Air pollution, greenness and risk of overweight among middle-aged and older adults: A cohort study in China

The association of residential greenness and ambient particulate matter with hearing impairment in Chinese middle-aged and elderly adults: a nationwide cohort study

OBJECTIVE

To examine the association of residential greening and atmospheric particulate matter (PM2.5, PM10) with the risk of hearing impairment in Chinese middle-aged and elderly adults.

METHODS

Data from the China Health and Retirement Longitudinal Study (2011 to 2018 wave) were used. The degree of greening of residential areas were quantified using the Normalized Difference Vegetation Index (NDVI) from the Moderate Resolution Imaging Spectroradiometer (MODIS). PM concentrations were obtained from the CHAP dataset. Hearing impairment was self-reported by the participants. Cox proportional hazards models were used to assess the risk of hearing impairment associated with exposure to residential green spaces and PM. Additionally, the study investigated the potential modifying and mediating role between residential greenery, PM exposure and hearing impairment.

RESULTS

A total of 13,585 participants aged 61.84 years (Standard deviation: 9.17) were included in this study. Over a span of 7 years, 2,527 cases of hearing impairment were reported, with an incidence rate of 18.6%. A higher degree of residential greenness was inversely associated with the risk of hearing impairment, showing a HR of 0.688 (95%CI: 0.659-0.719) for every 0.1 unit increment in NDVI. In contrast, a 10 µg/m3 elevation in PM2.5 and PM10 concentration was linked to a 67.6% (HR: 1.676; 95%CI: 1.625-1.729) and 30.4% (HR: 1.304; 95%CI: 1.284-1.324) increased risk of hearing impairment, respectively. The harmful effects of PM2.5 and PM10 were attenuated with higher levels of residential greenness. Furthermore, the mediation analysis revealed that PM2.5 and PM10 played a significant mediating role in the association between residential greenery exposure and hearing impairment, with mediation proportions of 47.91% for PM2.5 and 52.83% for PM10.

CONCLUSIONS

High residential greenness was associated with a reduced risk of hearing impairment, whereas exposure to PM2.5 and PM10 may increase the risk of hearing impairment. Additionally, residential greenness may modify the relationship between PM exposure and hearing impairment by reducing exposure to PM2.5 and PM10.

Greenness, air pollution, and mortality risk: a retrospective cohort study of patients with lung cancer in China

The association between long-term exposure to air pollution and mortality from lung cancer has been established, yet evaluations of the potential mitigating effects of greenness on this impact are scarce. We conducted a cohort study in Pingyi County. A two-level Cox proportional hazards regression model was used to examine the associations among long-term exposure to air pollution, residential greenness, and lung cancer mortality. Among the examined pollutants, nitrogen dioxide exhibited the most significant adverse effects and highest risk of lung cancer mortality, with hazard ratio (HR) = 2.783 (95% confidence interval [CI]: 1.885-4.107) for all-cause mortality, HR = 2.492 (95%CI: 1.659-3.741) for tumour-related mortality, and HR = 2.431 (95%CI: 1.606-3.678) for lung cancer mortality. Higher greenness values were associated with a reduced risk of lung cancer mortality. These findings suggest the importance of implementing strategies for increasing greenness to reduce the health impacts of air pollution.

Environmental mixtures and body mass index in two prospective US-based cohorts of female nurses

We estimated the joint effect of particulate matter ≤ 2.5 µm in diameter (PM2.5), nitrogen dioxide (NO2), seasonal temperature, noise, greenness, light at night, and neighborhood socioeconomic status (NSES) on body mass index (BMI) in a mixture context among 194,966 participants from the Nurses' Health Study (NHS) and Nurses' Health Study II (NHSII) over 30 years. BMI was calculated from self-reported weight and height. Single- and multi-exposure generalized estimating equations models were used to estimate the difference in BMI per interquartile range (IQR) increase of environmental factors, and quantile g-computation methods were used to estimate joint associations. In both cohorts, we consistently observed positive associations of BMI with PM2.5 and NO2 concentrations as well as negative associations with light at night and NSES regardless modeling approach. A positive association with noise was only observed in NHS. Negative associations with greenness and winter temperature were only observed in NHSII. Overall, the changes in BMI per quintile increase in all eight exposures were -0.11 (-0.13, -0.08) in NHS and -0.39 (-0.41, -0.37) in NHSII, which were largely driven by air pollution and nighttime noise (18-45 %) in the positive direction and NSES (>70 %) in the negative direction. Future intervention on environmental factors, especially reducing PM2.5, NO2 and noise or improving the NSES, might be helpful to lower BMI.

