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Background: Polycyclic aromatic hydrocarbons (PAHs) and its DNA adducts has been suggested to increase the risk of preterm birth (PB). Yet, few studies have been conducted to investigate this association, and the role of dietary nutrients intakes including vitamins, folate, and carotene during pre- and post-conception on this association has not been studied. Methods: Building upon a birth cohort in Taiyuan China, we conducted a nested case control study including 83 PB and 82 term births. Benzo[a]pyrene (BaP)-DNA adducts were measured by an improved LC-MC/MC analytic method. Dietary nutrient intakes were estimated from food frequency questionnaire using the Chinese Standard Tables of Food Consumption. Multivariable logistic regression model was used to examine the associations. Results: Increased risk of PB was observed as per interquartile increase in maternal BaP-DNA adduct level (OR = 1.27, 95%CI 0.95–1.67). Compared to low level (below mean) of maternal adducts, high level (above mean) of adducts was associated with the risk of PB (OR = 2.05, 95%CI 1.05–4.01). After stratified by dietary nutrients intakes, high adducts levels were associated with approximately 2–fourfold times increases in risk of PB among women with low vitamin A, C, E, folate, and carotene intakes during pre- and/or post-conception. Stronger stratified associations were consistently seen during preconception. Similar patterns were observed after additional adjustment for supplementation. Conclusions: Our study supports the hypothesis that high level of maternal PAHs exposure was significantly associated with increased risk of PB, and provides the first evidence that dietary vitamins, carotene, and folate intake levels may modify this association during different pregnancy windows. Our findings are relevant to identify recommendation for environment management and prenatal nutrition regarding pregnant women and newborns. Further investigation in other populations is warranted. [ABSTRACT FROM AUTHOR]

Background: Polycyclic aromatic hydrocarbons (PAHs) and its DNA adducts has been suggested to increase the risk of preterm birth (PB). Yet, few studies have been conducted to investigate this association, and the role of dietary nutrients intakes including vitamins, folate, and carotene during pre- and post-conception on this association has not been studied. Methods: Building upon a birth cohort in Taiyuan China, we conducted a nested case control study including 83 PB and 82 term births. Benzo[a]pyrene (BaP)-DNA adducts were measured by an improved LC-MC/MC analytic method. Dietary nutrient intakes were estimated from food frequency questionnaire using the Chinese Standard Tables of Food Consumption. Multivariable logistic regression model was used to examine the associations. Results: Increased risk of PB was observed as per interquartile increase in maternal BaP-DNA adduct level (OR = 1.27, 95%CI 0.95–1.67). Compared to low level (below mean) of maternal adducts, high level (above mean) of adducts was associated with the risk of PB (OR = 2.05, 95%CI 1.05–4.01). After stratified by dietary nutrients intakes, high adducts levels were associated with approximately 2–fourfold times increases in risk of PB among women with low vitamin A, C, E, folate, and carotene intakes during pre- and/or post-conception. Stronger stratified associations were consistently seen during preconception. Similar patterns were observed after additional adjustment for supplementation. Conclusions: Our study supports the hypothesis that high level of maternal PAHs exposure was significantly associated with increased risk of PB, and provides the first evidence that dietary vitamins, carotene, and folate intake levels may modify this association during different pregnancy windows. Our findings are relevant to identify recommendation for environment management and prenatal nutrition regarding pregnant women and newborns. Further investigation in other populations is warranted. [ABSTRACT FROM AUTHOR]

Exposure to air pollutants may be associated with preterm birth (PB) through oxidative stress, metabolic detoxification, and immune system processes. However, no study has investigated the interactive effects of maternal air pollution and genetic polymorphisms in these pathways on risk of PB. The study included 126 PB and 310 term births. A total of 177 single nucleotide polymorphisms (SNPs) in oxidative stress, immune function, and metabolic detoxification-related genes were examined and analyzed. The China air quality index (AQI) was used as an overall estimation of ambient air pollutants. Among 177 SNPs, four SNPs (GPX4 -rs376102 , GLRX -rs889224 , VEGFA -rs3025039 , and IL1A -rs3783550) were found to have significant interactions with AQI on the risk of PB (P interaction were 0.001, 0.003, 0.03, and 0.04, respectively). After being stratified by the maternal genotypes in these four SNPs, 1.38 to 1.76 times of the risk of PB were observed as per interquartile range increase in maternal AQI among women who carried the GPX4 -rs376102 AC/CC genotypes, the GLRX -rs889224 TT genotype, the VEGFA -rs3025039 CC genotype, or the IL1A -rs3783550 GT/TT genotypes. After adjustment for multiple comparisons, only GPX4 -rs376102 and AQI interaction remained statistically significant (false discovery rate (FDR)=0.17). After additional stratification by preeclampsia (PE) status, a strongest association was observed in women who carried the GPX4 -rs376102 AC/CC genotypes (OR, 2.26; 95% CI, 1.41–3.65, P interaction =0.0002, FDR=0.035) in the PE group. Our study provided the first evidence that association between maternal air pollution and PB risk may be modified by the genetic polymorphisms in oxidative stress and immune function genes. Future large studies are necessary to replicate and confirm the observed associations. • An increase in air quality index (AQI) was slightly associated with an increased risk of PB. • Genetic variants in genes involved in oxidative stress and immune function modified the association between AQI and PB risk. • Statistically significant associations between AQI and PB were observed among women who carried GPX4 -rs376102 , GLRX -rs889224 , VEGFA -rs3025039 , and IL1A -rs3783550 polymorphisms. • GPX4 -rs376102 and AQI interaction remained statistically significant after adjustment for multiple comparisons. [ABSTRACT FROM AUTHOR]

