Increasing prevalence of overweight and obesity in Yi farmers and migrants from 2007 to 2015 in China: the Yi migrant study

Prevalence, associated factors, and gene polymorphisms of obesity in Tibetan adults in Qinghai, China

OBJECTIVES

To explore the prevalence and associated factors of obesity in Tibetan adults in Qinghai, China, and to determine the association between the FTO (rs1121980 and rs17817449) and MC4R gene (rs17782313 and rs12970134) polymorphisms with obesity.

METHODS

A cross-sectional survey was conducted in 2015 in Qinghai to selected Tibetan adults aged 20 to 80 years. Prevalence of obesity (BMI ≥ 28 kg/m2) and overweight (BMI 24 ~ 27.9 kg/m2) were evaluated. Multivariable logistic models were used to determine the associated factors. Pair-matched subjects of obesity cases and normal-weight controls were selected for the gene polymorphism analyses. Conditional logistic models were used to assess the association between gene polymorphisms with obesity. Additive and multiplicative gene-environment interactions were tested.

RESULTS

A total of 1741 Tibetan adults were enrolled. The age- and sex- standardized prevalence of obesity and overweight was 18.09% and 31.71%, respectively. Male sex, older age, heavy level of leisure-time exercise, current smoke, and heavy level of occupational physical activity were associated with both obesity and overweight. MC4R gene polymorphisms were associated with obesity in Tibetan adults. No significant gene-environment interaction was detected.

CONCLUSION

The prevalence of obesity and overweight in Tibetan adults was high. Both environmental and genetic factors contributed to the obesity prevalent.

Meteorin-like Protein and Asprosin Levels in Children and Adolescents with Obesity and Their Relationship with Insulin Resistance and Metabolic Syndrome

OBJECTIVE

Two newly discovered adipokines, including Meteorin-like protein (Metrnl) and asprosin, have been implicated in glucose and insulin metabolism. This study aimed to investigate the associations of these adipokines with obesity in children and adolescents.

METHODS

This study was performed on 35 normal-weight children and 35 children with obesity. Anthropometric and biochemical parameters were determined. Serum concentrations of Metrnl, asprosin, and insulin were measured using enzyme-linked immunosorbent assay.

RESULTS

Metrnl level was significantly lower in obese children than normal-weight children. Additionally, Metrnl was negatively correlated with body mass index (BMI), insulin, waist-to-hip ratio, and homeostatic model assessment of insulin resistance (HOMA-IR). Our results also revealed that circulating asprosin levels were significantly increased in obese children compared to the control subjects and were positively correlated with BMI, insulin, HOMA-IR, cholesterol, and LDL-C.

CONCLUSION

Obesity is accompanied by significant alterations in Metrnl and asprosin and therefore these adipokines, especially Metrnl, are suggested as new promising therapeutic targets for obesity and its associated metabolic imbalances.

Body fat and muscle were associated with metabolically unhealthy phenotypes in normal weight and overweight/obesity in Yi people: A cross-sectional study in Southwest China

This study aimed to determine the association between the absolute mass, distribution, and relative ratio of body fat and muscle with the metabolically unhealthy (MU) phenotypes in normal weight and overweight/obesity in Yi people in China. The cross-sectional data from the Yi Migrants Study was used, which included 3,053 Yi people aged 20-80 years from the rural and urban sets. Participants were classified according to body mass index and metabolic status. Body composition including body fat percentage (BFP), fat mass index (FMI), visceral fat grade (VFG), muscle mass index (MMI), and muscle/fat ratio (M/F) were measured by bioelectrical impedance analysis. Restricted cubic spline and logistics regression models were used to test the associations between body composition parameters with MU phenotypes. Receiver-operating characteristic curves (ROC) were used to analyze the predictive value of MU phenotypes. Among the normal weight and overweight/obesity, 26.31% (497/1,889) and 52.15% (607/1,164) were metabolically unhealthy. Stratified by BMI, covariance analysis showed higher body fat (BFP, FMI, and VFG) and MMI in MU participants than in healthy participants. BFP, FMI, VFG, and MMI were positively associated with MU phenotypes both in normal weight and overweight/obesity after adjustment. M/F was significantly lower than MU participants and was negatively associated with MU phenotypes. BFP, FMI, VFG, and M/F could better predict MU phenotypes than BMI. We concluded that BFP, FMI, and VFG were positively associated with MU phenotypes, while M/F was negatively associated with MU phenotypes across the BMI categories in Yi people. Body fat and muscle measurement could be a valuable approach for obesity management.

