Association of elevated mid-pregnancy maternal plasma ferritin concentrations and triglyceride concentrations with the risk of gestational diabetes mellitus: A prospective cohort study.

OBJECTIVE: Ferritin levels are well known to be associated with gestational diabetes mellitus (GDM). However, the association of the combination of ferritin and triglyceride (TG) levels in early mid-pregnancy with GDM has not been studied in depth. We investigated the independent and combined relationships of plasma ferritin and TG concentrations with the risk of GDM as well as the mediation effect of TG on ferritin. METHODS: We analysed 2071 pregnant women from the Tongji Maternal and Child Health Cohort who had their plasma ferritin and TG concentrations measured at 11-20 weeks of gestation. Associations between ferritin and TG concentrations and GDM risk were estimated using multivariable logistic regression models. Youden's index was calculated to find the cut-off values of ferritin and TG by ROC curve analysis. The mediation effect of the TG concentration on the ferritin level with GDM risk was explored by a mediation analysis. RESULTS: A total of 264 (12.3%) participants developed GDM. The median and IQR of ferritin was 53.9 (30.5-92.7) ng/mL. After adjusting for potential confounders, the relative risks (RRs) and 95% confidence intervals of GDM were 2.19 (1.42, 3.39) for ferritin and 2.02 (1.37, 2.97) for TG. The adjusted RR for combination was 2.40 (1.62, 3.55). Moreover, we found that the TG concentration mediated 15.0% of the total effect of the ferritin concentration on the risk of GDM. CONCLUSIONS: Women with a combination of both high plasma ferritin (˃55.7 ng/mL) and high TG (˃1.9 mmoL/L) were at the highest risk of GDM. Additionally, we have revealed for the first time that an elevated maternal TG concentration in early pregnancy mediates the relationship between ferritin concentration and GDM risk. TRIAL REGISTRATION: This trial is registered at https://ClinicalTrials.gov as NCT03099837.

Association of Breastfeeding Practices During the First 3 Months with Infant Sleep Trajectories: A Prospective Cohort Study.

BACKGROUND: Breastfeeding has numerous effects on maternal and child health. The effect of breastfeeding on infant sleep remains inconclusive. OBJECTIVES: We aimed to examine whether full breastfeeding (FBF) during the first 3 mo is associated with longitudinal infant sleep trajectories in their first 2 y of life. METHODS: The study was embedded in the Tongji Maternal and Child Health Cohort study. Information on infant feeding practices was collected at 3 mo of age, and maternal/child pairs were assigned to the FBF or the non-FBF group (including partially breastfeeding and exclusive formula feeding) on the basis of feeding practices during the first 3 mo of life. Sleep data of infants were obtained at 3, 6, 12, and 24 mo. Total, night, and day sleep trajectories across 3 to 24 mo were estimated with group-based models. Each sleep trajectory was differentiated on the basis of sleep duration at 3 mo (long/moderate/short) and the interval from 6 to 24 mo (moderate/short). Multinomial logistic regression was used to investigate the association of breastfeeding practices with infant sleep trajectories. RESULTS: Among the 4056 infants studied, 2558 (63.1%) received FBF for 3 mo. When compared with FBF infants, non-FBF infants had shorter sleep duration at 3, 6, and 12 mo (P < 0.01). Non-FBF infants were more likely to experience Moderate-Short (OR: 1.31; 95% CI: 1.06, 1.61) and Short-Short (OR: 1.56; 95% CI: 1.12, 2.16) total sleep trajectories and more likely to experience Moderate-Short (OR: 1.84; 95% CI: 1.22, 2.77), and Short-Moderate (OR: 1.40; 95% CI: 1.06, 1.85) night sleep trajectories than FBF infants. CONCLUSIONS: Full breastfeeding for ≥3 mo were positively associated with longer infant sleep duration. Infants fully breastfed were more likely to experience better sleep trajectories characterized by longer duration in their first 2 y of life. Full breastfeeding may benefit infants through healthy sleep.

Plasma Manganese Levels and Risk of Gestational Diabetes Mellitus: A Prospective Cohort Study.

Manganese (Mn) intake has been found to be linked with risk of type 2 diabetes. However, the role of Mn in the development of gestational diabetes mellitus (GDM) remains to be investigated. This prospective study included pregnant women from the Tongji Maternal and Child Health Cohort. A total of 2327 participants with plasma specimens before 20 weeks were included. Among the pregnant women, 9.7% (225/2327) were diagnosed with GDM. After adjustment, pregnant women with the third and highest quartile of plasma Mn levels had 1.31-fold (RR, 2.31 [1.48, 3.61]) and 2.35-fold (RR, 3.35 [2.17, 5.17]) increased risk of GDM compared with those with the lowest quartile. A 1 standard deviation increment of ln-transformed plasma Mn levels (0.53 µg/L) was related to elevated risks of GDM with RRs of 1.28 [1.17, 1.40]. The positive associations between Mn and GDM remained consistent in all the subgroups. The weighted quantile sum index was significantly related to GDM (RR, 1.60 [1.37, 1.86]). The contribution of Mn (58.69%) to the metal mixture index was the highest related to GDM. Higher plasma Mn levels were found to be linked with elevated fasting and 2 h post-load blood glucose. This study revealed relationships of higher plasma Mn levels in early pregnancy and increased risk of GDM, suggesting that though essential, excess Mn in the body might be a potential important risk factor for GDM.

