The Interactions between Maternal Iron Supplementation and Iron Metabolism-Related Genetic Polymorphisms on Birth Outcomes: A Prospective Study in Chinese.

BACKGROUND: The effect of iron supplementation during pregnancy on birth outcomes may vary with maternal genetic background and needs more investigation. OBJECTIVES: This prospective study aimed to evaluate the interactions between maternal iron supplementation and iron metabolism-related genetic polymorphisms on birth outcomes. METHODS: This was a substudy from a community-based randomized control trial conducted in Northwest China, which included 860 women from the 2 micronutrient supplementation groups (folic acid [FA] and FA + iron group). Maternal peripheral blood, sociodemographic and health-related information, and neonatal birth outcomes were collected. Six single nucleotide polymorphisms in iron metabolism-related genes were genotyped. The alleles associated with decreased iron/hemoglobin status were used as the effect alleles. The genetic risk score (GRS) that reflected the genetic risk of low iron/hemoglobin status was estimated using the unweighted and weighted methods. Generalized estimating equations with small-sample corrections were applied to evaluate the interactions between iron supplementation and SNPs/GRS on birth outcomes. RESULTS: There were significant interactions between maternal iron supplementation and rs7385804 (P = 0.009), rs149411 (P = 0.035), rs4820268 (P = 0.031), the unweighted GRS (P = 0.018), and the weighted GRS (P = 0.009) on birth weight. Compared with FA supplementation only, FA + iron supplementation significantly increased birth weight among women with more effect alleles in rs7385804 (ß: 88.8 g, 95% CI: 9.2, 168.3) and the GRSs (the highest unweighted GRS, ß: 135.5 g, 95% CI: 7.7, 263.4; the highest weighted GRS, ß: 145.9 g, 95% CI: 43.4, 248.5); it had a trend of decreasing birth weight and increasing low birth weight risk among women with fewer effect alleles. CONCLUSIONS: In our population, maternal genetic background related to iron metabolism plays a significant role in determining the efficacy of iron supplementation. Routine iron supplementation could be more beneficial to fetal weight growth among mothers with higher genetic risk for low iron/hemoglobin status.

Maternal Dietary Inflammatory Potential and Offspring Birth Outcomes in a Chinese Population.

BACKGROUND: Chronic inflammation perturbations during pregnancy may impact fetal growth; however, research on the association between dietary inflammation and birth outcomes is limited and inconsistent. OBJECTIVES: This study seeks to assess whether the dietary inflammatory potential is related to birth outcomes among pregnant women in China. METHODS: A total of 7194 mothers aged 17-46 y and their infants in China were included in this cross-sectional study. Dietary intake was assessed by a FFQ, which yielded scores on the energy-adjusted dietary inflammatory index (E-DII). Birth outcomes included birth weight, gestational age, birth weight z score, low birth weight (LBW), macrosomia, preterm birth, small-for-gestational-age (SGA), large-for-gestational-age (LGA), and birth defects. Generalized estimating equation and restricted cubic spline fit each outcome on continuous or quartiles of E-DII after adjusting for covariates. RESULTS: The maternal E-DII ranged from -5.35 to 6.77. Overall, birth weight and gestation age (mean ± SD) were 3267.9 ± 446.7 g and 39.6 ± 1.3 wk, respectively, and the birth weight z score was 0.02 ± 1.14. A total of 3.2% of infants were born with LBW, 6.1% with macrosomia, 3.0% were preterm birth, 10.7% were born SGA, 10.0% were born LGA, and 2.0% were born with birth defects. E-DII was associated with a 9.8 g decrease in birth weight (95% CI: -16.9, -2.6) and a 1.09-fold (95% CI: 1.01, 1.18), 1.11-fold (95% CI: 1.02, 1.21), and 1.12-fold (95% CI: 1.02, 1.24) greater risk of LBW, preterm birth, and birth defects, respectively. The maternal E-DII score was nonlinearly associated with gestational age (P for linearity = 0.009, P for curvature = 0.044). CONCLUSIONS: Among pregnant Chinese women, proinflammatory diets during pregnancy were related to reduced offspring birth weight and an increased risk of LBW, preterm birth, and birth defects. These findings might inform potential prevention strategies for pregnant women in China.

Epidemiological profile of malnutrition status and spatial distribution of children and adolescents living with HIV/AIDS in Tanzania.

