Why have physical activity levels declined among Chinese adults? Findings from the 1991-2006 China Health and Nutrition Surveys

Egg, cholesterol and protein intake and incident type 2 diabetes mellitus: Results of repeated measurements from a prospective cohort study

BACKGROUND & AIMS

Epidemiological evidence on the associations of egg, cholesterol and protein intake with risk of type 2 diabetes is inconsistent. Therefore, we conducted this study to explore these associations among Chinese adults.

METHODS

Data from 4 waves (2004, 2006, 2009 and 2011) of the China Health and Nutrition Survey were used. A multistage random-cluster sampling method was employed to recruit the participants in both rural and urban areas. We included individuals who participated in 2004 and any waves afterwards. Those 1) below 18 years of age; 2) with diabetes at baseline; or 3) with extreme energy intake (men: <800 kcal or >6000 kcal; women: <600 kcal or >4000 kcal) were excluded. Respondents were classified into four groups according to quartiles of egg, cholesterol and protein intake per day. Numbers of eggs per day were calculated by dividing egg intake in grams by 50 g. Diagnosis of type 2 diabetes was self-reported. Logistic generalized estimation equation models were employed.

RESULTS

There were 7312 individuals included in 2004, 6390 in 2006, 4826 in 2009 and 4963 in 2011. The mean age of participants at baseline was 48.3 years and 47.2% were men. Over an average of 5.8-y follow-up, 209 developed type 2 diabetes. After adjustment for demographic, lifestyle and dietary confounders, the odds ratio of type 2 diabetes for those in the highest compared with the lowest protein intake quartile was 2.38 (95% CI: 1.43, 3.98). The odds ratio of individuals with ≥3 eggs/day versus none was 3.76 (95% CI, 2.05, 6.90). Cholesterol intake was not associated with type 2 diabetes.

CONCLUSIONS

Individuals with the highest protein intake had over a 2-fold increased risk of type 2 diabetes compared with those with the lowest protein intake. A high intake of egg, but not dietary cholesterol, was associated with type 2 diabetes. This association warrants further investigation.

Are the factors associated with overweight/general obesity and abdominal obesity different depending on menopausal status?

Rapid modernization in China has impacted the daily lives and health of women, including a rise in obesity. However, little is known about the impact of menopausal status, behavior, and psychosocial factors on the risk of obesity for rural women in China. The aim of this study is to identify risk factors, including demographic information (education, family history of T2DM, menopausal status), obesity-related behavior, and psychosocial factors associated with overweight/general obesity and abdominal obesity. In a cross-sectional study design, participants had their weight, height, and waist circumference measured and completed questionnaires regarding family demographics, obesity-related health behaviors (physical activity, diet, sleep), and psychosocial information (stress, social support, and self-efficacy related to physical activity and healthy diet). A total of 646 women were included in this study; 46.6% were overweight/generally obese, and 48% had abdominal obesity. Postmenopausal women had a higher prevalence of general and central obesity. Regular physical activity decreased the risk for overweight/general obesity and abdominal obesity (OR = .41 and .31, respectively, p = .04) in premenopausal women. Postmenopausal women who had not breastfed their infants and reported moderate/high-stress had a higher risk for overweight/general obesity (OR = 3.93, and 2, respectively) and those who reported less than 6 hours of sleep per day increased their risk for abdominal obesity (OR = 2.08). Different factors associated with obesity were found in Chinese women, depending on menopausal status. Future studies should examine the impact of menopause on a woman’s risk for obesity, as well as develop tailored interventions to improve health, well-being and reduce the risk of obesity.

Associations of Socioeconomic Status and Physical Activity With Obesity Measures in Rural Chinese Adults

Background: Although independent association of socioeconomic status (SES) or physical activity (PA) with obesity has been well-documented in urban settings, their independent and joint associations on obesity measures are limited in rural regions.

Methods: Almost 38,000 (n = 37,922) individuals were included from the Henan Rural Cohort Study. The International Physical Activity Questionnaire (IPAQ) was used to evaluate PA. Obesity was reflected by body mass index (BMI), waist circumference (WC), waist-to-hip ratio (WHR), waist-to-height ratio (WHtR), body fat percentage (BFP), and visceral fat index (VFI). The independent and interactive effects of SES and PA on obesity were analyzed by logistic regression models and generalized linear regression models, respectively.

Results: Compared with high education level, the OR (95%CI) of obesity defined by BMI with low education level was 1.466 (1.337, 1.608), 1.064 (0.924, 1.225), and 1.853 (1.625, 2.114) in total population, men and women, respectively. Besides, the OR (95%CI) of obesity defined by BMI associated with per capita monthly income were 1.089 (1.015, 1.170), 1.192 (1.055, 1.347), 1.038 (0.951, 1.133) in total population, men and women, respectively. Similar results had been observed in other obesity measures. Negative interactive association of low education level and PA on obesity measures were observed only in women (all P < 0.05).

Conclusions: This study suggests that women are more susceptible to obesity concerning low SES and that adequate PA may be a potential target for mitigating the negative effect of low SES on obesity in women.

Clinical Trial Registration: The Henan Rural Cohort Study has been registered at Chinese Clinical Trial Register (Registration number: ChiCTR-OOC-15006699) http://www.chictr.org.cn/showproj.aspx?proj=11375.

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.

Physical Inactivity, Non-Communicable Diseases and National Fitness Plan of China for Physical Activity

BACKGROUND

China has the world's largest population, going under health transition due to industrialization, urbanization, and a sedentary lifestyle. About 82% of China's disease burden is due to the prevalence of non-communicable diseases (NCDs). Physical activity (active travel) is the best preventive measure against NCDs. The Chinese government has introduced several steps to improve national fitness and overcome NCDs among the aging population. Exercise and sports play a vital role in promoting physical activity and helpful in accomplishing the national fitness level for Healthy China under the national fitness plan (NFP).

OBJECTIVE

The current study aimed to explore the role of national fitness plan (NFP) in promoting physical activity and health well-being preventing NCDs under built environment intervention.

METHODS

The study was exploratory, and the mixed-method approach was used to analyze the primary and secondary data. Quantitative content analysis was used to analyze the collected data. A purposive sampling technique was used to collect the primary data from those individuals rich in knowledge about the National Fitness Plan (NFP) of China and its role in promoting physical activity for physical fitness.

RESULTS

The majority of the participants (32.0%) said that the national fitness plan helps promote sports environment and health. About 28.0% reported that NFP helps promote cycling and walk environments for physical activity and health promotion and preventing non-communicable diseases (NCDs).

CONCLUSION

Participation in physical exercise and sports is the preferred approach to prevent different diseases. In the context of rising active living among the Chinese people, the facilities such as built environment and green parks under the national fitness plan (NFP) for sports play a crucial role in the mitigation of NCDs.

Diabetes, employment and behavioural risk factors in China: Marginal structural models versus fixed effects models

We use longitudinal data from the China Health and Nutrition Survey, covering the years 1997-2011, to estimate the effect of a diabetes diagnosis on an economic outcome (employment probabilities) and behavioural risk factors (alcohol consumption, smoking cessation, body mass index (BMI), physical activity and hypertension) for men and women. We apply two complementary statistical techniques-marginal structural models (MSMs) and fixed effects (FE) models-to deal with confounding. Both methods suggest, despite their different underlying assumptions, similar patterns that indicate important differences between men and women. Employment probabilities decline substantially after the diagnosis for women (-12.4 (MSM) and -15.5 (FE) percentage points), but do not change significantly for men. In particular, the MSM estimates indicate an increase in hypertension (13 percentage points) and a decrease in physical activity for women, while men have small and statistically insignificant changes in these outcomes. For BMI, the MSM results indicate statistically significant changes for men (-.76), but not for women, while the FE estimates show similar reductions for men and women (-.80 and -.73 respectively). Men also reduce their alcohol consumption, but do not cease to smoke. For women these risk factors have a prevalence close to zero to begin with, though women seem to still reduce alcohol consumption somewhat. These results suggest important gender differences in the impact of diabetes in China. To narrow these inequities policies supporting women to reduce diabetes related risk factors are likely important.

Levels of domain-specific physical activity at work, in the household, for travel and for leisure among 327 789 adults from 104 countries

OBJECTIVE

To compare the country-level absolute and relative contributions of physical activity at work and in the household, for travel, and during leisure-time to total moderate-to-vigorous physical activity (MVPA).

METHODS

We used data collected between 2002 and 2019 from 327 789 participants across 104 countries and territories (n=24 low, n=34 lower-middle, n=30 upper-middle, n=16 high-income) from all six World Health Organization (WHO) regions. We calculated mean min/week of work/household, travel and leisure MVPA and compared their relative contributions to total MVPA using Global Physical Activity Questionnaire data. We compared patterns by country, sex and age group (25-44 and 45-64 years).

