Symbiotic gut microbiota is essential for human health, and its compositional changes have been associated with various complex disorders. However, systematic investigation of the acquisition and development of gut microbial communities during early infancy are relatively rare, particularly for infants from non-Western countries. In this study, we characterize the colonization and development of infant microbiota in healthy Chinese infants and compare the pattern with those from other countries. The fecal microbiota of 2-month-old infants was considerably more diverse than that of neonates, as indicated by higher relative abundances of Veillonella, Clostridium, Bacteroides, Lactobacillus, Collinsella and Prevotella, and reduction of Escherichia and Enterococcus. The fecal microbiota of vaginally delivered infants (both neonates and 2-month-old) had significant enrichment of Bacteroides, Parabacteroides and Megamonas, whereas cesarean delivered infants had enrichment of Prevotella, Streptococcus and Trabulsiella. By global comparison, we identify three different enterotypes, referred as “P-type”, “A-type ”and “F-type” which were highly abundant in Proteobacteria, Actinobacteria and Firmicutes, respectively. The three enterotypes’ compositons vary geographically. All Chinese infants in our study belong to the P-type. These findings may provide novel insights into our understanding of the establishment of infant fecal bacterial communities.

Sample storage conditions are important for unbiased analysis of microbial communities in metagenomic studies. Specifically, for infant gut microbiota studies, stool specimens are often exposed to room temperature (RT) conditions prior to analysis. This could lead to variations in structural and quantitative assessment of bacterial communities. To estimate such effects of RT storage, we collected feces from 29 healthy infants (0–3 months) and partitioned each sample into 5 portions to be stored for different lengths of time at RT before freezing at −80 °C. Alpha diversity did not differ between samples with storage time from 0 to 2 hours. The UniFrac distances and microbial composition analysis showed significant differences by testing among individuals, but not by testing between different time points at RT. Changes in the relative abundance of some specific (less common, minor) taxa were still found during storage at room temperature. Our results support previous studies in children and adults and provided useful information for accurate characterization of infant gut microbiomes. In particular, our study furnished a solid foundation and justification for using fecal samples exposed to RT for less than 2 hours for comparative analyses between various medical conditions.

The current study examined the association between temperature change and clinical visits for childhood respiratory tract infections (RTIs) in Guangzhou, China. Outpatient records of clinical visits for pediatric RTIs, which occurred from 1 January 2012 to 31 December 2013, were collected from Guangzhou Women and Children’s Hospital. Records for meteorological variables during the same period were obtained from the Guangzhou Meteorological Bureau. Temperature change was defined as the difference between the mean temperatures on two consecutive days. A distributed lag non-linear model (DLNM) was used to examine the impact of temperature change on pediatric outpatient visits for RTIs. A large temperature decrease was associated with a significant risk for an RTI, with the effect lasting for ~10 days. The maximum effect of a temperature drop (−8.8 °C) was reached at lag 2~3 days. Children aged 0–2 years, and especially those aged <1 year, were particularly vulnerable to the effects of temperature drop. An extreme temperature decrease affected the number of patient visits for both upper respiratory tract infections (URTIs) and lower respiratory tract infections (LRTIs). A temperature change between consecutive days, and particularly an extreme temperature decrease, was significantly associated with increased pediatric outpatient visits for RTIs in Guangzhou.