Prevalence and determinants of obesity and abdominal obesity among rural workers in Southeastern Brazil

The objectives of this study were to assess the nutritional status of rural workers from a municipality in Southeastern Brazil and estimate the association of sociodemographic, labor, lifestyle, and dietary pattern factors with obesity and abdominal obesity of men and women of this rural area. This is a cross-sectional, epidemiological study of 740 farmers (51.5%, n = 381 males; 48.5%, n = 359 females). The sociodemographic, labor, lifestyle and dietary patterns determinants were assessed. Food intake data were obtained by applying three 24-hour recalls and dietary patterns were determined by Principal Component Analysis with Varimax orthogonal rotation. Poisson regression with robust variance stratified by sex was applied. The general prevalence of overweight status was 31.5% (95% CI 28.2-34.8%), 19.7% of obesity (95% CI 16.8-22.6%) and 31.5% of abdominal obesity (95% CI 28.2-34.8%), with higher rates in women (P < 0.001). Men of higher socioeconomic class had a 2.3 times higher prevalence of obesity (95% CI 1.08-4.90). In addition, the shorter travel time to purchase food increased the prevalence of abdominal obesity in males. For women, the older the age group, the greater the general and central obesity. A lower adherence to traditional dietary patterns (approximately PR [prevalence ratio] 1.6 for general obesity and PR 1.3 for abdominal obesity) and a greater number of places to buy food were associated with higher rates of obesity in women. Finally, women farmers with a higher workload had a 20% lower prevalence of central obesity (PR 0.80; 95% CI 0.65-0.97). Such findings demonstrate that obesity must be an issue in the health care of remote and rural populations. There is a need to promote healthier environments that respect traditional food culture through multiple approaches that consider the heterogeneity of rural areas and the differences between sexes.

MC4R Gene Polymorphisms Interact With the Urbanized Living Environment on Obesity: Results From the Yi Migrant Study

Objectives: This study aimed to determine the association of MC4R gene polymorphisms (rs17782313 and rs12970134) and urbanized living environment and the gene–environment interaction with obesity in Yi people in China.

Methods: A 1:2 frequency-matched case–control study based on the cross-sectional data was designed. Those with BMI ≥28 kg/m² were included as the case group. The age- and sex-matched controls were selected from those with BMI <24 kg/m². Unconditional logistic models were used to determine the association of SNPs with obesity. Additive interaction was evaluated by calculating relative excess risk due to interaction (RERI), attributable proportion due to interaction (AP), and synergy index (SI).

Results: A total of 322 cases and 643 controls were included. After adjustment, allele C of rs17782313 was significantly associated with obesity (additive model, OR = 1.52, 95%CI: 1.18–1.96) in Yi people. A similar association was found in allele A of rs12970134 (additive model, OR = 1.45, 95%CI: 1.13–1.89). Yi rural-to-urban migrants were found at 2.59-fold (95%CI: 1.70–3.95) higher odds of obesity than Yi farmers. Additive interactions were found between the two SNPs and rural-to-urban migration (rs17782313: AP = 0.65, 95%CI: 0.22–1.09; rs12970134: AP = 0.59, 95%CI: 0.02–1.17).

Conclusion:MC4R gene polymorphisms positively interacted with the urbanized living environment on obesity in Yi people. The effect of the MC4R gene on obesity was modified by the living environment.