RESULTS

Mean MVPA in work/household, travel and leisure domains across the 104 countries was 950 (IQR 618-1198), 327 (190-405) and 104 (51-131) min/week, respectively. Corresponding relative contributions to total MVPA were 52% (IQR 44%-63%), 36% (25%-45%) and 12% (4%-15%), respectively. Work/household was the highest contributor in 80 countries; travel in 23; leisure in just one. In both absolute and relative terms, low-income countries tended to show higher work/household (1233 min/week, 57%) and lower leisure MVPA levels (72 min/week, 4%). Travel MVPA duration was higher in low-income countries but there was no obvious pattern in the relative contributions. Women tended to have relatively less work/household and more travel MVPA; age groups were generally similar.

CONCLUSION

In the largest domain-specific physical activity study to date, we found considerable country-level variation in how MVPA is accumulated. Such information is essential to inform national and global policy and future investments to provide opportunities to be active, accounting for country context.

Dietary Diversity and the Risk of Fracture in Adults: A Prospective Study

Nutrition plays an important and modifiable role in bone health. This study aimed to investigate the effect of dietary diversity on the risk of any type of fracture in adults. Data from the China Health and Nutrition Survey collected between waves 1997 and 2015 were used. A total of 10,192 adults aged 40 years and older were included in the analysis. Both dietary diversity score (DDS) based on Chinese dietary guidelines (DDS-CDG) and minimum dietary diversity for women (DDS-MDD-W) were computed. Cox proportional hazards regression models were conducted to determine the association. Stratified analyses were conducted in women by the age of fracture using the case-control study approach. In men, higher scores in both the DDS-CDG (hazard ratio (HR) 0.70, 95% CI 0.56-0.88) and DDS-MDD-W (HR 0.67, 95% CI 0.54-0.82) were associated with decreased risk of fracture, however, the associations were not significant in women (DDS-CDG: HR 0.94, 95% CI 0.79-1.12; DDS-MDD-W: HR 0.93, 95% CI 0.79-1.09). In the stratified analyses, higher DDS-CDG (odds ratio (OR) 0.74, 95% CI 0.58-0.95) and higher DDS-MDD-W (OR 0.76, 95% CI 0.60-0.95) were associated with lower risks of fracture in women aged 40 to 60 years; in women aged over 60 years, no association was observed (DDS-CDG: OR 1.10, 95% CI 0.83-1.46; DDS-MDD-W: OR 1.00, 95% CI 0.79-1.27). In summary, higher dietary diversity was associated with decreased risk of fracture in men and middle-aged women, but not in women aged over 60 years.

Level of physical activity among middle-aged and older Chinese people: evidence from the China health and retirement longitudinal study

Background

With data from different regions accumulated, physical inactivity (PI) was found to be pandemic worldwide. Using China Health and Retirement Longitudinal Study (CHARLS), a nationwide longitudinal survey data, we aimed to delineate the prevalence, incidence and risk factors of physical inactivity (PI) among Chinese people aged 45 years and older.

Methods

The CHARLS covered nearly all provinces, autonomous regions, municipalities of mainland China. With data from CHARLS, three cross-sectional analyses and a cohort analysis were conducted. In cross-sectional studies, we used surveys at 2011, 2013 and 2015 to examine the prevalence and its trend of PI. Multivariate generalized linear model was conducted in survey at 2011 to examine the risk factors for prevalent PI. Multiple imputation of missing values was used and results before and after imputation were compared. In cohort analysis, we identified people free of PI at 2011 and followed them up until 2015 to estimate the incidence of PI. Generalized estimating equation was used to examine the risk factors associated with incidence PI. In all analyses, PI was defined as insufficient physical activity according to the International Physical Activity Questionnaire (IPAQ) criterion.

Results

6650, 5946 and 9389 participants were eligible for cross-sectional analyses, and 4525 participants were included for cohort analysis. The weighted prevalence of PI was 22.25% (95% CI: 20.63–23.95%) in 2011, 20.64% (95% CI: 19.22–22.14%) in 2013 and 19.31% (95% CI: 18.28–20.38%) in 2015. In multivariate analysis, PI was associated with older age, higher education, overweight, obesity and difficulties in daily living, and was negatively associated with working and higher level of expenditure. No material change was detected in results after multiple imputation. In cohort analysis, older age, abundant public facilities, difficulties in daily living were identified as risk factors of incidence PI, while urban areas, college and above education, and working were protective factors.

Conclusions

PI is pandemic in 45 years and older people in China. People with older age, difficulties in daily living and people who are not working are at higher risk. More efforts should be paid in estimating and promoting leisure-time physical activities.

Association between Physical Literacy and Physical Activity: A Multilevel Analysis Study among Chinese Undergraduates

AIM

To examine the association between the perceived physical literacy (PL) and physical activity (PA) levels among Chinese undergraduates.

METHODS

Simplified Chinese version of the Perceived Physical Literacy Instrument and the International Physical Activity Questionnaire were used to measure 536 students' perceived PL and PA levels. Pearson's product-moment correlation and multiple linear regression were then used to examine the relationship between the perceived PL and PA levels. Additionally, standard regression analysis was conducted to test for the effects at different demographics.

RESULTS

The correlation between perceived PL and PA level was low but significant (r = 0.350, p < 0.01). The multiple linear regression equation was significant (F = 25.228, p < 0.01, ΔR² = 0.120). Metabolic equivalent values were used to predict PA levels of participants, which were -3818.582 + 272.535 (motivation) + 249.848 (confidence and physical competence) + 149.899 (interaction with the environment). The association of factors such as socio-economic status (SES) (p = 0.092) and grade point average (GPA) (r = 0.119, p = 0.022) were examined using Pearson's product-moment correlation. Gender (p < 0.01) and body mass index (BMI) (p < 0.01) were also explored for their differences.

CONCLUSIONS

Perceived PL and PA levels were significantly related. The association between PL and GPA was identical. GPA and BMI showed significant difference between each group. The study offers a path to explore the concept of PL and how it can affect the PA of Chinese undergraduates. Furthermore, on the basis of this study, more research could develop practical interventions for Chinese undergraduates to enhance their PL and engagement in a lifetime of PA.

Elevated Fat Intake Increases Body Weight and the Risk of Overweight and Obesity among Chinese Adults: 1991-2015 Trends

Studies on fat intake and obesity have been inconclusive. This study examined the associations between dietary fat intake and body weight and the risk of overweight and obesity in China. We used data from 23,859 adults aged 20-60 years who participated in the China Health and Nutrition Survey, an ongoing open-cohort study, from 1991 to 2015. We collected detailed dietary data by conducting three 24-h dietary recalls and weighing foods and condiments in household inventories. We examined the associations between fat intake and body weight, body mass index (BMI), and the risk of overweight and obesity with random-effects linear or logistic regression models for panel data. The Chinese population's fat intake, percentage of energy intake from fat, and prevalence of high-fat diets (energy intake from fat > 30%) increased from 68.5 g per day (g/d), 23.1%, and 22.4%, respectively, in 1991 to 79.3 g/d, 35.6%, and 67.2%, respectively, in 2015. The prevalence of overweight and obesity increased from 12.3% to 37.3% during the same period. Fat intake, percentage of energy intake from fat, and a high-fat diet were positively associated with body weight, BMI, and the risk of overweight and obesity in both sexes (p < 0.001) after adjustment for nonfat energy intake, physical activity, and socioeconomic status. Increased fat intake and high-fat diets were associated with increased body weight, BMI, and risk of overweight and obesity. These findings could have a significant impact on Chinese policies and interventions to control overweight and obesity.

Beneficial Effect of Dietary Diversity on the Risk of Disability in Activities of Daily Living in Adults: A Prospective Cohort Study

Disability in activities of daily living (ADL) is common in elderly people. Dietary diversity is associated with several age-related diseases. The evidence on dietary diversity score (DDS) and ADL disability is limited. This study was based on the China Health and Nutrition Survey. Prospective data of 5004 participants were analyzed. ADL disability was defined as the inability to perform at least one of the five self-care tasks. Cox proportional regression models were conducted to estimate the association of cumulative average DDS with the risk of ADL disability. Logistic regression models were performed to estimate the odds ratios for the average DDS, the baseline DDS, and the recent DDS prior to the end of the survey in relation to ADL disability, respectively. The results indicate that higher average DDS was associated with a decreased risk of ADL disability (T3 vs. T1: hazard ratio 0.50; 95% confidence interval 0.39-0.66). The association was stronger among participants who did not had comorbidity at baseline than those who did (P-interaction 0.035). The average DDS is the most pronounced in estimating the association of DDS with ADL disability of the three approaches. In summary, higher DDS has beneficial effects on ADL disability, and long-term dietary exposure is more preferable in the investigation of DDS and ADL.

