Residential exposure to natural outdoor environments and general health among older adults in Shanghai, China

Self-rated health in old age, related factors and survival: A 20-Year longitudinal study within the Silver-MONICA cohort

INTRODUCTION

Self-rated health (SRH) offers insights into the evolving health demographics of an ageing population.

AIM

To assess change in SRH from old age to very old age and their associations with health and well-being factors, and to investigate the association between SRH and survival.

METHODS

All participants in the MONICA 1999 re-examination born before 1940 (n = 1595) were included in the Silver-MONICA baseline cohort. The Silver-MONICA follow-up started in 2016 included participants in the Silver-MONICA baseline cohort aged 80 years or older. Data on SRH was available for 1561 participants at baseline with 446 of them also participating in the follow-up. The follow-up examination included a wide variety of measurements and tests.

FINDINGS

Most participants rated their health as "Quite good" (54.5 %) at baseline. Over the study period, 42.6 % had stable SRH, 40.6 % had declined, and 16.8 % had improved. Changes in SRH were at follow-up significantly associated with age, pain, nutrition, cognition, walking aid use, self-paced gait speed, lower extremity strength, independence in activities of daily living, weekly physical exercise, outdoor activity, participation in organized activities, visiting others, morale, and depressive symptoms. SRH at baseline was significantly associated with survival (p < 0.05).

CONCLUSION

This study demonstrates associations between changes in SRH and a multitude of health- and wellbeing-related factors, as well as a relation between survival and SRH, accentuating their relevance within the ageing population.

Urban green, blue spaces and their joint effect are associated with lower risk of emotional and behavior problem in children and adolescents, a large population-based study in Guangzhou, China

Extensive research has been conducted on the impact of urban Green and blue spaces (GBS) on mental health. However, there is a dearth of studies examining the potential influence of GBS on Emotion and behavior problems (EBP) in youth populations. This study seeks to address this research gap by examining the association between GBS exposure and EBP in youths, utilizing a large population-based survey. Exposure indicators were derived for each participant, taking into account the 1-m resolution land coverage percentage measurements at their residential and school locations, with buffer sizes of 500m and 800m. The study employed the parent-reported Strengths and Difficulties Questionnaire (SDQ) as a measurement to EBP. To investigate this relationship, a Poisson linear mixed-effects model with comprehensive adjustment was utilized. Stratified analyses were conducted, taking into account demographic variables, while sensitivity analyses were performed to evaluate the reliability of the findings. The primary analysis encompassed a sample of 172,490 individuals, with an average age of 10.2 (standard deviation = 2.99), of whom 55.8% were male. Among young individuals residing within a 500-m radius of residential green spaces (GS), those in the second and third tertiles experienced a 5.0% and 7.6% decrease in the risk of developing total difficulties respectively, compared to those in the first tertile. Exposure to blue spaces (BS) around the residence yielded comparable results, with an AOR of 0.896 (95% CI: 0.866, 0.928) for the second tertile and an AOR of 0.991 (95% CI: 0.879, 0.943) for the third tertile, compared to the first tertile. The decrease in EBPs may also be linked to the joint effect of GS and BS. Young individuals were exposed to GS or BS, as well as the higher level of GS in conjunction with comparable BS, exhibited an inverse correlation with self-reported EBPs.

Residential greenness mitigates mortality risk from short-term airborne particulate exposure: An individual-level case-crossover study

BACKGROUND

Studies suggested that greenness could reduce death risks related to ambient exposure to particulate matter (PM), while the available evidence was mixed across the globe and substantially exiguous in low- and middle-income countries. By conceiving an individual-level case-crossover study in central China, this analysis primarily aimed to quantify PM-mortality associations and examined the modification effect of greenness on the relationship.

METHODS

We investigated a total of 177,058 nonaccidental death cases from 12 counties in central China, 2008-2012. Daily residential exposures to PM2.5 (aerodynamic diameter <2.5 µm), PMc (aerodynamic diameter between 2.5 and 10 µm), and PM10 (aerodynamic diameter <10 µm) were assessed at a 1 × 1-km resolution through satellite-derived machine-learning models. Residential surrounding greenness was assessed using satellite-derived enhanced vegetation index (EVI) and normalized difference vegetation index (NDVI) at multiple buffer sizes (250, 500, and 1000 m). To quantify the acute mortality risks associated with short-term exposure to PM2.5, PMc, and PM10, a time-stratified case-crossover design was utilized in conjunction with a conditional logistic regression model in our main analyses. To investigate the effect modification of greenness on PM-mortality associations, we grouped death cases into low, medium, and high greenness levels using cutoffs of 25th and 75th percentiles of NDVI or EVI exposure, and examined potential effect heterogeneity in PM-related mortality risks among these groups.

