Impact of age, sex, and thyroid autoimmunity on the association between selenium intake and type 2 diabetes mellitus.

BACKGROUND: The association between dietary selenium(Se) intake and type 2 diabetes mellitus (T2DM) remains controversial. The present study aimed to investigate this association using data from the National Health and Nutrition Examination Survey (NHANES) database for the years 2007-2012. METHODS: Three thousand seventy three individuals aged 20 years and above were eligible for inclusion in this cross-sectional study. The average age of the participants was 50.74 years and the proportions of males and females were nearly equal (49.12% vs. 50.88%). The odds ratios (OR) of the association between dietary Se intake (log2-transformed) and T2DM were examined through the multivariate logistic regression model. Subgroup analyses were conducted based on age, sex, and thyroid autoimmunity to assess the potential impact of these variables on the relationship. Fitted smoothing curves and threshold effect analysis were conducted to describe the nonlinear relationship. RESULTS: In the fully adjusted model, a significant positive association between Se intake and T2DM was observed (OR = 1.49, 95% CI: 1.16, 1.90, p = 0.0017). After stratifying the data by age, sex, and thyroid autoimmunity, a significant positive association between Se intake and T2DM was observed in individuals under 65 years of age, males, and those with negative thyroid autoimmunity. A two-segment linear regression model was analyzed for sex stratification, revealing a threshold effect in males with an inflection point of 90.51 µg, and an inverted U-shaped relationship in females with an inflection point of 109.90 µg, respectively. CONCLUSIONS: The present study found a positive relationship between Se intake and the prevalence of T2DM. This association is particularly significant in younger individuals, males, and those with negative thyroid autoimmunity. Our results should be validated in future large prospective studies in different populations.

Association of selenium intake with bone mineral density and osteoporosis: the national health and nutrition examination survey.

Background: Osteoporosis (OP) is a systemic metabolic skeletal disorder characterized by a decrease in bone mineral density (BMD) and an increase in the risk of fracture. The level of selenium (Se) in serum is associated with BMD. However, the relationship between dietary and total selenium intake and parameters such as osteoporosis and BMD is unclear. By conducting National Health and Nutritional Examination Surveys (NHANES), in this study, we assessed the association of Se intake with BMD and the risk of OP among general middle-aged and elderly people. Methods: The data were collected from three cycles of NHANES [2009-2010, 2013-2014, and 2017-2020]. Information on the dietary and supplementary Se intake was obtained from 24-h dietary recall interviews. Additionally, dual-energy X-ray absorptiometry (DXA) was performed to measure BMD, which was later transformed into T-scores; OP was diagnosed when the T-score was ≤ -2.5. We constructed a logistic regression model for the association between selenium intake and the risk of OP based on the estimated odds ratios (ORs) and the 95% confidence intervals (CIs). We also constructed a multivariable linear regression model to analyze the relationship between selenium intake and BMD. Results: In this study, 3,250 individuals (average age: 60.01 ± 10.09 years; 51.88% females) participated. The incidence of OP was 9.35% (3.30% for males and 17.75% for females). In the logistic regression model adjusted for every interested covariate, a higher quartile of dietary Se intake (OR for quartile 4 vs. quartile 1: 0.63; 95% CI: 0.41-0.96; P for trend = 0.027) was related to a lower risk of OP relative to the lowest quartile. The total selenium intake also exhibited a consistent trend (OR for quartile 4 vs. quartile 1: 0.67; 95% CI: 0.44-1.01; P for trend = 0.049). The results of the adjusted multivariate linear regression model showed that the participants with the highest quartile of dietary Se intake (Q4) had higher BMD in the total femur (ß = 0.069, P = 0.001; P for trend = 0.001), femoral neck (ß = 0.064, P = 0.001; P for trend = 0.001), and total spine (ß = 0.030, P = 0.136; P for trend = 0.064) compared to those in quintile 1 (Q1). A similar trend of associations was observed for the total selenium intake with BMD, which was more prominent among females, as determined by the subgroup analysis. Conclusion: In this study, the dietary intake and total intake of selenium were positively associated with BMD, whereas they were negatively associated with the risk of OP among adults in the US. Further studies are required to verify our results and elucidate the associated biological mechanism.

Review on the health-promoting effect of adequate selenium status.