Transition of cooking fuels and obesity risk in Chinese adults

BACKGROUND

Since 1990 s, China has witnessed a widespread transition to clean cooking fuels, presenting an opportunity to investigate whether household fuel transition could mitigate obesity risk and reconcile inconsistencies in the literature regarding the association between cooking fuels and obesity.

METHODS

The China Health and Nutrition Survey (CHNS) is a prospective cohort study covering 12 provinces of China (1989-2015). Participants were classified into persistent cleaner fuel users, fuel transitioners, and persistent polluting fuel users according to self-reported primary cooking fuels. Obesity and central obesity were defined as BMI ≥ 28.0 kg/m2 and waist circumference ≥ 90 cm in men and ≥ 85 cm in women according to Chinese criteria.

FINDINGS

Among 13,032 participants, 3657 (28.06 %) were persistent cleaner fuel users; 5264 (40.39 %) transitioned from using polluting fuels to cleaner fuels after the baseline survey; and 4111 (31.55 %) were persistent polluting fuel users. During the period of follow-up of 9.0 ± 6.8 years, 1248 (9.58 %) participants were classified into the obesity category, and 4703 (36.09 %) into the central obesity category. Persistent polluting fuel users had a significantly higher risk of developing obesity (hazard ratio [HR]: 1.45, 95 %CI: 1.22-1.72) and central obesity (HR: 1.32, 95 %CI: 1.21-1.44), compared to persistent cleaner fuel users. Persistent polluting fuel use was positively associated with developing obesity in women (HR: 1.64, 95 %CI: 1.30-2.06), but not in men. Subgroup analyses showed higher HR of persistent polluting fuel use among individuals aged 18-44 years (HR: 2.04, 95 %CI: 1.62-2.56). In contrast, the transitioners did not exhibit a significantly different risk of developing obesity (HR: 0.94, 95 %CI: 0.80-1.10) compared to persistent cleaner fuel users, which was consistent across different sex, age and urbanicity. Similar trends were observed for developing central obesity.

INTERPRETATION

Persistent polluting fuel use increased obesity risk while the obesity risk of the transition to cleaner fuels was similar to persistent use of cleaner fuels. The finding underscores the significance of advocating for the adoption of cleaner fuels as a strategy to mitigate the disease burden associated with obesity.

Association of ambient ozone exposure and greenness exposure with hemorrhagic stroke mortality at different times: A cohort study in Shandong Province, China

Evidence on the association between long-term ozone exposure and greenness exposure and hemorrhagic stroke (HS) is limited, with mixed results. One potential source of this inconsistency is the difference in exposure time metrics. This study aimed to investigate the association between long-term exposure to ambient ozone, greenness, and mortality from HS using exposure metrics at different times. We also examined whether greenness exposure modified the relationship between ozone exposure and mortality due to HS. The study population consisted of 45771 participants aged ≥40 y residing in 20 counties in Shandong Province who were followed up from 2013 to 2019. Ozone exposure metrics (annual mean and warm season) and the normalized difference a measure of greenness exposure, were calculated. The relationship between environmental exposures (ozone and greenness exposures) and mortality from HS was assessed using time-dependent Cox proportional hazards models, and the modification of greenness exposure was examined using stratified analysis with interaction terms. The person-years at the end of follow-up were 90,663. With full adjustments, the risk of death from hemorrhagic stroke increased by 5% per interquartile range increase in warm season ozone [hazard ratio =1.05; 95 % confidence interval: 1.01-1.08]. No clear association was observed between annual ozone and mortality HS. Both the annual and summer NDVI were found to reduce the risk of HS mortality. The relationships were influenced by age, sex, and residence (urban or rural). Furthermore, greenness exposure was shown to have a modifying effect on the relationship between ozone exposure and the occurrence of HS mortality (P for interaction = 0.001). Long-term exposure to warm season O3 was positively associated with HS mortality, while greenness exposure was inversely associated with HS mortality. Greenness exposure may mitigate the negative effects of warm season ozone exposure on HS mortality.

