The associations between residential greenness and allergic diseases in Chinese toddlers: A birth cohort study

Effects of residential greenness during pregnancy on childhood asthma, rhinitis, eczema, and their comorbidity: findings from the French mother-child cohort Pélagie

Maternal exposure to residential greenness during pregnancy may influence childhood respiratory and allergic diseases development. Yet, evidence is limited and results are not consistent, furthermore most studies focus on urban areas. In a predominantly rural population, we aimed to assess the effect of maternal residential greenness during pregnancy on childhood asthma, rhinitis, eczema, and their comorbidity. We analyzed data from 1325 to 1119 participants in the 6- and 12-year follow-ups of the Pélagie mother-child cohort in Brittany, France. Ever asthma, rhinitis, and eczema were defined using validated questionnaires, and a multimorbidity phenotype was constructed. Greenness was assessed using the Normalized Difference Vegetation Index (NDVI) within a 300m buffer around the residential address. Adjusted logistic regressions per 0.1-unit increase in NDVI were performed, further stratifying by urban and rural areas. At inclusion, 78 % of mothers were non-smokers, 64 % lived in rural areas, and their average age was 30 ± 4 years; 50 % of children were boys. Median NDVI differed significantly between urban (0.45) and rural (0.57) areas (p=<0.0001). Asthma, rhinitis, and eczema prevalence were respectively around 10 %, 20 %, and 20 % at both follow-ups. Overall, the NDVI within 300m did not show significant associations at either follow-up, across the whole study population, except for eczema (0.87 (0.76-1.00), p=0.05), and the single-disease category of the multimorbidity phenotype (0.87, (0.76-0.99), p=0.03) at 6 years, where it showed protective associations. Our findings highlight the need for further research, particularly in rural populations, to clarify the relationship between prenatal residential greenness and childhood health outcomes.

Association between long-term green space exposure and dry eye in China

PURPOSE

To evaluate the association between green space exposure and dry eye.

DESIGN

Part I: case-control study. Part II: cross-sectional study.

METHODS

Part I: The study contained 450 patients with dry eye and 900 controls recruited from Electronic Health Records. Logistic regression analysis was employed to investigate the relationship between green space exposure and the occurrence of dry eye. Part II: This study included 140 diabetic participants recruited from the community registry in Guangzhou, China. Linear regression analysis was used to assess the association between green space exposure and quantitative measures of the tear meniscus.

RESULTS

Part I: A total of 1,350 individuals were included in the study. On average individuals aged 31.07 ± 4.58 years and 59.33% were female. Higher 10-year green space exposure was significantly associated with lower odds of dry eye (OR = 0.96; 95% confidence interval [CI], 0.94, 0.97; P < 0.001) after adjusting for age, sex, rainfall, temperature, particulate matter, and other factors. Part II: A total of 140 diabetic patients were included in the study. On average individuals aged 64.48 ± 8.19 years and 53.57% were female. Greater 10-year green space exposure was associated with a higher tear meniscus area (β = 0.07, 95% CI, 0.02, 0.11; p = 0.007) after adjusting for age, sex, rainfall, temperature, particulate matter, and other factors.

CONCLUSIONS

Our findings suggest an association between green space exposure and diagnosis of dry eye and tear meniscus, offering novel insights into the strategies for preventing dry eye.

U-shaped association between residential greenness and keratoconus

Keratoconus is a blinding corneal disorder influenced by genetic factors. Whether environmental factors influence it remains unclear. Here, we observed a U-shaped association between residential greenness and keratoconus, with increased odds ratios (ORs) at low and high greenness levels. In the Chinese Environment-Ocular Surface (EOS) study, a case-control study of 4341 keratoconus and 3723 controls, the multivariate-adjusted ORs [95% confidence intervals (CIs)] of keratoconus associated with the lowest quartile and the highest quartile of residential greenness were 1.33 (1.23, 1.55) and 1.54 (1.37, 1.72) compared with the intermediate quartile, respectively. In spline analysis, the U-shaped association was consistently indicated, with the lowest odds of keratoconus at the 300 m buffer normalized difference vegetation index (NDVI) of 0.42. Specifically, the association was more pronounced for male, younger (<24 years), and urban-dwelling participants. Urban residents tend to benefit from increased greenness, whereas others may experience adverse effects due to hazards associated with high levels of residential greenness. The association was further validated in a prospective cohort of 502,367 participants from the United Kingdom Biobank (UKB). The results showed that participants with the first quartile residential greenness were 1.8 times (1.12, 2.91) more likely to develop keratoconus than those with intermediate greenness. The results suggested a U-shaped association between residential greenness and keratoconus; both low and high levels of residential greenness were associated with higher odds of keratoconus.