Selenium is an essential microelement involved in various biological processes. Selenium deficiency increases the risk of human immunodeficiency virus infection, cancer, cardiovascular disease, and inflammatory bowel disease. Selenium possesses anti-oxidant, anti-cancer, immunomodulatory, hypoglycemic, and intestinal microbiota-regulating properties. The non-linear dose-response relationship between selenium status and health effects is U-shaped; individuals with low baseline selenium levels may benefit from supplementation, whereas those with acceptable or high selenium levels may face possible health hazards. Selenium supplementation is beneficial in various populations and conditions; however, given its small safety window, the safety of selenium supplementation is still a subject of debate. This review summarizes the current understanding of the health-promoting effects of selenium on the human body, the dietary reference intake, and evidence of the association between selenium deficiency and disease.

Selenium intakes in the Irish adult population.

Selenium (Se) is an essential trace element which has an important role as a constituent of seleno-proteins involved in various physiological processes. Previous research in Irish adults suggests that intakes of this important nutrient are suboptimal. The aim of the present study was to estimate the current intakes and major food sources of Se by Irish adults. Mean daily intakes (MDIs) of Se were calculated using data from the National Adult Nutrition Survey which involved 1500 Irish adults aged 18-90 years. The Se content of foods and drinks consumed over a 4-d period was determined using data from the Irish Total Diet Study (TDS). Adequacy of Se intakes was assessed by calculating the proportion of the population with intakes below the adequate intake (AI) of 70 µg/d and lower reference nutrient intake of 40 µg/d (LRNI). The MDI of Se in the total population was 71⋅7 µg/d, with significantly higher intakes reported in men (80⋅2 µg/d) compared with women (63⋅4 µg/d, P < 0⋅01). Meat and meat products were the major contributing food group to Se intakes for both men (37 %) and women (31 %). Overall, 47 % of the population were not meeting the recommended AI, while 4 % of the total population were not meeting the LRNI. Although the average intake of Se is above the AI, a significant proportion of the population is not meeting this recommendation and continued monitoring of Se intakes is necessary, particularly by at-risk groups and also in the context of sustainability.

Association between Selenium Intake and Optimal Sleep Duration: A National Longitudinal Study.

Inconsistent findings have been discovered in studies examining the link between dietary selenium (Se) and sleep. Data were obtained from 17,176 people aged 20 and over who participated in the China Health and Nutrition Survey (CHNS) from 2004 to 2011. Face-to-face interviews were used to measure sleep duration in 2004, 2006, 2009, and 2011. To track dietary Se consumption, a 3-day, 24-h recall was undertaken. In the analysis, multilevel mixed-effects logistic regression was employed. The odds ratios (95% confidence intervals) of optimal sleep duration (7-9 h/day) in the regression of Model 4 were 1.00, 1.01 (0.89-1.15) and 1.19 (1.02-1.38) for the three tertiles of selenium consumption, respectively. Only overweight patients displayed a substantial positive connection between Se intake and the optimal sleep duration in the subgroup analysis. In summary, Se intake was significantly associated with optimal sleep duration.

The association between dietary selenium intake and Hashimoto's thyroiditis among US adults: National Health and Nutrition Examination Survey (NHANES), 2007-2012.

BACKGROUND: Selenium has been shown to influence the pathological processes and physiological functions of thyroid. Although growing evidence has shown that selenium can improve the treatment of Hashimoto's thyroiditis (HT), there is a need to evaluate the association between dietary selenium intake and HT in a large cross-sectional study. This study explored the association between dietary selenium intake and HT based on the National Health reand Nutrition Examination Survey (NHANES) database (2007-2012). METHODS: A total of 8756 of 30,442 participants were included in the study. Dietary selenium intake was the independent variable, while HT was the dependent variable. In addition, the relative importance of the selected variables was determined using the XGBoost model. A smooth curve was constructed based on the fully adjusted model to investigate the potential linear relationship between dietary selenium intake and HT. Smooth curves were also constructed to explore the linear/non-linear relationship between dietary selenium intake and thyroid peroxidase antibody (TPOAb)/ thyroglobulin antibody (TgAb). RESULTS: The mean age of the enrolled participants was 44.35 years (± 20.92). The risk of HT was significantly reduced by a 35% per-unit increase in dietary selenium intake after fully adjusting for covariates according to the model (log2-transformed data; OR 0.65; 95% CI 0.51, 0.83). The XGBoost model revealed that dietary selenium intake was the most important variable associated with Hashimoto's thyroiditis. Dietary selenium intake (Log2-transformed) was negatively correlated with TPOAb levels [- 16.42 (- 22.18, - 10.65), P < 0.0001], while a non-linear relationship was observed between dietary selenium intake and TgAb with an inflection point of 6.58 (95.67 µg, Log2-transformed). CONCLUSION: Dietary selenium intake is independently and inversely associated with HT risk. Moreover, dietary selenium intake is negatively correlated with TPOAb levels and non-linearly correlated with TGAb levels. Therefore, dietary selenium intake may be a safe and low-cost alternative for the prevention and treatment of HT.

