Effects of residential greenness on clinical outcomes of patients with chronic kidney disease: a large-scale observation study

Association of greenness exposure with serum vitamin D status and effects of ambient particulate matter among pregnant women in early pregnancy

Adequate vitamin D is essential for the health of both the mother and fetus, and it can be influenced by environmental factors. However, research on the associations between greenness exposure and vitamin D concentrations during pregnancy is limited. This retrospective birth cohort study, conducted from 2014 to 2018, assessed the greenness of residences using the satellite-derived normalised difference vegetation index (NDVI). Serum 25-hydroxyvitamin D [25(OH)D] concentrations were categorised as non-deficient (≥50 nmol/L) or deficient (<50 nmol/L). Multiple log-binomial regression models were used to estimate the association of NDVI with serum 25(OH)D concentrations and vitamin D deficiency (VDD). Subgroup and mediation analyses were conducted to estimate the association of ambient particulate matter (PM) on the association between NDVI and VDD. A total of 64,663 pregnant women with a mean maternal age of 30.6 (standard deviation: 3.86) years were included. 250-m NDVI was negatively associated with the risk of VDD (per 0.1-unit increase, relative risk [RR]: 0.98, 95 % CI: 0.97-0.99). With the highest quartile of NDVI exposure as the reference group, the upper-middle quartile (RR: 1.02, 95 % CI: 1.00-1.03), and lowest quartile (RR: 1.03, 95 % CI: 1.01-1.06) had an increased risk of VDD. At higher PM2.5 exposure concentrations, 250-m NDVI exposure was negatively associated with the risk of VDD (RR: 0.98, 95 %CI: 0.97-0.99, per 0.1-unit increase), but not at lower PM2.5 exposure concentrations. Among pregnant women with higher PM2.5, the mediation of PM2.5 exposure on the association between 250-m NDVI and VDD was 44.70 % (P = 0.0116). Among pregnant women with higher PM10 exposure, the mediation of PM10 exposure on the association between 250-m NDVI and VDD was 17.98 % (P = 0.002). These findings suggest that higher residential greenery significantly reduces the risk of VDD in pregnant women, particularly in those exposed to increased PM concentrations.

Built environment and chronic kidney disease: current state and future directions

PURPOSE OF REVIEW

Despite emerging studies on neighborhood-level risk factors for chronic kidney disease (CKD), our understanding of the causal links between neighborhood characteristics and CKD is limited. In particular, there is a gap in identifying modifiable neighborhood factors, such as the built environment, in preventing CKD, that could be targets for feasible place-based interventions.

RECENT FINDINGS

Most published studies on neighborhood factors and CKD have focused on a single social attribute, such as neighborhood disadvantage, while research on the role of the built environment is more nascent. Early studies on this topic have yielded inconsistent results, particularly regarding whether food deserts are an environmental risk factor for CKD onset. International studies have shown that walkable neighborhoods - characterized by features such as urban design, park access, and green spaces - can be protective against both the onset and progression of CKD. However, these findings are inconclusive and understudied in the context of United States, where neighborhood environments differ from those in other countries.

SUMMARY

Future research on modifiable neighborhood factors and CKD using advanced study designs and population-representative datasets can yield stronger evidence on potential causal associations and suggest feasible place-based interventions as strategies for preventing CKD. As an example, we demonstrated the potential of electronic health record-based studies to advance research in this area.

The general external exposome and the development or progression of chronic kidney disease: A systematic review and meta-analyses

The impact of environmental risk factors on chronic kidney disease (CKD) remains unclear. This systematic review aims to provide an overview of the literature on the association between the general external exposome and CKD development or progression. We searched MEDLINE and EMBASE for case-control or cohort studies, that investigated the association of the general external exposome with a change in eGFR or albuminuria, diagnosis or progression of CKD, or CKD-related mortality. The risk of bias of included studies was assessed using the Newcastle-Ottawa Scale. Summary effect estimates were calculated using random-effects meta-analyses. Most of the 66 included studies focused on air pollution (n = 33), e.g. particulate matter (PM) and nitric oxides (NOx), and heavy metals (n = 21) e.g. lead and cadmium. Few studies investigated chemicals (n = 7) or built environmental factors (n = 5). No articles on other environment factors such as noise, food supply, or urbanization were found. PM2.5 exposure was associated with an increased CKD and end-stage kidney disease incidence, but not with CKD-related mortality. There was mixed evidence regarding the association of NO2 and PM10 on CKD incidence. Exposure to heavy metals might be associated with an increased risk of adverse kidney outcomes, however, evidence was inconsistent. Studies on effects of chemicals or built environment on kidney outcomes were inconclusive. In conclusion, prolonged exposure to PM2.5 is associated with an increased risk of CKD incidence and progression to kidney failure. Current studies predominantly investigate the exposure to air pollution and heavy metals, whereas chemicals and the built environment remains understudied. Substantial heterogeneity and mixed evidence were found across studies. Therefore, long-term high-quality studies are needed to elucidate the impact of exposure to chemicals or other (built) environmental factors and CKD.

