Appropriate infant and young child feeding could reduce morbidity and mortality and could improve cognitive development of children. However, nationwide data on exclusive breastfeeding and complementary feeding status in China are scarce. The aim of this study was to assess current exclusive breastfeeding and complementary feeding status in China. A national representative survey (Chinese National Nutrition and Health Survey) of children aged under 6 years was done in 2013. Stratified multistage cluster sampling was used to select study participants. World Health Organization (WHO) infant and young child feeding indicators were firstly used to assess exclusive breastfeeding and complementary feeding practice nationwide. In total, 14,458 children aged under two years (0 to <730 days) were studied from 55 counties in 30 provinces in China. The crude exclusive breastfeeding rate under 6 months was 20.7% (908/4381) and the weighted exclusive breastfeeding rate was 18.6%. The crude prevalence of minimum dietary diversity, minimum meal frequency and minimum acceptable diet were 52.5% (5286/10,071), 69.8% (7027/10,071), and 27.4% (2764/10,071) among children aged 6–23 months, respectively. The weighted rate was 53.7%, 69.1%, and 25.1%, respectively. Residential area, household income and maternal education were positively associated with the three complementary feeding indicators. The exclusive breastfeeding rate under 6 months was low and complementary feeding practice was not optimal in China. Residential area, household income and maternal education might be used to target infants and young children to improve complementary feeding practice.

Background: Lactoferrin (Lf) is a multifunctional protein and one of the most abundant proteins in human milk. Various factors may affect its concentration in human milk, such as stage of lactation, ethnicity, and diet. Objectives: The objectives of the present study were to examine the dynamic change in milk Lf throughout the course of lactation and explore factors associated with milk Lf concentrations in various Chinese populations. Methods: This investigation was a part of a large cross-sectional study conducted in 11 provinces/autonomous regions/municipalities (Beijing, Gansu, Guangdong, Guangxi, Heilongjiang, Inner Mongolia, Shandong, Shanghai, Xinjiang, Yunnan, and Zhejiang) across China between 2011 and 2013. Lactating women (n = 6481) within 0–330 days postpartum were recruited in the original study. A sub-sample of 824 women was randomly selected, and milk Lf concentrations were determined by UPLC/MS. Results: The Lf concentration in milk from women delivering at term was 3.16 g/L, 1.73 g/L and 0.90 g/L for colostrum, transitional milk, and mature milk, respectively. Lf concentrations differed significantly between stages of lactation (colostrum vs. transitional milk, colostrum vs. mature milk, transitional milk vs. mature milk, all p < 0.001). Maternal BMI, age, mode of delivery, parturition, protein intake, and serum albumin concentration were not correlated with milk Lf concentration. However, milk Lf concentrations varied among different geographical regions (Guangdong (1.91 g/L) vs. Heilongjiang (1.44 g/L), p = 0.037; Guangdong (1.91 g/L) vs. Gansu (1.43 g/L), p = 0.041) and ethnicities (Dai (1.80 g/L) vs. Tibetan (0.99 g/L), p = 0.007; Han (1.62 g/L) vs. Tibetan (0.99 g/L), p = 0.002) in China. Conclusions: The concentration of Lf in human milk changes dynamically throughout lactation. Few maternal characteristics affect the milk Lf concentration, but it varies across different geographical regions and ethnicities in China.

Stunting remains a major public health issue for pre-school children globally. Dairy product consumption is suboptimal in China. The aim of this study was to investigate the relationship between dairy intake and linear growth in Chinese pre-school children. A national representative survey (Chinese Nutrition and Health Surveillance) of children aged under 6 years was done in 2013. Stratified multistage cluster sampling was used to select study participants. A food frequency questionnaire was used to collect dietary information. We calculated height-for-age Z-scores (HAZs) and estimated stunting using the 2006 WHO growth standard. In total, 12,153 children aged two to four years old (24 to <60 months) were studied from 55 counties in 30 provinces in China. Approximately 39.2% (4759/12,153) of those children consumed dairy at least once per day, 11.9% (1450/12,153) consumed dairy at least once in the last week, and nearly half (48.9%, 5944/12,153) did not have any dairy in the last week. The HAZ was −0.15 ± 1.22 and the prevalence of stunting was 6.5% (785/12,153). The HAZ for children who consumed dairy at least once per day or per week was 0.11 points or 0.13 points higher than the children without dairy intake. The risk of stunting for children who consumed dairy at least once per day was 28% lower than the children without dairy intake in the last week, and the risk was similar between weekly dairy consumption and no dairy consumption (AOR: 1.03, 95% CI: 0.74–1.42) after adjusting for potential confounders, including socioeconomic characteristics, lifestyle, health status, and the intake frequency of other foods. Dairy intake was significantly associated with a higher HAZ and a lower risk of stunting for children aged 2–4 years old in China. The proportion of dairy intake was still low in Chinese pre-school children. The promotion of dairy consumption might be an effective and feasible measurement for improving linear growth in Chinese pre-school children.