Selenium dietary intake and survival among CRC patients.

Background: Despite advances in prevention and treatment, colorectal cancer remains the second most common cause of cancer death. To date, little is known about the role of prediagnostic selenium intake in colorectal cancer survival. Objective: The purpose of the study was to verify whether selenium intake in habitual diet before diagnosis is associated with survival in colorectal cancer patients. Study design: This was a prospective observation of patients primarily recruited for a case-control study between 2000 and 2012 in Cracow, Poland. A group of 671 incident cases of colorectal cancer was included. Habitual diet was assessed using a validated 148-item food questionnaire. 338 deaths were identified throughout 2017 by the Polish National Vital Registry. To evaluate the impact of dietary selenium on survival, the multivariable Cox regression model was used. Results: After standardization for several potential confounders (including key determinants, such as radical surgery, chemotherapy, tumor stage, and dietary factors), a decrease in the risk of death from colorectal cancer was observed in the group with higher dietary selenium intake (≥48.8 µg/day, group mean: 63.9 µg/day) compared to the group with lower dietary selenium intake (<48.8 µg/day, mean: 38.5 µg/day) (HR=0.73; 95% CI: 0.54-0.98) (the median was used for categorization). Conclusion: Our study suggests selenium as an additional dietary factor which may be associated with survival among colorectal cancer patients referred to surgery. Due to the observational nature of the study, the results should be taken with caution. These preliminary findings, however, provide the basis for well-structured clinical trials.

Selenium Intake and its Interaction with Iron Intake Are Associated with Cognitive Functions in Chinese Adults: A Longitudinal Study.

Studies on the relation between selenium intake and cognitive function are inconclusive. This study aimed to examine the associations between dietary selenium intake and cognitive function among Chinese adults and tested the interaction effect of selenium intake and iron intake on cognition. Data from 4852 adults aged 55 years and above who attended the 1991-2006 China Health and Nutrition Survey (CHNS) were used. Cognitive function was assessed through face-to-face interviews in 1997, 2000, 2004, and 2006. A 3-day, 24-hour recall was used to collect dietary selenium intake. Multivariable mixed linear regression and logistic regression were used in the analyses. In fully adjusted regression models, the regression coefficients (95% confidence interval) were 0.00, 0.29 (-0.12-0.70), 0.26 (-0.18-0.70), and 0.50 (0.02-0.97) across the quartiles of selenium intake. In the subgroup analysis, the positive association between selenium intake and cognitive function was only observed in the participants who live in the southern region but not those in the northern region. The selenium-intake-to-iron-intake ratio was inversely associated with low global cognition scores. Furthermore, only those with a normal BMI had a positive association between selenium and cognition. In conclusion, high selenium intake was linked to better cognitive function and a lower risk of cognition decline in Chinese adults among those with low iron intake. A substantial interaction was found between selenium intake and BMI or region.

Selenium intakes and plasma selenium of New Zealand toddlers: secondary analysis of a randomised controlled trial.

Little is known about Se intakes and status in very young New Zealand children. However, Se intakes below recommendations and lower Se status compared with international studies have been reported in New Zealand (particularly South Island) adults. The Baby-Led Introduction to SolidS (BLISS) randomised controlled trial compared a modified version of baby-led weaning (infants feed themselves rather than being spoon-fed), with traditional spoon-feeding (Control). Weighed 3-d diet records were collected and plasma Se concentration measured using inductively coupled plasma mass spectrometry (ICP-MS). In total, 101 (BLISS n 50, Control n 51) 12-month-old toddlers provided complete data. The OR of Se intakes below the estimated average requirement (EAR) was no different between BLISS and Control (OR: 0·89; 95 % CI 0·39, 2·03), and there was no difference in mean plasma Se concentration between groups (0·04 µmol/l; 95 % CI -0·03, 0·11). In an adjusted model, consuming breast milk was associated with lower plasma Se concentrations (-0·12 µmol/l; 95 % CI -0·19, -0·04). Of the food groups other than infant milk (breast milk or infant formula), 'breads and cereals' contributed the most to Se intakes (12 % of intake). In conclusion, Se intakes and plasma Se concentrations of 12-month-old New Zealand toddlers were no different between those who had followed a baby-led approach to complementary feeding and those who followed traditional spoon-feeding. However, more than half of toddlers had Se intakes below the EAR.

