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Seasonal climate variability is an important component of Earth's climate system, and has a significant impact on ecosystems and social systems. However, the temporal resolution of most proxy-based paleoclimate records is limiting to fully understand the past seasonal changes. Here, we used high-precision monthly resolution Sr/Ca records of three Tridacna squamosa specimens from the northern South China Sea (SCS) to reconstruct the sea surface temperature (SST) seasonality during three time periods from the middle Holocene. The results suggested that SST seasonality in the northern SCS during the middle Holocene (3.21 ± 0.98°C) was smaller than that for recent decades (AD 1994–2004, 4.32 ± 0.59°C). Analysis of modern instrumental data showed that the SST seasonality in the northern SCS was dominated by the winter SST, which was deeply influenced by the intensity of East Asian winter monsoon (EAWM). A strong EAWM usually resulted in cooler winter SST and a larger SST seasonality in the northern SCS. The reconstructed Holocene EAWM records showed that the EAWM strengthened from the middle to late Holocene, which was seen in our reconstruction of less SST seasonality changes during the middle Holocene in the northern SCS. This study highlighted that the Sr/Ca ratios from Tridacna shells can be used as a potential high-resolution indicator of past seasonal climate changes.
To examine the association between sleep duration in different stages of life and amnestic mild cognitive impairment (aMCI).
Design, setting, and participants:
A total of 2472 healthy elderly and 505 patients with aMCI in China were included in this study. The study analyzed the association between aMCI and sleep duration in different stages of life.
We compared sleep duration in different stages of life and analyzed the association between Montreal Cognitive Assessment scores and sleep duration by curve estimation. Logistic regression was used to evaluate the association between aMCI and sleep duration.
In the analysis, there were no results proving that sleep duration in youth (P = 0.719, sleep duration < 10 hours; P = 0.999, sleep duration ≥ 10 hours) or midlife (P = 0.898, sleep duration < 9 hours; P = 0.504, sleep duration ≥ 9 hours) had a significant association with aMCI. In the group sleeping less than 7 hours in late life, each hour more of sleep duration was associated with approximately 0.80 of the original risk of aMCI (P = 0.011, odds ratio = 0.80, 95% confidence interval = 0.68–0.95).
Among the elderly sleeping less than 7 hours, there is a decreased risk of aMCI for every additional hour of sleep.
People with serious mental illness are at great risk of suicide, but little is known about the suicide rates among this population. We aimed to quantify the suicide rates among people with serious mental illness (bipolar disorder, major depression, or schizophrenia).
PubMed and Web of Science were searched to identify studies published from 1 January 1975 to 10 December 2020. We assessed English-language studies for the suicide rates among people with serious mental illness. Random-effects meta-analysis was used. Changes in follow-up time and the suicide rates were presented by a locally weighted scatter-plot smoothing (LOESS) curve. Suicide rate ratio was estimated for assessments of difference in suicide rate by sex.
Of 5014 identified studies, 41 were included in this analysis. The pooled suicide rate was 312.8 per 100 000 person-years (95% CI 230.3–406.8). Europe was reported to have the highest pooled suicide rate of 335.2 per 100 000 person-years (95% CI 261.5–417.6). Major depression had the highest suicide rate of 534.3 per 100 000 person-years (95% CI 30.4–1448.7). There is a downward trend in suicide rate estimates over follow-up time. Excess risk of suicide in males was found [1.90 (95% CI 1.60–2.25)]. The most common suicide method was poisoning [21.9 per 100 000 person-years (95% CI 3.7–50.4)].
The suicide rates among people with serious mental illness were high, highlighting the requirements for increasing psychological assessment and monitoring. Further study should focus on region and age differences in suicide among this population.
High-quality primary care reduces premature mortality in the general population, but evidence for psychiatric patients in China is scarce.
To confirm excess mortality in patients with severe mental illness (SMI), and to examine the impact of community-based mental healthcare and other risk factors on their mortality.
We included 93 655 patients in 2012 and 100 706 in 2013 from the national mental health surveillance system in Sichuan, China to calculate the standardised mortality ratio (SMR). A total of 112 576 patients were followed up from 2009 to 2014 for model analyses. We used growth models to quantify the patterns of change for community management measures, high-risk behaviour, disease stability and medication adherence of patients over time, and then used multilevel proportional hazard models to examine the association between change patterns of management measures and mortality.