OBJECTIVES: To determine the prevalence of malnutrition status, analyse the association between malnutrition status and individual-level factors, and explore the spatial variation among children and adolescents living with HIV/AIDS in Tanzania. METHODS: The study is based on large-scale baseline routine data from the National AIDS Control Programme on people living with HIV from January 2016 to December 2021 in mainland Tanzania. 70,102 children and adolescents aged 5-19 years receiving active antiretroviral therapy were included in the analysis. Nutritional status of participants was assessed by anthropometric measurement. Pearson's Chi-square test was used to describe the association between individual-level factors with all malnutrition outcomes and spatial analysis was used to investigate spatial distribution of malnutrition. The excess risk of malnutrition for each region was calculated while Anselin Local Moran's I and Getis-Ord statistical tools were used to identify significant hot spots regions of malnutrition. RESULTS: The mean age of participants was 11.1 (SD 4.7) years, with 71.7% in the 5-14-year age group and 58.4% being girls. 39.2% were attending care and treatment clinics services at hospital level with public ownership. 53.4% started using ARV at age 5-14 years and 55.5% had already switched to second- or third-line ARV with 61.1% using ARV for less than 3 years. 51.2% were in WHO HIV clinical stage III or IV. The prevalence of malnutrition was 36.0% for stunting, 28.9% for underweight, 13.0% for wasting, and 48.0% for anthropometric failure. Individual-level factors which accounted for a higher proportion of malnutrition based on anthropometric failure were male sex (56.3%), age 5-14 years (50.0%), being unmarried (52.9%), being on second- or third-line ARV treatment (51.4%), ART initiation at age 5-14 years (55.7%), ARV for more than 3 years (49.4%), and stage IV of WHO HIV clinical status (57.8%). There were regional hot spots (p < 0.05): the prevalence rate and excess risk of malnutrition for stunting and anthropometric failure were highest in the southern highlands regions, for underweight in the central regions, and for wasting in the northern regions. CONCLUSIONS: Children and adolescents living with HIV/AIDS in Tanzania suffer from poor nutritional status. Malnutrition does not occur arbitrarily, and the regions identified as hot spots should be given priority for nutritional intervention. Effective nutritional interventions for children living with HIV/AIDS should incorporate multiple approaches by considering unique geographical factors.

Maternal exposure to housing renovation during the periconceptional period and the risk of offspring with isolated congenital heart disease: a case-control study.

BACKGROUND: Congenital heart disease (CHD) is the most prevalent birth defect in recent decades. The aim of this research was to examine the association between maternal housing renovation exposure during the periconceptional period and isolated congenital heart disease (CHD) in their offspring. METHODS: A multi-hospitals case-control study was conducted from six tertiary A hospitals in Xi'an, Shaanxi, Northwest China based on questionnaires and interviews to address this question. The cases included fetuses or newborns diagnosed with CHD. Controls consisted of healthy newborns without birth defects. In total, 587 cases and 1180 controls were enrolled in this study. The association between maternal periconceptional housing renovation exposure and isolated CHD for offspring was assessed by estimating odds ratios (OR) with multivariate logistic regression models. RESULTS: After adjusting for potential confounding variables, it was found that maternal exposure to home improvement projects was associated with a higher probability of isolated CHD in offspring (adjusted OR: 1.77, 95% CI: 1.34, 2.33). Additionally, the risk of the ventricular septal defect (VSD) and patent ductus arteriosus (PDA) for CHD types was significantly associated with maternal exposure to housing renovations (VSD: adjusted OR = 1.56, 95% CI: 1.01, 2.41; PDA: adjusted OR = 2.50, 95% CI: 1.41, 4.45). CONCLUSIONS: Our study suggests that maternal exposure to housing renovation during the periconceptional period was associated with an increased risk of isolated CHD in offspring. Consequently, it would be beneficial to avoid living in a renovated home from 12 months before pregnancy through the first trimester to lower isolated CHD in infants.

Habitual intakes of sugar-sweetened beverages associated with gut microbiota-related metabolites and metabolic health outcomes in young Chinese adults.