Correlation between dietary selenium intake and stroke in the National Health and Nutrition Examination Survey 2003-2018.

BACKGROUND: Epidemiologic evidence of the effect of dietary selenium intake on stroke risk remains controversial. This study aimed to examine the cross-sectional correlation between dietary selenium intake and the risk of stroke in adults. MATERIALS AND METHODS: We retrospectively analysed 39,438 participants from the National Health and Nutrition Examination Survey 2003-2018, aged 20-85 years. Participants were divided into quartiles depending on daily dietary selenium intake: quartile 1 (0-77 µg), quartile 2 (77-108 µg), quartile 3 (108-148 µg), and quartile 4 (148-400 µg). The dose-response relationship was assessed using the restricted cubic spline function. RESULTS: The adjusted odds ratios (ORs) and 95% confidence intervals (CIs) of stroke were 0.70 (0.55, 0.88) for participants in quartile 2, 0.71 (0.53, 0.93) for quartile 3, and 0.61 (0.43, 0.85) for quartile 4 compared with that in quartile 1. p-Value for trend through quartiles was .007. A non-linear negative correlation between dietary selenium intake and stroke was observed in the threshold effect analysis and restricted cubic spline function (p-value for non-linearity < .001). An initial decrease in odds of stroke lower than 105 µg/day selenium intake (0.61 [0.44, 0.85], p = .004) was followed by a platform beyond 105 µg/day (0.97 [0.81, 1.16], p = .723). In the subgroup analysis, adjusted ORs (95% CIs) of stroke were 0.51 (0.36, 0.70) for female participants, 0.63 (0.40, 0.99) for participants with age <60 years, 0.63 (0.47, 0.85) for participants with poverty-income ratio < 2.14, 0.66 (0.50, 0.87) for participants with overweight and obesity, 0.66 (0.52, 0.84) for participants with hypertension, 0.72 (0.53, 0.97) for participants without diabetes, and 0.72 (0.56, 0.92) for non-anaemic participants. CONCLUSIONS: Dietary selenium had a negative and non-linear correlation with the risk of stroke in adults. The correlation varied across different population subgroups.KEY MESSAGESDietary selenium had a negative and non-linear correlation with the risk of stroke in adults.Non-linear negative correlation trends were observed in subpopulations of females, age <60 years, poverty-income ratio <2.14, overweight and obesity, hypertension, non-diabetes, and non-anaemia.Dietary selenium intake of approximately 105 µg per day has an optimum effect on stroke.

Selenium Status in Patients with Chronic Liver Disease: A Systematic Review and Meta-Analysis.

BACKGROUND: The potential role of selenium in preventing chronic liver diseases remains controversial. This meta-analysis aimed to summarize the available evidence from observational studies and intervention trials that had evaluated the associations between body selenium status and chronic liver diseases. METHODS: We comprehensively searched MEDLINE, Embase, Web of Science, and Cochrane Library from inception to April 2021. The study protocol was registered at PROSPERO (CRD42020210144). Relative risks (RR) for the highest versus the lowest level of selenium and standard mean differences (SMD) with 95% confidence intervals (CI) were pooled using random-effects models. Heterogeneity and publication bias were evaluated using the I2 statistic and Egger's regression test, respectively. RESULTS: There were 50 studies with 9875 cases and 12975 population controls in the final analysis. Patients with hepatitis (SMD = -1.78, 95% CI: -2.22 to -1.34), liver cirrhosis (SMD = -2.06, 95% CI: -2.48 to -1.63), and liver cancer (SMD = -2.71, 95% CI: -3.31 to -2.11) had significantly lower selenium levels than controls, whereas there was no significant difference in patients with fatty liver diseases (SMD = 1.06, 95% CI: -1.78 to 3.89). Moreover, the meta-analysis showed that a higher selenium level was significantly associated with a 41% decrease in the incidence of significant advanced chronic liver diseases (RR = 0.59, 95% CI: 0.49 to 0.72). CONCLUSION: Our meta-analysis suggested that both body selenium status and selenium intake were negatively associated with hepatitis, cirrhosis, and liver cancer. However, the associations for fatty liver diseases were conflicting and need to be established in prospective trials.

