The association between the essential metal mixture and fasting plasma glucose in Chinese community-dwelling elderly people.

BACKGROUND: Epidemiological studies about the effect of essential metal mixture on fasting plasma glucose (FPG) levels among elderly people are sparse. The object of this study was to examine the associations of single essential metals and essential metal mixture with FPG levels in Chinese community-dwelling elderly people. METHODS: The study recruited 2348 community-dwelling elderly people in total. Inductively coupled plasma-mass spectrometry was adopted to detect the levels of vanadium (V), selenium (Se), magnesium (Mg), cobalt (Co), calcium (Ca), and molybdenum (Mo) in urine. The relationships between single essential metals and essential metal mixture and FPG levels were evaluated by linear regression and Bayesian kernel machine regression (BKMR) models, respectively. RESULTS: In multiple-metal linear regression models, urine V and Mg were negatively related to the FPG levels (ß = - 0.016, 95 % CI: - 0.030 to - 0.003 for V; ß = - 0.021, 95 % CI: - 0.033 to - 0.009 for Mg), and urine Se was positively related to the FPG levels (ß = 0.024, 95 % CI: 0.014-0.034). In BKMR model, the significant relationships of Se and Mg with the FPG levels were also found. The essential metal mixture was negatively associated with FPG levels in a dose-response pattern, and Mg had the maximum posterior inclusion probability (PIP) value (PIP = 1.0000), followed by Se (PIP = 0.9968). Besides, Co showed a significant association with decreased FPG levels in older adults without hyperlipemia and in women. CONCLUSIONS: Both Mg and Se were associated with FPG levels, individually and as a mixture. The essential metal mixture displayed a linear dose-response relationship with reduced FPG levels, with Mg having the largest contribution to FPG levels, followed by Se. Further prospective investigations are necessary to validate these exploratory findings.

Prenatal Exposure to Air Pollution and Pre-Labor Rupture of Membranes in a Prospective Cohort Study: The Role of Maternal Hemoglobin and Iron Supplementation.

BACKGROUND: Exposure to air pollution in prenatal period is associated with prelabor rupture of membranes (PROM). However, the sensitive exposure time windows and the possible biological mechanisms underlying this association remain unclear. OBJECTIVE: We aimed to identify the sensitive time windows of exposure to air pollution for PROM risk. Further, we examined whether maternal hemoglobin levels mediate the association between exposure to air pollution and PROM, as well as investigated the potential effect of iron supplementation on this association. METHOD: From 2015 to 2021, 6,824 mother-newborn pairs were enrolled in the study from three hospitals in Hefei, China. We obtained air pollutant data [particulate matter (PM) with aerodynamic diameter ≤2.5µm (PM2.5), PM with aerodynamic diameter ≤10µm (PM10), sulfur dioxide (SO2), and carbon monoxide (CO)] from the Hefei City Ecology and Environment Bureau. Information on maternal hemoglobin levels, gestational anemia, iron supplementation, and PROM was obtained from medical records. Logistic regression models with distributed lags were used to identify the sensitive time window for the effect of prenatal exposure to air pollutant on PROM. Mediation analysis estimated the mediated effect of maternal hemoglobin in the third trimester, linking prenatal air pollution with PROM. Stratified analysis was used to investigate the potential effect of iron supplementation on PROM risk. RESULTS: We found significant association between prenatal exposure to air pollution and increased PROM risk after adjusting for confounders, and the critical exposure windows of PM2.5, PM10, SO2 and CO were the 21th to 24th weeks of pregnancy. Every 10-µg/m3 increase in PM2.5 and PM10, 5-µg/m3 increase in SO2, and 0.1-mg/m3 increase in CO was associated with low maternal hemoglobin levels [-0.94g/L (95% confidence interval (CI): -1.15, -0.73), -1.31g/L (95% CI: -1.55, -1.07), -2.96g/L (95% CI: -3.32, -2.61), and -1.11g/L (95% CI: -1.31, -0.92), respectively] in the third trimester. The proportion of the association between air pollution and PROM risk mediated by hemoglobin levels was 20.61% [average mediation effect (95% CI): 0.02 (0.01, 0.05); average direct effect (95%): 0.08 (0.02, 0.14)]. The PROM risk associated with exposure to low-medium air pollution could be attenuated by maternal iron supplementation in women with gestational anemia. CONCLUSIONS: Prenatal exposure to air pollution, especially in the 21st to 24th weeks of pregnancy, is associated with PROM risk, which is partly mediated by maternal hemoglobin levels. Iron supplementation in anemia pregnancies may have protective effects against PROM risk associated with exposure to low-medium air pollution. https://doi.org/10.1289/EHP11134.