BACKGROUND AND AIMS: Reducing consumption of sugar-sweetened beverages (SSBs) is a global public health priority because of their limited nutritional value and associations with increased risk of obesity and metabolic diseases. Gut microbiota-related metabolites emerged as quintessential effectors that may mediate impacts of dietary exposures on the modulation of host commensal microbiome and physiological status. METHODS AND RESULTS: This study assessed the associations among SSBs, circulating microbial metabolites, and gut microbiota-host co-metabolites, as well as metabolic health outcomes in young Chinese adults (n = 86), from the Carbohydrate Alternatives and Metabolic Phenotypes study in Shaanxi Province. Five principal component analysis-derived beverage drinking patterns were determined on self-reported SSB intakes, which were to a varying degree associated with 143 plasma levels of gut microbiota-related metabolites profiled by untargeted metabolomics. Moreover, carbonated beverages, fruit juice, energy drinks, and bubble tea exhibited positive associations with obesity-related markers and blood lipids, which were further validated in an independent cohort of 16,851 participants from the Regional Ethnic Cohort Study in Northwest China in Shaanxi Province. In contrast, presweetened coffee was negatively associated with the obesity-related traits. A total of 79 metabolites were associated with both SSBs and metabolic markers, particularly obesity markers. Pathway enrichment analysis identified the branched-chain amino acid catabolism and aminoacyl-tRNA biosynthesis as linking SSB intake with metabolic health outcomes. CONCLUSION: Our findings demonstrate the associations between habitual intakes of SSBs and several metabolic markers relevant to noncommunicable diseases, and highlight the critical involvement of gut microbiota-related metabolites in mediating such associations.

Gender-specific association of body fat mass with muscle meat-vegetable intake ratio in Shaanxi, China.

BACKGROUND AND OBJECTIVES: The effects of muscle meat and vegetable intake on body fat mass remain unclear in the general population. This study aimed to investigate the association of body fat mass and fat dis-tribution with a muscle meat-vegetable intake (MMV) ratio. METHODS AND STUDY DESIGN: In total, 29,271 par-ticipants aged 18-80 years were recruited from the Shaanxi cohort of the Regional Ethnic Cohort Study in Northwest China. The associations of muscle meat, vegetable and MMV ratio, as the independent variable, with body mass index (BMI), waist circumference, total body fat percentage (TBF) and visceral fat (VF), as dependent variables were evaluated by gender-specific linear regression models. RESULTS: There was 47.9% of men whose MMV ratio was greater than or equal to 1 and this figure was about 35.7% for women. For men, higher muscle meat intake was associated with higher TBF (standardized coefficient [ß], 0.508; 95% CI, 0.187-0.829), higher vegetable intake was associated with lower VF (ß, -0.109; 95% CI, -0.206 - -0.011), and higher MMV ratio was associated with higher BMI (ß, 0.195; 95% CI, 0.039-0.350) and VF (ß, 0.523; 95% CI, 0.209-0.838). For women, both higher muscle meat consumption and MMV ratio were associated with all fat mass markers, but vegetable intake was not correlated with body fat mass markers. The positive association of MMV on body fat mass was more pronounced in higher MMV ratio group, with both men and women. The intake of pork, mutton and beef was associated positively with fat mass markers but no such as-sociation was observed for poultry or seafood. CONCLUSIONS: An increased intake of muscle meat or a higher MMV ratio was associated with increased body fat, especially among women, and such impact may mainly be attributed to increasing intake of pork, beef and mutton. The dietary MMV ratio could be thus a useful parameter for nutritional intervention.

Comparing the pelvis of Tibetan and Chinese Han women in rural areas of China: two population-based studies using coarsened exact matching.

