The association between urbanization and reduced renal function: findings from the China Health and Nutrition Survey

Gender differences in association of urbanization with psychological stress in Chinese adults: A population-based study

Objective

To investigate the gender-specific associations between exposure to urbanization and psychological stress in China experiencing rapid urbanization.

Methods

Data were obtained from the 2015 China Health and Nutrition Survey. A total of 4,388 men and 5,098 women aged at least 18 years were obtained from 288 communities across 12 provinces and municipalities. Tertiles of the urbanization index, summarizing 12 urbanization dimensions at the community level, were used to define low, medium, and high levels of urbanization. The psychological stress was measured based on the 10-item Perceived Stress Scale. The gender-stratified multilevel analysis (Level-1: Individuals, Level-2: Communities, and Level-3: provinces/municipalities) was used to estimate the association between exposure to urbanization and psychological stress.

Results

After controlling for age, education status, marital status, work status, household income per capita, current smoking, alcohol drinking, sleep duration, BMI, and chronic conditions, the urbanization index was negatively associated with psychological stress in women (P _trend = 0.017) but not men (P _trend = 0.476). More specifically, a one-standard deviation increase in the score of community population density (β = -0.329, P = 0.329), modern markets (β = -0.247, P = 0.044), education (β = -0.448, P = 0.002), and housing (β = -0.380, P = 0.005) was negatively associated with psychological stress only in women, separately.

Conclusion

Our data revealed that living in the most urbanized communities is associated with lower levels of psychological stress for women but not men. Thus, this study can help empower decision-makers to accurately target vulnerable communities and plan effective strategies to address psychological outcomes.

Serum concentrations of per-/polyfluoroalkyl substances and its association with renal function parameters among teenagers near a Chinese fluorochemical industrial plant: A cross-sectional study

Currently, studies on the association between per-/polyfluoroalkyl substances (PFAS) concentrations and the renal function of residents, especially teenagers, living near fluorochemical industrial plants, are relatively rare, and not all these studies suggested associations. In this cross-sectional study, 775 local teenagers (11-15 years old) were included, and serum concentrations of 18 PFAS were measured. Perfluorooctanoic acid (PFOA) was found to be the dominant PFAS with a concentration of 22.3-3310 ng/mL (mean = 191 ng/mL), accounting for 71.5-99.1% of ΣPFAS. Statistical analyses demonstrated that internal exposure of perfluoroalkyl carboxylic acids (PFCA, C8-C10) was related to the plant. In addition, the prevalence rate of chronic kidney disease (CKD) (35.0%) in the participants was relatively high. A significantly positive association was observed between the increase in PFOA concentration and increasing risk of CKD (OR = 1.741; 95% CI: 1.004, 3.088; p = 0.048) by adjusting for gender, age, body mass index (BMI), and household income. Similar positive correlation was also observed in PFHpA with CKD (OR = 1.628, 95% CI: 1.031, 2.572; p = 0.037). However, no significant correlation was observed for concentrations of other PFAS and CKD (p > 0.05). Furthermore, linear regression analyses demonstrated that none of the PFAS concentrations were significantly correlated with estimated glomerular filtration rate (eGFR) or urine albumin/urine creatinine ratio (ACR) (p > 0.05). However, a significantly negative correlation was observed between PFOA concentration and abnormal ACR (β = -0.141, 95% CI: -0.283, 0.001; p = 0.048) after stratifying by CKD. Sensitivity analyses further confirmed these results. This cross-sectional study is the first, to our knowledge, to investigate the association between PFAS concentrations and renal function in teenagers living near a Chinese industrial plant. Further prospective and metabonomic studies are needed to interpret the results and clarify the biological mechanisms underlying this association.

Occupational Heat Exposure as a Risk Factor for End-Stage Kidney Disease: A Case-Control Study

OBJECTIVE

More patients are reaching end-stage kidney disease without evident cause. This study aims to explore occupational risk factors associated with hemodialysis.

METHODS

A multicenter matched case-control study included dialysis patients and age, sex, and diabetes-matched controls (normal kidney function). Conditional logistic regression analysis assessed occupational factors associated with dialysis.

RESULTS

Two hundred thirty eight hemodialysis patients and 238 controls were included. History of occupational heat exposure (odds ratio [OR] = 1.93; 95% confidence interval [CI]: 1.24 to 3.00), working as a cook (OR = 12; 95% CI: 1.56 to 92.29), as construction worker (OR = 10; 95% CI: 1.28 to 78.12) were associated with higher risk of dialysis. These results were significant in men and in those with kidney disease of unknown etiology.