Individual Capital Structure and Health Behaviors among Chinese Middle-Aged and Older Adults: A Cross-Sectional Analysis Using Bourdieu's Theory of Capitals

This study draws on Bourdieu’s theory of capitals to analyze the relative importance of economic, cultural, and social capital on health behaviors in Chinese middle-aged and older adults. Based on data from the China Family Panel Studies of 2016 (N = 15,147), we first harnessed a binary logistic regression model to discuss the associations between the three capitals and four types of health behaviors (i.e., physical exercise, smoking, binge drinking and stay-up). Using the sheaf coefficients technique, we then compared the relative effects of three of the capitals on health behaviors. The results suggest that cultural capital is the most influential one, which would significantly increase physical exercise and stay-up behaviors, and reduce smoking and binge drinking behaviors. Economic capital is also an important predictor, that may reduce smoking behavior but increase binge drinking and stay-up behaviors. Social capital has shown the least importance, although it would still be saliently associated with physical exercise, smoking and stay-up behaviors. In addition, some significant group disparities are also identified. This article is one of the first to explain health behavior inequalities through a Bourdieusian capital-based approach in Chinese contexts.

Autonomy support in physical education promotes autonomous motivation towards leisure-time physical activity: evidence from a sample of Chinese college students

Based on the trans-contextual model, two studies aimed to test whether autonomy-supportive physical education (PE) promotes autonomous motivation towards leisure-time physical activity among Chinese college students. Study 1 was conducted in September 2015 and used a cross-sectional design. Participants were students who provided data on perceived autonomy support and motivation for physical activity. Regression analysis was used to analyze the data. Study 2 took place from September to December 2015 and employed an experimental design. Participants were PE teachers and their students. The teachers were randomized to either an intervention or a control group and those in the intervention group received a 3-month long autonomy-supportive intervention program. Their students provided data on motivation. The data were analyzed with repeated measurement analysis of variance. A total of 681 students aged 16-26 years participated in Study 1. Perceived autonomy support predicted autonomous motivation in PE (β = 0.18, P = 0.001), which in turn predicted autonomous motivation towards leisure-time physical activity (β = 0.51, P = 0.001). Ten PE teachers (28-53 years) and 258 students (16-26 years) participated in Study 2. Students who were educated by the intervention teachers had significantly stronger autonomous motivation towards leisure-time physical activity than students educated by the control teachers after the intervention, (F = 12.41, P = 0.001). The results suggest that PE may serve as an effective platform to promote an active lifestyle among Chinese college students when teachers provide students with an experience of autonomy.

Physical Activity, Step Counts, and Grip Strength in the Chinese Children and Families Cohort Study

Objectives: This paper describes the development of a physical activity questionnaire (PAQ) designed for Chinese adolescents and their mothers in urban and rural settings, and reports on results of the PAQ, pedometry, and hand grip dynamometry from the Chinese Children and Families Cohort Study pilot investigation (CFCS). Methods: As part of a pilot investigation to evaluate the feasibility to follow-up and obtain detailed nutrition, dietary, physical activity, and ultraviolet radiation (UVR) data from CFCS participants, data were collected in 2013 for 93 adolescent/mother pairs from a rural (n = 41) and an urban site (n = 52) in two provinces. Respondents were asked to wear a pedometer for seven days (Omron HJ-151), use a Takei Digital Grip Strength Dynamometer on (each hand; three trials; two separate days), and complete a 39 item, eight domain PAQ covering the past year. Self-reported physical activity (PA) was linked to metabolic equivalent of task (MET) scores in kcal/kg/hr and used to calculate METs for different domains of PA and intensity categories. Results: Compliance was high (95%) in this measurement protocol administered by health staff during a series of data collection efforts at home and local clinics or health centers. Step counts were highly variable, averaging between 5000 and 10000 per day with somewhat higher step counts in rural adolescent boys. Maximum grip strength (Kgs) was greater in children (Mean = 36.5, SE = 0.8) than mothers (Mean = 28.8, SE = 0.8) and similar in the urban (Mean = 29.6, SE = 0.6) compared to the rural (Mean = 29.6, SE = 0.5) communities overall. Grip strength, step counts, and measures of time spent in different activities or activity intensities were uncorrelated. Conclusion: Device and question-based measurement of PA and strength were readily accepted in these Chinese urban and rural populations. The PAQ on physical activity in the past year produced some plausible population averages, but individual responses suggested recall challenges. If data about specific activities are required, future studies should explore use of standardized survey questions concerning such fewer specific activities or instruments examining shorter time periods such as one, three, or seven day recalls.

Demographic, behavioral, and cardiovascular disease risk factors in the Saudi population: results from the Prospective Urban Rural Epidemiology study (PURE-Saudi)

Background

Cardiovascular disease (CVD) is the major cause of death in Saudi Arabia. We aimed to assess associated demographic, behavioral, and CVD risk factors as part of the Prospective Urban Rural Epidemiology (PURE) study.

Methods

PURE is a global cohort study of adults ages 35–70 years in 20 countries. PURE-Saudi study participants were recruited from 19 urban and 6 rural communities randomly selected from the Central province (Riyadh and Alkharj) between February 2012 and January 2015. Data were stratified by age, sex, and urban vs rural and summarized as means and standard deviations for continuous variables and as numbers and percentages for categorical variables. Proportions and means were compared between men and women, among age groups, and between urban and rural areas, using Chi-square test and t-tests, respectively.

Results

The PURE-Saudi study enrolled 2047 participants (mean age, 46.5 ± 9.12 years; 43.1% women; 24.5% rural). Overall, 69.4% had low physical activity, 49.6% obesity, 34.4% unhealthy diet, 32.1% dyslipidemia, 30.3% hypertension, and 25.1% diabetes. In addition, 12.2% were current smokers, 15.4% self-reported feeling sad, 16.9% had a history of periods of stress, 6.8% had permanent stress, 1% had a history of stroke, 0.6% had heart failure, and 2.5% had coronary heart disease (CHD). Compared to women, men were more likely to be current smokers and have diabetes and a history of CHD. Women were more likely to be obese, have central obesity, self-report sadness, experience stress, feel permanent stress, and have low education. Compared to participants in urban areas, those in rural areas had higher rates of diabetes, obesity, and hypertension, and lower rates of unhealthy diet, self-reported sadness, stress (several periods), and permanent stress. Compared to middle-aged and older individuals, younger participants more commonly reported an unhealthy diet, permanent stress, and feeling sad.

Conclusion

These results of the PURE-Saudi study revealed a high prevalence of unhealthy lifestyle and CVD risk factors in the adult Saudi population, with higher rates in rural vs urban areas. National public awareness programs and multi-faceted healthcare policy changes are urgently needed to reduce the future burden of CVD risk and mortality.

The association between spatial access to physical activity facilities within home and workplace neighborhoods and time spent on physical activities: evidence from Guangzhou, China

BACKGROUND

Urban residents from the developing world have increasingly adopted a sedentary lifestyle and spend less time on physical activities (PA). Previous studies on the association between PA facilities and individuals' PA levels are based on the assumption that individuals have opportunities to use PA facilities within neighborhoods all day long, ignoring the fact that their willingness and opportunities to use nearby facilities depend on how much discretionary time (any time when people have a choice what to do) they have. Further, scant attention has been paid to the influence of PA facilities within both residential and workplace neighborhoods in the dense urban context. To address the above research gaps, this study investigated the links between the spatial access to PA facilities within home/workplace neighborhoods and time spent on PA among working adults, focusing on whether results were different when different measures of accessibility were used and whether participants' discretionary time over a week affected their time spent on PA.

METHOD

This study used data from a questionnaire survey (n = 1002) in Guangzhou between June and July 2017 and point of interest (POI) data from online mapping resources. Outcome variables included the amount of time spent on physical activity/moderate and vigorous intensity physical activity (PA/MVPA) over the past week. Home/workplace neighborhoods were measured as different distance buffers (500 m circular buffers, 1000 m circular buffers, and 1080 m network buffers) around each respondent's home/workplace. Spatial access to PA facilities was measured using two indicators: the counts of PA facilities and proximity to PA facilities within home/workplace neighborhoods. The amount of discretionary time was calculated based on activity log data of working day/weekend day from the Guangzhou questionnaire survey, and regression models were used to examine relationships between the spatial access of PA facilities, the time spent on PA/MVPA, and the amount of discretionary time, adjusted for covariates. Associations were stratified by gender, age, education, and income.