Pollen as a mediator between environmental greenness during pregnancy and infancy periods and childhood persistent asthma: A nationwide retrospective birth cohort study in Japan

The association between environmental greenness and childhood asthma remains unclear. Pollen has been proposed as a potential mechanism of detrimental associations. This study aimed to elucidate the mechanisms underlying the association between environmental greenness during the pre-, peri-, and postnatal periods and childhood persistent asthma. A nationwide retrospective birth cohort study was conducted using data from the Japan Medical Data Center (JMDC). Child-mother dyads between January 2010 and January 2017 were identified, and four subcohorts were developed based on the timing of exposure to the highest greenness season. The exposure of interest was environmental greenness levels between June and September, quantified using the normalized difference vegetation index (NDVI). The primary outcome was persistent asthma in children aged 4-5 years. Causal mediation analysis was conducted to evaluate pollen as a mediator between NDVI and asthma. In these analyses, linear and modified Poisson regression models were used to evaluate the association of NDVI with pollen levels and childhood persistent asthma. The analyses were stratified by metropolitan and non-metropolitan areas. Clinically meaningful confounders and predictors of asthma were adjusted in the statistical models. A total of 100,273 child-mother dyads were included in the entire cohort, with 24.1% of the children having persistent asthma at the ages of 4-5 years. Higher environmental greenness was associated with higher pollen levels. The modified Poisson regression models showed higher environmental greenness was associated with a slightly higher risk of persistent childhood asthma. In metropolitan areas, significant detrimental natural direct effects of NDVI were observed; however, the natural indirect effects were uncertain. A large part of the association between environmental greenness and childhood persistent asthma in metropolitan areas was attributed to mechanisms other than those involving pollen. The associations in non-metropolitan areas remain uncertain. Further studies are required to elucidate the underlying mechanisms.

Green space quantity and exposure in relation to the risk of immune-mediated diseases: a scoping review

The growing global incidence of immune-mediated and inflammatory diseases (IMIDs) is worrisome, with evidence suggesting that environmental factors, notably urbanization and the reduction of green spaces, may act as potential instigators. However, conflicting findings in studies necessitate a closer examination of recent research (January 2020 - February 2024) to elucidate the factors contributing to these inconsistencies. This review explores study protocols to avoid erroneously endorsing the null hypothesis of no association between green space coverage and IMID risks. A literature search adhering to PRISMA-ScR guidelines yielded 46 relevant papers from Google Scolar and Pub Meb. The studies varied in design, with 17 being longitudinal, 24 cross-sectional, and five focusing on longitudinal parent-offspring connections. Geographic scope differed, with 21 multi-location and 25 single-location studies. Participant numbers ranged from 144 to 982,131 across diverse demographics. Additionally, some studies examined disease frequencies in large groups (several million people) residing in specific regions. Green space metrics encompassed NDVI, land cover data, plant biodiversity, and novel indexes, measured within 7.5-5000 m diameter buffers around residences or schools. The review advises against making definitive statements regarding the relationship between urban green spaces and the prevalence of IMIDs. It suggests that inconsistencies in study results may stem from variations in study designs and methodologies, as well as the complex, interacting mechanisms through which green spaces affect immune health. Future research recommendations include larger cohorts, early-life exposure data, and testing specific hypotheses related to vegetation types and participants' genetic predispositions.

Association of residential greenness with incident allergic rhinitis among adults: A prospective analysis of UK Biobank

BACKGROUND

Limited studies have assessed the impact of residential greenness exposure on allergic rhinitis in adults, and its relationship with ambient air pollutants remains unknown.

OBJECTIVE

To investigate the association of residential greenness with allergic rhinitis incidence and explore the mediation effects of ambient air pollutants in adults using data from a prospective cohort study in UK Biobank.

METHODS

Greenness was defined as the area-weighted mean of greenness coverage based on the land used data from the Generalized Land Use Database for England (GLUD) 2005 in the UK Biobank. Multiple Cox proportional hazard models and a generalized additive model incorporating restricted cubic splines were used to model the potential nonlinear effect of residential greenness on allergic rhinitis incidence and the potential mediation effect of ambient air pollutants.

RESULTS

Among the 281,699 subjects included in the analysis, 3260 allergic rhinitis incident cases occurred after a median follow-up of 14 years. With per 10% increase in residential greenness at a 300-m buffer, a 2.5% (95% CI: 1.0%, 4.0%) decreased risk of allergic rhinitis was observed. An L-shaped, non-linear dose-response relationship was indicated with a threshold of 54.9% greenness above which no excess allergic rhinitis risk was seen. PM10 partially mediated the relationship between greenness and allergic rhinitis incidence with a mediation effect of 26.9% (95% CI: 12.6%, 41.2%). A similar pattern of association was found at 1000-m buffer size.

CONCLUSION

This study demonstrates a significant beneficial effect of residential greenness on reducing allergic rhinitis incidence. Greenness may erase air pollutants and mitigate the rhinitis risk from air pollution.

