganic arsenic, the primary form of arsenic of human health concern, in foods are based on extrapolation from adverse health effects observed at high levels of inorganic arsenic exposure; the potential for the occurrence of these health effects from lower levels of dietary inorganic arsenic exposure has not been established. In this review, longitudinal cohort studies are evaluated for their utility in estimating dietary inorganic arsenic exposure and quantifying statistically reliable associations with health outcomes. The primary limiting factor in longitudinal studies is incomplete data on inorganic arsenic levels in foods combined with the aggregation of consumption of foods with varying arsenic levels into a single category, resulting in exposure misclassification. Longitudinal cohort studies could provide some evidence to evaluate associations of dietary patterns related to inorganic arsenic exposure with risk of arsenic-related diseases. However, currently available data from longitudinal cohort studies limit causal analyses regarding the association between inorganic arsenic exposure and health outcomes. Any conclusions should therefore be viewed with knowledge of the analytical and methodological limitations.