The SMR was 6.44 (95% CI 4.94–8.26) in 2012 and 7.57 (95% CI 5.98–9.44) in 2013 among patients with SMI aged 15–34 years, and diminished with age. Unfavourable baseline socioeconomic status increased the hazard of death by 38–50%. Positive changes in high-risk behaviour, disease stability and medication adherence had a 54% (95% CI 47–60%), 69% (95% CI 63–73%) and 20% (4–33%) reduction in hazard of death, respectively, versus in those where these were unchanged.
High excess mortality was confirmed among younger patients with SMI in Sichuan, China. Our findings on the relationships between community management and socioeconomic factors and mortality can inform community-based mental healthcare policies to reduce excess mortality among patients with SMI.
The global outbreak of coronavirus disease 2019 (COVID-19) is greatly threatening the public health in the world. We reconstructed global transmissions and potential demographic expansions of severe acute respiratory syndrome coronavirus 2 based on genomic information. We found that intercontinental transmissions were rare in January and early February but drastically increased since late February. After world-wide implements of travel restrictions, the transmission frequencies decreased to a low level in April. We identified a total of 88 potential demographic expansions over the world based on the star-radiative networks and 75 of them were found in Europe and North America. The expansion numbers peaked in March and quickly dropped since April. These findings are highly concordant with epidemic reports and modelling results and highlight the significance of quarantine validity on the global spread of COVID-19. Our analyses indicate that the travel restrictions and social distancing measures are effective in containing the spread of COVID-19.
To establish optimal gestational weight gain (GWG) in Chinese pregnant women by Chinese-specific BMI categories and compare the new recommendations with the Institute of Medicine (IOM) 2009 guidelines.
Multicentre, prospective cohort study. Unconditional logistic regression analysis was used to evaluate the OR, 95 % CI and the predicted probabilities of adverse pregnancy outcomes. The optimal GWG range was defined as the range that did not exceed a 1 % increase from the lowest predicted probability in each pre-pregnancy BMI group.
From nine cities in mainland China.
A total of 3731 women with singleton pregnancy were recruited from April 2013 to December 2014.
The optimal GWG (ranges) by Chinese-specific BMI was 15·0 (12·8–17·1), 14·2 (12·1–16·4) and 12·6 (10·4–14·9) kg for underweight, normal weight and overweight pregnant women, respectively. Inappropriate GWG was associated with several adverse pregnancy outcomes. Compared with women gaining weight within our proposed recommendations, women with excessive GWG had higher risk for macrosomia, large for gestational age and caesarean section, whereas those with inadequate GWG had higher risk for low birth weight, small for gestational age and preterm delivery. The comparison between our proposed recommendations and IOM 2009 guidelines showed that our recommendations were comparable with the IOM 2009 guidelines and could well predict the risk of several adverse pregnancy outcomes.
Inappropriate GWG was associated with higher risk of several adverse pregnancy outcomes. Optimal GWG recommendations proposed in the present study could be applied to Chinese pregnant women.
Anaemia is a global public health problem affecting women worldwide, and reproductive-age women are at increased risk. We conducted a population-based cross-sectional study analysing the prevalence of overall anaemia and anaemia according to severity in Chinese pre-pregnant women to update current knowledge on anaemia epidemiology. Based on the National Free Preconception Check-up Projects supported by the Chinese government, 5 679 782 women participating in this project in 2017 were included in the present study. The cyanmethemoglobin method was applied to assess Hb concentrations. Univariate and multivariate logistic regressions were applied for associated factors. The prevalence of anaemia among Chinese pre-pregnant women was 21·64 % (mild: 14·10 %, moderate: 7·17 % and severe : 0·37 %). The prevalence of overall and severe anaemia was the highest in Tibet and the lowest in Beijing among thirty-one provinces. Women’s age, region, ethnic origin, educational level, occupation and pregnancy history were all correlated with anaemia. Women with B blood type (adjusted OR (aOR) = 0·89), higher BMI (overweight: aOR = 0·84; obesity: aOR = 0·70) and alcohol consumption (aOR = 0·69) were less likely to have anaemia, while those with rhesus negative blood type (aOR = 1·10), history of anaemia (aOR = 2·60), older age at menarche (aOR = 1·19), heavy menstrual blood loss (aOR = 1·39), longer menstrual period (aOR = 1·09) and shorter menstrual cycle (aOR = 1·08) were more likely to suffer from anaemia. Meat or egg eaters were not significantly associated with severe anaemia. Anaemia is of moderate public health significance among Chinese pre-pregnant women. Interventions should be considered to prevent anaemia to the greatest extent possible to avoid potential harm in this population.
