Originally published by 2 Minute Medicine® (view original article). Reused on AccessMedicine with permission.

1. Mean BMI and obesity prevalence increased more rapidly between 2004-2010 than between 2010-2018.

2. Divergent trends were seen between urban and rural populations, males and females, and between socioeconomic classes.

Evidence Rating Level: 2 (Good)

Study Rundown:

Due to rapid economic development in China, the general Chinese population has been noted to have an increase in the prevalence of obesity and rise in mean body-mass index (BMI) since the 1980s. In 2010, national obesity prevention programs were introduced; however, the effects of these programs have yet to be studied. This retrospective cohort study utilizes nationally representative health survey data to assess trends in obesity and BMI within the adult population in China between 2004-2018. BMI and obesity prevalence data were gathered annually, and sub-cohort analysis was performed based on sex, area of residence, age group, education level, and occupation. Additionally, the rates of change in mean BMI and obesity prevalence between 2004-2010 and 2010-2018 were compared to assess efficacy of national health interventions. The results of this study demonstrated the rate of increase in mean BMI between 2004-2010 was nearly double that of 2010-2018. The prevalence of obesity in 2018 was nearly twice that of 2004. Divergent changes were noted in rural female participants, as prevalence of obesity continued to increase in this sub-cohort compared to overall slowing rates of increase in the general population. The results of this study suggest a need for tailored national health interventions for different regions and for men and women.

In-Depth [retrospective cohort]:

The China Chronic Disease and Risk Factors Surveillance (CCDRFS) program surveyed 746,020 individuals between 2004 to 2018. Data from 645,223 individuals between ages 18-69 were included in this study. The rate of increase for mean BMI between 2004-2010 was 0.17 kg/m² annually (95% CI 0.12–0.22), compared to that of 2010-2018 as 0.09 kg/m² annually (0.06–0.11). The mean BMI at the start of the study in 2004 was 22.7 kg/m² (22.5–22.9) compared to 24.4 kg/m² (24.3–24.6) in 2018. The prevalence of obesity in 2004 was 3.1% (2.5–3.7) compared to 8.1% (7.6–8.7) in 2018. While the increase in BMI and obesity prevalence appeared to stabilize in urban populations, these measures continued to rise in the rural female cohort. These trends correlated with level of education attainment, with higher levels of education in women associated with lower BMI and obesity prevalence and inverse trends seen in men. The results of this study are limited by variable sampling among years, as well as individual surveyors conducting sampling for regional locations. Despite these limitations, the results of this study suggest changes in BMI and obesity in China with differential effects when comparing gender, regional, and educational status subgroups. These results suggest a need for tailored and targeted national health interventions to address obesity within the adult population of China.

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