This study aims to investigate the difference of pelvic size and shape between Tibetan and Chinese Han women. Data on pelvic dimension measures including interspinous diameter (IS), intercrestal diameter (IC), external conjugate (EC) and transverse outlet (TO) were acquired from two population-based studies amongst Tibetan women in Lhasa, and Chinese Han women in Shaanxi province in China. After coarsened exact matching, there was no statistical difference between any characteristics amongst Tibetan and Chinese Han women (p>.05). The generalised estimating equation models showed Tibetan women had significantly lower IS and IC means than Chinese Han women (IS: 24.39 cm vs. 24.77 cm, p<.001; IC: 26.35 cm vs. 26.93 cm, p<.001) but statistically higher in TO mean (9.12 cm vs. 9.03 cm, p<.001). This study showed Tibetan women have smaller pelvis compared to Chinese Han women. This should offer a useful literature on the comparison of pelvis between Tibetan and Chinese Han women although the difference is small.Impact StatementWhat is already known on this subject? Previous studies in China indicated different populations have different dimensions of pelvis, with the pelvis of Uighur women being bigger than Chinese Han women, and that of Zhuang and Tu women being smaller than Chinese Han women. Little research reports the specific size of Tibetan women's pelvis. Living at high altitude, the Tibetan population have differentiated demographics and show local adaptions, such as unelevated haemoglobin, and significant catch-up growth for infants compared with Chinese Han infants. Therefore, there is a strong rationale for better understanding pelvic characteristics amongst this population.What the results of this study add? This study showed Tibetan women have smaller pelvises compared to Chinese Han women. Tibetan women have a smaller interspinous diameter and intercrestal diameter than Chinese Han women, which leads to relatively narrow hip.What the implications are of these findings for clinical practice and/or further research? This study provides useful comparative information on pelvic features between Tibetan and Chinese Han women although the findings of differences were small. In addition, during the formulation of women's health policy, the results of this study can provide data to support the selection of appropriate indicators of obstetrics and gynaecology for different populations of pregnant women during antenatal care and delivery.

Association of antenatal vitamin B complex supplementation with neonatal vitamin B12 status: evidence from a cluster randomized controlled trial.

PURPOSE: Evidence about the effect of maternal vitamin B12 supplementation on offspring's vitamin B12 status is limited. The present interventional study sought to evaluate the association of antenatal vitamin B complex supplementation with neonatal vitamin B12 status. METHODS: In an ongoing cluster randomized controlled trial conducted in three rural counties in northwest China, pregnant women < 20 weeks of gestation were randomized to three treatment groups: blank control, iron supplements, or vitamin B complex supplements. All women were administered folic acid supplements during the periconceptional period. In a sub-study, we collected cord blood samples of 331 participants from the control or vitamin B complex groups in the Xunyi county from January 2017 to December 2017. Plasma concentrations of folate, vitamin B12, and homocysteine were measured. Linear mixed models with a random intercept for cluster were used to compare biochemical indexes between groups after controlling for covariates. RESULTS: Compared with newborns whose mothers were in the control group, newborns of the vitamin B complex-supplemented women had significantly higher cord plasma vitamin B12 (P = 0.001) and lower homocysteine concentrations (P = 0.043). The association of antenatal vitamin B complex supplementation with cord blood vitamin B12 concentrations appeared to be more pronounced among newborns with high folate status than those with low folate status (Pinteraction = 0.060). CONCLUSIONS: Maternal vitamin B complex supplementation during pregnancy was associated with better neonatal vitamin B12 status in rural northwest China.

Maternal exposure to life events during pregnancy and congenital heart disease in offspring: a case-control study in a Chinese population.

BACKGROUND: Previous studies have suggested that maternal stress could increase the risk of some adverse pregnancy outcomes, but evidence on congenital heart disease (CHD) is limited. We aimed to explore the association between maternal exposure to life events during pregnancy and CHD in offspring. METHODS: The data was based on an unmatched case-control study about CHD conducted in Shaanxi province of China from 2014 to 2016. We included 2280 subjects, 699 in the case group and 1581 in the control group. The cases were infants or fetuses diagnosed with CHD, and the controls were infants without any birth defects. The life events were assessed by the Life Events Scale for Pregnant Women, and were divided into positive and negative events for synchronous analysis. A directed acyclic graph was drawn to screen the confounders. Logistic regression was employed to estimate the odds ratio and 95% confidence interval for the effects of life events on CHD. RESULTS: After controlling for the potential confounders, the pregnant women experiencing the positive events during pregnancy had lower risk of CHD in offspring than those without positive events (OR = 0.38, 95%CI: 0.30 ~ 0.48). The risk of CHD in offspring could increase by 62% among the pregnant women experiencing the negative events compared to those without (OR = 1.62, 95%CI: 1.29 ~ 2.03). Both effects showed a certain dose-response association. Besides, the positive events could weaken the risk impact of negative events on CHD. CONCLUSION: It may suggest that maternal exposure to negative life events could increase the risk of CHD in offspring, while experiencing positive events could play a potential protective role.