RESULTS

Using different measures of accessibility (the counts of and proximity to PA facilities) generated different results. Specifically, participants spent more time on PA/MVPA when they lived in neighborhoods with more PA facilities and spent more time on MVPA when worked in closer proximity to PA facilities. A larger amount of discretionary time was associated with more time spent on PA/MVPA, but it did not strengthen the relationship between access to PA facilities and PA/MVPA time. In addition, relationships between access to PA facilities and PA levels varied by gender, age, education, and income.

CONCLUSION

This study contributes to the knowledge of PA-promoting environments by considering both the home and workplace contexts and by taking into account the temporal attributes of contextual influences. Policymakers and urban planners are advised to take into account the workplace context and the temporal variability of neighborhood influences when allocating public PA facilities and public spaces.

Associations of iron status with apolipoproteins and lipid ratios: a cross-sectional study from the China Health and Nutrition Survey

Background

Iron overload has been found to be related with various cardiometabolic disorders, like dyslipidemia, metabolic syndrome, and diabetes. The disturbance of the iron status and lipid metabolism can contribute to organ damage such as atherosclerotic plaque growth and instability. An assessment on the associations of iron status with apolipoproteins and lipid ratios would be informative for maintenance of metabolic homeostasis and hinderance of disease progression. Hence, this study aims to establish the relationships of iron status with apolipoproteins and lipid ratios.

Methods

A cross-sectional study of 7540 adult participants from the China Health and Nutrition Survey 2009 was conducted. Logistic regression analyses were used to investigate the relationships between indicators of iron status and the prevalence of unfavorable apolipoprotein profiles. Multivariate linear regression models were constructed to assess the dose-response correlations between serum ferritin and lipid parameters.

Results

After adjustment for confounding factors, in both sexes, the subjects in the top quartile of ferritin had the highest prevalence of an elevated apolipoprotein B (men: odds ratio (OR) 1.97, 95% confidence interval (CI) 1.50–2.62; women: OR 2.13, 95% CI 1.53–2.97) and an elevated apolipoprotein B/apolipoprotein A1 ratio (men: OR 2.00, 95% CI 1.50–2.66; women: OR 1.41, 95% CI 1.04–1.92) when compared with individuals in the lowest quartile. Hemoglobin were also independently associated with unfavorable apolipoprotein B and apolipoprotein B/apolipoprotein A1 ratio both in men and women. However, transferrin (men: OR 0.74, 95% CI 0.56–0.99; women: OR 0.73, 95% CI 0.56–0.95) and soluble transferrin receptor (men: OR 0.75, 95% CI 0.57–0.99; women: OR 0.71, 95% CI 0.55–0.91) were found to be negatively associated with a decreased apolipoprotein A1. Moreover, after controlling for potential confounders, the ferritin concentrations were significantly associated with the levels of lipid ratios including TG/HDL-C, non-HDL-C/HDL-C, TC/HDL-C, apoB/apoA1, and LDL-C/HDL-C ratio in men (β coefficient = 0.147, 0.061, 0.043, 0.038, 0.032, respectively, all P values < 0.001) and in women (β coefficient = 0.074, 0.034, 0.025, 0.020, 0.018, respectively, all P values < 0.05).

Conclusions

The indicators of iron status are significantly associated with unfavorable apolipoprotein profiles. Serum ferritin concentrations are positively correlated with the levels of lipid ratios. The management on the modifiable iron status and lipid metabolism has a clinical significance. The atherosclerotic lipid profiles of the patients with iron overload deserve special clinical concerns.

The association between physical activity and body fat percentage with adjustment for body mass index among middle-aged adults: China health and nutrition survey in 2015

BACKGROUND

The inverse association between physical activity and body fat percentage (%) varies among different populations. We aim to examine whether the significant association between them was uniform across the subpopulations after taking into account body mass index (BMI).

METHODS

Our study relied on data from China Health and Nutrition Surveys in 2015, including 5763 participants aged 40-64 years from 15 regions. Physical activity was calculated as metabolic equivalent task hours per day (MET·h/d). Body fat% was measured by bioelectrical impedance analysis. Body mass index < 24 kg/m2 was defined as normal weight and BMI ≥ 24 kg/m2 was overweight/obese. The effects of physical activity on body fat% were estimated using the Kruskal-Wallis test among sex, age, BMI groups, education, income, region and urbanization. Quantile regression analyses were utilized to describe the relationship between physical activity and body fat% distribution.

RESULTS

Older adults, overweight/obese, higher education, higher income, residents of central China and those living in areas of higher urbanization had the lower physical activity. Participants who engaged in the highest level of physical activity had 2.0 and 1.5% lower body fat% than the lowest level of physical activity group (23.4, 34.8%) for men and women, respectively. There were 10.4 and 8.8% of normal weight males and females called normal weight obese. Overall, 1 h extra 4.5 MET•h/d was significantly associated with 0.079 and 0.110% less total body fat% at the 75th and 90th percentiles in normal weight males, with 0.071% less at the 25th percentiles in overweight/obese males, with 0.046-0.098% less at the 25th to 90th percentiles in normal weight females, and with 0.035-0.037% less from the 50th to 90th percentiles in overweight/obese females. The inverse association between physical activity and total body fat% was stronger in normal weight obese participants than other subgroups.

CONCLUSIONS

In middle-aged Chinese adults, the inverse association between physical activity and body fat% was only in particular subpopulations rather than the entire population. We should pay much attention to normal weight obese and give a suitable physical activity guideline taking into account people with different body fat%.

Long-term exposure to ambient air pollution attenuated the association of physical activity with metabolic syndrome in rural Chinese adults: A cross-sectional study

BACKGROUND

Long-term exposure to ambient air pollution and physical activity are linked to metabolic syndrome (MetS). However, the joint effect of physical activity and ambient air pollution on MetS remains largely unknown in rural Chinese adult population.

METHODS

In this study, 39 089 individuals were included from the Henan Rural Cohort study that recruited 39 259 individuals at the baseline. Participants' exposure to air pollutants (including particulate matter with an aerodynamic diameter ≤ 1.0 µm (PM₁), ≤2.5 µm (PM_2.5), or ≤ 10 µm (PM₁₀) and nitrogen dioxide (NO₂)) were evaluated by using a spatiotemporal model based on satellites data. Individuals were defined as MetS according to the recommendation of the Joint Interim Societies. Physical activity-metabolic equivalent (MET) was calculated based on the formula of MET coefficient of activity × duration (hour per time) × frequency (times per week). Generalized linear models were used to analyze the individual air pollutant or physical activity and their interaction on MetS. Interaction effects of individual air pollutant and physical activity on MetS were assessed by using Interaction plots which exhibited the estimated effect of physical activity on MetS as a function of individual air pollutant.

RESULTS

The prevalence of MetS was 30.8%. The adjusted odd ratio of MetS with a per 5 µg/m³ increase in PM₁, PM_2.5, PM₁₀, NO₂ or a 10 MET (hour/day) of physical activity increment was 1.251(1.199, 1.306), 1.424(1.360, 1.491), 1.228(1.203, 1.254), 1.408(1.363, 1.455) or 0.814(0.796, 0.833). The protective effect of physical activity on MetS was decreased with accompanying air pollutant concentrations increased.

CONCLUSIONS

The results indicated that long-term exposure to ambient air pollutants related to increased risk of MetS and physical activity attenuated the effects of ambient air pollutants on increased risk for MetS.

Physical Activity and Cardiorespiratory Fitness in Tarahumara and Mestizo Adolescents from Sierra Tarahumara, Mexico

OBJECTIVES

Our purpose was to explore the levels of cardiorespiratory fitness (CRF) and the relationship between CRF, physical activity, and other physical traits in traditional and nontraditional Tarahumara, and Mestizo adolescents from Sierra Tarahumara, Mexico.

METHODS

A sample of 87 adolescents aged 16.9 ± 1.2 years (mean ± SD) performed the Margaria step test to quantify CRF. Physical activity was estimated using the International Physical Activity Questionnaire. Blood pressure (BP) and anthropometric measures were taken to estimate body composition and other physical characteristics.

RESULTS

Traditional Tarahumara showed higher levels of CRF than nontraditional Tarahumara and Mestizo adolescents (F = 5.5, p = .006). The time allotted to sedentary activities was higher in the Mestizo and nontraditional Tarahumara (χ² = 10.17, p = .006). In nontraditional Tarahumara, adiposity was associated with CRF reduction (r² = -.63, p = .00), while vigorous physical activities were positively associated with CRF (r² = .43, p = .03) and negatively associated with the z-score of body fat (r² = -.42 p = .03). Finally, CRF was negatively associated with fat percentage (r² = -.27, p = .00) and systolic blood pressure (r² = -.09, p = .04) in the Mestizo. In this group, walking activities (r² = -.25, p = .003) and total physical activity score (r² = -.11, p = .03) had a positive association with the CRF, while moderate activities had a negative association with the body mass index (r² = .09, p = .04), and vigorous activities were negatively associated with body weight (r² = .11, p = .03).