Characteristics of Se in water-soil-plant system and threshold of soil Se in seleniferous areas in Enshi, China.

Se-enrichment characteristics in water-soil-plant system and dietary Se status of local residents in seleniferous areas were investigated. Results showed that Se in well water might mainly derived from Se-enriched shales and coals, and Se mobility in seleniferous soils was relatively low with less than 6.7% bioavailable forms in high-Se areas. Soil Se with irrigation, precipitation and fertilization sources contributed more to soil Se than Se-enriched shales and coals in low-Se areas, resulting in slightly higher mobility of Se in low-Se soils. Se concentration in edible parts of main crops ranged from 0.005 mg kg-1 to 4.17 mg kg-1, and cereal plants had a higher Se-enrichment ability than tuber plants. The probable dietary Se intake (PDI) in high-Se areas was decreased to 959.3 µg d-1 in recent years, which might be attributed to tap water as drinking water in recent year rather than well water-dependent and changes in dietary structure, but still far above the permissible value of 400 µg d-1. Reducing cereal-derived dietary Se intake is an important strategy to better Se nutrition status in high-Se areas. After synthesis considerations on soil Se bioavailability and PDI of Se, the soil total Se of 4 mg kg-1 and the soil available Se content of 0.32 mg kg-1 were proposed to be the reference threshold values of soil Se excess in high-Se areas in Enshi, respectively.

Association between selenium intake, diabetes and mortality in adults: findings from National Health and Nutrition Examination Survey (NHANES) 2003-2014.

Se is a trace mineral that has antioxidant and anti-inflammatory properties. This study aimed to investigate the association between Se intake, diabetes, all-cause and cause-specific mortality in a representative sample of US adults. Data from 18 932 adults who attended the 2003-2014 National Health and Nutrition Examination Survey were analysed. Information on mortality was obtained from the US mortality registry updated to 2015. Multivariable logistic regression and Cox regression were used. Cross-sectionally, Se intake was positively associated with diabetes. When comparing the extreme quartiles of Se intake, the OR for diabetes was 1·44 (95 % CI 1·09, 1·89). During a mean of 6·6 years follow-up, there were 1627 deaths (312 CVD, 386 cancer). High intake of Se was associated with a lower risk of all-cause mortality. When comparing the highest with the lowest quartiles of Se intake, the hazard ratios for all-cause, CVD mortality, cancer mortality and other mortality were 0·77 (95 % CI 0·59, 1·01), 0·62 (95 % CI 0·35, 1·13), 1·42 (95 % CI 0·78, 2·58) and 0·60 (95 % CI 0·40, 0·80), respectively. The inverse association between Se intake and all-cause mortality was only found among white participants. In conclusion, Se intake was positively associated with diabetes but inversely associated with all-cause mortality. There was no interaction between Se intake and diabetes in relation to all-cause mortality.

A national cross-sectional analysis of selenium intake and risk of osteoarthritis: NHANES 2003-2016.

Background: The association between dietary selenium intake and arthritis, rheumatoid arthritis (RA), and osteoarthritis (OA) is inconsistent in previous studies and remain unclear. To investigate their relationship, this study was performed. Methods: Data from the National Health and Nutrition Examination Survey (2003-2016) were downloaded and further analyzed. Dietary Se intake was classified according to quartiles with quartile 1 (Q1) having the lowest intake and quartile 4 (Q4) having the highest intake. Weighted logistic regression was used to investigate the association between dietary selenium intake and arthritis, RA, and OA. Subgroup analyses were performed to verify the findings. To further examine the non-linear relationship between dietary selenium intake and OA, restricted cubic spline (RCS) was adopted. Results: In the crude model, the highest level of dietary selenium intake was siginificantly associated with decreased risks of arthritis (OR: 0.40, 95% CI: 0.37, 0.44) and rheumatoid arthritis (OR: 0.47, 95% CI: 0.40, 0.54), respectively. In the fully adjusted model, dietary selenium intake was not associated with risk of arthritis and RA (all P > 0.05). Conversely, the risk of OA was noted for participants with higher selenium intake (odds ratio of quartile 4 = 1.33, 95% CI = 1.07-1.65, P < 0.05). In the subgroup analyses, participants with diabetes had a higher risk of OA when ingested high selenium levels than those without diabetes (P < 0.001). The results of RCS showed that significant overall trends were found between dietary selenium intake and osteoarthritis (P for overall < 0.05). However, non-linear association was not detected in this association (P for non-linear > 0.05). Conclusion: Using data from NHANES, this study discloses that high dietary selenium intake might be associated with risk of OA. However, the generalization of conclusion needs further examination because of the limitation of dietary questionnaire survey.

