Summary
Background There are little recent data in China regarding contemporary nutritional inequities among children and
adolescents, particularly in relation to urban–rural residence and regional socioeconomic status (SES). We aim to
assess inequalities in thinness and obesity in Chinese children and adolescents.
Methods Weight and height measurements for 1 677261 children and adolescents aged 7–18 years were obtained from
seven cycles of the Chinese National Surveys on Students Constitution and Health (1985, 1995, 2000, 2005, 2010, 2014,
and 2019). Sex-specific BMI-for-age Z scores were applied to define thinness (Z scores <–2SD) and obesity (Z scores
>+2SD). Urban–rural classification came from the Statistical Urban and Rural Division Code, and gross domestic
product (GDP) per capita in the province in which the school was situated was used as a proxy for SES. T1 represented
the provinces with the most disadvantaged SES and T3 represented the provinces with the most advantaged SES.
General linear regression models assessed correlations between prevalence and GDP per capita, with projections to
2030 derived from best-fitting models.
Findings The mean prevalence of obesity rose from 0·10% (95% CI 0·09 to 0·11) in 1985 to 8·25% (8·13 to 8·37)
in 2019, whereas thinness prevalence decreased from 8·49% (8·41 to 8·58) to 3·37% (3·29 to 3·45). High SES
provinces exhibited a significant drop in obesity prevalence from 2014 (8·42% [8·19 to 8·65]) to 2019
(7·73% [7·52 to 7·95]). Nationally, the prevalence of obesity was consistently higher in urban areas than in rural areas
for both sexes from 1985 to 2019; however, a greater prevalence of obesity was observed in rural than urban girls
residing in T3 regions in 2019 (urban–rural gap: –0·37% [–0·07 to –0·80]). Rural boys had a higher prevalence of
thinness than their urban counterparts across all survey waves, with the exceptions of 1985 and 1995. For girls, no
significant urban–rural gap in thinness was observed in the most recent survey in 2019 (–0·10% [–0·24 to 0·04]).
From 1985 to 2014, boys and girls from high SES regions had a higher risk of obesity and a lower risk of thinness than
those from low SES regions. However, in 2019, a nationwide shift occurred, and the T3–T1 difference in obesity
approached or went below zero for boys (–0·49% [–1·02 to 0·04]) and girls (–0·68% [–1·00 to –0·35]). T3–T1
differences in thinness also approached zero for boys (–0·46% [–0·77 to –0·14]) and girls (–0·14% [–0·43 to 0·15]).
The projected estimates to 2030 for urban–rural obesity gaps (boys: –1·00% [–2·65 to 0·65]; girls:
–2·88% [–6·91 to 1·15]) and T3–T1 obesity differences (boys: –8·88% [–13·76 to –4·01]; girls: –8·82% [–12·78 to –4·85])
were both negative, with forecasted estimates for urban–rural gaps and T3–T1 differences in thinness prevalence
in 2030 close to zero for both boys and girls.
Interpretation China’s socioeconomic development continues to influence within-country inequities regarding the
regional distribution of child and adolescent weight according to urban–rural location and regional SES. Contemporary
Chinese children and adolescents in socioeconomically disadvantaged regions and rural areas constitute a vulnerable
population facing nutritional risk, but from obesity rather than thinness. Disrupting projected inequities in obesity
will require extensive preventive investments.
Funding National Natural Science Foundation of China, Beijing Natural Science Foundation, Peking University Talent
Introduction Program Project, and Clinical Medicine Plus X-Young Scholars Project of Peking University.