Income-related inequities of adult obesity and central obesity in China: evidence from the China Health and Nutrition Survey 1997-2011

Key influences on dysglycemia across Fujian's urban-rural divide

BACKGROUND

Screening and treatment of dysglycemia (prediabetes and diabetes) represent significant challenges in advancing the Healthy China initiative. Identifying the crucial factors contributing to dysglycemia in urban-rural areas is essential for the implementation of targeted, precise interventions.

METHODS

Data for 26,157 adults in Fujian Province, China, were collected using the Social Factors Special Survey Form through a multi-stage random sampling method, wherein 18 variables contributing to dysglycemia were analyzed with logistic regression and the random forest model.

OBJECTIVE

Investigating urban-rural differences and critical factors in dysglycemia prevalence in Fujian, China, with the simultaneous development of separate predictive models for urban and rural areas.

RESULT

The detection rate of dysglycemia among adults was 35.26%, with rates of 34.1% in urban areas and 35.8% in rural areas. Common factors influencing dysglycemia included education, age, BMI, hypertension, and dyslipidemia. For rural residents, higher income (OR = 0.80, 95% CI [0.74, 0.87]), average sleep quality (OR = 0.89, 95% CI [0.80, 0.99]), good sleep quality (OR = 0.89, 95% CI [0.80, 1.00]), and high physical activity (PA) (OR = 0.87, 95% CI [0.79, 0.96]) emerged as protective factors. Conversely, a daily sleep duration over 8 hours (OR = 1.46, 95% CI [1.03, 1.28]) and middle income (OR = 1.12, 95% CI [1.03, 1.22]) were specific risk factors. In urban areas, being male (OR = 1.14, 95% CI [1.02, 1.26]), cohabitation (OR = 1.18, 95% CI [1.02, 1.37]), and central obesity (OR = 1.35, 95% CI [1.19, 1.53]) were identified as unique risk factors. Using logistic regression outcomes, a random forest model was developed to predict dysglycemia, achieving accuracies of 75.35% (rural) and 76.95% (urban) with ROC areas of 0.77 (rural) and 0.75 (urban).

CONCLUSION

This study identifies key factors affecting dysglycemia in urban and rural Fujian residents, including common factors such as education, age, BMI, hypertension, and dyslipidemia. Notably, rural-specific protective factors are higher income and good sleep quality, while urban-specific risk factors include being male and central obesity. These findings support the development of targeted prevention and intervention strategies for dysglycemia, tailored to the unique characteristics of urban and rural populations.

The Association between Marital Status and Obesity: A Systematic Review and Meta-Analysis

BACKGROUND

Obesity was included in the International Classification of Diseases in 1990 as a chronic disease characterized by the excessive accumulation of body fat and a body mass index (BMI) greater than 30 kg/m2.

AIM

This systematic review was aimed to examine the role of marital status in determining body mass index and the risk of obesity.

METHODS

We performed a systematic literature search using three databases (PubMed (Medline), Embase, and Google Scholar) with the search query.

RESULTS

Of the 105 studies included in the systematic review, 76 studies (72%) reported a greater risk of obesity in married individuals compared to unmarried individuals. A meta-analysis of 24 studies included a total population of 369,499 participants: 257,257 married individuals (40,896 of whom had obesity) and 112,242 comparison subjects (single, divorced, or widowed individuals, 15,084 of whom had obesity). Odds ratios for obesity found a significant pooled odds ratio for obesity in married individuals compared with controls (OR 1.70; 95% CI 1.38-2.10). The socioeconomic environment was not the same throughout the period of studies analyzed. The odds of obesity in married individuals during economic crises was greater than during the period between crises: OR 2.56 (95% CI 2.09-3.13) during crises vs. OR 1.55 (95% CI 1.24-1.95) between crises.

CONCLUSION

The results of this review confirm the importance of considering marital status in determining the risk of obesity.