Regional Difference in the Association between the Trajectory of Selenium Intake and Hypertension: A 20-Year Cohort Study.

The effect of selenium on hypertension is inconclusive. We aimed to study the relationship between selenium intake and incident hypertension. Adults (age ≥20 years) in the China Health and Nutrition Survey were followed up from 1991 to 2011 (N = 13,668). The latent class modeling method was used to identify trajectory groups of selenium intake. A total of 4039 respondents developed hypertension. The incidence of hypertension was 30.1, 30.5, 30.6, and 31.2 per 1000 person-years among participants with cumulative average selenium intake of 21.0 ± 5.1, 33.2 ± 2.8, 43.8 ± 3.6, and 68.3 ± 25.2 µg/day, respectively. Region and selenium intake interaction in relation to hypertension was significant. In the multivariable model, cumulative intake of selenium was only inversely associated with the incident hypertension in northern participants (low selenium zone), and not in southern participants. Compared to selenium intake trajectory Group 1 (stable low intake), all three trajectory groups had a low hazard ratio for hypertension among the northern participants. However, Group 4 (high intake and decreased) showed an increasing trend of hypertension risk in the south. In conclusion, the association between selenium intake and the incidence of hypertension varied according to regions in China. In the low soil selenium zone, high selenium intake might be beneficial for hypertension prevention.

Soil Selenium Concentration and Residents Daily Dietary Intake in a Selenosis Area: A Preliminary Study in Yutangba Village, Enshi City, China.

In 1963, selenosis occurred in Yutangba Village, Enshi City, China. Subsequently, local residents migrated to a new area of Yutangba to avoid high selenium (Se) exposure. In this study, 19 soil samples, 43 food samples, 60 hair samples and 58 plasma samples from local residents were randomly collected in New Yutangba Village. The mean total Se concentrations in cultivated soil samples were 1753.6 ± 742.8 µg/kg (n = 14). The estimated daily Se intake in New Yutangba Village decreased to 63.2 ± 39.8 µg/day, slightly higher than the recommended dietary Se intake for adults in China (60 µg/day). The mean Se concentrations in hair and plasma samples were 549.7 ± 165.2 µg/kg (n = 60) and 98.4 ± 32.1 µg/L (n = 58), respectively. The result indicated that appropriate activities, such as relocation, consuming a mixture of local foods and market foods containing low Se concentration, could effectively reduce the risk of high Se exposure.

Association between selenium intake and breast cancer risk: results from the Women's Health Initiative.

PURPOSE: It has been hypothesized that selenium (Se) can prevent cancer, and that Se deficiency may be associated with an increased risk of breast cancer. However, findings from epidemiological studies have been inconsistent. The objective of this study was to assess the association between Se intake and risk of breast cancer in the Women's Health Initiative (WHI). METHODS: This study included 145,033 postmenopausal women 50-79 years who completed baseline questionnaires between October 1993 and December 1998, which addressed dietary and supplemental Se intake and breast cancer risk factors. The association between baseline Se intake and incident breast cancer was examined in Cox proportional hazards analysis. RESULTS: During a mean follow-up of 15.5 years, 9487 cases of invasive breast cancer were identified. Total Se (highest versus lowest quartile: HR 1.00, 95% CI 0.92-1.09, Ptrend = 0.66), dietary Se (highest versus lowest quartile: HR 0.99, 95% CI 0.89-1.08, Ptrend = 0.61), and supplemental Se (yes versus no: HR 0.99, 95% CI 0.95-1.03) were not associated with breast cancer incidence. CONCLUSIONS: This study indicates that Se intake is not associated with incident breast cancer among postmenopausal women in the United States. Further studies are needed to confirm our findings by using biomarkers such as toenail Se to reduce the potential for misclassification of Se status.

Determination of Selenium in Common and Selenium-Rich Rice from Different Areas in China and Assessment of Their Dietary Intake.