Late Mesozoic igneous rocks are important for deciphering the Mesozoic tectonic setting of NE China. In this paper, we present whole-rock geochemical data, zircon U–Pb ages and Lu–Hf isotope data for Early Cretaceous volcanic rocks from the Tulihe area of the northern Great Xing’an Range (GXR), with the aim of evaluating the petrogenesis and genetic relationships of these rocks, inferring crust–mantle interactions and better constraining extension-related geodynamic processes in the GXR. Zircon U–Pb ages indicate that the rhyolites and trachytic volcanic rocks formed during late Early Cretaceous time (c. 130–126 Ma). Geochemically, the highly fractionated I-type rhyolites exhibit high-K calc-alkaline, metaluminous to weakly peraluminous characteristics. They are enriched in light rare earth elements (LREEs) and large-ion lithophile elements (LILEs) but depleted in high-field-strength elements (HFSEs), with their magmatic zircons ϵHf(t) values ranging from +4.1 to +9.0. These features suggest that the rhyolites were derived from the partial melting of a dominantly juvenile, K-rich basaltic lower crust. The trachytic volcanic rocks are high-K calc-alkaline series and exhibit metaluminous characteristics. They have a wide range of zircon ϵHf(t) values (−17.8 to +12.9), indicating that these trachytic volcanic rocks originated from a dominantly lithospheric-mantle source with the involvement of asthenospheric mantle materials, and subsequently underwent extensive assimilation and fractional crystallization processes. Combining our results and the spatiotemporal migration of the late Early Cretaceous magmatic events, we propose that intense Early Cretaceous crust–mantle interaction took place within the northern GXR, and possibly the whole of NE China, and that it was related to the upwelling of asthenospheric mantle induced by rollback of the Palaeo-Pacific flat-subducting slab.
Echinococcus shiquicus is currently limited to the Qinghai–Tibet plateau, a large mountainous region in China. Although the zoonotic potential remains unknown, progress is being made on the distribution and intermediate host range. In this study, we report E. shiquicus within Gansu and Qinghai provinces in regions located not only around the central areas but also the southeast edge of the plateau and describe their genetic relationship with previous isolates from the plateau. From 1879 plateau pikas examined, 2.39% (95% CI 1.79–3.18) were infected with E. shiquicus. The highest prevalence of 10.26% (4.06–23.58) was recorded in Makehe town, Qinghai province. Overall the prevalence was marginally higher in Qinghai (2.5%, CI 1.82–3.43) than in Gansu (2%, CI 1.02–3.89). The cox1 and nad1 genes demonstrated high and low haplotype and nucleotide diversities, respectively. The median-joining network constructed by the cox1–nad1 gene sequences demonstrated a star-like configuration with a median vector (unsampled haplotype) occupying the centre of the network. No peculiar distinction or common haplotype was observed in isolates originating from the different provinces. The presence of E. shiquicus in regions of the southeast and northeast edges of the Qinghai–Tibet plateau and high genetic variation warrants more investigation into the haplotype distribution and genetic polymorphism by exploring more informative DNA regions of the mitochondrial genome to provide epidemiologically useful insight into the population structure of E. shiquicus across the plateau and its axis.