National and subnational mortality trends of multiple myeloma in China, 2013-2020: Empirical evidence from national mortality

The incidence of multiple myeloma (MM) has increased over time in China. Despite this increase, comprehensive and up-to-date statistics on its mortality at national and provincial scales are lacking. To bridge this gap, we used mortality data from the disease surveillance points system operated by the Chinese Center for Disease Control and Prevention. Mortality rates were standardized against the 2010 census population of China (ASMRC) and Segi's world population (ASMRW). Joinpoint regression models were used to analyze temporal trends. Our findings indicated an estimated 14,568 MM-related deaths in China. The observed crude mortality rates ASMRC, and ASMRW were 1.04, 0.80, and 0.62 per 100,000 individuals, respectively. A notable sex-related difference in mortality rates was evident, with male mortalities (8,319) surpassing female mortalities (6,249) by a factor of 1.33. Age-wise, mortality rates tended to increase after 55 years, reaching a maximum in those over 85 years (7.09 per 100,000 individuals). Provincial data revealed that the highest ASMRCs were in Zhejiang, Beijing, and Jiangxi, whereas the lowest were in Tibet, Qinghai, and Hainan. The period from 2013 to 2020 exhibited a significant increase of 58.09 % in MM mortality, with urban and rural areas exhibiting a 44.97 % and 70.94 % increase, respectively. This analysis highlights the growing mortality burden of MM across various demographics and regions, emphasizing the need for tailored disease management and preventive measures.

The Contribution of the Underlying Factors to Socioeconomic Inequalities in Obesity: A Life Course Perspective

Objectives: Socioeconomic disparities in obesity have been observed in both childhood and adulthood. However, it remains unclear how the role of risk factors influencing these inequalities has evolved over time. Methods: Longitudinal data on 2,866 children and adolescents (6-17 years old) from the China Health and Nutrition Survey were used to track their BMI during childhood, adolescence, and adulthood. Concentration Index was utilized to measure socioeconomic inequalities in obesity, while Oaxaca decomposition was employed to determine the share of different determinants of inequality. Results: The concentration index for obesity during childhood and adulthood were 0.107 (95% CI: 0.023, 0.211) and 0.279 (95% CI: 0.203, 0.355), respectively. Changes in baseline BMI (24.6%), parental BMI (10.4%) and socioeconomic factors (6.7%) were found to be largely responsible for the increasing inequality in obesity between childhood and adulthood. Additionally, mother's education (-7.4%) was found to contribute the most to reducing these inequalities. Conclusion: Inequalities in obesity during childhood and adulthood are significant and growing. Interventions targeting individuals with higher BMI, especially those who are wealthy, can significantly reduce the gap.

Trends in prevalence of obesity and its association with hypertension across socioeconomic gradients in rural Yunnan Province, China

BACKGROUND

This study aimed to uncover the changing prevalence of obesity and its association with hypertension across socioeconomic gradients in rural southwest China.

METHODS

Data were collected from two cross-sectional health interviews and surveys from 2011 to 2021 among individuals aged ≥ 35 years in rural China. Each participant's height, weight, waist circumference, and blood pressure were measured. The overall prevalence of obesity, central obesity, and hypertension was directly standardized by age based on the total population of the two surveys. Multivariate logistic regression was used to analyze the association between obesity and prevalence of hypertension and an individual socioeconomic position (SEP) index was constructed using principal component analysis.

RESULTS

From 2011 to 2021, the prevalence of obesity, central obesity, and hypertension increased substantially, from 5.9%, 50.2%, and 26.1-12.1%, 58.0%, and 40.4% (P < 0.01), respectively. These increasing rates existed in all subcategories, including sex, age, ethnicity, education, annual household income, access to medical services, and SEP (P < 0.05). In both 2011 and 2021, lower education level and poor access to medical services correlated with higher prevalence of central obesity, while higher SEP correlated with higher prevalence of obesity and central obesity (P < 0.01). Prevalence of obesity was higher in the Han ethnicity participants and individuals with poor access to medical services than in their counterparts (P < 0.01). Whereas the prevalence of central obesity was lower in Han participants than in ethnic minority participants in 2011 (P < 0.01), this trend reversed in 2021 (P < 0.01). A positive relationship between annual household income and prevalence of obesity and central obesity was only found in 2021 (P < 0.01). Obese and centrally obese participants were more likely to be hypertensive in both survey years (P < 0.01).