CONCLUSIONS

Occupational heat exposure was found to be associated with hemodialysis. This is an important step for future development of preventive strategies in high-risk professions.

Urbanization, ambient air pollution, and prevalence of chronic kidney disease: A nationwide cross-sectional study

An increasing number of studies have linked ambient air pollution to chronic kidney disease (CKD) prevalence. However, its potential effect modification by urbanization has not been investigated. Based on data of 47,204 adults from the China National Survey of Chronic Kidney Disease (CKSCKD) dataset, night light satellite remote sensing data and high-resolution air pollution inversion products, the present cross-sectional study investigated the association between fine particulate matter <2.5 mm in diameter (PM_2.5), nitrogen dioxide (NO₂), night light index (NLI) and CKD prevalence in China, and the effect modification by urbanization characterized by administrative classification and NLI on the pollutant-health associations. Our results showed that a 10-μg/m³ increase in PM_2.5 at 3-year moving average, a 10-μg/m³ increase in NO₂ at 5-year moving average, and a 10-U increase in NLI at 5-year moving average were significantly associated with increased odds of CKD prevalence [OR = 1.24 (95 %CI:1.14, 1.35); OR = 1.12 (95 %CI:1.09, 1.15); OR = 1.05 (95 %CI:1.02, 1.07)]. Meanwhile, the pollutant-health associations were more apparent in medium-urbanized areas compared to low- and high-urbanized areas. For instance, a 10-μg/m³ increase in PM_2.5 concentration at 2-year moving average was associated with increased odds of CKD in the areas with NLI level in the second [OR = 2.78 (95 %CI:1.77, 4.36)] and third quartiles [OR = 1.49 (95 %CI:1.14, 1.95)], compared to the lowest [OR = 0.96 (95% CI: 0.73, 1.26)] and highest [OR = 0.63 (95% CI: 0.39-1.02)] quartiles. PM_2.5 and NO₂ were associated with increased odds of CKD prevalence, especially in areas with medium NLI levels, suggesting the necessity of strengthening environmental management in medium-urbanized regions.

Nutrition Transition with Accelerating Urbanization? Empirical Evidence from Rural China

Although rapid urbanization is often considered as one of the most important drivers for changing dietary patterns, little attention has been paid to rural areas despite the profound transformation they have undergone. Using longitudinal data from the China Health and Nutrition Survey (CHNS) for the period from 2004 to 2011, this study seeks to better understand the relationship between the urbanization of rural areas and dietary transition, with the focus on nutrition intake and dietary quality. Our results suggest that with increasing urbanization, rural residents tend to have on average lower calorie intakes but higher dietary quality. Specifically, increasing urbanization consistently reduces carbohydrate consumption and reduces fat consumption after a turning point; protein consumption first decreases and then increases after the turning point with increasing urbanization. Urbanization shows a significant and positive effect on the Healthy Eating Index (HEI). In addition to sociodemographic changes, we find that changing consumer preferences and knowledge serve as important determinants in explaining the dietary transition in rural China from 2004 to 2011. In our study, urbanization appears to positively affect rural residents’ healthy food preferences and dietary knowledge. This study is a first attempt for better understanding the nutrition transition resulting from accelerating urbanization in rural China; several limitations and areas for future research have been highlighted.

Association between urbanisation and the risk of hyperuricaemia among Chinese adults: a cross-sectional study from the China Health and Nutrition Survey (CHNS)

OBJECTIVE

To explore the association between urbanicity and hyperuricaemia (HUA) and whether urbanicity is an independent risk factor for HUA in Chinese adults.

DESIGN

Data analysis from a cross-sectional survey.

SETTING AND PARTICIPANTS

8579 subjects aged 18 years or older were enrolled in the study from the 2009 wave of the China Health and Nutrition Survey to analyse the association between urbanicity and HUA. We divided them into three categories according to urbanisation index (low, medium and highly urbanised groups).

MAIN OUTCOME MEASURES

HUA was defined as serum uric acid ≥7 mg/dL in men and ≥6 mg/dL in women.