CONCLUSIONS

In the sampled nontraditional Tarahumara and Mestizo adolescents, moderate and vigorous physical activities were important factors in determining levels in CRF, fat percentage, and other health parameters.

Beneficial effects of moderate to vigorous physical activity on cardiovascular disease among Chinese adults

BACKGROUND

In China, lack of evidence remains a significant challenge for the national initiative to promote physical activity (PA). We aimed to quantify the beneficial effects of meeting or maintaining the recommended PA level [150 minutes per week (min/wk) of moderate PA or 75 min/wk of vigorous PA or an equivalent combination] on incident cardiovascular disease (CVD) among Chinese population.

METHODS

We included 100,560 participants without history of CVD from three cohorts in the Prediction for Atherosclerotic Cardiovascular Disease Risk in China (China-PAR) project. Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for CVD events and its subtypes, including stroke, coronary heart disease, heart failure, and CVD death.

RESULTS

During a median follow-up of 7.3 years (range: 6-15 years), 777,163 person-years and 4693 incident CVD events were observed. Compared with participants who were inactive at baseline, the multivariable adjusted HR (95% CI) of developing CVD was 0.74 (0.69-0.79) for those who met recommended moderate to vigorous physical activity (MVPA) level at baseline. Furthermore, the risk of CVD incidence was reduced with increment of MVPA (P trend < 0.001), and the HR (95% CI) of highly-active versus inactive category was 0.62 (0.56-0.68). Compared with individuals who were inactive both at the baseline and follow-up, those keeping active over the period of follow-up had a substantial lower risk of incident CVD with the HR (95% CI) of 0.57 (0.43-0.77).

CONCLUSIONS

The findings demonstrated that meeting and maintaining the recommended MVPA level could reduce the cardiovascular risk. Wider adoption of the PA recommendations would have considerable health impacts to the Chinese population.

Explaining Income-Related Inequalities in Dietary Knowledge: Evidence from the China Health and Nutrition Survey

Lack of adequate dietary knowledge may result in poor health conditions. This study aims to measure income-related inequality in dietary knowledge, and to explain the sources of the inequality. Data were from the China Health and Nutrition Survey (CHNS) conducted in 2015. A summary of the dietary knowledge score and dietary guideline awareness was used to measure the dietary knowledge of respondents. The concentration index was employed as a measure of socioeconomic inequality and was decomposed into its determining factors. The study found that the proportion of respondents who correctly answered questions on dietary knowledge was significantly low for some questions. Compared to rural residents, urban residents had a higher proportion of correctly answered dietary knowledge questions. In addition, there are pro-rich inequalities in dietary knowledge. This observed inequality is determined not only by individual factors but also high-level area factors. Our study recommends that future dietary education programs could take different strategies for individuals with different educational levels and focus more on disadvantaged people. It would be beneficial to consider local dietary habits in developing education materials.

Relation between residential density and walking time among urban adults in Nanjing, China

OBJECTIVES

The interest in built environment attributes on physical activity has been rapidly increasing over recent decades. This study aimed to investigate the associations between residential density (RD) and walking time (WT), a common mode of physical activity, among urban adults in China.

STUDY DESIGN

This is a cross-sectional study.

METHODS

Locally registered adults aged 35-74 years were randomly selected from eight urban neighbourhoods in Nanjing, China, in 2017. The outcome variable was self-reported WT (dichotomised), whereas RD (in tertiles) was the independent variable. Mixed-effects regression models were introduced to examine the RD-WT association via computing odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

Of 1568 eligible participants, 98.9% completed the survey, with a mean age (standard deviation) of 54.7 (11.1) years, in which 46% were men. After adjustment for potential confounders, a negative gradient RD-WT association was seen across RD tertiles among the participants (OR = 2.88 [95% CI = 1.79, 4.64] and 2.10 [95% CI = 1.35, 3.26] for lower and middle tertiles, respectively, compared with the upper RD tertile). The negative RD-WT association was observed for both men and women.

CONCLUSIONS

RD was negatively associated with the WT of urban adults in China. These results have public health implications for improving community-level physical activity through development of walking-friendly built environment.

Dietary sodium and potassium and risk of diabetes: A prospective study using data from the China Health and Nutrition Survey

AIMS

Dietary sodium and potassium intakes are well-known risk factors for cardiovascular outcomes. However, the associations between dietary sodium and potassium and diabetes are still controversial. Our study aimed to examine whether dietary sodium, potassium and the sodium-potassium ratio are associated with the risk of diabetes, based on a large sample of Chinese adults.

METHODS

The study data were from the 2004-2009 China Health and Nutrition Survey (CHNS), and 5867 participants were eligible for analysis. Sodium and potassium intakes were estimated based on three consecutive 24-h recalls at an individual level combined with a food inventory at a household level performed over the same 3-day period. Diabetes was defined as fasting glucose ≥7.0mmol/L (≥126mg/dL), HbA_1c ≥6.5% or use of antidiabetic drugs.

RESULTS

Over a mean follow-up of 4.7 years, there were 611 (10.4%) incident cases of diabetes. Participants in the higher quartiles (Q3 and Q4) of sodium intake had significantly higher risks of diabetes than those with the lowest sodium intake [Q3, RR: 1.41, 95% CI: 1.06-1.86 and Q4, RR: 1.35, 95% CI: 1.02-1.80; P<0.001 for trend]. In addition, high sodium intakes were significantly associated with levels of fasting glucose and HbA_1c (P<0.05 for trend), with similar associations also found with sodium-potassium ratios (P<0.05 for trend), but not for potassium intakes.

CONCLUSION

This study found that higher sodium intakes and sodium-potassium ratios were significantly associated with a higher risk of diabetes. Further clinical research is now necessary to confirm these results.

Changes in blood pressure during the transition of retirement: the role of physical activity in China

As baby boomers begin to retire, China faces an unprecedented transition in its labor market. A healthy transition into retirement, whereby a health status is retained, can curb medical care expenditures. However, little is known about health effects of retirement in China. Thus, this study investigated whether and to what extent retirement affected retirees' blood pressure, and the role that leisure physical activity played in this relationship. We used a nationally representative panel data collected during the 2004, 2006, 2009, and 2011 waves of the Chinese Health Nutrition Survey. Respondents who were older than 35 years and younger than 70 were included; our final sample size was 26,190. A four-step mediation model was constructed to examine the relationships between retirement, leisure physical activity, and blood pressure. Retirement predicted an decrease in systolic (coefficient of length time of retirement: -0.117; standard error:0.041; p < 0.01) and diastolic blood pressure level (coefficient of length time of retirement: -0.204; standard error: 0.062; p < 0.01), and a lower prevalence of hypertension (odd ratio of length time of retirement: 0.979; 95% CI: 0.968-0.990; p < 0.01) without leisure physical activity adjusted. However, these effects were reduced when the effects of physical activity were controlled for. A mediation effect of physical activity on the association between retirement and likelihood of hypertension/blood pressure was observed. These findings have implications for public policy that aims to promote health by taking advantage of postretirement adaptation; specifically, the findings suggest that the promotion of physical activity may facilitate a healthier transition into retirement.

Diabetes Mellitus and Its Association with Hypertension in Ethiopia: A Systematic Review and Meta-Analysis

BACKGROUND

Diabetes mellitus (DM) is a growing public health concern globally, including Ethiopia. Although numerous studies have been published from different parts of Ethiopia, no attempt is made so far to estimate the burden of DM at the national level. This study aims to estimate the pooled prevalence of DM and its association with hypertension in Ethiopia.

METHODS

A systematic search was conducted in major databases. Two authors extracted the necessary data and analysis was conducted using STATA version 14. Heterogeneity across the studies was evaluated by Cochran's Q test and I² statistics.

RESULTS

Eighteen studies with a total of 45,284 participants were included in this review. The pooled prevalence of DM was 4.99% (95% CI: 3.86%, 6.11%). Hypertension was significantly associated with DM (OR: 8.32; 95% CI: 3.05, 22.71).

CONCLUSION

The burden of DM in Ethiopia is considerable, and the association between diabetes and hypertension is significant. Based on the evidence, this review recommends establishing the coordinated national programs that counteract the increasing burden of DM in the country is very essential. In addition, Early hypertension screening should be done in diabetic patients to control co-morbidity and further complications.