CONCLUSIONS

Future interventions to prevent and manage obesity in rural China should give increased attention to high income, less educated, poor access to medical services, and high SEP individuals. The implementation of these obesity interventions would also help reduce the prevalence of hypertension.

Association between non-alcoholic fatty liver disease and metabolically healthy deterioration across different body shape phenotypes at baseline and change patterns

Non-alcoholic fatty liver disease (NAFLD) is a hepatic manifestation of metabolic syndrome (MetS), and the relationship between NAFLD and metabolic deterioration remains unclear. This study aimed to investigate dynamic changes in metabolically healthy phenotypes and to assess the impact of non-alcoholic fatty liver disease (NAFLD) on the conversion from metabolically healthy (MH) to metabolically unhealthy (MU) phenotypes across body shape phenotypes and phenotypic change patterns. We defined body shape phenotypes using both the body mass index (BMI) and waist circumference (WC) and defined metabolic health as individuals scoring ≤ 1 on the NCEP-ATP III criteria, excluding WC. A total of 12,910 Chinese participants who were MH at baseline were enrolled in 2013 and followed-up in 2019 or 2020. During a median follow-up of 6.9 years, 27.0% (n = 3,486) of the MH individuals developed an MU phenotype. According to the multivariate Cox analyses, NAFLD was a significant predictor of conversion from the MH to MU phenotype, independent of potential confounders (HR: 1.12; 95% confidence interval: 1.02–1.22). For the MH-normal weight group, the relative risk of NAFLD in phenotypic conversion was 1.21 (95% CI 1.03–1.41, P = 0.017), which was relatively higher than that of MH-overweight/obesity group (HR: 1.14, 95% CI 1.02–1.26, P = 0.013). Interestingly, the effect of NAFLD at baseline on MH deterioration was stronger in the “lean” phenotype group than in the “non-lean” phenotype group at baseline and in the “fluctuating non-lean” phenotype change pattern group than in the “stable non-lean” phenotype change pattern group during follow-up. In conclusion, lean NAFLD is not as benign as currently considered and requires more attention during metabolic status screening.

Global burden of asthma associated with high body mass index from 1990 to 2019

BACKGROUND

High body mass index (BMI) plays a key role in the progression of asthma and asthma related to high BMI resulted in a high burden of disease globally.

OBJECTIVE

This study aimed to explore the geographical and temporal trends in the global burden of asthma associated with high BMI from 1990 to 2019.

METHODS

This is a retrospective analysis with data based on the Global Burden of Disease Study 2019 database. The deaths, disability-adjusted life-years (DALYs), age-standardized mortality rate (ASMR) and age-standardized DALY rate (ASDR) were estimated according to sex, age and sociodemographic indexes (SDI) levels. Estimated annual percentage change (EAPC) was used to evaluate the variation trends of ASMR and ASDR from 1990 to 2019.

RESULTS

In 2019, the number of global asthma deaths and DALYs related to high BMI increased by 69.69% and 63.91% respectively compared with 1990, among which more deaths and DALYs occurred in females. The corresponding ASMR and ASDR showed a slightly decreasing tendency globally. South Asia accounted for the highest number of deaths and DALYs, with India ranked first worldwide in 2019. The number of deaths and DALYs mainly appeared in individuals 60-79 years old and 55-69 years old respectively from 1990 to 2019. The heaviest burden existed in the low-middle SDI region.

CONCLUSION

The global asthma burden associated with obesity increased in absolute value but the standardized burden decreased slightly. Large variations existed in the high BMI-related asthma burdens among sexes, ages and regions.