Selenium attenuates the association of co-exposure to arsenic, cadmium, and lead with cognitive function among Chinese community-dwelling older adults.

The effects of interactions between the toxic and essential metal mixtures on cognitive function are poorly understood. This study aims to identify the joint association of arsenic (As), cadmium (Cd), and lead (Pb) with cognitive function in older adults and the moderating role of selenium (Se), zinc (Zn), and copper (Cu) in this association. This study included 1000 community-dwelling older adults. Cognitive function was assessed by the Mini-Mental State Examination (MMSE). Blood concentrations of As, Cd, Pb, Se, Zn, and Cu were measured using inductively coupled plasma mass spectrometry. Linear regression and Bayesian kernel machine regression (BKMR) models were applied to assess the individual and joint associations of As, Cd, and Pb with cognitive function and to examine whether Se, Zn, and Cu (individually and as a mixture) modified these associations. In the adjusted single-metal models, both Cd (ß = - 0.37, 95% CI: - 0.73 to - 0.01) and Pb (ß = - 0.44, 95% CI: - 0.86 to - 0.02) were associated with MMSE scores, while Se (ß = 0.71, 95% CI: 0.30 to 1.13) exhibited a positive relationship with MMSE scores. Univariate exposure-response functions from BKMR models showed similar results. Moreover, the toxic metal mixture (As, Cd, and Pb) exhibited a significant negative association with MMSE scores in a dose-response pattern, with Pb being the greatest contributor within the mixture. The negative association of Pb alone or the toxic metal mixture with MMSE scores became weaker at higher concentrations of Se within its normal range, especially when Se levels were greater than the median (89.18 µg/L). Our findings support that Se can attenuate the negative associations of exposure to single Pb or the As, Cd, and Pb mixtures with cognitive function. Future prospective studies are needed to replicate our findings.

The association between essential trace element mixture and cognitive function in Chinese community-dwelling older adults.

BACKGROUND: The evidence about the effect of essential trace element (ETE) mixture on cognitive function amongst older adults is limited. This study aims to evaluate the associations of single ETEs and ETE mixture with cognitive function using a representative sample of community-dwelling older adults in China. METHODS: A total of 3814 older adults were included in the study. Urinary concentrations of selenium (Se), vanadium (V), cobalt (Co), strontium (Sr), and molybdenum (Mo) were detected by inductively coupled plasma mass spectrometry. Cognitive function in older adults was assessed using the Chinese version of the Mini-Mental State Examination (MMSE). Linear regression and Bayesian kernel machine regression (BKMR) were performed to explore the associations of single ETEs and ETE mixture with cognitive function, respectively. RESULTS: Linear regression showed that urinary levels of Se and V were positively associated with MMSE scores in the adjusted single-element models. BKMR also showed marginally positive associations of Se and V with MMSE scores. Moreover, higher urinary levels of ETE mixture were significantly associated with increased MMSE scores in a dose-response pattern, and Se was the most important contributor within the mixture. Both Se and V demonstrated positive additive effects on the associations of other ETEs with MMSE scores, whereas Co had a negative additive effect. CONCLUSIONS: V and Se are positively associated with cognitive function, individually and as a mixture. ETE mixture exhibits a linear dose-response association with improved cognitive function, with Se being the most important component within the mixture. Mixture analyses rather than single ETE analyses may provide a real-world perspective on the relationship between ETE mixture and cognitive function. Further cohort studies are needed to clarify the association of multiple ETEs with cognitive function.

Maternal selenium deficiency during gestation is positively associated with the risks for LBW and SGA newborns in a Chinese population.

BACKGROUND: Maternal selenium (Se) deficiency is associated with some adverse pregnant outcomes. However, it remains controversial whether maternal Se deficiency during gestation enhances the risks for low-birth-weight (LBW) and small-for-gestational-age (SGA) newborns. METHODS: For our cohort study, total 3133 mother-and-infant pairs were selected. Maternal serum Se concentration was detected by graphite furnace atomic absorption spectrometry. According to international references for maternal serum Se concentration, subjects were divided into Se deficiency (<45.0 µg/L), Se insufficiency (45.0-94.9 µg/L) and Se sufficiency (≥95.0 µg/L). RESULTS: There was a positive relation of maternal serum Se concentration in gestation and neonatal birth weight. Further analysis showed that the risks for LBW and SGA in SD group were significantly higher than that in SI and SS group, the adjusted ORs for LBW and SGA newborns were 1.87 (95%CI: 1.02, 3.45; P = 0.04) and 1.47 (95%CI: 1.07, 2.02; P = 0.02) in SI group, and 3.92 (95%CI: 2.03, 7.57; P < 0.001) and 2.77 (95%CI: 1.92, 4.02; P < 0.001) in SD group compared to SS group. In different gender subgroup, positive relations were observed between maternal Se deficiency and the risk for LBW girls, as well as the risks for both SGA girls and boys. CONCLUSION: Maternal Se deficiency in gestation was positively associated with the risk for LBW girls, as well as the risks for both SGA girls and boys.