The overall plant-based diet index during pregnancy and risk of gestational diabetes mellitus: a prospective cohort study in China.

The high overall plant-based diet index (PDI) is considered to protect against type 2 diabetes in the general population. However, whether the PDI affects gestational diabetes mellitus (GDM) risk among pregnant women is still unclear. We evaluated the association between PDI and GDM risk based on a Chinese large prospective cohort - the Tongji Maternal and Child Health Cohort. Dietary data were collected at 13-28 weeks of pregnancy by a validated semi-quantitative FFQ. The PDI was obtained by assigning plant food groups positive scores while assigning animal food groups reverse scores. GDM was diagnosed by a 75 g 2-h oral glucose tolerance test at 24-28 weeks of gestation. Logistic regression models were fitted to estimate OR of GDM, with associated 95 % CI, comparing women in different PDI quartiles. Among the total 2099 participants, 169 (8·1 %) were diagnosed with GDM. The PDI ranged from 21·0 to 52·0 with a median of 36·0 (interquartile range (IQR) 33·0-39·0). After adjusting for social-demographic characteristics and lifestyle factors etc., the participants with the highest quartile of PDI were associated with 57 % reduced odds of GDM compared with women in the lowest quartile of PDI (adjusted OR 0·43; 95 % CI 0·24, 0·77; Pfor trend = 0·005). An IQR increment in PDI was associated with 29 % decreased odds of GDM (adjusted OR 0·71; 95 % CI 0·56, 0·90). Findings suggest that adopting a plant-based diet during pregnancy could reduce GDM risk among Chinese women, which may be valuable for dietary counselling during pregnancy.

The association between intake of dietary lycopene and other carotenoids and gestational diabetes mellitus risk during mid-trimester: a cross-sectional study.

This study aimed to determine whether increased carotenoids intake was associated with reduced risk of gestational diabetes mellitus (GDM). We performed a cross-sectional analysis using data from Tongji Maternal and Child Health Cohort study. The dietary carotenoids intake of 1978 pregnant women was assessed using a researcher-administered FFQ before undertaking an oral glucose tolerance test at 24-28 weeks. Multivariate logistic and linear regression analyses were used to obtain the effect estimates. Participants in the highest quartile of lycopene intake showed a lower risk of GDM (OR 0·50; 95 % CI 0·29, 0·86; P for trend = 0·007) compared with those in the lowest quartile; each 1 mg increase in lycopene consumption was associated with a 5 % (95 % CI 0·91, 0·99; P for trend = 0·020) decrease in GDM risk. No significant association was found between α-carotene, ß-carotene, ß-cryptoxanthin, lutein/zeaxanthin intake and GDM risk. Multiple linear regression analysis suggested an inverse association between lycopene intake and fasting blood glucose (FBG) (P for trend < 0·001); each 1 mg increase in lycopene intake was associated with 0·005 (95 % CI 0·002, 0·007; P for trend < 0·001) mmol/l decrease in FBG. Interaction analysis indicated consistent effect on each age or pre-BMI subgroup; however, a stronger protective effect of lycopene intake against GDM was observed among primigravid women (OR 0·20; 95 % CI 0·07, 0·55 in the highest v. the lowest quartile of intake; P for interaction = 0·036). In conclusion, dietary lycopene intake was mainly assumed via reducing FBG to decrease GDM risk, and the protection was relatively increased among primigravid women.

[Optimal gestational weight gain for Chinese urban women].