RESULTS

Mean concentrations (standard deviation) on the day of death were 73.8 (33.4) μg/m3 for PM2.5, 43.9 (17.3) μg/m3 for PMc, and 117.5 (44.9) μg/m3 for PM10. Size-fractional PM exposures were consistently exhibited significant associations with elevated risks of nonaccidental and circulatory mortality. For every increase of 10-μg/m3 in PM exposure, percent excess risks of nonaccidental and circulatory mortality were 0.271 (95% confidence interval [CI]: 0.010, 0.533) and 0.487 (95% CI: 0.125, 0.851) for PM2.5 at lag-01 day, 0.731 (95% CI: 0.108, 1.359) and 1.140 (95% CI: 0.267, 2.019) for PMc at lag-02 day, and 0.271 (95% CI: 0.010, 0.533) and 0.386 (95% CI: 0.111, 0.662) for PM10 at lag-01 day, respectively. Compared to participants in the low-level greenness areas, those being exposed to higher greenness were found to be at lower PM-associated risks of nonaccidental and circulatory mortality. Consistent evidence for alleviated risks in medium or high greenness group was observed in subpopulations of female and younger groups (age <75).

CONCLUSIONS

Short-term exposure to particulate air pollution was associated with elevated risks of nonaccidental and circulatory death, and individuals residing in higher neighborhood greenness possessed lower risk of PM-related mortality. These findings emphasized the potential public health advantages through incorporating green spaces into urban design and planning.

Potential impacts of spatial restrictions on tobacco retail availability in China: a simulation study in Shanghai

OBJECTIVES

Regulating tobacco retail availability provides promising new opportunities for effective tobacco control. This study simulates the potential impacts of introducing spatial restrictions on the availability of tobacco in Shanghai, the largest city in China.

METHODS

Twelve stakeholder-informed simulation scenarios under four types of spatial restrictions were considered: (1) capping, (2) ban of sales, (3) minimum spacing and (4) school-buffer exclusion zone. Tobacco retailer data for Shanghai (n=19 413) were used. The main outcome was per cent reduction in retail availability measured by population-weighted kernel density estimation across neighbourhoods, and impacts on social inequality in availability were estimated using the Kruskal-Wallis test and effect size estimation. All analyses were further stratified by three levels of urbanity to examine geographical disparities in overall effectiveness and equity of the simulation scenarios.

RESULTS

All simulation scenarios have the potential to reduce availability, with overall reductions ranging from 8.60% to 85.45%. Compared with the baseline, the effect size regarding the association between availability and neighbourhood deprivation quintiles suggests that the most effective scenario, '500 m minimum spacing' between retailers, increased the social inequality in availability (p<0.001). Conversely, school-buffer scenarios were both effective and equitable. Additionally, the effectiveness and the equity impact of scenarios varied by urbanity level.

CONCLUSION

Spatial restrictions offer potential new policy opportunities to reduce retail availability, but some may increase social inequality in accessing tobacco. For effective tobacco control, policymakers should consider the overall and equity impacts of spatial restrictions when developing comprehensive tobacco retail regulations.

Sea swimming and snorkeling in tropical coastal blue spaces and mental well-being: Findings from Indonesian island communities during the COVID-19 pandemic

The COVID-19 pandemic has considerable mental health impacts. Immersive nature-based interventions, such as swimming or snorkeling, may help mitigate the global mental health crisis caused by the pandemic. To investigate this, we collected cross-sectional data from residents of coastal villages (n = 308) in Kepulauan Selayar, Indonesia. Analysis of Covariance (ANCOVA) was used with mental well-being as the outcome variable, operationalized as the Mental Component Summary (MCS) scores from the SF-12 (12-item Short Form Health Survey). After adjusting for covariates, the activity of sea swimming or snorkeling was found to be significantly associated with better mental well-being (η² = 0.036; p < 0.01). Predictive margins analysis revealed that those who engaged in sea swimming or snorkeling for one to three days a week gained a 2.7 increase in their MCS scores, compared to those who did not. A non-linear dose-response relationship was detected: for those swimming or snorkeling more than three days per week, there was only an increase of 1.7 MCS score compared to the 0-day. Overall this study contributes to the expanding of evidence base, showing that interactions with blue spaces can be beneficial for mental health, especially in a potentially stressful time such as the current pandemic.