Effect of socioeconomic characteristics and lifestyle on BMI distribution in the Chinese population: a population-based cross-sectional study.

BACKGROUND: Body mass index (BMI) is an accepted measurement that is widely used to quantify overweight and obesity at the population level. Previous studies have described the distribution variation of BMI through applying common statistical approaches, such as multiple linear or logistic regression analyses. This study proposed that associations between BMI and socioeconomic characteristics, diet, and lifestyle factors varied across the conditional BMI distribution. METHODS: This study was based on a sample of 10,023 Chinese adults who participated in the monitoring of chronic diseases and associated risk factors in Shaanxi Province, Northwest China, in 2013. Cross-quantile factors were observed in the relationships between major risk factors and BMI through quantile regression (QR) and ordinary least squares (OLS) regression. RESULTS: Participants' mean BMI was 24.19 ± 3.51 kg/m2 (range 14.33-52.82 kg/m2). The QR results showed that living in urban areas was associated with BMI in the low and central quantiles (10th-60th). Participants with 6-9 years of education were 0.23-0.38 BMI units higher in the first half of the BMI quantiles compared with those with ≤6 years of education. There was a positive association between consumption of red meat and BMI; however, the association diminished from the 10th to the 50th quantile. Intake of oil and alcohol were positively associated with all BMI quantiles. Cigarette smoking per day was negatively associated with BMI, which showed a U-shaped distribution. The above results were also observed in the OLS. CONCLUSION: This study implies that in addition to socioeconomic characteristics, limiting oil and alcohol intake may decrease BMI score. Consuming more red meat could be a strategy to increase BMI.

Body Fat Mass, Fat Distribution and Egg Consumption: a Population-Based Study in Chinese Adults.

Objective: Egg is the vital source for many nutrients. The present study aimed to evaluate how egg consumption contributes to body fat mass and fat distribution in general Chinese adults.Methods: In a representative study of Chinese adults, 2241 rural adults aged 18-80 years completed physical measurements and semi quantitative food frequency questionnaire (FFQ). Body fat percentage (BF%) was estimated through validated Chinese-specific equations including age, body mass index (BMI), waist circumference (WC), gender and their interaction.Results: The prevalence of excessive body fat and central obesity in males were 44.2% and 31.3%, lower than that in females (60.7% and 36.1%, p < 0.05). 37.3% of lean or normal-weight individuals by BMI experienced excessive body fat given their BF% and 43.5% were central obesity according to WC. In females, egg consumption was associated with better body fat mass and its distribution. Compared with non-consumers, individuals consumed egg >50 g/d had a 34% lower risk of central obesity (OR:0.66, 0.39-0.99) and 38% lower risk of excessive body fat (OR:0.62, 0.37-1.00). There were significant dose-response relationships between egg consumption and overweight with excessive body fat/central obesity (p for linear trend <0.05). However, these associations were not significant in males.Conclusion: Our findings underscore the necessity for future public health guidelines to assess body fat mass and distribution simultaneously in Chinese adults. Egg consumption might be beneficial for weight regulation, especially for overweight with excessive body fat/central obesity in females. Further research is warrant to establish the causal inference.

Maternal dietary patterns during pregnancy derived by reduced-rank regression and birth weight in the Chinese population.

Few studies have investigated the association between maternal dietary patterns (DP) during pregnancy, derived from reduced-rank regression (RRR), and fetal growth. This study aims to identify DP during pregnancy associated with macro- and micronutrient intakes, using the RRR method, and to examine their relationship with birth weight (BW). We used data of 7194 women from a large-scale cross-sectional survey in Northwest China. Dietary protein, carbohydrate, haem Fe density and the ratio of PUFA and MUFA:SFA were used as the intermediate variables in the RRR model to extract DP. Generalised estimating equation models were applied to evaluate the associations between DP and BW and related outcomes (including BW z-score, low birth weight (LBW) and small for gestational age (SGA)). Four DP during pregnancy were identified. Socio-demographically disadvantaged pregnant women were more likely to have lower BW and lower adherence to DP1 (high legumes, soyabean products, vegetables and animal-source foods, with relative low wheat and oils). Women with medium and high adherence to DP1 had significantly increased BW (medium 28·6 (95 % CI 7·1, 50·1); high 25·2 (95 % CI 2·7, 47·6)) and BW z-score and had significantly reduced risks of LBW and SGA. The associations were stronger among women with babies <3100 g. There is no association between other DP and outcomes. Higher adherence to the DP that was high in legumes, soyabean products, vegetables and animal-source foods was associated with improved BW in the Chinese pregnant women, particularly among those with disadvantageous socio-demographic conditions.