OBJECTIVE: To examine optimal gestational weight gain(GWG) for Chinese pregnant women. METHODS: A total of 6998 women with singleton and term pregnancy recruited to the Tongji Maternal and Child Health Cohort during January 2013 to May 2016 in Wuhan, Hubei were included. Information on sociodemographic, medical and family history of disease was obtained by questionnaire, body weight and height were measured at the first antenatal care during 8-16 weeks of gestation. Prenatal weight of mothers were measured, and gestational week, mode of delivery, pregnancy complications, gender of newborn, birth weight and length were collected from medical records after delivery. Restricted cubic spline was used to model nonlinear relationships between GWG and the occurrence of small for gestational age(SGA), large for gestational age(LGA), low birth weight(LBW), macrosomia, cesarean, gestational hypertension(GH)and gestational diabetes mellitus(GDM), respectively. The GWG of the lowest risks for adverse pregnant outcomes was regarded as optimal GWG recommended by Tongji(TJ) for pregnant women. The P25-P75 of GWG was defined as the optimal GWG recommended by percentile method. Logistic regression was used to analyze the effect of excessive or insufficient GWG on adverse pregnancy outcomes, while the recommendations of TJ and percentile method were used as references, respectively. RESULTS: (1) The GWG with lower risk of adverse pregnant outcomes based on pre-gravid body mass index(BMI) are 12. 0-17. 0 kg for underweight, 9. 0-14. 0 kg for normal weight and 7. 0-11. 0 kg for overweight, respectively, which are defined as TJ recommendations. The recommended GWG by percentile method are 14. 0-19. 0 kg for underweight, 13. 0-19. 0 kg for normal weight, 10. 8-18. 0 kg for overweight and 9. 0-15. 8 kg for obesity, respectively. (2) Compared to women gain within the TJ recommendations, OR of LGA is 2. 94(95%CI 2. 31-3. 73), macrosomia is 3. 13(95%CI 2. 38-4. 13), cesarean is 1. 53(95%CI 1. 38-1. 71) and GH is 2. 18(95%CI 1. 50-3. 17) for those with excessive GWG, OR of SGA is 1. 82(95%CI 1. 32-2. 53) for those who gain less. The corresponding ORs according to percentile method are 2. 11(95%CI 1. 76-2. 54) for LGA, 2. 16(95%CI 1. 76-2. 65) for macrosomia, 1. 53(95%CI 1. 36-1. 72) for cesarean, 1. 39(95%CI 1. 02-1. 90) for GH and 1. 60(95%CI 1. 29-1. 99) for SGA, respectively. CONCLUSION: The optimal GWG of Chinese pregnant women recommended by the study are 12. 0-17. 0 kg for pre-gravid underweight women, 9. 0-14. 0 kg for normal weight women and 7. 0-11. 0 kg for overweight, respectively.

Higher level of GGT during mid-pregnancy is associated with increased risk of gestational diabetes mellitus.

OBJECTIVE: This study was to explore the link between gamma-glutamyl transferase (GGT), alanine transaminase (ALT) and aspartate transaminase (AST) levels during early-middle pregnancy and subsequent risk of gestational diabetes mellitus (GDM). METHODS: In a prospective cohort study, pregnant women enrolled prior to 16 weeks of gestation were followed up until delivery. GGT, AST and ALT levels were tested during weeks 14-18 of gestation and oral glucose tolerance test was conducted during 24-28 weeks to screen GDM. RESULTS: The GDM rate was 8.1% (122/1512). Mean GGT level was higher in GDM than non-GDM women (18.7 ± 13.0 vs 14.5 ± 7.0, P < .001). The higher GGT level was 26.9~74.0 U/L, which was significantly associated with increased risk of GDM. The adjusted RR (95% CI) comparing higher GGT level versus lower was 5.40 (3.36-8.68). No significant correlation was found between ALT or AST levels and the risk of GDM. CONCLUSIONS: The results suggest that pregnant women with higher serum GGT during early-middle pregnancy have higher risk of developing GDM. A GGT level >26.9 U/L may indicate an increased risk of developing GDM later and should be further concerned.

Maternal Iodine Insufficiency and Excess Are Associated with Adverse Effects on Fetal Growth: A Prospective Cohort Study in Wuhan, China.

Background: Maternal iodine status has been suggested to affect birth outcomes. Few studies have focused on its effects on fetal growth during pregnancy. Objective: This study aimed to assess maternal iodine status during early pregnancy and further examine the relation between maternal iodine status and fetal growth. Methods: A total of 2087 singleton-pregnant women participating in the Tongji Maternal and Child Health Cohort study were involved. Urinary iodine concentration (UIC) and creatinine concentration were measured in spot urine samples collected in early pregnancy (<20 wk of gestation). Fetal head circumference (HC), femur length (FL), and estimated fetal weight (EFW) were evaluated by ultrasonography in each trimester. A multiple linear regression model was used to examine the association of iodine status with fetal growth characteristics, and a mixed-effects model was used to assess longitudinal effect. Results: The median UIC and iodine-to-creatinine (I/Cr) ratio were 178 µg/L and 234 µg/g, respectively. The prevalence of insufficient iodine status (I/Cr ratio <150 µg/g) was 19.8%(n = 414), of adequate iodine status (150-249 µg/g) was 34.8% (n = 726), of iodine status above the requirements (250-499 µg/g) was 32.1% (n = 669), and of excessive iodine status (≥500 µg/g) was 13.3% (n = 278). Maternal iodine insufficiency was inversely associated with fetal FL in the second and third trimesters. In stratified analysis, significant interactions were found between maternal iodine status and age as well as parity (all P < 0.05). The longitudinal analyses showed negative associations of maternal insufficient, more than adequate, or excessive iodine status with fetal growth during pregnancy (all P < 0.05). Conclusions: In central China, maternal iodine insufficiency and excess coexisted during early pregnancy and they both adversely affected fetal growth. There is an urgent need for ongoing monitoring of iodine status among vulnerable pregnant women in order to optimize iodine nutrition during pregnancy.