Management implications

The positive association between the activity of swimming or snorkeling in open seas and the mental well-being of rural coastal communities in Indonesia during the COVID-19 pandemic indicates that access to coastal blue spaces is important in a time of uncertainties and high stress. Ensuring that local communities have continuous access to these spaces is the key challenge for all relevant stakeholders, particularly in light of the growing privatization of the local coastal environment for the sake of tourism. However, considering the importance that these blue spaces hold for the mental well-being of local communities, intensive dialogue amongst these stakeholders must be pursued to ensure that the development of the area does not jeopardize the collective well-being of the people already living there.

A Cross-sectional Analysis of Socio-spatial Patterning of Tobacco Retail in Shanghai, China

INTRODUCTION

International evidence from high-income countries demonstrates that the availability of tobacco tends to be greater in more urban and more deprived neighborhoods. However, little is known about the socio-spatial disparities in other settings, including megacities in China. This study investigated the patterning of tobacco retailers across Shanghai by types of tobacco retailers, including the relationship with levels of urbanity and neighborhood deprivation.

AIMS AND METHODS

Tobacco retailer data (n = 19 413) was extracted from a web-scraped Points-of-Interest database. For all communities (n = 5432) across Shanghai, neighborhood tobacco retail availability was calculated using population-weighted kernel density estimation and grouped by quintiles of neighborhood deprivation and a 3-level urban classification. Associations were analyzed using the Kruskal-Wallis tests and epsilon squared.

RESULTS

Across Shanghai, tobacco retail availability decreased from more urbanized areas to less urbanized areas. There was a statistical difference (p < .001) in the availability of tobacco retail across quintiles of deprivation, with the highest availability in the less deprived neighborhoods, and the lowest availability in the most deprived neighborhoods. However, this trend was reversed in the urban center, where retail availability was greatest in the most deprived areas. Convenience stores were the most common type of tobacco retailer across the city, while tobacco-only outlets were most strongly associated with levels of neighborhood deprivation.

CONCLUSIONS

The results show an association between tobacco retail availability and neighborhood deprivation, which varied with levels of urbanity and types of tobacco retailers. These findings provide supportive evidence for further interventions that target reducing inequalities in exposure to tobacco retail.

IMPLICATIONS

This is the first study to examine the relationship between tobacco retail availability and neighborhood deprivation in the context of Chinese megacities. Using data from Shanghai, China, we found a significant non-linear association between tobacco retail availability and neighborhood deprivation across the city. It is plausible that the socio-spatial disparities in tobacco retail availability at the neighborhood level may be a key factor explaining differences in smoking behaviors between sociodemographic groups. The findings emphasize the need for greater efforts in regulating neighborhood-level tobacco retailing in China.

Age-dependent and sex-dependent differences in mortality from influenza-associated cardiovascular diseases among older adults in Shanghai, China: a population-based study

OBJECTIVES

Influenza epidemics lead to substantial morbidity and mortality among older adults. This study aimed to analyse and assess the age-specific and sex-specific differences in mortality rates for cardiovascular disease (CVD) associated with influenza in older adults.

DESIGN

We obtained weekly data on mortality from CVD in adults≥60 years, categorised into five age groups. We used a quasi-Poisson model and adjusted for long-term and seasonal trends and absolute humidity as confounding factors. The male-to-female ratio (M/F ratio) was an indicator for assessing sex differences.

SETTING

Shanghai, China.

PARTICIPANT

We analysed 440 107 CVD deaths in adults aged ≥60 years, including 44 913 cases positive for influenza and 1 927 487 outpatient visits for influenza-like illness from 2010 to 2019.

MAIN OUTCOME MEASURES

Age-specific and sex-specific excess CVD mortality rates in older adults for various combinations of CVDs and influenza viruses.

RESULTS

Variations were observed in the excess mortality from CVD, ischaemic heart disease (IHD) and stroke depending on the influenza types/subtypes in different age and sex categories. The ≥85 years group had the highest excess mortality rates per 100 000 persons for CVD, IHD and stroke, while influenza A (H3N2) virus accounted for the highest mortality from CVD, IHD and stroke in people aged ≥65 years. Older men had a significantly lower influenza-associated IHD mortality rate than women, with an M/F ratio of 0.77 (p<0.05).

CONCLUSIONS

Excess mortality rates for CVDs associated with influenza increased with age in older adults. The risk for influenza-associated IHD mortality was significantly higher in older women than men. Our findings will help implement targeted health strategies, including the promotion of influenza vaccination and early therapeutic intervention for the older population with CVD, to curb the influenza burden effectively.