Influence of China's 2009 healthcare reform on the utilisation of continuum of care for maternal health services: evidence from two cross-sectional household surveys in Shaanxi Province.

BACKGROUND: Continuum of care for maternal health services (CMHS) is a proven approach to improve health and safety for mothers and newborns. This study aims to explore the influence of China's 2009 healthcare reform on improving the CMHS utilisation. METHODS: This population-based cross-sectional quantitative study included 2332 women drawn from the fourth and fifth National Health Service Surveys of Shaanxi Province, conducted in 2008 and 2013 respectively, before and after China's 2009 healthcare reform. A generalised linear mixed model (GLMM) was applied to analyse the influence of this healthcare reform on utilisation of CMHS. Concentration curves, concentration indexes and its decomposition method were used to analyse the equity of changes in utilisation. RESULTS: This study showed post-reform CMHS utilisation was higher in both rural and urban women than the CMHS utilisation pre-reform (according to China's policy defining CMHS). The rate of CMHS utilisation increased from 24.66 to 41.55% for urban women and from 18.31 to 50.49% for rural women (urban: χ2 = 20.64, P < 0.001; rural: χ2 = 131.38, P < 0.001). This finding is consistent when the WHO's definition of CMHS is applied for rural women after reform (12.13% vs 19.26%; χ2 = 10.99, P = 0.001); for urban women, CMHS utilisation increased from 15.70 to 20.56% (χ2 = 2.57, P = 0.109). The GLMM showed that the rate of CMHS utilisation for urban women post-reform was five times higher than pre-reform rates (OR = 5.02, 95%CL: 1.90, 13.31); it was close to 15 times higher for rural women (OR = 14.70, 95%CL: 5.43, 39.76). The concentration index for urban women decreased from 0.130 pre-reform (95%CI: - 0.026, 0.411) to - 0.041 post-reform (95%CI: - 0.096, 0.007); it decreased from 0.104 (95%CI: - 0.012, 0.222) to 0.019 (95%CI: - 0.014, 0.060) for rural women. The horizontal inequity index for both groups of women also decreased (0.136 to - 0.047 urban and 0.111 to 0.019 for rural). CONCLUSIONS: China's 2009 healthcare reform has positively influenced utilisation rates and equity of CMHS's utilisation among both urban and rural women in Shaanxi Province. Addressing economic and educational attainment gaps between the rich and the poor may be effective ways to improve the persistent health inequities for rural women.

Dietary patterns of Chinese women of childbearing age during pregnancy and their relationship to the neonatal birth weight.

OBJECTIVE: To examine the type of maternal dietary patterns during pregnancy and the distribution characteristics of children's birth weight and the association between dietary patterns and neonatal birth weight in China. METHODS: Data were derived from a cross-sectional program named "The prevalence and risk factors of birth defects in Shaanxi Province" in July to November in 2013. A stratified multistage random sampling method was used to select women and their children. The mother's diet during pregnancy was investigated using semi-quantitative food frequency questionnaire (FFQ) to collect the frequency and amount of food consumption, and the newborn birth weight as well as related social demographic information was collected at the same time. In our study, 0-1 year old children and their mothers with complete dietary survey data were selected as research objects. The main dietary patterns were identified according to factor analysis, and latent class analysis (LCA) was used to investigate the social demographic factors affecting dietary patterns. The logistic regression model was used to assess the association between birth weight and maternal dietary patterns during pregnancy by establishing three adjusting models and the data were stratified for further analysis by urban-rural and regions. RESULTS: A total of 15,980 participants were involved in this study. Four dietary patterns were identified: "vegetarian pattern", "balance pattern", "traditional pattern" and "processing pattern". Compared with moderate tertile, women in the highest tertile of adherence to vegetarian pattern increased the risk of low birth weight in offspring in rural areas (OR = 1.61, 95%CI:1.06-2.93) and middle region (OR = 1.75, 95%CI:1.18-2.62), and the traditional pattern had greater odds of lower birth weight in the middle region (OR = 1.55, 95%CI:1.05-3.75). The processing pattern was found a protective factor for the occurrence of low birth weight in rural areas (OR = 0.98, 95%CI:0.43-0.99) but was a risk factor for low birth weight in the southern region (OR = 8.83, 95%CI:1.22-15.16). The balance pattern was a protective factor for the occurrence of low birth weight in the northern region(OR = 0.35, 95%CI:0.14-0.83). CONCLUSION: The vegetarian and traditional pattern may be positively related to a higher risk of low birth weight while the balanced pattern may keep birth weight of offspring within the appropriate range. Health education of balanced diet and individual nutrition guidance during pregnancy should be strengthened, to make the dietary structure during pregnancy are more reasonable, reduce the occurrence of adverse birth weight of newborns.