In this study, 41 common rice varieties and 211 selenium-rich rice varieties from ten representative areas in China were collected in 2017-2019. The selenium contents of rice were analyzed with optimized inductively coupled plasma mass spectrometry (ICP-MS). Selenium concentrations of common rice and selenium-rich rice ranges were 0.81-7.26 and 0.76-180.73 µg/100 g, respectively. The selenium contents in selenium-rich rice from different areas were significantly different (p < 0.001) while those in common rice from different areas were not. The selenium-rich rice in Harbin and Keshan showed the lowest selenium level and those from selenium-rich areas (Enshi and Ankang) were highest. Based on the estimation of the risk assessment software @risk7.0 (Palisade Corporation, New York, NY, USA), the consumption of selenium-rich rice can effectively increase dietary selenium intake for the population. However, the risk index of P95 (Percentile 95) selenium exposure at the tolerable upper intake level for children at 2-14 years old exceeded 100%, with potential risk currently. Therefore, the consumption of selenium-rich rice should be properly monitored for young children and adolescents.

Association of dietary selenium intake with telomere length in middle-aged and older adults.

BACKGROUND: Growing evidence suggested that lifestyle factors including dietary habits may influence the telomere length which is a reliable marker of biological aging and predictor for chronic diseases. However, the role of dietary selenium intake in telomere length maintenance is rarely examined. OBJECTIVE: We aimed to test the relationship between dietary selenium intake and telomere length among middle-aged and older adults in America. METHODS: A total of 3194 United States adults older than 45 years old were extracted from the National Health and Nutrition Examination Survey (NHANES) in 1999-2000 and 2001-2002. Leukocyte telomere length was measured using the quantitative real-time polymerase chain reaction (qPCR). Dietary selenium intake was assessed by a trained interviewer using 24-h dietary recall method. Generalized linear models were performed to evaluate the association of dietary selenium intake with telomere length. The restricted cubic spline analysis was used to further explore the nonlinear dose-response relationship between dietary selenium intake and telomere length. RESULTS: After adjusting potential confounders, every 20 µg increase in dietary selenium intake was associated with 0.42% (95% CI: 0.02%, 0.82%) longer telomere length in all participants. In the subgroup analyses, dietary selenium intake was related to longer telomere length in females (Percentage change: 0.87%; 95% CI: 0.26%, 1.49%) and non-obese participants (Percentage change: 0.53%; 95% CI: 0.04%, 1.02%), but not in males (Percentage change: 0.04%; 95% CI: -0.49%, 0.57%) and obese participants (Percentage change: 0.21%; 95% CI: -0.47%, 0.91%). The restricted cubic spline analysis showed a linear association between dietary selenium intake and telomere length. CONCLUSIONS: This study indicated that the increased dietary selenium intake was associated with longer telomere length among middle-aged and older adults in America. These findings require further corroboration from future prospective studies.

Maternal dietary selenium intake is associated with increased gestational length and decreased risk of preterm delivery.

The first positive genome-wide association study on gestational length and preterm delivery showed the involvement of an Se metabolism gene. In the present study, we examine the association between maternal intake of Se and Se status with gestational length and preterm delivery in 72 025 women with singleton live births from the population-based, prospective Norwegian Mother, Father and Child Cohort Study (MoBa). A self-reported, semi-quantitative FFQ answered in pregnancy week 22 was used to estimate Se intake during the first half of pregnancy. Associations were analysed with adjusted linear and Cox regressions. Se status was assessed in whole blood collected in gestational week 17 (n 2637). Median dietary Se intake was 53 (interquartile range (IQR) 44-62) µg/d, supplements provided additionally 50 (IQR 30-75) µg/d for supplement users (n 23 409). Maternal dietary Se intake was significantly associated with prolonged gestational length (ß per sd = 0·25, 95 % CI, 0·07, 0·43) and decreased risk of preterm delivery (n 3618, hazard ratio per sd = 0·92, 95 % CI, 0·87, 0·98). Neither Se intake from supplements nor maternal blood Se status was associated with gestational length or preterm delivery. Hence, the present study showed that maternal dietary Se intake but not intake of Se-containing supplements, during the first half of pregnancy was significantly associated with decreased risk of preterm delivery. Further investigations, preferably in the form of a large randomised controlled trial, are needed to elucidate the impact of Se on pregnancy duration.