RESULTS

The prevalence of HUA in low, medium and highly urbanised groups was 12.2%, 14.6% and 19.8%, respectively. The independent factors influencing serum uric acid included age, gender, hypertension, diabetes, chronic kidney disease, drinking, obesity and community-level urbanisation index (β=0.016, p<0.001). The risk of HUA in the highly urbanised group was significantly higher than that of the low urbanised group (OR 1.771, 95% CI 1.545 to 2.029, p<0.001), even after adjusting for other covariates (OR 1.661, 95% CI 1.246 to 2.212, p=0.001). In a subgroup analysis, we found that age, gender, comorbidity (such as hypertension, diabetes, obesity and chronic kidney disease) and physical activity affected the association between urbanisation and the risk of HUA.

CONCLUSIONS

Our findings suggest that living in highly urbanised areas is linked with higher risk of HUA independent of cardiometabolic and health-related behavioural risk factors, which have been shown to increase along with urbanisation.

Urban index and lifestyle risk factors for cardiovascular diseases in China: A cross-sectional study

China is at a stage of rapid urbanization over the past decades, and the association of urbanization with cardiovascular disease has been confirmed by previous studies. However, few studies assessed the association of urbanization with cardiovascular risk factors, especially in Chinese population. We conducted a cross-sectional, populational-based study, using data from China Health and Nutrition Survey (CHNS) in 2009. The logistic regression was used to assess the association of urbanization measured by urban index with cardiovascular risk factors (diabetes mellitus, hypertension, dyslipidemia, obesity, smoking, physical activity and fruits and vegetables consumption), varied with sex. The current study included 18,887 participants enrolled (mean age 39.8 ± 19.8 years; 52.2% female) who live in China. In regression model, the urban index was significantly associated with the variations of cardiovascular risk factors for male, including diabetes (OR 1.34, 95% CI: 1.22-1.48), hypercholesterolemia (OR 1.15, 95% CI: 1.09-1.22), never smoking (OR 0.92, 95% CI: 0.89-0.96), higher fruits and vegetables consumptions (OR 0.93, 95% CI: 0.87-0.99), higher body mass index (BMI) (OR 1.16, 95% CI: 1.10-1.22), and higher physical activity (OR 0.69, 95% CI: 0.66-0.73). Compared with the male, the associations of urban index with cardiovascular risk factors for female were similar, but not for BMI (OR 1.00, 95% CI: 0.96-1.05). The present finding emphasizes the changes of cardiovascular risk factors associated with urbanization in China, and indicated that close attention should be paid to the risk of hypercholesterolemia, diabetes and men's obesity in the process of urbanization.

Association of physical activity with chronic kidney disease: a systematic review and dose-response meta-analysis

BACKGROUND

The relationship between physical activity (PA) and chronic kidney disease (CKD) risk was inconsistent. We therefore conducted a systematic review and dose-response meta-analysis to comprehensively evaluate the association of PA and CKD.

RESULTS

A total of 14 studies from 13 articles with 353,975 participants were included. By comparing the highest vs. the lowest level of PA, we found that PA was inversely associated with CKD risk (odds ratio [OR] = 0.94, 95% confidence interval [CI] = 0.91-0.98). Seven studies from 6 articles were included in dose-response analysis. Restricted cubic splines showed no evidence of a nonlinear dose-response relationship of PA and CKD risk (P_nonlinearity = 0.135). The risk of CKD was reduced by 2% (OR = 0.98, 95% CI = 0.96-1.00) with each 10 metabolic equivalent h/week increment of PA.

CONCLUSIONS

The findings demonstrated that the higher level of PA might have a protective effect against the risk of CKD.

METHODS

Electronic databases PubMed and Embase were searched up to March 11, 2020. Observational studies investigated the relationship between PA and CKD risk with estimated effects (relative risk, hazard ratio, or OR) with 95 % CI among adults were included.