Correction to: Dietary patterns of Chinese women of childbearing age during pregnancy and their relationship to the neonatal birth weight.

An amendment to this paper has been published and can be accessed via the original article.

Maternal folic acid supplementation and more prominent birth weight gain in twin birth compared with singleton birth: a cross-sectional study in northwest China.

OBJECTIVE: To investigate the association of folic acid (FA) supplementation with birth weight, the risk of small for gestational age (SGA) and low birth weight (LBW) in singleton and twin pregnancy. DESIGN: A population-based cross-sectional survey. SETTING: Twenty counties and ten districts in Shaanxi Province of northwestern China, 2013. PARTICIPANTS: 28 174 pregnant women with their infants, covering 27 818 single live births and 356 twin live births. RESULTS: The prevalence of FA supplementation in singletons and twins was 63·9 and 66·3 %. The mean birth weight was 3267 (sd 459·1) g, 2525 (sd 534·0) g and 2494 (sd 539·5) g; the prevalence of SGA was 14·3, 51·4 and 53·4 %; the prevalence of LBW was 3·4, 42·4 and 46·6 % among singleton, twin A and twin B, respectively. Compared with non-users, women with FA supplementation were (ß 17·3, 95 % CI 6·1, 28·4; ß 166·3, 95 % CI 69·1, 263·5) associated with increased birth weight, lower risk of SGA (OR 0·85, 95 % CI 0·80, 0·92; OR 0·45, 95 % CI 0·30, 0·68) and LBW (OR 0·82, 95 % CI 0·71, 0·95; OR 0·50, 95 % CI 0·33, 0·75) in singletons and twins, and more prominent effects in twins. Moreover, there were significant interactions between FA supplementation and plurality on birth weight, SGA and LBW. CONCLUSIONS: The present study suggests the association of periconceptional 0·4 mg/d FA supplementation with increased birth weight and reduced risk of SGA and LBW in both singletons and twins, and this association may be more prominent in twins.

A propensity-matched study of the association between pre-pregnancy maternal underweight and perinatal outcomes of singletons conceived through assisted reproductive technology.

RESEARCH QUESTION: Is pre-pregnancy maternal underweight associated with perinatal outcomes of singletons who were conceived through assisted reproductive technology (ART)? DESIGN: A 10-year (2006-2015) Chinese sample of 6538 women and their singleton infants who were conceived through ART was used to examine the association between pre-pregnancy maternal underweight and perinatal outcomes. Propensity scores for underweight were calculated for each participant using multivariable logistic regression, which was used to match 740 (91.36% of 810) underweight women with 740 normal weight women; the effects of underweight on birth weight and gestational age were then assessed by generalized estimating equation model. RESULTS: After propensity score matching, the birth weight was lower (difference -136.83 g, 95% CI -184.11 to -89.55 g) in the underweight group than in the normal weight group. The risks of low birth weight (LBW) and small for gestational age (SGA) were increased in the underweight group compared with those in the normal weight group (LBW: RR 1.64, 95% CI 1.01 to 2.67; SGA: RR 1.46, 95% CI 1.06 to 2.02). The risks of fetal macrosomia and being large for gestational age (LGA) were decreased in the underweight group compared with those in the normal weight group (macrosomia: RR 0.39, 95% CI 0.26 to 0.61; LGA: RR 0.36, 95% CI 0.24 to 0.53). The associations between underweight, gestational age and preterm birth were not statistically significant. CONCLUSIONS: Among women undergoing ART, pre-pregnancy maternal underweight was associated with lower birth weight, increased LBW and SGA risks, and decreased fetal macrosomia and LGA risks in singleton infants.