Maternal dietary pattern characterised by high protein and low carbohydrate intake in pregnancy is associated with a higher risk of gestational diabetes mellitus in Chinese women: a prospective cohort study.

Maternal dietary patterns and macronutrients intake have been shown to affect the development of gestational diabetes mellitus (GDM), but the findings are inconsistent. We aimed to identify maternal dietary patterns and examine their associations with GDM risk, and to evaluate the contributions of macronutrients intake to these associations. We included 2755 Chinese pregnant women from the Tongji Maternal and Child Health Cohort. Dietary intakes were assessed using a validated semi-quantitative FFQ 2 weeks before the diagnosis of GDM. GDM (n 248) was diagnosed based on the results of a 75-g, 2-h oral glucose tolerance test at 24-28 weeks gestation. We derived five different dietary patterns from a principal component analysis. The results showed that high fish-meat-eggs scores, which were positively related to protein intake and inversely related to carbohydrate intake, were associated with a higher risk of GDM (adjusted OR for quartile 4 v. quartile 1: 1·83; 95 % CI 1·21, 2·79; P trend=0·007) and higher plasma glucose levels. In contrast, high rice-wheat-fruits scores, which were positively related to carbohydrate intake and inversely related to protein intake, were associated with lower risk of GDM (adjusted OR for quartile 3 v. quartile 1: 0·54; 95 % CI 0·36, 0·83; P trend=0·010) and lower plasma glucose levels. In addition, dietary protein and carbohydrate intake significantly contributed to the associations between dietary patterns and GDM risk or glucose levels. These findings suggest that a dietary pattern characterised by high protein and low carbohydrate intake in pregnancy was associated with a higher risk of GDM, which may provide important clues for dietary guidance during pregnancy to prevent GDM.

Prenatal NO2 exposure and ultrasound measures of foetal growth: a prospective cohort study in Wuhan, China.

OBJECTIVES: To examine the relationship between prenatal nitrogen dioxide (NO2) exposure and foetal growth in a prospective cohort of 1001 Chinese women. METHODS: The maternal NO2 exposure levels were estimated using land-use regression models based on home address. The biparietal diameter (BPD), head circumference (HC), abdominal circumference (AC), femur length (FL) and estimated foetal weight (EFW) were evaluated via ultrasonography. The multiple linear regression model was used to adjust for confounders, and the mixed-effect model was used to assess longitudinal effect. RESULTS: With a 10 µg/m3 increase in NO2 exposure, the BPD, HC, AC, FL and EFW in the second trimester decreased by 0.40 mm (95% CI -0.56 to -0.24), 1.07 mm (95% CI -1.60 to -0.54), 1.02 mm (95% CI -1.57 to -0.48), 0.24 mm (95% CI -0.37 to -0.12) and 7.84 g (95% CI -11.59 to -4.08), respectively; the BPD and HC in the third trimester decreased by 0.26 mm (95% CI -0.50 to -0.02) and 0.71 mm (95% CI -1.37 to -0.06), respectively. The longitudinal analyses showed inverse associations of NO2 exposure with BPD, HC, AC and FL (all p<0.05). The stratified analyses showed that the effects of NO2 on the HC, FL and EFW in the second trimester were stronger among female babies and that the effect of NO2 on EFW in the third trimester was stronger among smoking mothers (all p<0.05). CONCLUSIONS: In this prospective study of Chinese women, maternal NO2 exposure was inversely associated with foetal growth, and the association was stronger among female babies and smoking mothers.

Association between environmental tobacco smoke before and during pregnancy and the risk of adverse birth outcomes: a birth cohort study in Wuhan, China.