Income-related health inequality in urban China (1991-2015): The role of homeownership and housing conditions

Unprecedented economic growth has been experienced over the several decades worldwide, but such rapid economic growth wasn't accompanied by equally-substantial improvement in health, especially health inequalities between the rich and poor. This study examines the role of housing in income-related health inequalities (income-health gradient) in urban China. We here analyze 1991-2015 China Health and Nutrition Survey data to ask how housing affects income-related health inequalities in urban China. We find pro-poor inequalities in self-reported bad health but pro-rich inequalities in objective bad health (general overweight/obesity, central obesity and high blood pressure). Housing conditions serve to reduce the health gradient, especially for objective health. On the contrary, homeownership exacerbates the health gradient. Improving housing conditions thus appears to be an effective way of reducing the income-health gradient in urban China.

Body-mass index and obesity in urban and rural China: findings from consecutive nationally representative surveys during 2004-18

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/m2vs 23·9 kg/m2; p=0·0045), but remained lower in rural than urban men (24·5 kg/m2vs 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.

Epidemiology and determinants of obesity in China

Obesity has become a major public health issue in China. Overweight and obesity have increased rapidly in the past four decades, and the latest national prevalence estimates for 2015-19, based on Chinese criteria, were 6·8% for overweight and 3·6% for obesity in children younger than 6 years, 11·1% for overweight and 7·9% for obesity in children and adolescents aged 6-17 years, and 34·3% for overweight and 16·4% for obesity in adults (≥18 years). Prevalence differed by sex, age group, and geographical location, but was substantial in all subpopulations. Strong evidence from prospective cohort studies has linked overweight and obesity to increased risks of major non-communicable diseases and premature mortality in Chinese populations. The growing burden of overweight and obesity could be driven by economic developments, sociocultural norms, and policies that have shaped individual-level risk factors for obesity through urbanisation, urban planning and built environments, and food systems and environments. Substantial changes in dietary patterns have occurred in China, with increased consumption of animal-source foods, refined grains, and highly processed, high-sugar, and high-fat foods, while physical activity levels in all major domains have decreased with increasing sedentary behaviours. The effects of dietary factors and physical inactivity intersect with other individual-level risk factors such as genetic susceptibility, psychosocial factors, obesogens, and in-utero and early-life exposures. In view of the scarcity of research around the individual and collective roles of these upstream and downstream factors, multidisciplinary and transdisciplinary studies are urgently needed to identify systemic approaches that target both the population-level determinants and individual-level risk factors for obesity in China.

Unhealthy Diet Pattern Mediates the Disproportionate Prevalence of Obesity among Adults with Socio-Economic Disadvantage: An Australian Representative Cross-Sectional Study

The role of unhealthy dietary pattern in the association between socio-economic factors and obesity is unclear. The aim was to examine the association between socio-economic disadvantage and obesity and to assess mediation effect of unhealthy dietary pattern defined using the Mediterranean diet criteria. The data source was the Australian National Nutrition and Physical Activity Survey. The study sample included 7744 participants aged 18 years and over, 28% of whom had obesity. We used the Australian Socio-Economic Indexes for Areas (SEIFA) classification system for categorizing socio-economic disadvantage; calculated the Mediterranean Diet Score (MDS) using standard criteria; and used measured body mass index to define obesity. We conducted a mediation analysis using log–binomial models to generate the prevalence ratio for obesity and the proportion mediated by the MDS. The most disadvantaged group was associated with higher level of obesity after controlling for covariates (1.40, 95% CI 1.25, 1.56) compared to the least disadvantaged group, and in a dose–response way for each decreasing SEIFA quintile. The relationship between socio-economic disadvantage and obesity was mediated by the MDS (4.0%, 95% CI 1.9, 8.0). Public health interventions should promote healthy dietary patterns, such as the Mediterranean diet, to reduce obesity, especially in communities with high socio-economic disadvantage.