The association of vitamin D status and supplementation during pregnancy with gestational diabetes mellitus: a Chinese prospective birth cohort study.

BACKGROUND: Previous studies have shown conflicting findings regarding the relation of vitamin D status and supplementation during pregnancy with gestational diabetes mellitus (GDM). Most of these studies hypothesized that 25-hydroxyvitamin D [25(OH)D] concentrations were associated with GDM risk and glucose metabolism based on linear association models. OBJECTIVES: We aimed to estimate the associations of 25(OH)D concentrations and vitamin D supplementation with GDM risk and glucose metabolism and determine the threshold concentrations of 25(OH)D that could significantly affect glucose metabolism and GDM risk. METHODS: In a prospective birth cohort study, we collected information about sociodemographic characteristics, health status, and lifestyle from 4984 pregnant women. Vitamin D supplementation and 25(OH)D concentrations were assessed in the second trimester. Data from the 75-g oral-glucose-tolerance test were obtained at 24-28 weeks of gestation. RESULTS: A total of 922 (18.5%) women were diagnosed with GDM. Compared with women with 25(OH)D concentrations <25 nmol/L, the GDM risk was significantly lower in women with 25(OH)D concentrations ranging from 50 to 75 nmol/L (RR: 0.74; 95% CI: 0.58, 0.95) and >75 nmol/L (RR: 0.40; 95% CI: 0.22, 0.70). The curve-fitting models suggested a significant large reduction in GDM risk, fasting plasma glucose, and area under the curve of glucose with increasing 25(OH)D concentrations only for concentrations >50 nmol/L. Consistently, GDM risk was significantly reduced only in women who took 400-600 IU vitamin D/d (RR: 0.83; 95% CI: 0.70, 0.97) with a mean 25(OH)D concentration of 50 nmol/L but not in women taking vitamin D sometimes with a mean 25(OH)D concentration of 40 nmol/L. CONCLUSIONS: GDM risk was significantly reduced only in pregnant women with 25(OH)D concentrations >50 nmol/L. Pregnant women taking 400-600 IU vitamin D/d with mean 25(OH)D concentrations of 50 nmol/L had a lower risk of GDM.

Current Recommended Vitamin D Prenatal Supplementation and Fetal Growth: Results From the China-Anhui Birth Cohort Study.

Context: Maternal vitamin D insufficiency has been associated with fetal growth restriction. However, the effect of maternal vitamin D supplementation on fetal growth has not been confirmed. Objective: To assess the effect of maternal vitamin D supplementation recommended by the Institute of Medicine (IOM) during pregnancy on the neonatal vitamin D status and the risk of small for gestational age (SGA). Design and Participants: As part of the China-Anhui Birth Cohort study, maternal sociodemographic characteristics, food intake, lifestyle, information on vitamin D supplementation, and birth outcomes were prospectively collected. For participants, 600 IU/d of vitamin D3 was routinely advised to take during pregnancy. Cord blood levels of 25-hydroxyvitamin D [25(OH)D], calcium, and phosphorus were measured in 1491 neonates who were divided into three groups based on the duration of maternal vitamin D supplementation during pregnancy. Results: Mean cord blood concentrations of 25(OH)D were 3.5 nmol/L higher [95% confidence interval (CI), 0.8, 6.2] in neonates (median, 37.9 nmol/L) whose mother took vitamin D supplementation for >2 months during pregnancy compared with those (median, 34.3 nmol/L) whose mother did not take any supplement. These significant differences on cord blood concentrations of 25(OH)D occurred regardless of the season of birth. The adjusted risk of SGA in pregnant women with vitamin D supplementation for >2 months was significantly decreased than that in women without any vitamin D supplementation (11.8% vs 6.9%; adjusted odds ratio = 0.53; 95% CI, 0.32, 0.87). Conclusions: The findings from China suggest that maternal vitamin D supplementation recommended by the IOM results in a slight but significantly higher fetal level of 25(OH)D and improves fetal growth.