This experiment was designed to investigate the effect of supplementing conjugated linoleic acid (CLA) in breeder hens diet on development and hepatic lipid metabolism of chick offspring. Hy-Line Brown breeder hens were allocated into two groups, supplemented with 0 (CT) or 0.5% CLA for 8 weeks. Offspring chicks were grouped according to the mother generation and fed for 7 days. CLA treatment had no significant influence on development, egg quality, and fertility of breeder hens, but darkened the egg yolks in shade and increased yolk sac mass compared to CT group. Addition of CLA resulted in increased body mass and liver mass, and decreased deposition of subcutaneous adipose tissue in chick offspring. The serum triglyceride (TG) and cholesterol (TC) levels of chick offspring were decreased in CLA group. CLA treatment increased the incorporation of both CLA isomers (c9t11 and t10c12) in liver of chick offspring, accompanied by the decreased hepatic TG levels, related to the significant reduction of fatty acid synthase (FAS) and acetyl-CoA carboxylase (ACC) enzyme activities and the increased of carnitine palmitoyltransferase-1 (CPT1) enzyme activity. Meanwhile, CLA treatment reduced the mRNA expression of genes related to fatty acid biosynthesis (FAS, ACC, and sterol regulatory element-binding protein-1c), and induced the expression of genes related to β-oxidative (CPT1, AMP-activated protein kinase, and peroxisome proliferator-activated receptor α) in chick offspring liver. In summary, the addition of CLA in breeder hens diet significantly increased incorporation of CLA in liver of chick offspring, which further regulate hepatic lipid metabolism.
Network approach has been applied to a wide variety of psychiatric disorders. The aim of the present study was to identify network structures of remitters and non-remitters in patients with first-episode psychosis (FEP) at baseline and the 6-month follow-up.
Participants (n = 252) from the Korean Early Psychosis Study (KEPS) were enrolled. They were classified as remitters or non-remitters using Andreasen's criteria. We estimated network structure with 10 symptoms (three symptoms from the Positive and Negative Syndrome Scale, one depressive symptom, and six symptoms related to schema and rumination) as nodes using a Gaussian graphical model. Global and local network metrics were compared within and between the networks over time.
Global network metrics did not differ between the remitters and non-remitters at baseline or 6 months. However, the network structure and nodal strengths associated with positive-self and positive-others scores changed significantly in the remitters over time. Unique central symptoms for remitters and non-remitters were cognitive brooding and negative-self, respectively. The correlation stability coefficients for nodal strength were within the acceptable range.
Our findings indicate that network structure and some nodal strengths were more flexible in remitters. Negative-self could be an important target for therapeutic intervention.
Hypertension represents one of the most common pre-existing conditions and comorbidities in Coronavirus disease 2019 (COVID-19) patients. To explore whether hypertension serves as a risk factor for disease severity, a multi-centre, retrospective study was conducted in COVID-19 patients. A total of 498 consecutively hospitalised patients with lab-confirmed COVID-19 in China were enrolled in this cohort. Using logistic regression, we assessed the association between hypertension and the likelihood of severe illness with adjustment for confounders. We observed that more than 16% of the enrolled patients exhibited pre-existing hypertension on admission. More severe COVID-19 cases occurred in individuals with hypertension than those without hypertension (21% vs. 10%, P = 0.007). Hypertension associated with the increased risk of severe illness, which was not modified by other demographic factors, such as age, sex, hospital geological location and blood pressure levels on admission. More attention and treatment should be offered to patients with underlying hypertension, who usually are older, have more comorbidities and more susceptible to cardiac complications.
In this paper, the generation of relativistic electron mirrors (REMs) and the reflection of an ultra-short laser off this mirrors are discussed, applying two-dimensional particle-in-cell (2D-PIC) simulations. REMs with ultra-high acceleration and expanding velocity can be produced from a solid nanofoil illuminated normally by an ultra-intense femtosecond laser pulse with a sharp rising edge. Chirped attosecond pulse can be produced through the reflection of a counter-propagating probe laser off the accelerating REM. In the electron moving frame, the plasma frequency of the REM keeps decreasing due to its rapidly expanding. The laser frequency, on the contrary, keeps increasing due to the acceleration of REM and the relativistic Doppler shift from the lab frame to the electron moving frame. Within an ultra-short time interval, the two frequencies will be equal in the electron moving frame, which leads the resonance between laser and REM. The reflected radiation near this interval and the corresponding spectra will be amplified due to the resonance. Through adjusting the arriving time of the probe laser, certain part of the reflected field could be selectively amplified or depressed, leading to the selectively adjusting of the corresponding spectra.