Associations between environmental tobacco smoke (ETS) and the risk of adverse birth outcomes may be confounded. We aimed to clarify the associations of ETS before and during pregnancy with the risk of adverse birth outcomes and determine whether the associations were modified by key potential confounders. A total of 7147 non-smoking mothers from the Tongji Maternal and Child Health Cohort (TMCHC) in Wuhan, China, were included in the final analyses. ETS status was self-reported by pregnant women at their first antenatal care visit before 16 gestational weeks. Information on birth outcomes was extracted from delivery records. Poisson regression was used to identify the association between ETS before and during pregnancy and the risk of adverse birth outcomes. Exposures to ETS before and during pregnancy were reported by 645 (9.0%) and 464 (6.5%) mothers, respectively. Compared with no ETS, continued ETS during pregnancy was associated with an increased risk of preterm birth (PTB) (RR: 1.55, 95% CI: 1.07, 2.25) after adjustment for potential confounders. The association remained consistent in medically indicated PTB and late PTB. The risk of PTB associated with continued ETS during pregnancy was significantly increased in mothers more educated (P for interaction < 0.05). However, the increased risk of low birth weight (LBW) or small for gestational age (SGA) births by ETS during pregnancy was not observed. Exposure to ETS during pregnancy was associated with a higher risk of PTB, but not LBW or SGA births in a Chinese birth cohort.

Association of Maternal Dietary Patterns With Birth Weight and the Mediation of Gestational Weight Gain: A Prospective Birth Cohort.

The associations among maternal diet, birth weight, and gestational weight gain are still inconclusive. This study aimed to investigate the associations between maternal dietary patterns and birth weight, and further explore whether GWG mediates these associations. A total of 3,334 pregnant women who completed a validated semi-quantitative food frequency questionnaire from the Tongji Maternal and Child Health Cohort were included. Dietary patterns were extracted by using principal component analysis. Regression models and mediation analyses were performed to explore the associations between dietary patterns and birth weight and the effects of GWG on these associations. Five dietary patterns were identified: "Beans-vegetables," "Fish-meat-eggs," "Nuts-whole grains," "Organ-poultry-seafood" and "Rice-wheat-fruits." Only women following the "Beans-vegetables" pattern had heavier newborns (ß = 47.39; 95% CI: 12.25, 82.54). Women following the "Beans-vegetables" pattern had significantly lower GWG (ß = -0.7; 95% CI: -1.15, -0.25) and had a 16% lower risk of excessive GWG and 11% higher odd of adequate GWG. The association between the "Beans-vegetables" pattern and birth weight was negatively mediated by GWG. A dietary pattern enriched in beans and vegetables is beneficial for effectively controlling GWG and increasing birth weight. GWG serves. Clinical Trial Registry: This trial was registered at ClinicalTrials.gov (NCT03099837).

Association between dietary inflammatory index and gestational diabetes mellitus risk in a prospective birth cohort study.

OBJECTIVE: Information is limited regarding the possible relationship between diet-related inflammation and the risk of gestational diabetes mellitus (GDM). This study investigated the association between the inflammatory potential of the diet, measured by the dietary inflammatory index (DII), and GDM risk in pregnant Chinese women. METHODS: This study included 2639 eligible women from the Tongji Maternal and Child Health Cohort. Dietary intake was assessed by a validated semiquantitative food frequency questionnaire and was used to calculate the DII score. The DII was then validated using C-reactive protein measurements in a subsample of 133 pregnant women. GDM diagnoses were collected from medical records based on the results of a 75 g oral glucose tolerance test at 24 to 28 wk gestation. Multivariable-adjusted logistic regression models were performed to estimate the odds ratios (ORs) for GDM risk by DII score, modeled continuously and in tertiles. RESULTS: Of the 2639 participants, 13.1% were diagnosed with GDM. DII scores ranged from -4.45 to 3.15 and were positively associated with C-reactive protein (adjusted ß : 1.28, 95% confidence interval [CI]: 0.16, 2.40; P trend = 0.023) when comparing DII tertile 3 (most pro-inflammatory) to tertile 1 (most anti-inflammatory). A significant and positive association was observed between DII scores and GDM risk (adjusted OR: 1.43; 95% CI: 1.05, 1.95; P trend = 0.022) comparing the highest versus lowest tertiles. The stratified analysis showed that this association was stronger in pregnant women who were overweight or obese before pregnancy (adjusted OR: 2.20; 95% CI: 1.03, 4.69). CONCLUSIONS: These findings suggest that a higher DII score, corresponding to a more proinflammatory diet, is associated with a higher risk of GDM, particularly in pregnant women who were overweight or obese before pregnancy.

Inverse association of total polyphenols and flavonoids intake and the intake from fruits with the risk of gestational diabetes mellitus: A prospective cohort study.