Background: Vitamin D deficiency is prevalent globally and there is lack of evidence as to how 25(OH)D2 contributes to vitamin D status. The aim of this study was to describe vitamin D status and to assess the role of vitamin D2, a dietary vitamin D source, against the vitamin D status of children aged 3–5 years in China. Methods: Data were extracted from the Chinese National Nutrition and Health Surveillance (CNNHS) in 2013. The concentration of serum 25(OH)D2 and 25(OH)D3 was measured by using LC-MS/MS. Results: A total of 1435 subjects were enrolled and serum 25(OH)D were analyzed. The prevalence of total serum 25(OH)D < 30 nmol/L was 8.9%. Serum 25(OH)D2 was detected in 10.9% of the studied children. After adjusting for confounding factors, total 25(OH)D concentration was 8.48 nmol/L lower and odds ratio of vitamin D deficiency was 4.20 times (OR (95%CI): 4.20 (1.64, 10.77)) in children without 25(OH)D2 than those with 25(OH)D2 detected. Conclusions: Vitamin D deficiency was common among children aged 3–5 years in China. Vitamin D2 may play a role in preventing vitamin D deficiency in Chinese children aged 3–5 years.

Background: To investigate relationships between five single nucleotide polymorphisms (SNP) in four maternal genes involved in one carbon metabolism and adverse pregnancy outcomes, including preterm birth (PTB), low birth weight (LBW), and small-for-gestational-age (SGA). Methods: This was a prospective mother and child cohort study in Wuqiang, China. Pregnant women (n = 939) were recruited from Jun 2016 to Oct 2018. Pregnancy outcomes (PTB, LBW, and SGA) were extracted from medical records and other information including age at childbearing, maternal education level, gravidity, parity, pre-pregnancy weight and height was collected by using a structured questionnaire. The maternal serum folate concentration was measured by using Abbott Architect i2000SR chemiluminescence analyzer in the first prenatal care visit. DNA genotyping of methylenetetrahydrofolate reductase (MTHFR) C677T and A1298C, methionine synthase reductase (MTRR) A66G, methionine synthase (MTR) A2756G, and thymidylate synthetase (TYMS) rs3819102 was processed by Sequenom MassARRAY iPLEX Platform. Univariate and multivariate logistics regression analysis were used to test the relationships between 5 SNPs and PTB, LBW, SGA. Results: Totally, 849 dyads of women and infants were included in the analysis. The prevalence of PTD, LBW, and SGA were 3.76%, 1.58%, and 5.31% respectively. The homozygote frequencies of MTHFR C677T, MTHFR A1298C, MTRR A66G, MTR A2756G, and TYMS rs3819102 were 44.2%, 1.4%, 6.7%, 1.3%, and 3.2%, and the alt allele frequencies were 66.1%, 10.8%, 24.9%, 10.5%, and 20.5% respectively. The average serum folate concentration was 11.95 ng/mL and the folate deficiency rate was 0.47%. There were no significant associations between MTHFR C677T, MTHFR A1298C, MTRR A66G, MTR A2756G, TYMS rs3819102 alleles and PTD, LBW, SGA (p > 0.05). Conclusions: In the population with adequate folate status and low prevalence of adverse pregnancy outcomes, MTHFR C677T, MTHFR A1298C, MTRR A66G, MTR A2756G, TYMS rs3819102 alleles may not be related to PTD, LBW, and SGA.

What is already known on this topic? Low folate status in pregnancy has been associated with multiple adverse pregnancy outcomes, including neural tube defects, congenital heart defects, fetal growth restriction, low birth weight, and preterm delivery. Low folate status is common in China, especially in northern areas. What is added by this report? Folate status remains suboptimal among pregnant Chinese women in 2015. The median serum folate concentrations of pregnant women were 8.02 ng/mL in China. Low folate status was widespread, especially in rural aeras (9.88 ng/mL) and in northern China Folate concentration was in widespread rural area (9.88 ng/mL) and especially in the northern of China (9.10 ng/mL). Pregnant women in the last trimester had the lowest folic acid concentration (9.18 ng/mL). Taking folic acid supplements every day would achieve adequate serum folate concentrations (10.87 ng/mL vs. 10.11 ng/mL vs. 9.38 ng/mL, P<0.001). What are the implications for public health practice? Folic acid interventions should be strengthened, especially for pregnant women in rural areas and in northern China, those under 25 years old, those with junior school or below education, those pregnant during spring and winter, those overweight and obese, or those with late pregnancy.