Background: With increasing prevalence of gestational diabetes mellitus (GDM) and changing management of GDM in pregnancy, it is imperative to understand the evolution of its current outcomes. The present study aimed to explore whether birth weight and large for gestational age (LGA) trends in women with GDM have changed over time in southern China.Methods: In this hospital-based retrospective study, all singleton live births for the period 2012 to 2021 were collected from the Guangdong Women and Children Hospital, China. GDM was diagnosed following the criteria of the International Association of Diabetes and Pregnancy Study Group. The cutoff points for defining LGA (>90th centile) at birth based on INTERGROWTH-21st gender-specific standards. Linear regression was used to evaluate trends for birth weight over the years. Logistic regression analysis was used to determine the odds ratios (ORs) of LGA between women with GDM and those without GDM.Results: Data from 115097 women with singleton live births were included. The total prevalence of GDM was 16.8%. GDM prevalence varied across different years, with the lowest prevalence in 2014 (15.0%) and the highest prevalence in 2021 (19.2%). The mean birth weight displayed decrease in women with GDM from 3.224kg in 2012 to 3.134kg in 2021, and the z score for mean birth weight decreased from 0.230 to -0.037 (P for trend < 0.001). Among women with GDM, the prevalence of macrosomia and LGA reduced significantly during the study period (from 5.1% to 3.0% in macrosomia and from 11.8% to 7.7% in LGA, respectively). Compared to women without GDM, women with GDM had 1.30 (95% CI: 1.23 - 1.38) times odds for LGA, and the ORs remained stable over the study period.Conclusions: Among offspring of women with GDM, there are decreased trends of birth weight in parallel with reductions in LGA prevalence between 2012 and 2021. However, the risk of LGA in women with GDM remains stable at relatively high level over the 10-year period, and efforts are still needed to address regarding causes and effective intervention strategies.

Purpose: Pandemic-related confinement helps to contain the transmission of the novel coronavirus disease (COVID-19) but restricts children’s exposure to sunlight, thereby possibly affecting their 25-hydroxyvitamin D [25(OH)D] levels. This study aimed to examine the effect of COVID-19 measures on 25(OH)D levels in children. Patients and Methods: This study included children who underwent health checks between March 1 and June 30, 2020, and those over the equivalent period during 2017– 2019 (N = 3600). Children’s 25(OH)D levels and the proportion of children with vitamin D deficiency were compared between different observation periods. Results: The mean serum 25(OH)D level was 84 ± 25nmol/L. The overall proportion of children with vitamin D deficiency (25(OH)D level < 50 nmol/L) was 4.6%. Home confinement led to an increase in the proportion of children aged 3– 6 years with vitamin D deficiency during March 1–June 30, 2020 compared with the same months in previous years, and the most noticeable increase was found in March 2020. In children aged 3– 6 years, 25(OH)D levels were lower in 2020 (65 ± 17nmol/L) than during 2017– 2019, and the proportion of those with vitamin D deficiency was higher in 2020 (19.0%) than in previous years. Among children aged 0.5– 1 and 1– 3 years, 25(OH)D levels were higher (97 ± 25 nmol/L, 91 ± 27 nmol/L), while the proportion of children with vitamin D deficiency was lower in 2020 (2.3%, 3.0%) than during 2017– 2019. Conclusion: The 25(OH)D levels tended to decrease gradually with increasing age. Reduced sunlight exposure during confinement is associated with lower 25(OH)D levels among children aged 3– 6 years. Therefore, vitamin D supplementation for children aged > 3 years is recommended.

Purpose: Evidence on the role of the gut microbiota in atopic dermatitis is inconsistent as human intestinal microbiota is influenced by geography. This cross-sectional study therefore aimed to compare differences in the gut microbiota of infants with atopic dermatitis and healthy infants in Guangzhou, China, by analyzing their stool. Patients and Methods: The composition of the intestinal microbiota was analyzed from the stool samples of 20 infants with atopic dermatitis (AD group) and 25 healthy infants (non-AD group) (1– 6 months old), using full-length 16S rRNA gene sequencing. The Wilcoxon test was used to analyze the relative abundance of bacteria by phylum, family, genus, and species between groups; microbial community richness and diversity were compared between the two groups. Results: There were no significant differences in the microbial community richness and diversity between the two groups. At the phylum level, 11 bacterial phyla were found; most sequences belonged to one of the three dominant bacterial phyla – Firmicutes, Proteobacteria, and Bacteroidetes. The top 10 microbes at the phylum, family, and genus levels showed no significant changes in their composition within the gut microbiota between the AD and non-AD groups. A decrease in the ratio of the Streptococcus genus was found in atopic dermatitis group when compared with healthy controls (p=0.048). Conclusion: A decrease in the abundance of Streptococcus was found in children with AD. The role of Streptococcus in the development of AD needs to be confirmed in a large cohort study.