Socioeconomic disparities in obesity among children and future actions to fight obesity in China

Associations between socioeconomic status and risk of obesity and overweight among Chinese children and adolescents

BACKGROUND

In China, the threat of obesity and overweight in children and adolescents is developing quickly. It may be possible to lower the risk of obesity and overweight in children and adolescents by understanding the factors that drive these conditions. Therefore, this study aimed to investigate the association between SES and risk of obesity and overweight among children and adolesecnts in China's provinces of Jiangsu, Anhui, Zhejiang, and Shanghai.

METHODS

Chinese children and adolescents (n = 2,746; 46.3% boys) were recruited using multistage sampling. SES was measured using self-reported questionnaires, the specific indicators were parental education, perceived family wealth, and Family Affluence Scale II. Height and weight were measured and used to calculate body mass index (BMI, categorized into obesity or overweight). The definition of obesity or overweight was based on the Chinese standard "Screening for obesity and overweight among school-age children and adolescents". Descriptive statistics, independent sample t-tests, and a Chi-square test were used to report the sample characteristics and analyse BMI differences across different sociodemographic groups. A binary logistic regression was then applied to analyse the association of SES indicators with BMI in children and adolescents.

RESULTS

Overall, 22.5% of children and adolescents were obese or overweight. Participants with medium and high maternal education levels were 1.48 [95% CI 1.15-1.91] and 1.47 [95% CI 1.03-2.11] times more likely to be obese/overweight. Girls with medium maternal education levels were 1.70[95% CI 1.21-2.40] times more likely to be obese/overweight. For boys, no association was observed. Junior middle school students with medium maternal education levels were 1.51[95% CI 1.10-2.07] times more likely to be obese/overweight. Participants with medium or high FAS, perceived family wealth, or paternal education levels were not associated with obesity/overweight.

CONCLUSIONS

The findings of this study indicated a positive association between SES and risk of overweight/obesity in girls, suggesting that maternal education level may have a substantial impact on future prevention efforts for these conditions in girls. To increase the effectiveness of interventions, longitudinal studies are necessary to better understand the causal association between SES and obesity/overweight.

Socio-economic disparities in child-to-adolescent growth trajectories in China: Findings from the China Health and Nutrition Survey 1991–2015

Backgrounds

Socio-economic disparities in growth trajectories of children from low-/middle-income countries are poorly understood, especially those experiencing rapid economic growth. We investigated socio-economic disparities in child growth in recent decades in China.

Methods

Using longitudinal data on 5095 children/adolescents (7–18 years) from the China Health and Nutrition Survey (1991–2015), we estimated mean height and BMI trajectories by socio-economic position (SEP) and sex for cohorts born in 1981–85, 1986–90, 1991–95, 1996–2000, using random-effects models. We estimated differences between high (urbanization index ≥median, household income per capita ≥median, parental education ≥high school, or occupational classes I–IV) and low SEP groups.

Findings

Mean height and BMI trajectories have shifted upwards across cohorts. In all cohorts, growth trajectories for high SEP groups were above those for low SEP groups across SEP indicators. For height, socio-economic differences persisted across cohorts (e.g. 3.8cm and 2.9cm in earliest and latest cohorts by urbanization index for boys at 10 year, and 3.6cm and 3.1cm respectively by household income). For BMI, trends were greater in high than low SEP groups, thus socio-economic differences increased across cohorts (e.g. 0.5 to 0.8kg/m² by urbanization index, 0.4 to 1.1kg/m² by household income for boys at 10 year). Similar trends were found for stunting and overweight/obesity by SEP. There was no association between SEP indicators and thinness.

Interpretation

Socio-economic disparities in physical growth persist among Chinese youth. Short stature was associated with lower SEP, but high BMI with higher SEP. Public health interventions should be tailored by SEP, in order to improve children's growth while reducing overweight/obesity.

Funding

MG is supported by UCL Overseas Research Scholarship and China Scholarship Council for her PhD study. WJ is supported by a UK Medical Research Council (MRC) New Investigator Research Grant (MR/P023347/1) and acknowledges support from the National Institute for Health Research (NIHR) Leicester Biomedical Research Centre, which is a partnership between University Hospitals of Leicester NHS Trust, Loughborough University, and the University of Leicester.

Gender-specific temporal trends in overweight prevalence among Chinese adults: a hierarchical age-period-cohort analysis from 2008 to 2015

Background

As a key health risk, the prevalence of overweight has been strikingly increasing worldwide. This study aimed to disentangle the net age, period, and cohort effects on overweight among Chinese adults by gender.

Methods

Data came from the Chinese General Social Survey from 2008 to 2015, which was a repeated cross-sectional survey (n = 55,726, aged 18 and older). χ² or t tests were used to estimate the gender disparities in overweight and socioeconomic status (SES). A series of hierarchical age-period-cohort cross-classified random-effects models were performed using SAS version 9.4 to estimate the overall and gender-specific temporal trends of overweight, as well as the association between SES and overweight. Further, a series of line charts were used to present the age and cohort variations in overweight.

Results

After controlling for covariates, significant age and cohort effects were observed among adults in China (b = 0.0205, p < 0.001; b = 0.0122, p < 0.05; respectively). Specifically, inverted U-shaped age effects were identified for both genders, with a high probability of overweight occurring in middle age (b = -0.0012, p < 0.001). Overweight was more prevalent among men than women before 60 years old, and this trend reversed thereafter (b = -0.0253, p < 0.001). Moreover, men born during the war (before 1950) and reform cohorts (after the 1975s) demonstrated a substantial decline in overweight, while men born in 1950-1975 showed an increasing trend in overweight prevalence (b = 0.0378, p < 0.05). However, the cohort effect on women was not statistically significant. Additionally, a higher SES was related to an elevated probability of overweight.

Conclusion

Gender-specific age and cohort effects on the prevalence of overweight were observed among Chinese adults. Both China and other developing countries need to pay attention to the coming obesity challenge and related health inequality. Full life-cycle overweight prevention interventions should focus on middle-aged adults, men born in the war and reform eras, and adults with a higher SES.

The impacts of multiple obesity-related interventions on quality of life in children and adolescents: a randomized controlled trial

BACKGROUND AND PURPOSE

Obesity has become a serious public health problem and family- and school-based interventions including physical exercise and diet control have been widely applied to attempt to combat this issue. The purpose of our study was to verify the effectiveness of an obesity-related comprehensive intervention model aimed at improving quality of life (QoL) among adolescents.

METHODS

A cluster randomized controlled trial (RCT) was conducted involving 948 subjects who were divided into an intervention group (n = 518) and a control group (n = 430). The intervention group received 1 year of obesity-related health education, physical exercise, and diet control. Their baseline body mass index (BMI) was calculated, and their QoL and basic information were assessed both before and after the intervention period using a self-designed Adolescent Quality of Life Scale and a basic information questionnaire.

RESULTS

After the intervention, significant differences in the psychological, social, and pubertal dimensions, and in total QoL (P < 0.05) were observed in the intervention group relative to the control group. Improved psychological QoL in the intervention group was our most robust study finding, with increases in psychological (B = 1.883, SE = 0.646, P = 0.004), pubertal (B = 0.853, SE = 0.296, P = 0.004) and total (B = 3.024, SE = 1.214, P = 0.013) QoL all being higher in this group. This intervention effect was found to be more substantial in boys than in girls.

CONCLUSIONS

Family-individual-school-based interventions combining obesity-related health education, physical exercise, and diet control can improve psychological, pubertal, and total QoL in children, with these effects being most pronounced in boys.

TRIAL REGISTRATION

retrospectively registered NCT02343588 .