Patterns and sociodemographic determinants of water intake by children in China: results from the first national population-based survey

Hotspot mapping and risk prediction of fluoride in natural waters across the Tibetan Plateau

Intake of high fluoride concentrations through water affects up to 1 billion people worldwide, and the Tibetan Plateau (TP) is one of the most severely affected areas. Knowledge regarding the high fluoride risk areas, the driving factors, and at-risk populations on the TP remains fragmented. We collected 1581 natural water samples from the TP to model surface water and groundwater fluoride hazard maps using machine learning. The geomean concentrations of surface water and groundwater were 0.26 mg/L and 0.92 mg/L, respectively. Surface water fluoride hazard hotspots were concentrated in the north-central region; high fluoride risk areas of groundwater were mainly concentrated in the southern TP. Hazard maps showed a maximum estimate of 15% of the total population in the TP (approximately 1.47 million people) at risk, and 500,000 people considered the most reasonable estimate. Critical environment driving factors were identified, in which climate condition was taken for the vital one. Under the moderate climate change scenario (SSP2.45) for 2089-2099, the high fluoride risk change rate differed inside the TP (surface water -24%-55% and groundwater -56%-50%), and the overall risk increased in natural waters throughout the TP, particularly in the southeastern TP.

Chemical constituents of ambient fine particulate matter and obesity among school-aged children: A representative national study in China

BACKGROUND

Studies show that fine particulate matter (PM_2.5) contributes to childhood obesity. However, evidence on the effects of its constituents on obesity has not been explored.

METHODS

Using multistage stratified cluster sampling, we enrolled 41,439 school-age children (aged 6-17 years) from a representative nationwide survey of 30 provinces in China (mean age ± standard deviation: 12.0 ± 3.3 years). Weight and height were measured using a physician beam scale with a height rod, and covariates were determined using a standard questionnaire. The concentration of PM_2.5 chemical constituents was estimated by a chemical transport (GEOS-Chem) model using input satellite data and ground-based observations. The constituents included black carbon, ammonium, nitrate, organic matter, sulfate, and soil dust. Generalized linear models were used to estimate the association between the chemical constituents of PM_2.5 and obesity.

RESULTS

A positive association between the constituents of PM_2.5 and obesity were observed. Children were more susceptible to black carbon than other species. A 1-μg/m³ increase in black carbon led to a 0.079 (95 % confidence interval [CI]:0.028, 0.130)-kg/m² increase in body mass index (BMI). This also increased the odds of being obese and overweight to 1.174 (95 % CI: 1.111, 1.240) and 1.165 (95 % CI: 1.116, 1.216), respectively. Stratified analyses showed that the effects were stronger in girls and older children, as well as in urban and Northeast regions. The effect of the PM_2.5 constituents on obese and overweight children from urban areas significantly interacted with that of rural areas.

CONCLUSIONS

The PM_2.5 constituents were associated with an increased BMI and childhood obesity. Further studies are warranted to validate these results and clarify their potential mechanisms. We suggest focusing on black carbon and Northeast regions.

Association between exposure to fine particulate matter and obesity in children: A national representative cross-sectional study in China

BACKGROUND

Childhood obesity is a global health issue, and limited evidence suggests that air pollution may be a contributing factor. This study aims to examine whether exposure to fine particulate matter (PM_2.5) is associated with obesity status in a nationally representative sample of schoolchildren in China.

METHODS

The study population consisted of 41,439 schoolchildren of 6-17 years old, recruited from 30 provinces in China using a multi-stage stratified sampling method. Weights and heights were measured for all the participants, and sociodemographic information was collected using a questionnaire. The obesity status was classified following the Chinese national standards. The PM_2.5 exposure was estimated as the 5-year average concentration at the school location for each participant. The association between obesity status and PM_2.5 exposure was examined using weighted logistic regressions adjusted for potential confounders.

RESULTS

The prevalence of normal weight, overweight, and obesity were 78.5%, 12.4%, and 9.0%, respectively. PM_2.5 exposure averaged 59.8 ± 17.6 μg/m³ with a range of 30.5-115.2 μg/m³ among all the participants. The risk of obesity increased by 10.0% (95% confidence interval: 3.0-16.0%) per 10 μg/m³ increase in PM_2.5 exposure. The PM_2.5-associated risk was significantly elevated in older age groups and children living in urban areas (interaction p-values < 0.05).

CONCLUSIONS

This national survey revealed that approximately 1 in 5 Chinese schoolchildren were overweight or obese. Exposure to PM_2.5 in the ambient air was significantly associated with childhood obesity. The findings suggest the need for further research to uncover the roles of PM_2.5 exposure in childhood obesity development.

Association between milk intake and childhood growth: results from a nationwide cross-sectional survey

PURPOSE

The literature is inconsistent regarding milk intake and physical growth. This study aims to evaluate the association of milk intake with body height and weight in a nationally representative sample of Chinese children.

METHODS

A total of 41,439 children ages 6-17 were recruited from 30 provinces in mainland China in 2013-2016 using a multistage stratified cluster sampling approach. Milk intake information was collected using a questionnaire aided with standard containers. Weight and height were measured using a standard physician beam scale with a height rod. Milk intake was categorized into no-, low-, and high-intake groups based on the intake rate, and weight status into normal, overweight, and obese groups based on the body-mass-index (BMI). Associations between height/weight status and milk intake were evaluated using multivariate weighted linear and logistic regression models.

RESULTS

Chinese children had low milk intake: 1/5 of children did not drink milk, and those drinking milk had a median intake of 100 ml/month. The low- and high-intake groups were 0.83 cm (95% confidence interval: 0.00, 1.68 cm) and 1.26 cm (0.34, 2.19 cm) taller than the no-intake group for girls, respectively, after adjusting for confounding factors. Boys with high milk intake had lower BMI (-0.56, 95% CI: -1.00, -0.12 kg/m²) and risk of obesity (OR = 0.67, 95% CI: 0.46, 0.97) than those without milk intake.

CONCLUSIONS

This study revealed the association of increased milk intake with increased body height and lowered obesity risk among Chinese children. Given the cross-sectional nature of the study and the possibility of residual confounding, further research is warranted to uncover the role of milk intake in promoting children's growth.