Figure 1 - available via license: Creative Commons Attribution-NonCommercial 4.0 International
Content may be subject to copyright.
Secular trend in body mass index by gender for Chinese adults age 21 and older, 1991-2009. Note: error bars indicate 95% confidence intervals of observed values. Source: China Health and Nutrition Survey (1991, 1993, 1997, 2000, 2004, 2006, and 2009).
Source publication
Using data from the 1991–2009 China Health and Nutrition Surveys, this paper examines the temporal–spatial variation in the education gradient of body weight relative to height among Chinese adults, and how the variation is associated with levels of economic development. We find different variation patterns for men and women. For women, the educati...
Contexts in source publication
Context 1
... first obvious finding in the data is that body weights have been steadily and dramatically increasing in China from 1991 to 2009, the time period of our study. Figure 1 displays the trend in BMI from 1991 to 2009 for women and men separately. Both women and men experienced weight gains over the period. ...
Context 2
... then plot the county/sub-city specific coefficients against a measure of local level of economic development, per-capita income. Results from this exercise are presented in Appendix Figure A1 for men and in Appendix Figure A2 for women. While we gain insights by examining unconstrained county/sub-city specific estimated coefficients, this strategy is unduly conservative and does not allow us to test interesting hypotheses theoretically. ...
Similar publications
This paper examines trends in the gender wage gap observed in urban China during the post-reform era. Using China Health and Nutrition Survey (CHNS) data, changes to the gap between 1989 and 2011 are analyzed using the Wellington decomposition method. While women's gains in observed characteristics have narrowed the wage gap, they are more than off...
Citations
... Second, county effects are much smaller than interviewer effects for interviewer ratings of physical appearance, but they are larger than interviewer effects for respondents' reported body weight. This high variance component for counties in terms of reported body weight may reflect the high regional variation in China's socioeconomic development and its differential impact on individuals' weights (Luo and Xie 2018). ...
Interviewer ratings of respondents’ physical appearance have been collected in several major social surveys. While researchers have made good use of such ratings data in substantive studies, empirical evidence on their measurement properties is rather limited. This study evaluates two potential threats to the quality of interviewer ratings of physical appearance: interviewer effects and halo effects. Using data from the China Family Panel Studies, we show large interviewer effects on interviewer ratings of respondents’ physical appearance based on cross-classified models. We also provide possible evidence for halo effects based on high correlations between physical appearance ratings and other theoretically distinct constructs, after controlling for interviewer effects. However, we find support for convergent and discriminant validity of physical appearance ratings when both interviewer effects and halo effects are controlled for. Empirical studies using interviewer observation data should take into account interviewer effects and halo effects when possible or at least discuss their potential impact on the substantive findings.
Background
In China, mean body-mass index (BMI) and obesity in adults have increased steadily since the early 1980s. However, to our knowledge, there has been no reliable assessment of recent trends, nationally, regionally, or in certain population subgroups. To address this evidence gap, we present detailed analyses of relevant data from six consecutive nationally representative health surveys done between 2004 and 2018. We aimed to examine the long-term and recent trends in mean BMI and prevalence of obesity among Chinese adults, with specific emphasis on changes before and after 2010 (when various national non-communicable disease prevention programmes were initiated), assess how these trends might vary by sex, age, urban–rural locality, and socioeconomic status, and estimate the number of people who were obese in 2018 compared with 2004.
Methods
We used data from the China Chronic Disease and Risk Factors Surveillance programme, which was established in 2004 with the aim to provide periodic nationwide data on the prevalence of major chronic diseases and the associated behavioural and metabolic risk factors in the general population. Between 2004 and 2018 six nationally representative surveys were done. 776 571 individuals were invited and 746 020 (96·1%) participated, including 33 051 in 2004, 51 050 in 2007, 98 174 in 2010, 189 115 in 2013, 189 754 in 2015, and 184 876 in 2018. After exclusions, 645 223 participants aged 18–69 years remained for the present analyses. The mean BMI and prevalence of obesity (BMI ≥30 kg/m²) were calculated and time trends compared by sex, age, urban–rural locality, geographical region, and socioeconomic status.
Findings
Standardised mean BMI levels rose from 22·7 kg/m² (95% CI 22·5–22·9) in 2004 to 24·4 kg/m² (24·3–24·6) in 2018 and obesity prevalence from 3·1% (2·5–3·7) to 8·1% (7·6–8·7). Between 2010 and 2018, mean BMI rose by 0·09 kg/m² annually (0·06–0·11), which was half of that reported during 2004–10 (0·17 kg/m², 95% CI 0·12–0·22). Similarly, the annual increase in obesity prevalence was somewhat smaller after 2010 than before 2010 (6·0% annual relative increase, 95% CI 4·4–7·6 vs 8·7% annual relative increase, 4·9–12·8; p=0·13). Since 2010, the rise in mean BMI and obesity prevalence has slowed down substantially in urban men and women, and moderately in rural men, but continued steadily in rural women. By 2018, mean BMI was higher in rural than urban women (24·3 kg/m² vs 23·9 kg/m²; p=0·0045), but remained lower in rural than urban men (24·5 kg/m² vs 25·1 kg/m²; p=0·0007). Across all six surveys, mean BMI was persistently lower in women with higher levels of education compared with women with lower levels of education, but the inverse was true among men. Overall, an estimated 85 million adults (95% CI 70 million–100 million; 48 million men [95% CI 39 million–57 million] and 37 million women [31 million–43 million]) aged 18–69 years in China were obese in 2018, which was three times as many as in 2004.
Interpretation
In China, the rise in mean BMI among the adult population appears to have slowed down over the past decade. However, we found divergent trends by sex, geographical area, and socioeconomic status, highlighting the need for a more targeted approach to prevent further increases in obesity in the Chinese general population.
Funding
China National Key Research and Development Program, China National Key Project of Public Health Program, and Youth Scientific Research Foundation of the National Center for Chronic and Noncommunicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention.