Vitamin D and risk of preterm birth: Up-to-date meta-analysis of randomized controlled trials and observational studies.

AIM: We performed a meta-analysis of randomized controlled trials (RCT) and observational studies to answer the two following questions: (i) whether low maternal circulating 25 hydroxyvitamin D (25-OHD) is associated with an increased risk of preterm birth (PTB) or spontaneous PTB (sPTB); and (ii) whether vitamin D supplementation alone during pregnancy can reduce the risk of PTB. METHODS: Literature search was carried out using Pubmed, Web of Science and Embase databases up to June 2016. Pooled OR or relative risk (RR) with 95%CI were computed using fixed or random effects models depending on the size of heterogeneity. Subgroup analysis was used to explore potential sources of between-study heterogeneity. Publication bias was evaluated using Egger's test and Begg's test. RESULTS: Twenty-four articles (six RCT and 18 observational studies) were identified. Maternal circulating 25-OHD deficiency (pooled OR, 1.25; 95%CI: 1.13-1.38) rather than insufficiency (pooled OR, 1.09; 95%CI: 0.89-1.35) was associated with an increased risk of PTB, and vitamin D supplementation alone during pregnancy could reduce the risk of PTB (pooled RR, 0.57; 95%CI: 0.36-0.91). This was also the case for the sPTB subgroup (circulating 25-OHD <50 vs >50 nmol/L; pooled OR, 1.45; 95%CI: 1.20-1.75). CONCLUSIONS: Maternal circulating 25-OHD deficiency could increase PTB risk and vitamin D supplementation alone during pregnancy could reduce PTB risk. Extrapolation of the results, however, must be done with caution, and there is urgent need for larger, better-designed RCT to confirm this effect.

Supplementation with vitamin D3 during pregnancy protects against lipopolysaccharide-induced neural tube defects through improving placental folate transportation.

Several reports demonstrated that maternal lipopolysaccharide (LPS) exposure at middle gestational stage caused neural tube defects (NTDs). This study investigated the effects of supplementation with vitamin D3 (VitD3) during pregnancy on LPS-induced NTDs. Pregnant mice except controls were ip injected with LPS (25 µg/kg) daily from gestational day (GD)8 to GD12. In LPS+VitD3 group, pregnant mice were orally administered with VitD3 (25 µg/kg) before LPS injection. As expected, a 5-day LPS injection resulted in 62.5% (10/16) of dams and 20.3% of fetuses with NTDs. Additional experiment showed that a 5-day LPS injection downregulated placental proton-coupled folate transporter (pcft) and reduced folate carrier 1 (rfc1), 2 major folate transporters in placentas. Consistent with downregulation of placental folate transporters, folate transport from maternal circulation into embryos was disturbed in LPS-treated mice. Interestingly, VitD3 not only inhibited placental inflammation but also attenuated LPS-induced downregulation of placental folate transporters. Correspondingly, VitD3 markedly improved folate transport from maternal circulation into the embryos. Importantly, supplementation with VitD3 during pregnancy protected mice from LPS-induced NTDs. Taken together, these results suggest that supplementation with VitD3 during pregnancy prevents LPS-induced NTDs through inhibiting placental inflammation and improving folate transport from maternal circulation into the embryos.

[Relationship between folic acid supplements during peri-conceptional period and the adverse pregnancy outcomes: a cohort study].

OBJECTIVE: To examine the association between folic acid supplements during peri-conception and the related adverse birth outcome. METHODS: Pregnant women who received first prenatal care at 4 municipal-level medical institutions in Maanshan, from Oct. 2008 to Oct. 2010 were selected as the target population. All participants were asked to complete a self-administered questionnaire which including data on demographic characteristics, interval, complications and frequency of taking folic acid etc., during pregnancy. The follow-up-records after delivery would include factors as: fetal weight, height, circumference of head, chest circumference of the neonates. Finally, 4448 valid questionnaires were gathered, including 190 premature, 147 small for gestational age and 104 low birth weight babies. Descriptive statistics and logistic regression models were used for data analysis. RESULTS: Data showed that the weight, height and head circumference of the fetal at birth among pregnant women who had taken supplementary standard folic acid during peri-conception period or only during the first trimester, were all better than those pregnant women who had not taken the standard folic acid supplements. After adjustment for potential confounders as gestational weeks, maternal age, mather's education level, results from the logistic regression showed that intake of standard folic acid supplements appeared a protective factor for those babies who were smaller than the gestational age (RR = 0.45, 95%CI: 0.24 - 0.86), at premature delivery (RR = 0.52, 95%CI: 0.32 - 0.87) or with low birth weight (RR = 0.39, 95%CI: 0.19 - 0.80). However, data from this study showed that provision of folic acid supplements to the pre-pregnant or at first trimester alone did not make obvious impact on those babies as prematured, small for gestational age and at low birth weight. CONCLUSION: Standardized provision of folic acid supplements during peri-conceptional period could improve the outcomes of birth.