Air pollution exposure and cardiometabolic risk

The Global Burden of Disease assessment estimates that 20% of global type 2 diabetes cases are related to chronic exposure to particulate matter (PM) with a diameter of 2·5 μm or less (PM2·5). With 99% of the global population residing in areas where air pollution levels are above current WHO air quality guidelines, and increasing concern in regard to the common drivers of air pollution and climate change, there is a compelling need to understand the connection between air pollution and cardiometabolic disease, and pathways to address this preventable risk factor. This Review provides an up to date summary of the epidemiological evidence and mechanistic underpinnings linking air pollution with cardiometabolic risk. We also outline approaches to improve awareness, and discuss personal-level, community, governmental, and policy interventions to help mitigate the growing global public health risk of air pollution exposure.

Residential greenspace counteracts PM2.5 on the risks of preterm birth subtypes: A multicenter study

BACKGROUND

The association between residential greenspace and preterm birth (PTB) risk remained inconclusive. The PTB subtypes have been ignored and the effect of co-exposure of PM2.5 on PTB risk is still unclear.

OBJECTIVE

To investigate the independent, interactive, and mixed effects of residential greenspace and PM2.5 on the risk of PTB subtypes.

METHODS

A total of 19,900 singleton births from 20 hospitals in Shanghai, China, from 2015 to 2017 were included. The Normalized Difference Vegetation Index (NDVI) within 500 m and 1000 m buffers of the maternal residence and a combined geoscience-statistical model-derived PM2.5 and its six components were used as the exposure measures. PTB (<37 completed weeks of gestation) were divided into early PTB (24-33 weeks) vs. late PTB (34-36 weeks) and into spontaneous PTB (sPTB), preterm premature rupture of the fetal membranes (PPROM), and iatrogenic PTB. Multivariable logistic regression models were applied to assess the independent and interactive effects of NDVI and PM2.5 on PTB in each trimester. The quantile g-computation approach was employed to explore the mixture effect of PM2.5 components and greenspace across the pregnancy and to determine the main contributors.

RESULTS

Levels of PM2.5 and greenspace were associated with increased [aOR (95%CI) ranging from 1.18 (1.07, 1.30) to 3.36 (2.45, 4.64)] and decreased risks [aORs (95%CI) ranging from 0.64 (0.53, 0.78) to 0.86 (0.73, 0.99)] of PTB subtypes, respectively. At the same PM2.5 level, higher residential greenspace was associated with lower risks, and vice versa. All these associations were more pronounced in late pregnancy. Early PTB and PPROM were the main affected subtypes, and the main drivers in PM2.5 were black carbon and ammonium.

CONCLUSIONS

Residential greenspace may mitigate the PTB risks due to PM2.5 exposure during pregnancy.

The combined effects of exposure to multiple PM2.5 components on overweight and obesity in middle-aged and older adults: a nationwide cohort study from 125 cities in China

The prevalence of overweight or obesity increased rapidly over the past decades in most countries, including China. However, little evidence exists about the effects of long-term exposure to PM2.5 components on overweight or obesity, particularly in developing countries. We measured different weight stages according to body mass index (BMI), and investigated the effects of exposure to PM2.5 components (ammonium [[Formula: see text]], sulfate [[Formula: see text]], nitrate [[Formula: see text]], black carbon and organic matter) on different BMI levels in middle-aged and elderly people of China. Our study explored the effects of single and multiple air pollution exposures on overweight and obesity by using the Generalized Linear Model and Quantile g-Computation model (QgC). This study found a significantly positive association between five PM2.5 components and overweight/obesity. In the QgC model, there was still a positive association between multiple exposure to PM2.5 components and overweight when all PM2.5 components were considered as a whole. In addition, males, the elderly, and urban residents were also more sensitive to five PM2.5 components.