Greenspace and mortality in the U.K. Biobank: Longitudinal cohort analysis of socio-economic, environmental, and biomarker pathways

Exposure to natural greenspace benefits health through direct and indirect pathways: increasing physical activity, improving mental health, relieving social isolation, reducing exposure to extreme temperature, noise, and air pollution. Understanding the etiologic pathway of greenspace and health is needed. Here, we used a large cohort follow-up data from the U.K. Biobank to quantify the magnitude of behavioural factors, psychological factors, biomarkers/physiological measurements, co-morbid diseases, and environmental exposure as potential mediators in the relationship between greenspace and mortality. We estimated hazard ratios (HR) with Cox proportional hazards models, and undertook exploratory mediation analyses to quantify the relative contribution of five types of mediators. Our results indicate greenspace was strongly associated with lower mortality risks [per IQR of public greenspace (HR = 0.90 (95% CI 0.86-0.84)) and domestic gardens (HR = 0.91, (95% CI 0.88-0.94))]. The protective associations were especially pronounced among those with lower individual-level socioeconomic status or living in places with area-level deprivation. Exploratory mediation analysis detected benefits in pathways through reducing air pollution, relieving social isolation and depression, increased physical activity and time spent outdoor, better lung function (FEV1/FVC), and having higher serum vitamin D levels.

Amount of and proximity to blue spaces and general health among older Chinese adults in private and public housing: A national population study

A growing body of research indicates that exposure to outdoor blue spaces is associated with better physical and mental health. However, few studies have explored the associations between different blue space indicators (e.g., amount of and proximity to freshwater and seawater) and general health. Moreover, research has rarely attempted to address the residential selection bias associated with the salutogenic effect of access to blue spaces. Therefore, this study explores the associations between the amount (percentage of blue space within a 1 km circular buffer) of and proximity (Euclidean distance to the edge of the nearest blue space) to blue space and older adults' general health across the entire country of China using the micro-data sample of one-percent national population sample survey in 2015. It adds to the existing literature by taking into account the neighbourhood selection mechanism for different housing tenures and examining the salutogenic effect of blue spaces separately for public housing residents and private housing residents. The results indicated that greater neighbourhood seawater coverage and living near a coastline were associated with better general health among older adults in both private and public housing, while the percentage of freshwater blue spaces within neighbourhoods and the distance to freshwater blue spaces were associated with better general health among private housing residents only. The blue spaces-general health associations were stronger among urban participants, participants in deprived neighbourhoods, males, participants aged under 80 years, and low- and medium-educated participants. Our findings indicated that living near the coast was beneficial to older adults' health, and residential selection bias confounded the association between freshwater blue spaces and health.

Association of Residential Proximity to the Coast With Incident Myocardial Infarction: A Prospective Cohort Study

Background

Little is known about how the residential distance to the coast is associated with incident myocardial infarction (MI) and which mechanisms may explain the association. We aim to explore this association using data from a prospective, population-based cohort with unprecedented sample size, and broad geographical coverage.

Methods

In this study, 377,340 participants from the UK Biobank were included.

Results

It was shown that 4,059 MI occurred during a median 8.0 years follow-up. Using group (<1 km) as reference, group (20–50 km) was associated with a lower risk of MI (hazard ratio, HR 0.79, 95% CI 0.64–0.98) and a U-shaped relation between distance to the coast and MI was shown with the low-risk interval between 32 and 64 km (p_non−linear = 0.0012). Using participants of the intermediate region (32–64 km) as a reference, participants of the offshore region (<32 km) and inland region (>64 km) were both associated with a higher risk of incident MI (HR 1.12, 95% CI 1.04–1.21 and HR 1.09, 95% CI 1.01–1.18, respectively). HR for offshore region (<32 km) was larger in subgroup with low total physical activity (<24 h/week) (HR 1.24, 95% CI 1.09–1.42, p_interaction = 0.043). HR for inland region (>64 km) was larger in subgroup in urban area (HR 1.12, 95% CI 1.03–1.22, p_interaction = 0.065) and in subgroup of high nitrogen dioxide (NO₂) air pollution (HR 1.29, 95% CI 1.11–1.50, p_interaction = 0.021).

Conclusion

We found a U-shaped association between residential distance to the coast and incident MI, and the association was modified by physical activity, population density, and air pollution.