Prevalence and Risk Factors of Chronic Kidney Disease among Type 2 Diabetes Patients: A Cross-Sectional Study in Primary Care Practice

This cross-sectional study aimed to investigate the prevalence and risk factors of chronic kidney disease (CKD) among 1,096 primary care type 2 diabetes (T2DM) patients in northern Thailand between October 2016 and September 2017. CKD was defined as estimated glomerular rate filtration values of <60 mL/min/1.73 m². Prevalence with confidence intervals across CKD advanced stages 3–5 were estimated. Factors associated with CKD were evaluated by multivariate logistic regression. The overall prevalence of CKD was 24.4% (21.9–27.0), with severities of 11.4% (9.7–13.4), 6.8% (5.5–8.5), 4.6% (3.5–6.0), and 1.6% (1.0–2.5) for stages 3 A, 3B, 4, and 5, respectively. Regarding age and glycaemic control, individuals older than 75 years and those with a haemoglobin A1c ≥ 8% had the highest prevalence of 61.3% (51.7–70.1) and 38.6% (34.3–43.2), respectively. The multivariable logistic regression model explained 87.3% of the probability of CKD. The six independent significant risk factors of CKD were older age, retinopathy, albuminuria, haemoglobin A1c ≥ 7%, anaemia, and uric acid>7.5 mg/dL. A relatively high prevalence of CKD, especially in older patients and those with diabetic complications-related to poor glycaemic control, was encountered in this primary care practice. Early identification may help to target optimise care and prevention programs for CKD among T2DM patients.

Alcohol Consumption Can be a "Double-Edged Sword" for Chronic Kidney Disease Patients

Excessive drinking of alcohol is becoming a worldwide problem, and people have recognized that there exists a close relationship between chronic kidney disease (CKD) and alcohol consumption. However, there are many inconsistencies between experimental and clinical studies on alcohol consumption and kidney damage. The possible reason for this contradictory conclusion is the complex drinking pattern of humans and some bioactivators in wine. In addition, the design itself of the clinical studies can also produce conflicting interpretations of the results. Considering the benefits of light-to-moderate alcohol consumption, we recommend that CKD patients continue light-to-moderate drinking, which is beneficial to them. Because alcohol consumption can lead to adverse events, we do not advise non-drinkers to start to drink. Although light-to-moderate alcohol consumption may not pose a risk to patients with CKD, the patients’ condition needs to be considered. Consumption of even small amounts of alcohol can be associated with increased death risk. Additional clinical and experimental studies are needed to clarify the effect of alcohol on the kidneys and alcohol consumption on CKD patients.

Individual and Environmental Factors Associated with Proteinuria in Korean Children: A Multilevel Analysis

Proteinuria is a significant sign of childhood renal disorders. However, little is known about how sociodemographic and environmental factors are related to the presence of proteinuria among children and adolescents. This paper focuses on the prevalence of proteinuria and its risk factors among children and adolescents. This study conducted a secondary analysis of data from the 2016 Sample Schools Raw Data of Health Examination for School Students (SSRDHESS). Data collected from 27,081 students who had undergone a health screening were analyzed using Chi-square tests, independent t-tests, and multilevel logistic regression analysis. The prevalence of proteinuria was higher in the thin group than in the normal weight group (adjusted odds ratio (aOR) = 1.77; 95% confidence interval (CI) = 1.34–2.33) and lower in the overweight/obese group (aOR = 0.64; 95% CI = 0.51–0.80). Additionally, those in metropolitan and small–medium sized cities had a proteinuria prevalence about 1.5-fold higher than that of those in rural areas (95% CI = 1.08–2.02, 95% CI = 1.19–1.92, respectively). Proteinuria was associated with environmental pollution, including smoking rate, ambient particulate matter and heavy metals in drinking water (aOR = 1.10; 95% CI = 1.01–1.20; aOR = 1.06; 95% CI = 1.01–1.11, aOR = 1.001; 95% CI = 1.0001–1.0015). These results suggest that to improve health management effectiveness, kidney disease prevention efforts for children and adolescents should focus on geographical area and environmental pollution, as well as body weight as individual factors.

Effects of urbanization on metabolic syndrome via dietary intake and physical activity in Chinese adults: Multilevel mediation analysis with latent centering

RATIONALE

China has undergone rapid urbanization in the past decades. Metabolic syndrome refers to a cluster of cardiometabolic risk factors such as abdominal obesity, raised blood pressure, and elevated glucose. Existing studies have not explicitly examined the urbanization effect on metabolic syndrome.

OBJECTIVE

The present study aims to examine the temporal effects of urbanization on metabolic syndrome in the Chinese context and evaluate dietary intake and physical activity as potential mediating factors.