Greenness and kidney? A review of epidemiological studies on the association between green space and kidney disease

Recent accumulating epidemiological evidence underlines the important role of environmental exposures on kidney diseases. Among environmental exposures, this study addresses "Green space," which has been recognized as one of the major environmental exposures at the population level. We review a total of seven epidemiological studies currently published on greenness and kidney disease. We also discuss knowledge gaps in the epidemiological evidence in relation to study design, greenness exposure index, emerging kidney outcomes, and inequalities. With an increase in public attention regarding environmental risks and climate change, an improved understanding of the beneficial effects of green space can play an important role in promoting kidney health.

Relations of residential green and blue spaces with new-onset chronic kidney disease

OBJECTIVE

We investigated the associations of residential green and blue spaces with chronic kidney disease (CKD) incidence, which have rarely been examined.

METHODS

A total of 346,697 participants from UK Biobank without CKD at baseline were included. Land coverage percentages of residential green and blue spaces at 300 m and 1000 m buffer were estimated using land use data. The primary outcome was new-onset CKD ascertained through linkage to health administrative datasets.

RESULTS

During a median follow-up of 12.0 years, 10,101 new-onset CKD were documented. Overall, there were significant inverse associations of residential green space coverage at 300 m (per SD [21.7 %] increment, HR,0.96, 95%CI, 0.94-0.98) and 1000 m (per SD [20.7 %] increment, HR, 0.96, 95%CI, 0.94-0.98) buffer, and blue space at 300 m (per SD [1.1 %] increment, HR, 0.97, 95%CI, 0.95-1.00) and 1000 m (per SD [1.2 %] increment, HR, 0.97, 95%CI, 0.95-1.00) buffer with the risk of new-onset CKD. Moreover, at 300 m buffer, a significantly lower risk of new-onset CKD (HRs ranging from 0.88 to 0.90) was found in participants with both higher green space and higher blue space (both of them in the 2nd or 3rd tertile, and at least one in the 3rd tertile). At 1000 m buffer, a significantly lower risk of new-onset CKD (HRs ranging from 0.79 to 0.89) was found in participants with either higher green space or higher blue space (either one in the 2nd or 3rd tertile). Furthermore, PM2.5 did not significantly modify the association of exposure to green and blue space with the risk of CKD (all P for interactions >0.05).

CONCLUSIONS

Residential green and blue spaces, especially at larger buffer sizes, might be protective factors against new-onset CKD.

Residential greenness and kidney function: A cohort study of Thai employees

Higher residential greenness is associated with a lower risk of chronic kidney disease, but evidence on the association between greenness exposure and kidney function has not been conducted. Using cohort data from Electricity Generating Authority of Thailand (EGAT) employees, we investigated the association between long-term exposure to greenness and kidney function using estimated glomerular filtration rate (eGFR) in Bangkok Metropolitan Region (BMR), Thailand. We analyzed data from 2022 EGAT workers (aged 25-55 years at baseline) from 2009 to 2019. The level of greenness was calculated using the satellite-derived Enhanced Vegetation Index (EVI) and Normalized Difference Vegetation Index (NDVI). From 2008 to 2019, the average concentration of each air pollutant (PM₁₀, O₃, NO₂, SO₂, and CO) at the sub-district level in BMR was generated using the Kriging method. Long-term exposure for each participant was defined as the 1-year average concentrations before the date of the physical examination in 2009, 2014, and 2019. We employed linear mixed effects models to evaluate associations of NDVI and EVI with eGFR. The robustness of the results was also tested by including air pollutants in the models. After relevant confounders were controlled, the interquartile range increase in NDVI was associated with higher eGFR [1.03% (95%CI: 0.33, 1.74)]. After PM₁₀ and SO₂ were included in the models, the associations between NDVI and eGFR became weaker. The additions of O₃, NO₂, and CO strengthened the associations between them. In contrast, we did not find any association between EVI and eGFR. In conclusion, there was a positive association between NDVI and eGFR, but not for EVI. Air pollutants had a significant impact on the relationship between NDVI and eGFR. Additional research is needed to duplicate this result in various settings and populations to confirm our findings.