Long-term ambient PM2.5 exposure associated with cardiovascular risk factors in Chinese less educated population

INTRODUCTION

Long-term exposure to ambient air pollution is related to major cardiovascular risk factors including diabetes, hypertension, hyperlipidemia and overweight, but with few studies in high-concentration nations like China so far. We aimed to investigate the association between long-term exposure to ambient fine particulate matter (particles with an aerodynamic diameter ≤ 2.5 μm, PM_2.5) and major cardiovascular risk factors in China.

METHODS

Adult participants with selected biochemical tests were recruited from the Chinese Physiological Constant and Health Condition (CPCHC) survey conducted from 2007 to 2011. Gridded PM_2.5 data used were derived from satellite-observed data with adjustment of ground-observed data. District-level PM_2.5 data were generated to estimate the association using multivariate logistic regression model and generalized additive model.

RESULTS

A total of 19,236 participants from the CPCHC survey were included with an average age of 42.8 ± 16.1 years, of which nearly half were male (47.0%). The annual average PM_2.5 exposure before the CPCHC survey was 33.4 (14.8-53.4) μg/m³, ranging from 8.0 μg/m³ (Xiwuqi) to 94.7 μg/m³ (Chengdu). Elevated PM_2.5 was associated with increased prevalence of hypertension (odds ratio (OR) =1.022, 95% confidence interval (95%CI): 1.001, 1.043) and decreased prevalence of overweight (OR = 0.926, 95%CI: 0.910, 0.942). Education significantly interacted with PM_2.5 in association with all the interesting risk factors. Each 10 μg/m³ increment of PM_2.5 was associated with increased prevalence of diabetes (OR = 1.118, 95%CI: 1.037, 1.206), hypertension (OR = 1.101, 95%CI: 1.056, 1.147), overweight (OR = 1.071, 95%CI: 1.030, 1.114) in participants with poor education, but not in well-educated population. PM_2.5 exposure was negatively associated with hyperlipidemia in all participants (OR = 0.939, 95%CI: 0.921, 0.957). The results were robust in all the sensitivity analyses.

CONCLUSION

Association between long-term PM_2.5 exposure and cardiovascular risk factors might be modified by education. PM_2.5 was associated with a higher prevalence of diabetes, hypertension, and overweight in a less-educated population with time-expose dependency. Long-term exposure to PM_2.5 might be associated with a lower prevalence of hyperlipidemia.

Prevalence and Influencing Factors of Overweight and Obesity among Adult Residents of Western China: A Cross-Sectional Study

Background

Overweight and obesity have become a serious health problem. There are a few data on the prevalence of overweight and obesity in Baoji city of western China, this study was conducted to investigate the epidemiologic features of overweight and obesity and explored influencing factors among Baoji adult residents.

Methods

A cross-sectional study, including 36,600 participants aged above 15 years, was carried out in Baoji city in 2018. Each participant's weight and height were measured, and demographic and behavioral characteristics were collected using questionnaires. Data were analyzed by means of logistic regression considering 95% level of significance.

Results

Overall, the prevalence of overweight and obesity was 30.73% and 3.11%, respectively. Male had a significantly higher prevalence of overweight (31.45% vs. 29.98%, P < 0.05) while female had a higher prevalence of obesity (3.50 vs. 2.74, P < 0.001). In the logistic regression analysis, being married or living with a partner (OR = 1.266, P < 0.001), unemployed or retired (OR = 1.183, P < 0.001), former smokers (OR = 1.116, P < 0.05), drinking alcohol (OR = 1.410, P < 0.001), sleeping more than 10 hours (OR = 1.274, P < 0.001), and increasing age were all significantly associated with a higher prevalence of overweight/obesity, whereas people who lived in rural areas (R = 0.904, P < 0.001) or had a sufficient leisure time physical activity per week (R = 0.945, P < 0.05) were associated with a lower prevalence.

Conclusion

Our results demonstrate that demographic and behavioral factors play an important role in prevalence of overweight/obesity, which can support the implementation of interventions aimed at weight control and consequently prevention of related diseases in this population.

