Effects of the Duration of Ying Yang Bao Consumption on Hemoglobin Concentration in Infants and Young Children in Less Developed Areas of China

Hemoglobin as a mediator between air pollution and growth outcomes in children under 60 months: the moderating role of nutritional supplementation

BACKGROUND

Prior research has yielded incongruent results about the association between air pollutants and offspring hemoglobin levels, as well as between air pollutants and child development. This may be because previous studies have not taken both air pollution and nutrition into account. This study sought to examine the correlations between postnatal exposure to air pollution (PM2.5, PM10, SO2, and CO), offspring hemoglobin levels, stunting, and underweight. Furthermore, we investigated whether hemoglobin levels mediate these connections and assessed the moderating influence of dietary supplementation on hemoglobin levels and growth outcomes.

METHODS

A unified nutrition package intervention study was conducted in western, China between 2016 and 2023. In accordance with WHO guidelines, stunting, underweight, height-for-age z score (HFA), weight-for-age z score (WFA), and anemia status were all defined. A daily average of PM2.5, PM10, SO2, and CO levels was collected from the National Urban Air Quality Real-Time Dissemination Platform ( http://www.cnemc.cn/sssj/ ) of the China Environmental Monitoring General Station. Linear regression and logistic regression models were used to assess the correlation between air pollution and the above indicators. The mediating role of hemoglobin and the moderating effect of nutritional supplementation were also evaluated.

FINDINGS

This study examined the impact of postnatal air pollution exposure on child growth, mediated by hemoglobin levels and moderated by nutritional supplementation (YingYangBao, YYB). Our findings suggest that air pollution negatively affects growth via reduced hemoglobin levels, but extended nutritional supplementation mitigates this effect. A total of 10,766 children under 5 years of age participated in this study. All four air pollutants were associated with reduced hemoglobin levels, but their effects on growth and development were not uniform. Specifically, PM2.5 and PM10 showed stronger negative associations with HFA and WFA, while SO2 and CO had weaker effects. Air pollution had a greater impact on growth outcomes in anemic children compared to non-anemic children. Hemoglobin levels mediated 13.4% of the effect of air pollution on HFA (VAF = 13.4%, Cohen's f² = 0.15). Furthermore, the duration of YYB moderates the effects of air pollution on hemoglobin and HFA. The direct negative effect of air pollution on HFA was attenuated when the duration of use was > 10 months, whereas in the low use group the pollution effect was enhanced (β=-0.0444, 95%CI: -0.0613, -0.03).

CONCLUSION

Postnatal exposure to air pollution (PM2.5, PM10, SO2, CO) increases the risk of stunting, particularly during the critical developmental window of 6-23 months of age. This effect is partially mediated by hemoglobin levels, and YYB can moderate this relationship. These findings highlight the importance of prolonged nutritional interventions in mitigating the adverse effects of air pollution on child growth and development, with significant implications for public health policies targeting air quality and child nutrition in high-pollution regions.

Impact of Early Ying Yang Bao Nutritional Support on Growth and Neurodevelopment in Preschool Children in China

Background: Providing early nutritional support through Ying Yang Bao (YYB) can assist children in achieving their full developmental potential. We aimed to examine the lasting impact of YYB and how growth affects neurodevelopment in preschool children. Methods: 1104 children aged 1 year were divided into a YYB control group (YYB-CG) and a YYB intervention group (YYB-IG). Information on basic characteristics, anthropometric measurements, dietary status, YYB consumption, and neurodevelopment for these children was taken annually from 2018 to 2022 until they reached 5 years old. Confounders were well balanced using propensity score matching (PSM), and then 474 pairs of children were included in subsequent analyses. The comparison between groups was performed using t-tests or chi-square analyses. Linear regressions were used to examine the independent associations between children's dimensions (Z-score for weight relative to age [WAZ], Z-score for height relative to age [HAZ], Z-score for body mass index by age [BAZ], and conditional measures of height- and weight-based growth) and neurodevelopment. Results: Children in the YYB-IG had higher scores in the mental index (MI), the developmental quotient (DQ), height, and BAZ (p < 0.05) and had a lower risk of stunting. Accelerated weight gain from ages 1 to 5 (β (95% confidence interval [CI]): 0.26 (0.08-0.45)) and increased height gain during this period (β (95% CI): 0.68 (0.14-1.23)) were associated with greater MI. A higher WAZ was linked to increased MI at 1 year (β (95% CI): 0.89 (0.09-1.68)), 2 years (β (95% CI): 0.99 (0.20-1.78)), 3 years (β (95% CI): 0.92 (0.15-1.69)), 4 years (β (95% CI): 0.88 (0.09-1.68)), and 5 years of age (β (95% CI): 1.01 (0.28-1.74)). An increased HAZ corresponded with a higher MI score at ages 1 year (β (95% CI): 1.47 (0.75-2.20)), 2 years (β (95% CI): 1.25 (0.49-2.02)), 3 years (β (95% CI): 1.11 (0.31-1.90)), 4 years (β (95% CI): 0.93 (0.12-1.74)), and 5 years old (β (95% CI): 1.17 (0.43-1.90)); higher DQ levels were also recorded at 1 year (β (95% CI): 0.82 (0.10-1.55)) and 5 years of age (β (95% CI): 0.79 (0.06-1.51)). Conclusions: YYB can improve specific areas of neurodevelopment and growth in preschool children. Additionally, children's linear growth is positively linked to neurodevelopment in those of preschool age.