Using street view data and machine learning to assess how perception of neighborhood safety influences urban residents' mental health

Previous studies have shown that perceptions of neighborhood safety are associated with various mental health outcomes. However, scant attention has been paid to the mediating pathways by which perception of neighborhood safety affects mental health. In addition, most previous studies have evaluated perception of neighborhood safety with questionnaires or field audits, both of which are labor-intensive and time-consuming. This study is the first attempt to measure perception of neighborhood safety using street view data and a machine learning approach. Four potential mediating pathways linking perception of neighborhood safety to mental health were explored for 1029 participants from 35 neighborhoods of Guangzhou, China. The results of multilevel regression models confirm that perception of neighborhood safety is positively associated with mental health. More importantly, physical activity, social cohesion, stress and life satisfaction mediate this relationship. The results of a moderation analysis suggest that the beneficial effects of physical activity and social cohesion on mental health are strengthened by a perception of neighborhood safety. Our findings suggest the need to increase residents' perception of neighborhood safety to maintain mental health in urban areas of China.

Population health impacts of China's climate change policies

Rapid and wide-ranging reductions in greenhouse gas emissions are required to meet the climate targets agreed upon at the 2015 Paris climate conference. There will be significant transition risks for health, livelihoods, and ecosystems associated with large-scale mitigation, but also opportunities. The aim of this study was to investigate the impacts, positive and negative, of climate policies on population health in China. We review the Intended Nationally Determined Contribution (INDC) that China took to the Paris meeting, link commitments in the INDC to national planning documents relevant to environment and health, and search the literature for Chinese publications on health trade-offs and synergies. Synergies are evident in the measures taken to reduce local air pollution in China: controls on coal burning have materially improved local air quality and benefited health. But there may be risks to health also, depending on how policies are implemented and what safeguards are provided. To date most assessments of the health impacts of climate policies in China have been modelling studies. We recommend work of this kind is complemented by observational research to identify unexpected impacts and vulnerabilities. It will become even more important to undertake this work as emission reductions accelerate to meet the Paris climate targets.

Decomposing adult obesity trends in China (1991-2011)

Using data from the China Health and Nutrition Survey, this study analyses two decades (1991-2011) of change in adult obesity in China with a focus on whether rising obesity rates result from all population cohorts becoming more obese across time (intra-cohort change) or recent cohorts being more obese than their earlier counterparts (inter-cohort change or cohort replacement). To do so, we decompose changes in the body mass index (BMI), waist circumference (WC), general obesity and abdominal obesity of adults aged 20+ using both Firebaugh's linear decomposition and Das Gupta's non-linear technique. Our analysis not only reveals significant increases in both general and abdominal obesity (8.1 and 32 percentage points, respectively) in the two decades studied but shows that the rising means in all four measures are mostly attributable to intra-cohort change. In fact, contrary to findings for the U.S., inter-cohort change for the Chinese sample is actually negative, implying that cohort replacement attenuates intra-cohort change over time. Given that intra-cohort change is the central force for the increase in BMI, WC and obesity with individual increases in obesity widely distributed across all cohorts and age groups over time, policy interventions should focus more broadly on all age groups and birth cohorts.

Cardiovascular Health and Disease Among Asian-Americans (from the National Health and Nutrition Examination Survey)

Variable propensity toward cardiovascular disease in the different ethnicities in the United States has been reported. We aimed to characterize the prevalence trends of cardiovascular health, as defined by the American Heart Association's Life's Simple 7 metrics, and cardiovascular diseases amongst Asian-Americans. We used the National Health and Examination Nutrition Survey from 2011 to 2016 to capture self-identified American-born Asian-Americans and foreign-born Asian-Americans. The prevalence trends of cardiovascular health metrics and diseases were evaluated in Asian-Americans and also compared between American-born and foreign-born Asian-Americans. Results were presented as weighted percentages and odds ratios with 95% confidence intervals. From 2011-2012 to 2015-2016, the prevalence of Asian-Americans reporting no physical activity increased from 21.5% to 32.4% (p for linear trend = 0.001) and the prevalence of Asian-American participants reporting a healthy diet decreased from 44.1% to 36.8% (p for quadratic trend = 0.02). There was a concomitant decline in the prevalence of Asian-Americans with normal weight (body mass index <25 kg/m²) from 60.5% from 2011-2012 to 55.3% in 2015-2016 (p for linear trend = 0.04). The prevalence of congestive heart failure and chronic kidney disease increased from 2011-2012 to 2015-2016. Foreign-born Asian-Americans had lower odds of having a nonhealthy diet and blood pressure compared with American-born Asians. In conclusion, in the National Health and Examination Nutrition Survey 2011 to 2016 cycles, Asian-Americans exhibited a declining prevalence of healthy weight and an increasing prevalence of poor diet, physical activity levels, congestive heart failure, and chronic kidney disease. Foreign-born Asian-Americans also exhibited a different cardiometabolic risk profile compared with American-born Asian-Americans.

Exploring the association between urbanisation and self-rated health of older adults in China: evidence from a national population sample survey

OBJECTIVES

This study investigated the association between urbanisation and self-rated health of older adults in China, particularly how different dimensions, rate and level of urbanisation are related to older people's health. Additionally, it examined the moderating effect of education on the association between each of the four dimensions of urbanisation and older people's health.

DESIGN

The study uses a cross-sectional survey design.

PARTICIPANTS

This study analysed 236 030 individuals (aged 60-79 years) nested within 267 prefecture-level cities from 2005 China's 1% population sample survey.

OUTCOME MEASURES

Self-rated health was the outcome variable. Four groups of predictors assessed prefectures' level and rate of urbanisation: land-use conversion, economic growth, population concentration and health services. Multilevel logistic regression was used to examine the association between self-rated health and the level and rate of urbanisation, after adjusting for individual-level covariates. Multiplicative interactions explored variations by education.

RESULTS

The odd of reporting fair or poor health was negatively associated with the level and rate of population concentration (OR 0.93,95%CI 0.87 to 0.99 and 0.74,95%CI 0.59 to 0.93, respectively) and positively associated with the level of health services (OR 1.12, 95% CI 1.06 to 1.19). Land-use conversion, economic growth and health service improvements (the forms of rate of urbanisation) were not significantly associated with self-rated health. Education had a moderating effect on the association between urbanisation and self-rated health.

CONCLUSIONS

Older people living in more densely populated areas and areas undergoing rapid population concentration were less likely to report fair or poor health. This result supports healthy migration and 'salmon bias' hypotheses. No urban health penalty was observed for the older adults in China; therefore, the following pathways linking urbanisation to health are unclear: lifestyle changes, environmental pollution and cultivated land reduction.

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.

Excessive physical activity duration may be a risk factor for hypertension in young and middle-aged populations

Physical inactivity is known to cause many health problems globally each year. However, evidence regarding the interaction between excessive physical activity (PA) and blood pressure in young and middle-aged populations is limited.A multistage, stratified, random cluster sampling design was adopted to recruit representative samples. Participants were asked to complete a questionnaire and undergo physical examinations. Associations between prehypertension, hypertension and PA durations were examined by multivariable logistic regression.Overall, 8206 subjects (4110 men, 50.1%) aged 15 to 45 years were enrolled. The prevalence rates of prehypertension and hypertension were 45.7% and 5.0%, respectively. Among the 1913 participants who performed moderate-intensity PA for more than 700 min/wk, 118 had hypertension (6.2%) and 845 had prehypertension (44.2%). Among the 1003 participants who performed vigorous-intensity PA for more than 450 min/wk, 82 had hypertension (8.2%) and 479 had prehypertension (47.8%).Long-term and sustained PA may increase the risk for hypertension in young and middle-aged subjects. An appropriate recommendation of PA duration should be encouraged in this cohort.

Rising rural body-mass index is the main driver of the global obesity epidemic in adults

Body-mass index (BMI) has increased steadily in most countries in parallel with a rise in the proportion of the population who live in cities1,2. This has led to a widely reported view that urbanization is one of the most important drivers of the global rise in obesity3-6. Here we use 2,009 population-based studies, with measurements of height and weight in more than 112 million adults, to report national, regional and global trends in mean BMI segregated by place of residence (a rural or urban area) from 1985 to 2017. We show that, contrary to the dominant paradigm, more than 55% of the global rise in mean BMI from 1985 to 2017-and more than 80% in some low- and middle-income regions-was due to increases in BMI in rural areas. This large contribution stems from the fact that, with the exception of women in sub-Saharan Africa, BMI is increasing at the same rate or faster in rural areas than in cities in low- and middle-income regions. These trends have in turn resulted in a closing-and in some countries reversal-of the gap in BMI between urban and rural areas in low- and middle-income countries, especially for women. In high-income and industrialized countries, we noted a persistently higher rural BMI, especially for women. There is an urgent need for an integrated approach to rural nutrition that enhances financial and physical access to healthy foods, to avoid replacing the rural undernutrition disadvantage in poor countries with a more general malnutrition disadvantage that entails excessive consumption of low-quality calories.