The FNDC5 gene encodes the fibronectin type III domain-containing protein 5 that is a membrane protein mainly expressed in skeletal muscle, and the FNDC5 rs3480 polymorphism may be associated with liver disease severity in non-alcoholic fatty liver disease (NAFLD). We investigated the influence of the FNDC5 rs3480 polymorphism on the relationship between sarcopenia and the histological severity of NAFLD. A total of 370 adult individuals with biopsy-proven NAFLD were studied. The association between the key exposure sarcopenia and the outcome liver histological severity was investigated by binary logistic regression. Stratified analyses were undertaken to examine the impact of FNDC5 rs3480 polymorphism on the association between sarcopenia and the severity of NAFLD histology. Patients with sarcopenia had more severe histological grades of steatosis and a higher prevalence of significant fibrosis and definite non-alcoholic steatohepatitis than those without sarcopenia. There was a significant association between sarcopenia and significant fibrosis (adjusted OR 2·79, 95 % CI 1·31, 5·95, P = 0·008), independent of established risk factors and potential confounders. Among patients with sarcopenia, significant fibrosis occurred more frequently in the rs3480 AA genotype carriers than in those carrying the FNDC5 rs3480 G genotype (43·8 v. 17·2 %, P = 0·031). In the association between sarcopenia and liver fibrosis, there was a significant interaction between the FNDC5 genotype and sarcopenia status (P value for interaction = 0·006). Sarcopenia is independently associated with significant liver fibrosis, and the FNDC5 rs3480 G variant influences the association between sarcopenia and liver fibrosis in patients with biopsy-proven NAFLD.
Sugarcane brown rust, caused by Puccinia melanocephala, is one of the main diseases of sugarcane in China. The identification and discovery of new resistance genes have important theoretical and practical significance for preventing outbreaks of brown rust and ensuring the sustainable production of sugarcane. To screen for polymorphic simple-sequence repeat (SSR) molecular markers for localization of brown rust resistance genes, we used two populations that are suitable for genetic linkage map construction and mapping of new resistance genes to construct resistant and susceptible genetic pools. We then screened 449 pairs of primers to identify polymorphic SSR markers in the parental lines and the resistant/susceptible genetic pools. The results showed that 25 pairs of primers directed amplification of polymorphic DNA fragments between the parents of the cross combination ‘Yuetang 03-393’ × ‘ROC 24’, and 16 pairs of primers amplified polymorphic fragments between the parents of the cross combination ‘Liucheng 03-1137’ × ‘Dezhe 93-88’. Four pairs of primers (SMC236CG, SCESSR0928, SCESSR0636 and SCESSR2551) amplified polymorphic DNA fragments between the parental lines and the resistant/susceptible genetic pools in ‘Yuetang 03-393’ × ‘ROC 24’. The results of this study will establish a solid foundation for the mapping of new brown rust resistance genes, genetic linkage map construction and the development of closely-associated molecular markers in sugarcane.
Cysticercosis caused by the metacestode larval stage of Taenia hydatigena formerly referred to as Cysticercus tenuicollis is a disease of veterinary importance that constitutes a significant threat to livestock production worldwide, especially in endemic regions due to condemnation of visceral organs and mortality rate of infected young animals. While the genetic diversity among parasites is found to be potentially useful in many areas of research including molecular diagnostics, epidemiology and control, that of T. hydatigena across the globe remains poorly understood. In this study, analysis of the mitochondrial DNA (mtDNA) of adult worms and larval stages of T. hydatigena isolated from dogs, sheep and a wild boar in China showed that the population structure consists of two major haplogroups with very high nucleotide substitutions involving synonymous and non-synonymous changes. Compared with other cestodes such as Echinococcus spp., the genetic variation observed between the haplogroups is sufficient for the assignment of major haplotype or genotype division as both groups showed a total of 166 point-mutation differences between the 12 mitochondrial protein-coding gene sequences. Preliminary analysis of a nuclear protein-coding gene (pepck) did not reveal any peculiar changes between both groups which suggests that these variants may only differ in their mitochondrial makeup.