Green Space and Health in Mainland China: A Systematic Review

Non-communicable diseases (NCDs) have become a major cause of premature mortality and disabilities in China due to factors concomitant with rapid economic growth and urbanisation over three decades. Promoting green space might be a valuable strategy to help improve population health in China, as well as a range of co-benefits (e.g., increasing resilience to climate change). No systematic review has so far determined the degree of association between green space and health outcomes in China. This review was conducted to address this gap. Five electronic databases were searched using search terms on green space, health, and China. The review of 83 publications that met eligibility criteria reports associations indicative of various health benefits from more green space, including mental health, general health, healthier weight status and anthropometry, and more favorable cardiometabolic and cerebrovascular outcomes. There was insufficient evidence to draw firm conclusions on mortality, birth outcomes, and cognitive function, and findings on respiratory and infectious outcomes were inconsistent and limited. Future work needs to examine the health benefits of particular types and qualities of green spaces, as well as to take advantage of (quasi-)experimental designs to test greening interventions within the context of China's rapid urbanization and economic growth.

Green and Blue Space Availability and Self-Rated Health among Seniors in China: Evidence from a National Survey

Many empirical studies have shown evidence of multiple health benefits provided by green and blue spaces. Despite the importance of these spaces, investigations are scarce in details for blue spaces rather than green. Moreover, most research has focused on developed regions. A limited number of studies on blue spaces can be found in China with a focus on the city level. Outcomes have been mixed due to varying research scales, methodologies, and definitions. This study relies on a national-level social survey to explore how the self-rated health (SRH) of senior individuals is associated with local green and blue space availability in urban and rural areas. Results indicate that the coverage ratio of overall green spaces and waterbodies around a resident’s home have marginal effects on SRH status in both urban and rural areas. In urban areas, living close to a park can is marginally beneficial for older people’s health. Regarding different types of blue spaces, the presence of a major river (within 0.3–0.5 km) or coastline (within 1 km and 1–5 km) in the vicinity of home negatively affects SRH among the elderly in urban areas. Close proximity to lakes and other types of waterbodies with a water surface larger than 6.25 ha did not significantly influence SRH. These findings not only evaluate general health impacts of green/blue space development on senior populations across the county but inform decision makers concerning the health-promoting qualities and features of different green/blue spaces to better accommodate an aging population in the era of urbanization.

Associations of greenness with gestational diabetes mellitus: The Guangdong Registry of Congenital Heart Disease (GRCHD) study

Gestational diabetes mellitus (GDM) is associated with adverse short- and long-term health outcomes among mothers and their offspring. GDM affects 0.6%-15% of pregnancies worldwide and its incidence is increasing. However, intervention strategies are lacking for GDM. Previous studies indicated a protective association between greenspace and type 2 diabetes mellitus (T2DM), while few studies have explored the association between greenness and GDM. This study aimed to investigate the association between residential greenness and GDM among women from 40 clinical centers in Guangdong province, south China. The study population comprised 5237 pregnant mothers of fetuses and infants without birth defects, from 2004 to 2016. There were n = 157 diagnosed with GDM according to World Health Organization criteria. We estimated residential greenness using the Normalized Difference Vegetation Index (NDVI), derived from satellite imagery using a spatial-statistical model. Associations between greenness during pregnancy and GDM were assessed by confounder-adjusted random effects log-binomial regression models, with participating centers as the random effect. One interquartile increments of NDVI_250m, NDVI_500m and NDVI_1000m were associated with 13% (RR = 0.87, 95%CI: 0.87-0.87), 8% (RR = 0.92, 95%CI: 0.91-0.92) and 3% (RR = 0.97, 95%CI: 0.97-0.97) lower risks for GDM, respectively. However, NDVI_3000m was not significantly associated with GDM (RR = 0.96, 95%CI: 0.78-1.19). The risk for GDM decreased monotonically with greater NDVI. The protective effect of greenness on GDM was stronger among women with lower socioeconomic status and in environments with a lower level air pollutants. Our results suggest that greenness might provide an effective intervention to decrease GDM. Greenness and residential proximity to greenspace should be considered in community planning to improve maternal health outcomes.