Urban developments and health: Evidence from the distributional analysis of biomarkers in China

This study explores the association between urban developments and health in China, a country that has experienced unprecedented economic growth and consequential rapid urbanisation over the last few decades. Exploiting the Chinese Health and Nutrition Survey, this study analyses the effect of these urban developments on the entire distribution of 11 objectively measured health outcomes related to non-communicable diseases. Quantification of the effects on health distribution is achieved by estimating health distribution in a counter-factual situation in which every individual is exposed to the minimum level of urban development. In decomposing the estimated effect into the part attributable to the observed path through which urban developments change observed health-related behaviours (behavioural effect), and the remaining part which cannot be attributable to this observed path (non-behavioural effect), this study sheds light on the mechanisms underlying how urban developments are associated with health outcomes. The results indicate that urban developments are negatively associated in this regard, especially with health outcomes related to body lipids such as triglycerides and cholesterols, blood pressure and kidney-related biomarkers. Furthermore, the results provide strong evidence of heterogeneity in the degrees of association across the distribution.

Association between nutrient patterns and serum lipids in Chinese adult women: A cross-sectional study

AIM

To investigate the association between patterns of nutrient intake and serum lipids in Chinese women aged 18-80 years.

METHODS

In the present study, cross-sectional data were analysed from 2886 female participants aged 18-80 years from the China Health and Nutrition Survey wave 2009. Nutrient patterns were identified using factor analysis combined with cluster analysis based on the data of nutrient intake for three consecutive days. Multivariate linear regression models were used to estimate the association of nutrient patterns with serum lipids.

RESULTS

Four nutrient patterns were identified in Chinese adult women, which were the plant-based pattern, carbohydrate and animal fat pattern, plant fat and sodium pattern, and the animal-based pattern. Participants following different patterns varied significantly in sociodemographic characteristics, lifestyle behaviours and food consumption. Compared with the plant-based pattern, the carbohydrate and animal fat pattern was positively associated with low-density lipoprotein cholesterol (β = 4.57, 95% CI: 0.29-8.85, P = 0.036) and total cholesterol (β = 4.89, 95% CI: 0.34-9.44, P = 0.035). The corresponding rises for the animal-based pattern were 4.91 (95% CI: 0.99-8.82, P = 0.014) and 4.98 (95% CI: 0.82-9.15, P = 0.019), respectively.

CONCLUSIONS

Nutrient patterns with a high intake of animal fat and a low intake dietary fibre and with high intakes of animal fat, animal protein and cholesterol may increase the serum cholesterol in Chinese women.

Plain Water Intake and Association With the Risk of Overweight in the Chinese Adult Population: China Health and Nutrition Survey 2006-2011

Background

The prevalence of overweight is increasing dramatically worldwide. The aim of our study was to investigate the association of plain water intake (PWI) with the risk of new-onset overweight risk among Chinese adults.

Methods

A total of 3,200 adults aged 18–65 who were free of overweight at baseline were enrolled from China Health and Nutrition Survey (CHNS) cohort study in 2006–2011. The risk of new-onset overweight with different amounts of PWI per day was analyzed in this 5-year cohort. A multiple logistic regression model was used to assess the association of PWI and the risk of new-onset overweight and adjust for potential confounders. Moreover, dose-response models were developed to estimate the linear relationship.

Results

During 5 years of follow-up, 1,018 incident cases were identified. Our analysis indicated an inverse association of more than 4 cups of PWI per day and the risk of new-onset overweight among normal weight individuals. Compared with participants who drank 2 to 3 cups PWI, the adjusted odds ratios (OR) of overweight were 0.741 (95% confidence interval [CI], 0.599–0.916) in participants who drank 4 to 5 cups PWI, and 0.547 (95% CI, 0.435–0.687) in participants who drank more than 6 cups PWI. The dose-response analysis showed that every cup of PWI was associated with a 6.5% and 8.4% decrease in the risk of new-onset overweight among men and women, respectively. The interactions of PWI and covariates on the risk of overweight were not found.

Conclusion

Drinking more than 4 cups (≈1 liter) per day of plain water is associated with decrease in the risk of new-onset overweight among normal-weight individuals.

Urban-rural differences in the association between blood lipids and characteristics of the built environment: a systematic review and meta-analysis

Introduction

The built environment defines opportunities for healthy eating and physical activity and may thus be related to blood lipids. The aim of this study is to systematically analyse the scientific evidence on associations between built-environment characteristics and blood lipid levels in adults.

Methods

PubMed, EMBASE and Web of Science were searched for peer-reviewed papers on population-based studies up to 9 October 2017. We included studies that reported on built-environment characteristics and blood lipid levels in adult populations (≥18 years). Two reviewers independently screened titles/abstracts and full-texts of papers and appraised the risk of bias of included studies using an adapted version of the Quality Assessment Tool for Quantitative Studies. We performed meta-analyses when five or more studies had sufficient homogeneity in determinant and outcome.

Results

After screening 6902 titles/abstracts and 141 potentially relevant full-text articles, we included 50 studies. Forty-seven studies explored associations between urban versus rural areas with blood lipid levels. Meta-analyses on urban versus rural areas included 133 966 subjects from 36 studies in total. Total cholesterol levels were significantly and consistently higher in urban areas as compared with rural areas (mean difference 0.37 mmol/L, 95% CI 0.27 to 0.48). Urban/rural differences in high density lipoprotein cholesterol were inconsistent across studies and the pooled estimate showed no difference (0.00 mmol/L 95% CI −0.03 to 0.04). Low density lipoprotein (LDL) cholesterol and triglyceride levels were higher in urban than in rural areas (mean difference 0.28, 95% CI 0.17 to 0.39 and 0.09, 95% CI 0.03 to 0.14, respectively).

Conclusions

Total and LDL cholesterol levels and triglycerides were consistently higher in residents of urban areas than those of rural areas. These results indicate that residents of urban areas generally have less favourable lipid profiles as compared with residents of rural areas.

Prospero registration number

CRD42016043226.

Mediating factors explaining the associations between polycyclic aromatic hydrocarbons exposure, low socioeconomic status and diabetes: A structural equation modeling approach

Exposure to polycyclic aromatic hydrocarbons (PAHs) is linked with increased risk of diabetes, whereas socioeconomic status (SES) may contribute to the development of diabetes. However, the mechanisms underlying the relationships between them are unclear. We used structural equation modeling (SEM) to identify mediating factors in the associations of PAHs exposure, low SES with diabetes risk. Data were collected from 2751 Wuhan participants at baseline from the Wuhan-Zhuhai Cohort Study (n = 3053). They answered the questionnaires regarding socio-demographic, participated physical examinations and provided urine samples for measurements of urinary monohydroxy-polycyclic aromatic hydrocarbons (OH-PAHs) levels. SEM was used to identify the mediating factors (such as hypertension, body mass index (BMI), triglycerides (TG) and total cholesterol (TCHO)) in the associations of low SES or PAHs exposure with diabetes risk. We observed that partial effect of PAHs exposure (β = 0.281, p = 0.034), BMI (β = 0.182, p = 0.000), TG (β = 0.358, p = 0.000), TCHO (β = 0.203, p = 0.009) or hypertension (β = 0.385, p = 0.000) on diabetes was directive. Moreover, low SES also exhibited a directive effect on PAHs exposure (β = -0.084, p = 0.000), BMI (β = 0.301, p = 0.000), hypertension (β = 0.134, p = 0.003) and TG (β = 0.087, p = 0.001). PAHs exposure directly affected TCHO levels (β = 0.080, p = 0.002) and TG (β = 0.076, p = 0.017). The proportion of the effect of PAHs exposure on diabetes mediated by TG and TCHO was 15.6%. The proportion of the effect of low SES on diabetes mediated by BMI, hypertension and TG was 89.1%. The results suggested that low SES increased diabetes risk, which may be partially explained by BMI, hypertension and triglycerides, and exposure to high levels of PAHs may have indirect contribution to increased risk for diabetes with dyslipidemia.