BACKGROUND & AIMS: Emerging evidence has shown the inverse association between dietary polyphenols intake and type 2 diabetes mellitus risk, however, few studies focus on the prospective effects of polyphenols on gestational diabetes mellitus (GDM). Thus, the aim was to evaluate whether higher polyphenols intake and the intake from fruits and vegetables was correlated to a lower risk of GDM. METHODS: Dietary intake of polyphenols of women with a singleton pregnancy and without any history of diabetes were obtained by a validated food frequency questionnaire from Tongji Maternal and Child Health Cohort study. Oral glucose tolerance tests were conducted at 24-28 weeks to screen for GDM. Logistic regression models were used to evaluate the association between dietary intake of polyphenols, and the results were presented as odds ratios (ORs) with 95% confidence interval (CIs). Generalized linear models were adopted to determine the association of polyphenols intake with blood glucose concentrations, and the results were presented as coefficients (ß) with 95% CIs. RESULTS: 185 (8.3%) of 2231 pregnant women were diagnosed with GDM. The intake of total polyphenols was 319.9 (217.8-427.0) mg/d, and the intake from fruits and vegetables was 201.6 (115.3-281.8) mg/d and 63.2 (41.1-92.7) mg/d, respectively. Compared with the lowest quartile, the adjusted ORs (95% CIs) of GDM risk for women with the highest quartile of total polyphenols and flavonoids intake was 0.55 (0.30, 0.99), and 0.57 (0.32, 0.99). The adjusted ORs (95% CIs) of GDM risk was 0.55 0.51 (0.30, 0.87) (Pfor trend = 0.017) for polyphenols from fruits, 0.58 (0.34, 0.99) (Pfor trend = 0.038) for flavonoids from fruits, and 0.62 (0.38, 1.00) (Pfor trend = 0.065) for anthocyanidins from fruits comparing the highest versus lowest quartile. In addition, each 100 mg increase of total polyphenols and polyphenols from fruits was associated with 0.054 (0.008, 0.096) (P = 0.021) and 0.061 (0.012, 0.109) (P = 0.015) decrease in 2-h post-load blood glucose. No significant association was found between total polyphenols from vegetables intake and the risk of GDM. CONCLUSIONS: Higher dietary intake of total polyphenols and flavonoids and the intake from fruits was associated with lower GDM risk. This study was registered at clinicaltrials.gov as NCT03099837.

Association between Chinese Dietary Guidelines Compliance Index for Pregnant Women and Risks of Pregnancy Complications in the Tongji Maternal and Child Health Cohort.

BACKGROUND: Compliance with dietary guidelines among pregnant women can positively influence not only their own health but also the health of their babies. Measuring the compliance requires professional skills in nutrition and dietary counseling. In China, few simple and effective techniques assess dietary quality among pregnant women, especially in rural areas. We aimed to establish a new simple and effective assessment technique, the "Chinese Dietary Guidelines Compliance Index for Pregnant Women (CDGCI-PW)" and assess the association between maternal dietary compliance and risks of pregnancy complications. METHODS: The CDGCI-PW consists of 13 main components which were based on the 2016 edition of the Chinese dietary guidelines for pregnant women. Each component was assigned a different score range, and the overall score ranged from 0 to 100 points. The Tongji Maternal and Child Health Cohort study (from September 2013 to May 2016) was a prospective cohort study designed to examine maternal dietary and lifestyle effects on the health of pregnant women and their offspring. The maternal diet during the second trimester was compared with the corresponding recommended intake of the Chinese balanced dietary pagoda for pregnant women to verify their compliance with dietary guidelines. The association between maternal dietary quality and risks of pregnancy complications was estimated by regression analysis. Receiver operating characteristic (ROC) curves were constructed to identify the optimal cut-off values of CDGCI-PW for gestational hypertension and gestational diabetes mellitus (GDM). RESULTS: Among the 2708 pregnant women, 1489 were eventually followed up. The mean CDGCI-PW score was 74.1 (standard deviation (SD) 7.5) in the second trimester. The majority of foods showed the following trend: the higher the CDGCI-PW score, the higher the proportion of pregnant women who reported food intake within the recommended range. Moreover, a higher maternal CDGCI-PW score was significantly associated with lower risks of gestational hypertension [odds ratio (OR) (95% confidence interval [(CI): 0.30 (0.20, 0.37)] and GDM [OR (95% CI): 0.38 (0.31, 0.48)]. The optimal CDGCI-PW cut-off value for gestational hypertension was ≥68.5 (sensitivity 82%; specificity: 61%; area under the ROC curve, AUC = 0.743), and the optimal CDGCI-PW cut-off score for GDM was ≥75.5 (sensitivity 43%; specificity: 81%; area under the ROC curve, AUC = 0.714). CONCLUSIONS: The CDGCI-PW is a simple and useful technique that assesses maternal diet quality during pregnancy, while adherence to the CDGCI-PW is associated with a lower risk of gestational hypertension and GDM.

Periconceptional iron supplementation and risk of gestational diabetes mellitus: A prospective cohort study.