Associations of residential greenness and ambient air pollution with overweight and obesity in older adults

OBJECTIVE

This study aimed to examine the impact of greenness and fine particulate matter <2.5 μm (PM2.5 ) on overweight/obesity among older adults in China.

METHODS

A total of 21,355 participants aged ≥65 years were included from the Chinese Longitudinal Healthy Longevity Survey between 2000 and 2018. Normalized difference vegetation index (NDVI) with a radius of 250 m and PM2.5 in a 1 × 1-km grid resolution were calculated around each participant's residence. Cox proportional hazards models were used to estimate the effects of NDVI and PM2.5 on overweight/obesity. Interaction and mediation analyses were conducted to explore combined effects.

RESULTS

The study observed 1895 incident cases of overweight/obesity over 109,566 person-years. For every 0.1-unit increase in NDVI the hazard ratio of overweight/obesity was 0.91 (95% CI: 0.88-0.95), and for every 10-μg/m3 increase in PM2.5 the hazard ratio was 1.11 (95% CI: 1.07-1.14). The effect of NDVI on overweight/obesity was partially mediated by PM2.5 , with a relative mediation proportion of 20.10% (95% CI: 1.63%-38.57%).

CONCLUSIONS

Greenness exposure appears to lower the risk of overweight/obesity in older adults in China, whereas PM2.5 , acting as a mediator, partly mediated this protective effect.

Spatial analysis of overweight prevalence in China: exploring the association with air pollution

BACKGROUND

Overweight is a known risk factor for various chronic diseases and poses a significant threat to middle-aged and elderly adults. Previous studies have reported a strong association between overweight and air pollution. However, the spatial relationship between the two remains unclear due to the confounding effects of spatial heterogeneity.

METHODS

We gathered height and weight data from the 2015 China Health and Retirement Long-term Survey (CHARLS), comprising 16,171 middle-aged and elderly individuals. We also collected regional air pollution data. We then analyzed the spatial pattern of overweight prevalence using Moran's I and Getis-Ord Gi* statistics. To quantify the explanatory power of distinct air pollutants for spatial differences in overweight prevalence across Southern and Northern China, as well as across different age groups, we utilized Geodetector's q-statistic.

RESULTS

The average prevalence of overweight among middle-aged and elderly individuals in each city was 67.27% and 57.39%, respectively. In general, the q-statistic in southern China was higher than that in northern China. In the north, the prevalence was significantly higher at 54.86% compared to the prevalence of 38.75% in the south. SO2 exhibited a relatively higher q-statistic in middle-aged individuals in both the north and south, while for the elderly in the south, NO2 was the most crucial factor (q = 0.24, p < 0.01). Moreover, fine particulate matter (PM2.5 and PM10) also demonstrated an important effect on overweight. Furthermore, we found that the pairwise interaction between various risk factors improved the explanatory power of the prevalence of overweight, with different effects for different age groups and regions. In northern China, the strongest interaction was found between NO2 and SO2 (q = 0.55) for middle-aged individuals and PM2.5 and SO2 (q = 0.27) for the elderly. Conversely, in southern China, middle-aged individuals demonstrated the strongest interaction between SO2 and PM10 (q = 0.60), while the elderly showed the highest interaction between NO2 and O3 (q = 0.42).

CONCLUSION

Significant spatial heterogeneity was observed in the effects of air pollution on overweight. Specifically, air pollution in southern China was found to have a greater impact on overweight than that in northern China. And, the impact of air pollution on middle-aged individuals was more pronounced than on the elderly, with distinct pollutants demonstrating significant variation in their impact. Moreover, we found that SO2 had a greater impact on overweight prevalence among middle-aged individuals, while NO2 had a greater impact on the elderly. Additionally, we identified significant statistically interactions between O3 and other pollutants.

Effects of green space on physical activity and body weight status among Chinese adults: a systematic review

Background

Green space may provide many benefits to residents' health behaviors and body weight status, but the evidence is still relatively scattered among Chinese adults. The purpose of this study was to review the scientific evidence on the effects of green space on physical activity (PA) and body weight status among Chinese adults.