Differing Contributions of Classical Risk Factors to Type 2 Diabetes in Multi-Ethnic Malaysian Populations

The prevalence of type 2 diabetes is escalating rapidly in Asian countries, with the rapid increase likely attributable to a combination of genetic and lifestyle factors. Recent research suggests that common genetic risk variants contribute minimally to the rapidly rising prevalence. Rather, recent changes in dietary patterns and physical activity may be more important. This nested case-control study assessed the association and predictive utility of type 2 diabetes lifestyle risk factors in participants from Malaysia, an understudied Asian population with comparatively high disease prevalence. The study sample comprised 4077 participants from The Malaysian Cohort project and included sub-samples from the three major ancestral groups: Malay (n = 1323), Chinese (n = 1344) and Indian (n = 1410). Association of lifestyle factors with type 2 diabetes was assessed within and across ancestral groups using logistic regression. Predictive utility was quantified and compared between groups using the Area Under the Receiver-Operating Characteristic Curve (AUC). In predictive models including age, gender, waist-to-hip ratio, physical activity, location, family history of diabetes and average sleep duration, the AUC ranged from 0.76 to 0.85 across groups and was significantly higher in Chinese than Malays or Indians, likely reflecting anthropometric differences. This study suggests that obesity, advancing age, a family history of diabetes and living in a rural area are important drivers of the escalating prevalence of type 2 diabetes in Malaysia.

The longitudinal trajectory of body mass index in the Chinese population: A latent growth curve analysis

Aims

The objective of this study was to investigate the longitudinal trajectory of BMI in the Chinese population, and to assess whether the gender or other personal characteristics were related to BMI, and whether there was a change in trajectory over time.

Methods

Data were obtained from 3,574 Chinese (5 to 89 years of age) who participated in the 2000–2011 of the China Health and Nutrition Survey. Latent growth curve models were used to investigate the longitudinal trajectory of BMI, and to examine the effect of some personal characteristics on BMI trajectory.

Results

The linear model resulted in a mean initial BMI value of 22.90 and a significant mean slope (Ms = 0.19, t = 10.73, p<0.001), suggesting a steady increase in BMI over time for the whole sample. For covariates, the educational level, alcohol and physical activity had differences on initial scores for BMI (β = 0.05, p<0.001; β = -0.12, p<0.05; β = -0.08, p<0.05; respectively.), and the age had differences on both the initial scores and slope for BMI (β = 0.01, p = <0.05; β = -0.03, p<0.01; respectively.). Baseline measures revealed gender-associated differences on initial scores for BMI, and the slope for male was significantly steeper than that for female (β = -0.11, p<0.05). The initial BMI status of Chinese living in the rural areas was significantly higher than that of Chinese living in the urban areas, and the slope for rural status was significantly steeper than that for urban status (β = 0.21, p<0.001).

Conclusions

Results indicated a linear trajectory of BMI in the Chinese population over a 12-year period. The longitudinal trajectories differed by age, gender and urban-rural status, suggesting different interventions should be adopted for different groups.

Multilevel socioeconomic differentials in allostatic load among Chinese adults

Capitalizing on the biomarker data from the 2009 wave of the China Health and Nutrition Survey (CHNS), this study examines the extent to which multilevel socioeconomic status (SES) gets "under the skin" to affect individuals' health, measured by allostatic load (AL). Multilevel analyses suggest that in the context of China's socioeconomic and health transitions, high income, prestigious but sedentary occupations, and high level of urbanization were independently associated with higher AL scores, or increased health risks of physiological dysfunction in cardiovascular, metabolic, inflammation, and urinary systems. Higher educational attainment was related to a decrease in AL, but the significant difference was only observed among the college-educated compared to lower levels of education.

Effect of characteristics and life in cities in China on residents' smoking behaviour

Objective

This study aimed to identify the relationship between city-level economic development and smoking behaviour.

Methods

Using multilevel mixed-effects logistic methods, we examined the relationship between smoking/passive smoking and respondents’ lifestyles in the city.

Results

We found that respondents living in cities with higher per capita gross domestic product (GDP) were less likely to smoke than those living in cities with lower per capita GDP (odds ratio [OR] = 0.977, 95% confidence interval [CI]: 0.958–0.997). Further, respondents with higher levels of life satisfaction and subjective social status were less likely to smoke than those with lower levels of these variables (OR = 0.942, 95% CI: 0.893–0.994; OR = 0.955, 95% CI: 0.928–0.983, respectively). In terms of passive smoking, respondents with higher levels of subjective social status in their cities were less likely to smoke than those with lower levels (OR = 0.972, 95% CI: 0.948–0.996). Smoking and exposure to second-hand smoke were more common among those with lower socioeconomic status.

Conclusions

Smoking is one of the most serious public health hazards in China. People’s smoking behaviour is significantly related to characteristics of their cities and their socioeconomic status. Improved smoking-prevention measures are urgently required in China.

Variation in the education gradient of body weight in contemporary China

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 education gradient in body weight shifted from being positive to being negative over time for China as a whole, as well as across regions with different levels of economic development. In contrast, for men, higher education remained consistently associated with higher body weight over the 18-year period studied in China as a whole, as well as across regions with different levels of economic development.

Prevalence, awareness, treatment and control of diabetes mellitus among middle-aged and elderly people in a rural Chinese population: A cross-sectional study

Diabetes mellitus ranks high on the international health agenda as a global pandemic and as a threat to human health and global economies. A total of 10851 participants aged over 40 years were included in the cross-sectional analysis. This observational study analyzed the prevalence of diabetes mellitus and the awareness, treatment and glycemic control of diabetes in a rural Chinese population. Approximately 25% of middle-aged and elderly rural Chinese residents had diabetes in 2010–2011. The prevalence was higher with older age, dyslipidemia, higher body mass index and larger waist circumference. Among the subjects with diabetes, 40.3% were aware of their condition; 62.9% were receiving treatment, and 16.9% had controlled diabetes. Metformin was the majority oral antidiabetic drug treatment most often prescribed, for either monotherapy or combined therapy. These results indicate that diabetes has become an urgent public health problem in the Chinese rural population because of its high prevalence and low rates of awareness, treatment and control. The management and prevention of diabetes mellitus should be considered an essential strategy at the level of public health.

The feasibility of two anthropometric indices to identify metabolic syndrome, insulin resistance and inflammatory factors in obese and overweight adults

OBJECTIVES

A body shape index (ABSI) and body roundness index (BRI) were reported to predict diabetes and hypertension in general population, but their validity was regularly questioned. The aim of this study was to evaluate whether ABSI and BRI are the best anthropometric indices to reflect metabolic syndrome (MetS), insulin resistance (IR), and inflammatory factors in obese and overweight Chinese adults.

METHODS

Cross-sectional data on sociodemographic, lifestyle, anthropometric indices, clinical characteristics, and biochemical measurements were collected for 1442 Chinese obese and overweight adults. Logistic regression analysis examined the associations between anthropometric indices with incidences of MetS and IR in both sexes. Furthermore, the correlation between anthropometric indices and inflammatory factors was assessed.

RESULTS

Multivariate regression analysis depicting BRI and waist circumference (WC) were associated significantly with MetS and IR. BRI had the highest odds ratios (ORs) for IR and WC had the highest ORs for MetS in all anthropometric indices. However, ABSI did not exhibit any association between the MetS and IR. The ABSI adjusted regression coefficients (β values) were 0.403 for high-sensitivity C reactive protein, 0.077 for tumor necrosis factor-α, and 0.022 for interleukin-6. BRI and WC were also significantly associated with three inflammatory factors. Comparing the lowest with the highest quintile, BRI had the largest ORs for MetS (OR, 5.778; 95% confidence interval [CI], 2.954-11.303; P < 0.01) and IR (OR, 6.212; 95% CI, 2.912-13.250; P < 0.01).

CONCLUSION

Only BRI and WC, not ABSI, can significantly determine the presence of MetS and IR. BRI showed the optimal capability to identify IR in obese and overweight population.

The Physical Activity Patterns among Rural Chinese Adults: Data from China National Nutrition and Health Survey in 2010⁻2012

China has experienced a rapid increase in non-communicable diseases (NCDs), especially in rural China. In addition to a dramatic increase in energy intake, the decrease in physical activity (PA) may be a reason. The study described the patterns and factors of physical activity and sedentary behaviors of 70,038 adults in rural China, based on data from the Chinese Nutrition and Health Survey (CNNHS) in 2010–2012. The mean working time of the employed subjects was 6.04 ± 1.3 day/week, 8.38 ± 2.2 h/day, of which 3.37 ± 2.8 h was sitting time. The occupational PA intensity was significantly relevant with occupation. The average transportation time of the rural Chinese adults was 57.9 ± 45.4 min, and 60.0% took the active transportation mode. The leisure-time PA (LTPA) participation rate was 3.8%, the LTPA time of those who had LTPA was 234.9 ± 231.3 min/week, lower participation was found in farmers and those in younger age groups, and those with lower educational and economic levels. The average domestic PA time, sedentary leisure-time, and sleeping time was 93.0 ± 72.7 min, 2.5 ± 1.4 h, and 7.9 ± 1.1 h, respectively. PA programs should be implemented in rural China, and the PA guidelines for farmers should be developed separately for the farming and non-farming seasons.