AIMS: Iron supplementation has been recommended for healthy pregnancy, but concerns have been raised regarding the potential adverse effects. We sought to examine the impact of periconceptional iron supplement use on subsequent gestational diabetes mellitus (GDM) risk. METHODS: Participants (N = 5101) with information on periconceptional micronutrient supplementation and diagnosis of GDM were involved. Information on iron supplementation and general characteristics were collected at enrollment and follow-up visits. GDM was diagnosed by oral glucose tolerance tests (OGTT) conducted at 24-28 weeks of gestation. Robust Poisson regression model was used to estimate the relative risks (RRs) and 95% confidence intervals (CI) for the effect of iron supplement use on GDM. RESULTS: 10.5% of the participants were diagnosed with GDM and the incidence was significantly higher in users with iron >30 mg/d for more than 3 months (Iron >30-L) than in nonusers. Adjusted RRs (95% CI) were 1.53 (1.21, 1.93) in Iron >30-L group, 1.14 (0.80, 1.61) in users with iron >30 mg/d for<3 months (Iron > 30-S) and 1.15 (0.86, 1.54) in users with iron ≤30 mg/d for any duration (Iron ≤30) respectively, compared to nonusers. This link in Iron >30-L group was even stronger (adjusted RR: 1.70, 95% CI: 1.25, 2.31) when restricting the analysis among primiparous and iron-replete participants without family history of diabetes. There were no significant differences in birth outcomes among groups. CONCLUSIONS: Periconceptional iron supplementation >30 mg/d for long-term was associated with increased GDM risk. The need and safety of prophylactic iron supplement in iron-replete pregnant women should be reconsidered.

Association between maternal plasma ferritin concentration, iron supplement use, and the risk of gestational diabetes: a prospective cohort study.

BACKGROUND: The association between iron supplementation and gestational diabetes mellitus (GDM) is still inconclusive, and this association has not been extensively studied in relation to plasma ferritin in the early second trimester. OBJECTIVES: We aimed to prospectively examine the independent and combined associations of plasma ferritin concentrations and iron supplement use with GDM. METHODS: We studied 2117 women from the Tongji Maternal and Child Health Cohort in Wuhan, China. Plasma ferritin around 16 weeks' gestation was measured by ELISA kits and information on iron supplement use was collected by questionnaires. GDM was diagnosed by a 75-g oral-glucose-tolerance test (OGTT) at 24-28 weeks' gestation. A log-Poisson regression model was used to estimate the RR of GDM associated with plasma ferritin and iron supplementation. RESULTS: The median and IQR of plasma ferritin was 52.1 (29.6-89.9) ng/mL, and 863 (40.8%) participants reported use of iron supplements during the second trimester. A total of 219 (10.3%) participants developed GDM. Adjusted RRs (95% CIs) for GDM across increasing quartiles of plasma ferritin were 1.00 (reference), 2.14 (1.37, 3.34), 2.03 (1.30, 3.19), and 2.72 (1.76, 4.21), respectively. After adjustment, supplemental iron ≥60 mg/d during the second trimester was associated with an increased risk of GDM compared with nonusers (RR: 1.37; 95% CI: 1.02, 1.84). CONCLUSIONS: Both elevated plasma ferritin concentrations in the early second trimester and use of ≥60 mg/d of supplemental iron during pregnancy are independently associated with increased risk of GDM. Further clinical trials with precision nutrition approaches considering both baseline iron status and supplement use are needed to evaluate the benefits and risks of iron supplementation during pregnancy.

Pregnancy dietary cholesterol intake, major dietary cholesterol sources, and the risk of gestational diabetes mellitus: A prospective cohort study.

BACKGROUND & AIMS: The Scientific Report of 2015 Dietary Guidelines Advisory Committee recommended the elimination of dietary cholesterol limits. However, cholesterol intake increases during pregnancy and studies regarding the association between dietary cholesterol and gestational diabetes mellitus (GDM) are limited. We evaluate the association of total dietary cholesterol and different sources of cholesterol intake during pregnancy, with GDM risk and blood glucose levels in a Chinese prospective cohort study. METHODS: A total of 2124 pregnant women from the Tongji Maternal and Child Health Cohort was included. A validated semi-quantitative food frequency questionnaire was used to assess dietary cholesterol intake prior to GDM diagnosis. GDM was diagnosed by the 75-g 2-h oral glucose tolerance test. Cubic-restricted spline function and logistic regression analyses were used to evaluate the association between dietary cholesterol intake during pregnancy and GDM. Generalized linear models were conducted to examine the associations of cholesterol intake with fasting blood glucose (FBG), 1-h post-load blood glucose (PBG) and 2-h PBG. RESULTS: The average dietary cholesterol intake was 379.1 mg/d, and cholesterol from eggs explained 64.2% of the variability. Total dietary cholesterol intake and cholesterol from eggs rather than other foods, were linearly associated with GDM risk, with adjusted OR for GDM of 2.10 (95%CI: 1.24, 3.58) for total cholesterol intake and 1.83 (95%CI: 1.08, 3.07) for cholesterol from eggs comparing the highest versus lowest quintile. A 100-mg/d increase in total cholesterol and cholesterol from eggs intake were associated with an increased GDM risk by 18% and 16%, respectively. Moreover, higher maternal dietary total cholesterol could increase FBG and 1-h PBG, while cholesterol from eggs increased FBG only. CONCLUSION: Higher dietary cholesterol from eggs intake during pregnancy was associated with greater risk of GDM.