Methods

A keyword and reference search was conducted in Pubmed, Web of Science, MEDLINE, and PsycINFO. Studies examining the associations between green space and PA, body mass index (BMI) among Chinese adults were included. The quality of the included literature was evaluated using the National Institutes of Health's Observational Cohort and Cross-Sectional Study Quality Assessment Tool.

Results

A total of 31 studies were included that met the inclusion criteria, including 25 studies with a cross-sectional design, 3 studies with a longitudinal design, and 3 studies with an experimental design. Street-level green view index and green space accessibility were found to be positively associated with PA, but negatively associated with BMI. In most studies, there was a correlation between green space ratio in local areas and BMI. In addition, green space interventions were effective in increasing PA and decreasing BMI among Chinese adults. In contrast, further evidence is needed to support the association between the design characteristics of green space and PA and BMI.

Conclusion

Preliminary evidence suggests that green space has a positive effect on PA and BMI among Chinese adults. However, there are contradictory findings, and future studies adopting longitudinal and quasi-experimental studies are needed to further explore the causal relationship between green space and PA and BMI to provide a relevant theoretical basis for policymakers.

Link between obesity and atopic dermatitis: Does obesity predispose to atopic dermatitis, or vice versa?

Two serious health conditions, obesity and atopic dermatitis (AD), share some pathological features such as insulin resistance, leptin resistance and inflammation, and a growing body of evidence suggests a link between obesity and AD. Obesity predisposes an individual to and/or worsens AD, whereas AD increases the risk of obesity. Obesity and AD's interactions are mediated by cytokines, chemokines and immune cells. Obese individuals with AD are more resistant to anti-inflammatory therapy, while weight loss can alleviate AD. In this review, we summarize the evidence linking AD and obesity. We also discuss the pathogenic role of obesity in AD, and vice versa. Because of the connection between these two conditions, mitigation of one could possibly prevent the development of or alleviate the other condition. Effective management of AD and weight loss can enhance the wellness of individuals with both of these conditions. However, proper clinical studies are warranted to validate this speculation.

Green space, air pollution and gestational diabetes mellitus: A retrospective cohort study in central China

Emerging evidence suggests residential surrounding green space is beneficial for human health. The association between green space and GDM showed inconsistent results, and potential effect modification of green space with air pollution is still unclear. This study aims to evaluate the association between green space and GDM, and further explore potential interaction and medication effects. Participants were recruited from a retrospective cohort study between 2015 and 2020 in Henan, China. Residential green space based on normalized difference vegetation index (NDVI) and air pollution exposure were estimated using spatial-statistical models. Multivariate logistic regression was applied to evaluate the association between per 0.1 unit increase in NDVI with 4 buffer sizes (250 m, 500 m, 1000 m, 2000 m) and GDM. We examined potential interaction of green space and air pollutants on GDM. Mediating effects of air pollution associated with green space exposure on GDM were also investigated by causal mediation analyses. A total of 46,665 eligible pregnant women were identified. There were 4092 (8.8 %) women diagnosed with GDM according to the IADPSG criteria. We found that per 0.1-unit increment in NDVI250 m, NDVI500 m, NDVI1000 m and NDVI2000 m in second trimester were associated with the decreased risk of GDM, with adjusted OR of 0.921(95 %CI: 0.890-0.953), 0.922 (95 %CI: 0.891-0.953), 0.921 (95 %CI: 0.892-0.952) and 0.921 (95 %CI: 0.892-0.951), respectively. We identified significant interactions between second trimester PM2.5 and O3 exposure and NDVI for GDM (Pinteraction < 0.001). The causal mediation analysis showed that PM2.5 mediated approximately 2.5-5.5 % of the association between green space and GDM, while the estimated mediating effect of O3 was approximately 30.1-38.5 %. In conclusion, our study indicates that residential green space was associated with a reduced risk of GDM, particularly second trimester. Green space may benefit to GDM partly mediated by a reduction in PM2.5 and O3.