The association of maternal dietary folate intake and folic acid supplementation with small-for-gestational-age births: a cross-sectional study in Northwest China.

The effect of maternal folate intake on small-for-gestational-age (SGA) births remains inconclusive. The present study aimed to investigate the associations of maternal folate intake from diet and supplements with the risk of SGA births using data from a cross-sectional study in Shaanxi Province of Northwest China. A total of 7307 women who were within 12 months (median 3; 10th-90th percentile 0-7) after delivery were included. Two-level models were adopted to examine the associations of folate (dietary folate, supplemental folic acid and total folate) intake with the risk of SGA births and birth weight Z score, controlling for a minimum set of confounders that were identified in a directed acyclic graph. Results showed that a higher supplemental folic acid intake during the first trimester was negatively associated with the risk of SGA births (≤60 d v. non-use: OR 0·80; 95 % CI 0·66, 0·96; >60 d v. non-use: OR 0·78; 95 % CI 0·65, 0·94; Ptrend = 0·010; per 10-d increase: OR 0·97; 95 % CI 0·95, 0·99). A higher total folate intake during pregnancy was associated with a reduced risk of SGA births (highest tertile v. lowest tertile: OR 0·77; 95 % CI 0·64, 0·94; Ptrend = 0·010; per one-unit increase in the log-transformed value: OR 0·81; 95 % CI 0·69, 0·95). A similar pattern was observed for the birth weight Z score. Our study suggested that folic acid supplementation during the first trimester and a higher total folate intake during pregnancy were associated with a reduced risk of SGA births.

Effect of maternal pre-pregnancy BMI and weekly gestational weight gain on the development of infants.

OBJECTIVE: The aim of the present study is to identify the average effect across different time points and to specify the time effects of maternal pre-pregnancy BMI and weekly gestational weight gain on the mental development and physical growth of infants. METHODS: The present cohort study used a repeated measures study design that began in 2004 with follow up at 3, 6, 12, 18, and 24 months of age. The participants were a subset from a controlled, cluster-randomized, double-blind trial. Bayley Scales of Infant Development (BSID) were used to estimate the mental development of infants. A generalized estimating equation linear model was used to estimate the effects of maternal BMI and weight gain. RESULTS: The average effect of maternal BMI and weight gain on the weight for age Z scores (WAZ), length for age Z scores (LAZ) and mental development index (MDI) across the different time points of infants was significant. In addition, the maternal BMI and weight gain were positively and significantly associated with the WAZ and LAZ in infants of different ages. However, the effect of weekly gestational weight gain was significant only during the earlier period of life (3 months, Coefficient: 11.15, 95%CI: 4.89-17.41). CONCLUSIONS: Our results indicate positive effects of pre-pregnancy and prenatal nutrition on the physical growth of infants. Weekly gestational weight gain of the pregnant women had a positive effect on the mental development of the infants, but this effect appears to decline over time.

Association between early prenatal exposure to ambient air pollution and birth defects: evidence from newborns in Xi'an, China.

BACKGROUND: The aim of this study was to investigate an association between birth defects and exposure to sulfur dioxide (SO2), nitrogen dioxide (NO2) and particles ≤10 µm in an aerodynamic diameter (PM10) during early pregnancy in Xi'an, China. METHODS: Birth defect data were from the Birth Defects Monitoring System of Xi'an, and data on ambient air pollutants during 2010-15 were from the Xi'an Environmental Protection Bureau. A generalized additive model (GAM) was used to investigate the relationship between birth defects and ambient air pollutants. RESULTS: Among the 8865 cases with birth defects analyzed, the overall incidence of birth defects was 117.33 per 10 000 infants. Ambient air pollutant exposure during the first trimester increased the risk of birth defects by 10.3% per 10 µg/m3 increment of NO2 and 3.4% per 10 µg/m3 increment of PM10. No significant association was found between birth defects and SO2. Moreover, NO2 increased risk of neural tube defects, congenital heart disease, congenital polydactyly, cleft palate, digestive system abnormalities and gastroschisis, and PM10 was associated with congenital heart disease and cleft lip with or without cleft palate. CONCLUSIONS: Chinese women should avoid exposure to high levels of NO2 and PM10 during the first 3 months of pregnancy.