Non-communicable disease risk factors and management among internal migrant in China: systematic review and meta-analysis

Background

In 2019, there are more than 290 million people who have ever migrated from rural to urban areas in China. These rural-to-urban internal migrants account for more than one-fifth of China’s population and is the largest internal migrant group globally. We present the first systematic review that examines whether internal migrants are more likely to exhibit non-communicable diseases (NCDs) risk factors and have worse NCD management outcomes than non-migrant counterparts in China.

Methods

A systematic review was conducted via medical, public health, and economic databases including Scopus, MEDLINE, JSTOR, WHO Library Database and World Bank e-Library from 2000 to 2020. Study quality was assessed using the National Institute of Health Quality Assessment tool. We conducted a narrative review and synthesised differences for all studies included, stratified by different types of outcomes. We also conducted random-effects meta-analysis where we had a minimum of two studies with 95% CIs reported. The study protocol has been registered with PROSPERO: CRD42019139407.

Results

For most NCD risk factors and care cascade management, comparisons between internal migrants and other populations were either statistically insignificant or inconclusive. While most studies found migrants have a higher prevalence of tobacco use than urban residents, these differences were not statistically significant in the meta-analysis. Although three out four studies suggested that migrants may have worse access to NCD treatment and both studies suggested migrants have lower blood pressure control rates than non-migrants, these findings were not statistically significant.

Conclusion

Findings from this systematic review demonstrate that there is currently insufficient evidence on migrant and non-migrant differences in NCD risk factors and management in China. Further research is expected to investigate access to healthcare among internal and its effect on both their NCD outcomes and long-term healthcare costs in China.

Association of Socioeconomic Status and Overweight/Obesity in Rural-to-Urban Migrants: Different Effects by Age at Arrival

This study aims to investigate the association between socioeconomic status and overweight/obesity in rural-to-urban Yi migrants in China, and to explore whether the association varied by the age at arriving urban areas. The cross-sectional population-based data from the Yi Migrants Study in 2015 was used, which included 1,181 Yi migrants aged 20–80 years. Socioeconomic status was evaluated by education level, personal annual income, and a composited variable (socioeconomic status index, SESI). Measured weight and height were used to calculate BMI and to define overweight/obesity (BMI ≥ 24 kg/m²). The results suggested that the association of income and SESI with overweight/obesity was not significant when age at arrival (two groups, <20 and ≥20 years) was considered as a covariate. In the stratification analysis, reversed association was observed in the two groups of age at arrival. In migrants of <20 years of age at arrival, higher level of education and SESI were related to decreased risk of overweight/obesity. In contrary, in those of ≥20 years at arrival, higher socioeconomic status level was found to be related to increased risk. Our findings suggest that the effect of socioeconomic status on overweight/obesity was modified by the age at arrival in Yi migrants. Especially, the association between socioeconomic status and overweight/obesity was negative when migration before 20 years of age, and transfer to positive after 20 years.

Trends in the prevalence of overweight, obesity, and abdominal obesity among Chinese adults between 1993 and 2015

BACKGROUND

Most previous studies on trends in the prevalence of obesity or abdominal obesity in Chinese adults were based on regional data and/or short time intervals, and recent trends are not available. We aimed to examine the secular trends in the prevalence of overweight, obesity, and abdominal obesity among Chinese adults at the national level from 1993 to 2015.

METHODS

A total of 70,242 Chinese adults aged 18-80 years were from the cross-sectional surveys conducted from 1993 to 2015. According to the World Health Organization criteria, overweight was defined as body mass index (BMI) ≥23.0 kg/m² and <27.5 kg/m², and obesity was defined as BMI ≥27.5 kg/m². According to the International Diabetes Federation criteria, abdominal obesity was defined as waist circumference (WC) ≥90 cm for men and ≥80 cm for women. Mean values and prevalence of adiposity markers were standardized to the age distribution of the China population in 2010.