METHOD

The study sample comprised 6,217 Chinese adults aged between 30 and 65 recruited in 218 communities from 2000 to 2009 waves of the China Health and Nutrition Survey. Growth in urbanization of the communities was derived using latent growth modeling on continuous urbanization index from 2000 to 2009. The participants reported their physical activity and dietary intake. Body mass index and biomarkers were measured at 2009 for diagnosis of metabolic syndrome. Multilevel mediation analysis with novel latent centering approach was conducted across gender to evaluate direct and indirect effects of urbanization on metabolic syndrome via changes in dietary intake and physical activity.

RESULTS

The sample displayed linear increasing trends in urbanization, intakes of red meat, dairy products and fast food and declining cereal intake and physical activity with significant inter-individual variations. Controlling for individual-level and community-level covariates, urbanization showed a positive but non-significant direct effect on metabolic syndrome across gender. There were significant and positive indirect effects from urbanization to metabolic syndrome via changes in physical activity in males and via changes in fast food intake in females.

CONCLUSIONS

The present results highlight the health impact of urbanization as a dynamic process at the community level on metabolic syndrome via different indirect pathways of lifestyle factors across gender. Methodological and practical implications are discussed in relation to these modifiable lifestyle factors in the urbanizing Chinese society.

Effects of long-term exposure to CO and PM2.5 on microalbuminuria in type 2 diabetes

OBJECTIVE

No study has examined the effects of air pollutants on albuminuria in type 2 diabetes. Therefore, the present study investigated this association.

METHODS

This follow-up study enrolled 812 patients with type 2 diabetes between 2003 and 2012. The urinary albumin-to-creatinine ratio (ACR) was recorded annually. Exposure to the air pollutants CO, NO₂, O₃, SO₂, and PM_2.5 was interpolated from 72 air-quality monitoring stations to residences by using the kriging method. The association between air pollutants and ACR increase was assessed using mixed-effect model with random intercepts for 36 clinics.

RESULTS

The study objects (mean age: 55.4 years) were followed for 3 or more years (average period: 5.4 years). ACR increase was found to be positively associated with the male sex, baseline hemoglobin A1c, and exposure to CO and PM_2.5, and negatively associated with waist circumference through multiple linear regression. Annually urine albumin/creatinine ratio increase was estimated by the final model, Patients exposed to higher levels of CO (e.g., third quartile, 1025 ppb) and lower levels of CO (e.g., first quartile, 850 ppb) had an annual ACR increase of 3.73 and 3.54 mg/g, respectively. Patients exposed to higher levels of PM_2.5 (e.g., third quartile, 38.8 μg/M3) and lower levels of PM_2.5 (e.g., first quartile, 27.7 μg/M3) had an annual ACR increase of 3.96 and 3.17 mg/g, respectively.

CONCLUSIONS

Exposure to high CO and PM_2.5 levels increased albuminuria in type 2 diabetes.

Environmental exposures and pediatric kidney function and disease: A systematic review

BACKGROUND

Environmental chemical exposures have been implicated in pediatric kidney disease. No appraisal of the available evidence has been conducted on this topic.

METHODS

We performed a systematic review of the epidemiologic studies that assessed association of environmental exposures with measures of kidney function and disease in pediatric populations. The search period went through July 2016.

RESULTS

We found 50 studies that met the search criteria and were included in this systematic review. Environmental exposures reviewed herein included lead, cadmium, mercury, arsenic, fluoride, aflatoxin, melamine, environmental tobacco, bisphenol A, dental procedures, phthalates, ferfluorooctanoic acid, triclosan, and thallium/uranium. Most studies assessed environmental chemical exposure via biomarkers but four studies assessed exposure via proximity to emission source. There was mixed evidence of association between metal exposures, and other non-metal environmental exposures and pediatric kidney disease and other kidney disease biomarkers. The evaluation of causality is hampered by the small numbers of studies for each type of environmental exposure, as well as lack of study quality and limited prospective evidence.

CONCLUSION

There is a need for well-designed epidemiologic studies of environmental chemical exposures and kidney disease outcomes.

Urbanization and kidney function decline in low and middle income countries

Urbanization is expected to increase in low and middle-income countries (LMICs), and might contribute to the increased disease burden. The association between urbanization and CKD is incompletely understood among LMICs. Recently, Inoue et al., explored the association of urbanization on renal function from the China Health and Nutrition Survey. The study found that individuals living in an urban environment had a higher odds of reduced renal function independent of behavioral and cardiometabolic measures, and this effect increased in a dose dependent manner. In this commentary, we discuss the results of these findings and explain the need for more surveillance studies among LMICs.