Identification of modifiable dietary factors, which are involved in the development of gestational diabetes mellitus (GDM), could inform strategies to prevent GDM. Therefore, we examined the dietary nutrient patterns and evaluated their relationship with GDM risk in a Chinese population using a case control study design. A total of 1,464 GDM cases and 8,092 non-GDM controls were included in the final analysis. Dietary intake was assessed using a 33-item food frequency questionnaire, and nutrients were estimated using the Chinese Standard Tables of Food Consumption. Dietary nutrient patterns were identified using factor analysis, and their associations with GDM risk were evaluated using unconditional logistic regression models adjusting for total energy intake, maternal age, high blood pressure, education, maternal body mass index (BMI), parity, and family history of diabetes. A "vitamin" nutrient pattern was characterized as the consumption of diet rich in vitamin A, carotene, vitamin B2, vitamin B6, vitamin C, dietary fiber, folate, calcium, and potassium. For every quartile increase in the vitamin factor score during one year prior to conception, the first trimester, and the second trimester of pregnancy, the GDM risk decreased by 9% (OR: 0.91, 95%CI: 0.86-0.96), 9% (OR: 0.91, 95%CI: 0.86-0.96), and 10% (OR: 0.90, 95%CI: 0.85-0.95), respectively. The significant reduced GDM risk was seen in women regardless of age and parity, and slightly stronger effect was found in women whose age≤30 and women who are nulliparous across the three time periods. The significant association was also found in women whose BMI≤24 with similar effect size across the three time periods. Our study suggests that the vitamin nutrient pattern diet is associated with decreased GDM risk. Additional studies are necessary to explore the underlying mechanism of this relationship. [ABSTRACT FROM AUTHOR]

• Exposure to higher levels of multiple metals was associated with preeclampsia. • The observed association is driven by a Cr, As, Hg and Pb metal mixture. • Pre-pregnancy BMI may modify the association between Cr and preeclampsia. Several studies with small sample size have reported inconsistent associations between single metal and preeclampsia (PE). Very few studies have investigated metal mixtures and PE. Blood concentrations of chromium (Cr), cadmium, mercury (Hg), arsenic (As), lead (Pb), nickel, cobalt, and antimony were measured using inductively coupled plasma-mass spectrometry among 427 PE women and 427 matched controls from Taiyuan, China. Multivariate logistic regression models, weighted quantile sum (WQS) regression, and principal component analysis were employed to examine exposure to single metals and metal mixtures in relation to PE. An increased prevalence of PE was associated with Cr (OR = 1.76, 95% CI: 1.18, 2.62 and 1.90, 1.22, 2.93 for the middle and high vs. low), Hg (OR = 1.60, 95% CI: 1.08, 2.38 for the high vs. low) and As (OR = 1.64, 95% CI: 1.07, 2.52 for the middle vs. low). The WQS index, predominated by Cr, Hg, Pb, and As, was positively associated with PE. A principal component characterized by Cr and As also exhibited excessive association with PE. The highest PE prevalence was found among women who were overweight/obese before pregnancy and had high Cr levels compared to women who had pre-pregnancy normal body mass index (BMI) and low Cr levels. Our study provided evidence that exposure to multiple metals was associated with increased prevalence of PE, and the observed association with multiple metals was dominated by Cr, As. Our study also suggested that pre-pregnancy BMI might modify the association between Cr and PE. [ABSTRACT FROM AUTHOR]

The association between multiple metal concentrations and gestational diabetes mellitus (GDM) is poorly understood. A total of 776 women with GDM and an equal number of controls were included in the study. Concentrations of metals in participants' blood (nickel (Ni), arsenic (As), cadmium (Cd), antimony (Sb), thallium (Tl), mercury (Hg), lead (Pb)) were measured using inductively coupled plasma-mass. We used unconditional logistical regression models to estimate the associations between metals and GDM. We also employed weighted quantile sum (WQS) regression and principal components analysis (PCA) to examine metal mixtures in relation to GDM. An increased risk of GDM was associated with As (OR = 1.49, 95% CI: 1.11, 2.01 for the 2nd tertile vs. the 1st tertile) and Hg (OR = 1.43, 95% CI: 1.09, 1.88 for the 3rd tertile vs. the 1st tertile). In WQS analysis, the WQS index was significantly associated with GDM (OR = 1.20, 95% CI: 1.02, 1.41). The major contributor to the metal mixture index was Hg (69.2%), followed by Pb (12.8%), and As (11.3%). Based on PCA, the second principal component, which was characterized by Hg, Ni, and Pb, was associated with an increased risk of GDM (OR = 1.46, 95% CI: 1.02, 2.08 for the highest quartile vs. the lowest quartile). Our study results suggest that high metal levels are associated with an increased risk of GDM, and this increased risk is mainly driven by Hg and, to a lesser extent, by Ni, Pb, and As. • First study to examine multiple metals and risk of gestational diabetes mellitus. • High levels of toxic metals increase the risk of gestational diabetes mellitus. • The increased risk was mainly driven by Hg, followed by Ni, Pb, and As. [ABSTRACT FROM AUTHOR]