The Effects of Ying Yang Bao on Nutritional Status of Children Aged 6-60 Months in Underdeveloped Rural Areas of China

The Ying Yang Bao (YYB) intervention, a national policy in China, has been implemented for over two decades. Most previous studies have focused only on the short-term effects of YYB, while the long-term effects remain unexplored. This study was designed to evaluate the long-term effects of YYB in children aged 6-60 months. A sample of 4666 children was divided into intervention and control groups. Information on basic characteristics, physical examination, YYB consumption, etc., was obtained annually from 2018 to 2021. T-tests or chi-square tests were used to compare differences between the groups for continuous or categorical variables. Children in the intervention group showed greater incremental improvements in hemoglobin levels and physical development (p < 0.05). Prevalence of anemia, underweight, and stunting were lower in the intervention group than in the control group (all p < 0.05). Two-level regression models were constructed to assess the long-term effects of YYB. YYB reduced the risk of anemia and wasting by 37% (OR: 0.63, 95% CI: 0.52-0.75) and 49% (OR: 0.51, 95% CI: 0.39-0.67), respectively. This study indicates that YYB could significantly improve the nutritional status of children aged 6-60 months in underdeveloped rural areas of China.

Intervention Effect of a Soybean-Based Complementary Food Supplement on Anemic Infants in a Poor Rural Region in China: Evidence from Quasi-RCT

The soybean-based Yingyang Bao complementary food supplement represents a special nutritional improvement method for anemic infants in many intervention projects across China, while its benefits lack rigorous evidence. Using a quasi-randomized controlled trial design, which adhered to randomization and control except for the blinding method, 248 anemic infants were divided randomly into an intervention group (128 cases received the Yingyang Bao intervention based on routine feeding) and a control group (120 cases only received routine feeding). Anthropometric indicators and 16 blood indicators were measured at baseline and 1 year after intervention. The levels of hemoglobin, 1,25-dihydroxy vitamin D, homocysteine, retinol, vitamin D3, and soluble transferrin receptor and the height-age-Z score and weight-age-Z score of the intervention group were significantly improved after the intervention (p < 0.05). The homocysteine level improvement appeared to be moderately negatively correlated with the cobalamin level improvement (p < 0.05). The improvements of five indicators were significant correlated with the intervention duration (p < 0.05), and the corresponding three significant regression equations could predict the intervention effect and the intervention duration to a certain extent. This quasi-randomized controlled trial provided more convincing evidence that Yingyang Bao can effectively improve three kinds of malnutrition compared to previous research which only adopted self before and after comparison.

Yingyangbao Reduced Anemia among Infants and Young Children Aged 6-23 Months When Delivered through a Large-Scale Nutrition Improvement Program for Children in Poor Areas in China from 2015 to 2020

The purpose of this study was to assess the effectiveness of intervention with Yingyangbao (YYB) on hemoglobin (Hb) and anemia status among infants and young children (IYC) aged 6-23 months (mo) through a large-scale Nutrition Improvement Program for Children in Poor Areas (NIPCPA) in China from 2015 to 2020. Five rounds of cross-sectional surveys were conducted using a stratified and multi-stage probability proportional to size sampling of IYC in 2015, 2017, 2018, 2019 and 2020. Multivariable regression analyses were fitted to determine the effectiveness of the YYB intervention on Hb and anemia, respectively. A total of 36,325, 40,027, 43,831, 44,375 and 46,050 IYC aged 6-23 mo were included, and the prevalence of anemia was 29.7%, 26.9%, 24.1%, 21.2% and 18.1% in 2015, 2017, 2018, 2019 and 2020, respectively. Compared with the results in 2015, the Hb concentrations significantly improved and anemia prevalence significantly decreased among IYC in 2017, 2018, 2019, and 2020 (p < 0.001). Regression analysis showed that higher YYB consumption was significantly associated with the increment in Hb concentration and reduction in anemia stratified by age group (p < 0.001). The most significant increment in Hb concentration of 2.189 mg/L and the most significant reduction in odds of anemia were observed among IYC aged 12-17 mo who consumed 270 to 359 sachets of YYB (OR: 0.671; 95% CI: 0.627, 0.719; p < 0.001). This study suggests that YYB intervention is a successful public health strategy for reducing the risk of anemia among IYC when delivered through a large-scale NIPCPA in China. It is necessary to continue to advance the program and increase the adherence of YYB.

Yingyangbao Intervention Was Associated with the Improvement of Body Growth and Nutrition Status of Infants and Young Children in Poor Rural Areas of China: The Annual Comparison from 2012 to 2020

Yingyangbao (YYB) is a soy-based micronutrient-fortified powder used in the Nutrition Improvement Project on Children in Poor Areas of China. After the baseline study in 2012, YYB intervention gradually spread to 21 provinces in China. From 2015 to 2020, a secular trend study was carried out to evaluate the body growth and nutritional status of 6-23-month-old infants and young children (IYC) under YYB intervention. The aim of this research was to investigate whether YYB intervention was associated with the improvement of body growth and development in large populations from broad areas with national and multi-year survey results. The anthropometric data collected in the baseline study and cross-sectional surveys were compared, and the correlation between YYB intake amount and body growth were analyzed. Compared with the results of the baseline study, the 6-23-month-old IYC under YYB intervention showed a significant increase in body weight, body length and Z scores since 2015, and the stunting rate decreased from 9.7% in 2012 to 5.3% in 2020. Significantly positive correlations were observed between the YYB intake amount and the body growth indicators. Therefore, YYB intervention was associated with the improvement of body growth and nutrition status of Chinese IYC. In the future, long-term and continuous efforts are still needed to further reveal the health benefits of YYB in depth.