The Beneficial Effects of Short-Term Exposure to Scuba Diving on Human Mental Health

Exposure to outdoor blue spaces can help improve human health by reducing stress, promoting social relationships, and physical activity. While most studies have focused on the adverse health effects of scuba diving, very few have assessed its health benefits. Moreover, when scuba diving is done in large groups with no diving instructor or pre-dive briefing, negative environmental impacts are generated and negative impacts on human health may also occur due to overcrowding, which may create stress. This is the first study to evaluate the effects of scuba diving on divers' mental health using their diving practices to estimate the impacts on the ecosystem. In the marine-protected area of Cap de Creus and adjacent areas, we assessed the mental health of 176 divers and 70 beach users (control group) by employing a 29-item version of Profile of Mood State (POMS) questionnaires. According to the parameters associated with reduced environmental impacts, two scuba diving experiences were established. Poisson regression models were performed to assess both the contribution of the activity and diving experiences to POMS scores. Both groups (scuba divers and beach goers) reduced their POMS scores after carrying out the activities. Although no significant differences were found between beach and scuba diving activities, nor between the two different scuba diving experiences, our results showed that subjects with regular medication intake due to a chronic or psychiatric illness had a POMS reduction score significantly higher than other subjects. We conclude that both beach and scuba diving activities have positive effects for human mental health, particularly among subjects with regular medication intake.

A Review of Advancement on Influencing Factors of Acne: An Emphasis on Environment Characteristics

Background: Acne vulgaris is known as a commonly-seen skin disease with a considerable impact on the quality of life. At present, there have been a growing number of epidemiological, medical, demographic and sociological researches focusing on various influencing factors in the occurrence of acne. Nevertheless, the correlation between environmental factors and acne has yet to be fully investigated. Objective: To assess the impacts of individual, natural and social environmental factors on acne and to construct a framework for the potential impact of built environment on acne. Methods: A thorough review was conducted into the published social demographical, epidemiological, and environmental studies on acne through PubMed, Google Scholar and Web of Science, with reference made to the relevant literature. Results: The influencing factors in acne are classed into four major categories. The first one includes individual socio-economic and biological factors, for example, gender, age, economic level, heredity, obesity, skin type, menstrual cycle (for females), diet, smoking, cosmetics products, electronic products, sleep quality and psychological factors. The second one includes such natural environmental factors as temperature, humidity, sun exposure, air pollution and chloracne. The third one relates to social environment, including social network and social media. The last one includes built environmental factors, for example, population density, food stores, green spaces, as well as other built environment characteristics for transport. Acne can be affected negatively by family history, overweight, obesity, oily or mixed skin, irregular menstrual cycles, sugary food, greasy food, dairy products, smoking, the improper use of cosmetics, the long-term use of electronics, the poor quality of sleep, stress, high temperature, sun exposure, air pollution, mineral oils and halogenated hydrocarbons. Apart from that, there are also potential links between built environment and acne. Conclusions: It is necessary to determine the correlation between the built environment and acne based on the understanding of the impact of traditional factors (sociology of population and environment) on acne gained by multidisciplinary research teams. Moreover, more empirical studies are required to reveal the specific relationship between built environment and acne.

Establishing associations between residential greenness and markers of adiposity among middle-aged and older Chinese adults through multilevel structural equation models

OBJECTIVES

Residential greenness may prevent overweight/obesity, but the matter has not been investigated among middle-aged and older adults in China. This study 1) assessed associations between residential greenness and markers of adiposity among middle-aged and older Chinese adults and 2) investigated physical activity, sedentary behaviours, particulate matter (PM) with a diameter of <2.5 μm (PM_2.5) concentrations, and perennial mean temperature as mediators of the associations.

METHODS

We used data from the World Health Organization's Study on Global Ageing and Adult Health (SAGE) between 2007 and 2010. Overweight/obesity and abdominal obesity were measured by body mass index and waist circumference. Exposure to neighbourhood greenness was measured by the normalized difference vegetation index (NDVI). Multilevel structural equation models were fitted to investigate the associations between neighbourhood greenness, the four potential mediators, and the prevalence of overweight/obesity and central obesity.

RESULTS

The results showed that greenness was inversely associated with the odds of overweight/obesity (odds = 0.73, 95% confidence interval (CI) 0.58-0.92) and abdominal adiposity (odds = 0.55, 95% CI 0.33-0.91). The greenness-overweight/obesity association varied significantly by sex and age, and the greenness-central obesity varied significantly by sex, age, and education. We found some indication that PM_2.5 concentrations had a suppressive effect on the greenness-adiposity associations. There was no evidence that physical activity, sedentary behaviours, and perennial mean temperature mediated the associations between neighbourhood greenness and markers of adiposity.

CONCLUSIONS

Exposure to higher levels of residential greenness was associated with lower odds of overweight/obesity and abdominal obesity among middle-aged and older Chinese adults. However, underlying mechanisms explaining these associations remain unclear requiring longitudinal studies and natural experiments.