Residential greenness during pregnancy and early life and development of asthma up to 27 years of age: The Espoo Cohort Study

Previous studies have suggested that living close to green spaces has protective health effects, but potential effects on asthma are contradictory. We investigated the association between the amount of greenness in the residential area during pregnancy and early life and development of asthma in the first 27 years of life. The study population included all 2568 members of the Espoo Cohort Study, Finland. We calculated individual-level exposure to green space measured as cumulative Normalized Difference Vegetation Index (cumNDVI in unit-months) within 300 m of the participant's residence during pregnancy and the first two years of life in both spring and summer seasons. The onset of asthma was assessed using information from the baseline and follow-up surveys. Exposure to residential greenness in the spring season during pregnancy was associated with an increased risk of asthma up to 6 years of age, with an adjusted hazard ratio (aHR) of 3.72 (95% confidence interval (CI): 1.11, 12.47) per 1 unit increase in cumNDVI. Increased greenness in the summer during pregnancy associated with asthma up to 6 years, with an aHR of 1.41 (95% CI: 0.85, 2.32). The effect was found to be related to increased greenness particularly during the third trimester of pregnancy, with an aHR of 2.37 (95% CI: 1.36, 4.14) per 1 unit increase of cumNDVI. These associations were weaker at the ages of 12 and 27 years. No association was found between NDVI in the first two years of life and the development of asthma. Our findings provide novel evidence that exposure to greenness during pregnancy increases the risk of developing asthma. The adverse effects were strongest for the prenatal greenness in the spring season and in the third trimester of pregnancy. Both the season and trimester of exposure to greenness are critical in the development of asthma.

Different greenness exposure in Europe and respiratory outcomes in youths. A systematic review and meta-analysis

The existing evidence on the association between greenness and respiratory outcomes remains inconclusive. We aimed at systematically summarizing existing literature on greenness exposure and respiratory outcomes in European children and adolescents, with a preliminary attempt to qualify the distribution of dominant tree species across different geographical areas and bioclimatic regions. Overall, 4049 studies were firstly identified by searching PubMed/MEDLINE, EMBASE, Scopus, Web of Science, GreenFile and CAB direct, up to 29 August 2023. Eighteen primary studies were included in the systematic review and six were meta-analyzed. No overall significant association was observed between the Normalized Difference Vegetation Index, assessed within 500-m buffers (i.e. NDVI-500), and the odds of asthma for 0.3-increase in the exposure (OR: 0.97, 95% CI from 0.53 to 1.78). Similarly, an overall exposure to the NDVI-300 highest tertile, as compared to the lowest tertile, was not significantly associated with asthma (OR: 0.65, 95% CI from 0.22 to 1.91): heterogeneity among studies was significant (p = 0.021). We delineated some key elements that might have mostly contributed to the lack of scientific consensus on this topic, starting from the urgent need of harmonized approaches for the operational definition of greenness. Additionally, the complex interplay between greenness and respiratory health may vary across different geographical regions and climatic conditions. At last, the inconsistent findings may reflect the heterogeneity and complexity of this relationship, rather than a lack of scientific consensus itself. Future research should compare geographical areas with similar bioclimatic parameters and dominant or potentially present vegetation species, in order to achieve a higher inter-study comparability.

Greenness and chronic respiratory health issues: a systematic review and meta-analysis

Introduction

The number of chronic respiratory disease (CRD) individuals worldwide has been continuously increasing. Numerous studies have shown that greenness can improve chronic respiratory health issues through different mechanisms, with inconsistent evidence. By quantitatively summarizing existing studies, our purpose is to determine the connection between greenness exposure and various chronic respiratory health.

Methods

We conducted a comprehensive search on PubMed, EMBASE, and Web of Science core databases to identify relevant studies on the correlation between greenness exposure and chronic respiratory health issues. Studies published up to January 2023 were included in the search. The study used the most frequent indicator (normalized difference vegetation index [NDVI]) as the definition of greenness exposure.

Results

We finally identified 35 studies for meta-analysis. We calculated pooled effects across studies using a random-effects model and conducted a subgroup analysis by age and buffer zones to discuss the effects on chronic respiratory health issues. This study showed that 0.1 increments in NDVI were significantly related to lower rates of asthma incidence, lung cancer incidence, and chronic obstructive pulmonary disease (COPD) mortality risk; the pooled RRs were 0.92 (95% CI: 0.85-0.98), 0.62 (95% CI: 0.40-0.95), and 0.95 (95% CI: 0.92- 0.99), respectively. For the age subgroup, the higher greenness exposure level was related to the incidence rate of asthma among teenagers aged 13-18years (RR: 0.91; 95% CI: 0.83-0.99). For the buffer subgroup, a positive relationship with greenness exposure and asthma incidence/prevalence at 200-300m and 800- 1000m buffers, as well as the COPD mortality at 800-1000m buffer, the pooled RRs were 0.92 (95% CI: 0.86-0.98), 0.87 (95% CI: 0.81-0.93), and 0.93 (95% CI: 0.88- 0.98), respectively. Evidence of publication bias was not detected in this study.