Higher dietary vitamin C intake is associated with a lower risk of gestational diabetes mellitus: A longitudinal cohort study.

BACKGROUND & AIMS: Oxidative stress has been implicated in the pathogenesis of gestational diabetes mellitus (GDM). Vitamin C as natural antioxidant may help to increase the body's antioxidant capacity. The study is aimed to determine whether vitamin C intake during pregnancy is associated with lower risk of GDM. METHODS: Women with singleton pregnancy and without any history of diabetes were drawn from the ongoing Tongji Maternal and Child Health Cohort (TMCHC). Oral glucose tolerance tests (OGTT) were conducted during weeks 24-28 of gestation to screen for GDM. A validated food frequency questionnaire (FFQ) was used to assess dietary intake during mid pregnancy. Use of multivitamins and specific supplements of vitamin C was assessed by questionnaires. Odds ratios (ORs) of GDM risk were calculated by logistic regression models, adjusted for potential confounders. RESULTS: 344 (11.4%) of the 3009 women were diagnosed with GDM. Dietary vitamin C intake was inversely associated with the risk of GDM. Women with above adequate dietary vitamin C intake (more than 200 mg/day) experienced lower odds of GDM (OR 0.68, 95% CI: 0.49-0.95) than those with adequate intake (115-200 mg/day). There was no association between the total consumption of vitamin C and the risk of GDM (OR 1.04, 95% CI: 0.71-1.53). CONCLUSION: This data suggests that higher dietary consumption of vitamin C during pregnancy is independently associated with lower odds of GDM. Above 200 mg/day of dietary vitamin C intake may help reduce the odds of GDM. However, no such association between total vitamin C intake and the risk of GDM was found. Hence, sufficient vegetables and fruits rich in vitamin C should be recommended to protect pregnant women from developing gestational diabetes.

Exposure to multiple metals in early pregnancy and gestational diabetes mellitus: A prospective cohort study.

BACKGROUND: A growing number of epidemiologic studies have estimated associations between type 2 diabetes mellitus and exposure to metals. However, studies on the associations of internal assessments of metal exposure and gestational diabetes mellitus (GDM) are limited in scope and have inconsistent outcomes. OBJECTIVES: This investigation aimed to explore the associations between urinary nickel (Ni), arsenic (As), cadmium (Cd), antimony (Sb), cobalt (Co), or vanadium (V) in early pregnancy and the subsequent risk of GDM in Chinese pregnant women. METHODS: The study population included 2090 women with singleton pregnancy from the Tongji Maternal and Child Health Cohort (TMCHC). Urine samples were collected before 20 gestational weeks, and an oral glucose tolerance test (OGTT) was conducted at 24-28 gestational weeks to diagnose GDM. The concentrations of urinary metals were measured using inductively coupled plasma mass spectrometry (ICP-MS) and were corrected for urinary creatinine. The associations between the risk of GDM and urinary metals were assessed using Poisson regression with a robust error variance with generalized estimating equations (GEE) models and Bayesian kernel machine regression (BKMR). RESULTS: A total of 241 participants (11.53%) were diagnosed with GDM. Five metals (Ni, As, Sb, Co, and V) were found significantly and positively associated with GDM based on single-metal models. In multiple-metal models, for each unit increase of ln-transformed urinary Ni or Sb, the risk of GDM increased 18% [relative risk (RR):1.18, 95%confidence interval (CI): 1.00, 1.38 or RR: 1.18, 95%CI: 1.00, 1.39, respectively]. The BKMR analysis revealed a statistically significant and positive joint effect of the six metals on the risk of GDM, when the urinary levels of the six metals were all above the 55th percentile, compared to the median levels. The effect of metal Ni was significant when the concentrations of the other metals were all fixed at their 25th percentile, and metal Sb displayed a significant and positive effect when all the other metals were fixed at 25th, 50th, and 75th percentiles. CONCLUSIONS: To the best of our knowledge, this study is the first to demonstrate that increased concentrations of urinary Ni in early pregnancy are associated with an elevated risk of GDM, either evaluated individually or as a metal mixture. All six metals mixed exposure was positively associated with the risk of GDM, while Sb and Ni were demonstrated more important effects than the other four metals in the mixture.