RESULTS

Between 1993 and 2015, and based on age-standardized values, mean BMI increased from 21.9 kg/m² in 1993 to 23.9 kg/m² (+2.0 kg/m²) in 2015 (P for trend < 0.001), and mean WC increased from 76.0 cm to 83.4 cm (+7.4 cm) (P for trend <0.001). From 1993 to 2015, the prevalence increased from 26.6% to 41.3% (+14.7%) for overweight, from 4.2% to 15.7% (+11.5%) for obesity, and from 20.2% to 46.9% (+26.7%) for abdominal obesity (all P for trends < 0.001). In multivariate linear regression analysis, time (calendar years), older age and urban regions were strongly and independently associated with BMI.

CONCLUSIONS

The prevalence of overweight, obesity, and abdominal obesity increased markedly among Chinese adults during the past two decades. Weight control programs and public health measures to address the societal causes of obesity should be strengthened.

Association between age at arrival, duration of migration, and overweight/obesity in Chinese rural-to-urban migrants: the Yi migrant study

Background:

Urbanization in China is rapidly proceeding, but rural-to-urban migration and its association with overweight and obesity is not well studied. This study aimed to explore the age at arrival, duration of migration, and the corresponding association with overweight/obesity in Yi migrants in China.

Methods:

A cross-sectional study was conducted in rural and urban areas in 2015 in Sichuan province, China. Demographic characteristics, lifestyle factors, and anthropometry were collected. General linear regression models were used to assess the effect of duration of migration (1–10, 11–20, 21–30, and >30 years) on body mass index (BMI). Multi-variable logistic regression was used to examine the association between duration of migration and overweight/obesity (BMI ≥ 25 kg/m²).

Results:

A total of 3056 Yi people (1894 Yi farmers and 1162 Yi migrants) aged 20 to 80 years were enrolled. After adjusting for age, sex, and other potential confounders, Yi migrants had 1.71 kg/m² (95% confidence interval [CI]: 1.36–2.06) higher BMI and a 2.13-fold (95% CI: 1.71–2.65) higher risk of overweight/obesity than Yi farmers. In Yi migrants, stratified by age at arrival, no significant association between duration of migration and overweight/obesity was observed in those who were 0 to 20 years old at arrival. In comparison, in migrants >20 years old at arrival, compared with the reference group (1–10 years), long-term migration (>30 years) was found to be associated with overweight/obesity after adjustment (odds ratio: 1.85, 95% CI: 1.04–3.29).

Conclusions:

Yi migrants were observed to have greater risk of overweight/obesity than Yi farmers. In Yi migrants, the risk of overweight/obesity increased according to the duration of migration, especially in those who were older upon their arrival.

Secular Trends of the Impact of Overweight and Obesity on Hypertension in Yi People: Yi Migrant Study, 1996-2015

Background

Rising hypertension prevalence, coupled with increasing overweight and obesity rates, has been observed in Yi people. Moreover, the growing blood pressure level among Yi people was mostly attributable to the continuous increase of body mass index (BMI). However, little is known about the trend of association between them.

Methods

Consequently, we investigated the impact of overweight/obesity on hypertension over three periods (1996, 2007-2008, 2015) using data from Yi Migrant Study (n = 8749). The Yi Migrant Study incorporated three successive cross-sectional studies which were implemented by the same team with consistent protocols.

Results

Compared with period 1 (1996), the influence of overweight/obesity on hypertension risk significantly increased in period 2 (2007-2008) and period 3 (2015); relative excess risk due to interaction (RERI) was 1.59 (95% CI: 0.12, 3.05) and 1.41 (95% CI: 0.30, 2.78), respectively. Meanwhile, the overweight/obese population in period 3 did not show hypertension risk higher than that in period 2 (RERI = 0.15; 95% CI: -0.76, 1.07). Additionally, we observed a continuously growing trend of hypertension risk among normal weight Yi people.

Conclusions

During the past two decades, there was a significant increase in the association between overweight/obesity and hypertension in Yi people, whereas the increasing trend has leveled off in more recent years. These findings suggest that overweight/obesity and hypertension are becoming more epidemic comorbidity over time. Interventions to prevent hypertension should focus not only on the overweight/obese population, but also on those with normal weight.