Periconceptional folic acid supplementation among women attending antenatal clinic in Anhui, China: data from a population-based cohort study.

OBJECTIVES: to examine the rate of periconceptional and optimal folic acid supplementation, and to characterise their patterns and determinants among antenatal women in central China. DESIGN: data from 4290 women in the Anhui Birth Defects and Child Development Cohort Study recruited between October 2008 and September 2009 were analysed. SETTING: seven Maternal and Child Health Centres of two cities (Hefei and Maanshan) in Anhui province of central China. PARTICIPANTS: women initiating prenatal care were included and asked to complete a structured questionnaire regarding folic acid supplementation. FINDINGS: sixty-eight per cent (2905/4290) of pregnant women reported taking folic acid supplementation periconceptionally (i.e. at some point before or during early pregnancy), and 32.8% (1405/4290) and 65.2% (2797/4290) had taken it before or during early pregnancy, respectively. However, only 16.1% (690/4290) used it optimally (i.e. regularly from four weeks before pregnancy throughout four weeks after pregnancy). Use of periconceptional folic acid was significantly associated with educational level, household income, registered residence, age, gestational age at recruitment, and planning of pregnancy. CONCLUSION: optimal folic acid supplementation was relatively low. IMPLICATIONS FOR PRACTICE: further efforts are needed to inform the population and promote the use of folic acid supplementation.

[Differences in serum retinol level between the breastfed and non-breastfed children aged 0 to 23 months].

OBJECTIVE: Some recent studies found that high prevalence of vitamin A deficiency in the breastfed children. This study aimed to understand the differences in serum retinol level between breastfed and bottle-fed children aged 0 to 23 months and the possible causes of low level of serum retinol for the breastfed children. METHODS: Data for children aged 0 to 23 months were extracted from a population-based cross sectional study for vitamin A nutrition status. Fluorescence method was used to measure the serum retinol. Mothers or caregivers were asked to answer a pre-designed questionnaire and socioeconomic status, peri-natal care, breastfeeding status, morbidity histories and other related factors were collected. Semi-quantitative food frequency questionnaire was used to investigate the child's dietary intake one week prior to the survey. Data were analyzed using SAS 8.1. RESULTS: Of 401 children aged 0 to 23 months, the breastfeeding rate was 50.37%. The means of the serum retinol level between bottle-fed (30.67 +/- 0.57) microg/dl and the breastfed children (27.60 +/- 0.56) microg/dl was significantly different (P < 0.01). The corresponding figures were (31.82 +/- 0.98) microg/dl and (29.46 +/- 0.96) microg/dl after adjustment for confounders, which also showed significant difference (P < 0.01). After stratified by age groups, the breastfeeding rates in the 0-, 6-, 12- and 18-months groups were 92.1%, 70.1%, 32.0% and 17.1%, respectively. We calculated the difference in means of the serum retinol level between the bottle-fed and breastfed children for each of four age groups, and the 95% confidence limits of the differences. The differences in means and the 95% confidence limits for 0-, 6-, 12- and 18-months group were 4.70 microg/dl (-2.52-1.92), 0.82 microg/dl (-2.32-3.95), 2.95 microg/dl (-0.68-6.58) and 6.05 microg/dl (2.34-9.77), respectively. After adjustment for confounders and covariates, the adjusted figures were 0.00 microg/dl (-7.18-7.19), 1.35 microg/dl (-1.76-4.45), 2.92 microg/dl (-0.82-6.65) and 4.26 microg/dl (0.71-7.81), respectively. The significant difference in means of serum retinol level was only found in the 18-months group before or after adjustments (P < 0.01 for both). The Cochrane-Atmitage chi square trend test showed that the breastfed children tended to have lower frequencies of complementary dietary intakes than that of the bottle-fed aged 12 months and above. CONCLUSIONS: The breastfed children aged 0 to 23 months had relative low serum retinol level while compared with the bottle-fed. However, the significant differences seemed to be only confined to those aged 18 months and above. Low level of vitamin A in breast milk and low frequent complimentary food supplements might have served as the potential for the differences.