The aim of this study was to explore the application of the flipped classroom approach in the training of Mass Casualty Triage (MCT) to medical undergraduate students.
In this study, 103 fourth-year medical students were randomly divided into a Flipped Classroom (FC) group (n = 51) and a Traditional Lecture-based Classroom (TLC) group (n = 52). A post-class quiz, simulated field triage (SFT) and feedback questionnaires were performed to assess both groups of students for their learning of the course.
In the post-quiz, the median (IQR) scores achieved by students from the FC and TLC groups were 42(5) and 39(5.5), respectively. Significant differences were found between the two groups. In the SFT, overall triage accuracy was 67.06% for FC, and 64.23% for TLC students. Over-triage and under-triage errors occurred in 18.43% and 14.50% of the FC group, respectively. The TLC group had a similar pattern of 20.77% over-triage and 15.0% under-triage errors. No significant differences were found regarding overall triage accuracy or triage errors between the two groups.
The FC approach could enhance course grades reflected in the post-quiz and improve students’ satisfaction with the class. However, there was no significant difference of competency between the two groups demonstrated in the SFT exercise.
Despite high altitude was implicated in adverse birth outcomes, there remained a paucity of evidence on low-to-medium altitude effect. This study aimed to explore the association of low-to-medium altitude with birth outcomes. A population-based cross-sectional survey was performed using a stratified multistage random sampling method among women with their infants born during 2010–2013 in Northwestern China. Altitude was determined in meters based on the village or community of the mother’s living areas. Birth outcomes involved birth weight, gestational age, and small for gestational age (SGA). Generalized linear models were fitted to investigate the association of altitude with birth outcomes. Moreover, the dose–response relationship between altitude and birth outcomes was evaluated with a restricted cubic spline function. A total of 27 801 women with their infants were included. After adjusting for potential confounders, every 100-m increase in the altitude was associated with reduced birth weight by 6.4 (95% CI −8.1, −4.6) g, the slight increase of gestational age by 0.015 (95% CI 0.010, 0.020) week, and an increased risk of SGA birth (odds ratio 1.03, 95% CI 1.02, 1.04). Moreover, there was an inversely linear relationship between altitude and birth weight (P for overall < 0.001 and P for nonlinear = 0.312), and a positive linear relationship between altitude and SGA (P for overall < 0.001 and P for nonlinear = 0.194). However, a nonlinear relationship was observed between altitude and gestational age (P for overall < 0.001 and P for nonlinear = 0.010). The present results suggest that low-to-medium altitude is possibly associated with adverse birth outcomes.
To assess the prevalence and to identify the associated factors of malnutrition among elderly Chinese with physical functional dependency.
Face-to-face interviews using standardised questionnaires were conducted to collect demographic information, health-related issues and psychosocial status. Physical function was measured by the Barthel Index (BI), and nutrition status was assessed by the Mini Nutritional Assessment–Short Form. Multivariate binary logistic regression was used to assess associated factors of malnutrition.
A total of 2323 participants (aged ≥ 60 years) with physical functional dependency in five provinces in China were enrolled using a multistage cluster sampling scheme.
The prevalence of malnutrition was 17·9 % (95 % CI 16·3, 19·4). Multivariable binary logistic regression revealed the independent risk factors of poor nutrition status were being female, older age, lower educational status, poor hearing, poor physical functional status, lack of hobbies, low religious participation, poor social support, lack of social participation and changes in social participation. The study found that the most significant independent risk factor for malnutrition was complete physical functional dependence (OR 4·46, 95 % CI 2·92, 6·82).
The findings of the study confirm that malnutrition and the risk of malnutrition are prevalent in Chinese older adults with physical functional dependency. In addition to demographic and physical health-related factors, psychosocial factors, which are often overlooked, are independently associated with nutrition status in Chinese older adults with physical functional dependency. A holistic approach should be adopted to screen for malnutrition and develop health promotion interventions in this vulnerable population.
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.
A population-based cross-sectional survey.
Twenty counties and ten districts in Shaanxi Province of northwestern China, 2013.
28 174 pregnant women with their infants, covering 27 818 single live births and 356 twin live births.
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 (β 17·3, 95 % CI 6·1, 28·4; β 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.
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.