Discussion

Our study is the first global meta-analysis between greenness and various CRDs to report an inverse association. Further research is needed in order to determine the effect of greenness exposure on different CRDs. Therefore, when planning for green development, more consideration must be given to public health and green management as intervention measures.

https://www.crd.york.ac.uk/PROSPEROFILES/384029_STRATEGY_20230116.pdf.

Impact of the exposome on food allergy development

PURPOSE OF REVIEW

The increasing global prevalence of food allergy indicates that environmental exposures are likely contributing to food allergy development. This review summarizes recent studies on how specific factors within the external exposome may impact the development of food allergy.

RECENT FINDINGS

There is strong evidence that nonoral exposure to food allergens within the living environment is a risk factor for food sensitization and food allergy. The role of air pollution in food allergy development remains unclear, as cohort studies have not found consistent relationships between air pollutant exposure and food sensitization. Early-life microbial exposures linked to a rural lifestyle are likely protective against food allergy development, possibly through alteration of the infant microbiome. In contrast, factors associated with urbanization and decreased exposure to microbes may contribute to food allergy development. Recent studies on the role of residential greenness in food allergy development suggest either no relationship or a possible increased risk for food allergy.

SUMMARY

The external exposome comprises a number of exposures that can modify food allergy risk. Improved understanding of how complex environmental exposures interact with genetic factors will be necessary for developing effective interventions aimed at preventing food allergy development in children.

The effect of greenness on allergic rhinitis outcomes in children and adolescents: A systematic review and meta-analysis

BACKGROUND

The relationship between greenness and health emerges as new public health concern. More published studies from multiple areas have explored the relationship between greenness and allergic rhinitis (AR) in children and adolescents. This study aims to determine the association between greenness and allergic rhinitis by systematic review and meta-analysis, in order to provide a more comprehensive assessment of the impact of greenness on AR in children and adolescents.

METHODS

The relative literature was systematically searched in PubMed, Embase, and Web of science lastly on September 25, 2022. Terms related to greenness and allergic rhinitis were used for searching. Summary effect estimates of greenness on AR in children and adolescents were calculated for per 10 % increase of greenness exposure with different buffer sizes by random-effects model.

RESULTS

A total of 579 studies were screened, and fourteen studies from Europe, Asia and North America were finally included. Most greenness exposure were measured by normalized difference vegetation index (NDVI). Enhanced vegetation index, outdoor-green environmental score and existed to measuring different greenness types. Greenness surrounding residences and schools were assessed. The overall effect of greenness on primary outcome was 1.00 (95%CI = 0.99-1.00). Most effect estimates of greenness were included in the NDVI-500 m group, and the pooled OR was 0.99 (95%CI = 0.97-1.01). No significant pooled estimates were found in analyses with study locations.

CONCLUSION

This study indicates no significant association between greenness exposure and AR in children and adolescents. Various exposure measures and conversion of data may affect the results of this meta-analysis. More precise assessment of personal greenness exposure in well-designed prospective studies are vital for drawing a definite association in future. Furthermore, greenness exposure surrounding schools should be paid considerable attention for its effect on AR in school-aged children and adolescents.

Association between exposure to greenness and atopic march in children and adults-A systematic review and meta-analysis

Introduction

Allergic diseases are a global public health problem. Food allergy, atopic dermatitis (AD), allergic rhinoconjunctivitis, allergic rhinitis (AR) and asthma represent the natural course of allergic diseases, also known as the "atopic march". In recent years, a large number of studies have been published on the association between greenness exposure and allergic diseases. However, systematic reviews on the association between greenness exposure and multiple allergic diseases or atopic march are lacking.

Methods

In this study, PubMed, EMBASE, ISI Web of Science, and Scopus were systematically searched. Meta-analyses were performed if at least three studies reported risk estimates for the same outcome and exposure measures.

Results

Of 2355 records, 48 studies were included for qualitative review. Five birth cohort studies, five cross-sectional studies, and one case-control study were included for asthma meta-analysis, respectively. Four birth cohort studies were included for AR meta-analysis. Our results support that exposure to a greener environment at birth reduces the risk of asthma and AR in childhood. In addition, higher greenness exposure was associated with decreased odds of current asthma in children.

Discussion

There was a large heterogeneity among the included studies and most of them did not specify the vegetation type and causative allergens. Therefore the study results need to be further validated. In addition, a small number of studies evaluated the association between greenness and food allergy, AD and allergic rhinoconjunctivitis. More research is needed to strengthen our understanding of the association between greenness and allergic diseases.