Associations between greenness and kidney disease in Massachusetts: The US Medicare longitudinal cohort study

BACKGROUND

Recent studies have identified the association of environmental stressors with reduced kidney function and the development of kidney disease. While residential greenness has been linked to many health benefits, the association between residential greenness and the development of kidney disease is not clear. We aimed to investigate the association between residential greenness and the development of kidney disease.

METHODS

We performed a longitudinal population-based cohort study including all fee-for-service Medicare Part A beneficiaries (aged 65 years or older) in Massachusetts (2000-2016). We assessed greenness with the annual average Enhanced Vegetation Index (EVI) based on residential ZIP codes of beneficiaries. We applied Cox-equivalent Poisson models to estimate the association between EVI and first hospital admission for total kidney disease, chronic kidney disease (CKD), and acute kidney injury (AKI), separately.

RESULTS

Data for 1,462,949 beneficiaries who resided in a total of 644 ZIP codes were analyzed. The total person-years of follow-up for total kidney disease, CKD, and AKI were 9.8, 10.9, and 10.8 million person-years, respectively. For a 0.1 increase in annual EVI, the hazard ratios (HRs) were 0.95 (95% CI: 0.93 to 0.97) for the first hospital admission for total kidney disease, and the association was more prominent for AKI (HR: 0.94 with 95% CI: 0.92 to 0.97) than CKD (HR: 0.98 with 95% CI: 0.95-1.01]). The estimated effects of EVI on kidney disease were generally more evident in White beneficiaries and those residing in metropolitan areas compared to the overall population.

CONCLUSIONS

This study found that higher levels of annual residential greenness were associated with a lower risk of the first hospital admission for kidney diseases. Results are consistent with the hypothesis that higher residential greenness benefits kidney patients.

Assessing the effects of ultraviolet radiation, residential greenness and air pollution on vitamin D levels: A longitudinal cohort study in China

Vitamin D metabolism is essential in aging and can be affected by multiple environmental factors. However, most studies conducted single exposure analyses. We aim to assess the individual and combined effects of ultraviolet (UV) radiation, residential greenness, fine particulate matter (PM_2.5), and ozone (O₃) on vitamin D levels in a national cohort study of older adults in China. We used the 2012 and 2014 Chinese Longitudinal Healthy Longevity Survey data, and measured the environmental exposure in the same year. We interpolated the UV radiation from monitoring stations, measured residential greenness through satellite-derived Normalized Difference Vegetation Index (NDVI), modeled PM_2.5 with satellite data, and estimated O₃ using machine learning. We dichotomized serum 25-hydroxy vitamin D (25(OH)D), the primary circulating form of vitamin D, into non-deficiency (≥50 nmol/L) and deficiency (<50 nmol/L) categories. We used the generalized estimating equation for analysis, adjusted for sociodemographic information, lifestyle, physical condition, and season of blood draw, and calculated joint odds ratios based on the Cumulative Risk Index. We also explored the interaction between interested exposures, modification of participants' characteristics, and potential mediation. We included 1,336 participants, with a mean age of 83 at baseline. In single exposure models, the odds ratios of vitamin D deficiency (VDD) for per interquartile range increase in UV radiation, NDVI, PM_2.5, and O₃ and decrease were 0.39 (95 % CI:0.33,0.46), 0.90 (0.81,1.00), 1.65 (1.53,1.78), 1.67 (1.46,1.92), respectively. UV radiation mediated nearly 48 % and 78 % of the relationship between VDD and PM_2.5 and O₃, respectively. The association between UV radiation and VDD was stronger in females than men (OR: 2.25 vs 1.22). UV radiation, residential greenness can protect against VDD, while, PM_2.5 and O₃ increase the risk of VDD. UV radiation partly mediated the association between air pollution and VDD.

Multiple pathways and mediation effects of built environment on kidney disease rate via mitigation of atmospheric threats

Air pollution and high temperatures can increase kidney disease rate, especially under climate change. A well-designed urban environment has mediating effects on atmospheric environmental threats and promoting human health, but previous studies have overlooked these effects. This study used partial least squares modeling and urban-scale data from Taiwan to identify the crucial effects (i.e., direct, indirect, and total effects) and pathways of urban form (i.e., urban development intensity, land-use mix, and urban sprawl), urban greening (i.e., green coverage), urban industrial status (e.g., industrial level), atmospheric environment (i.e., high temperature and air pollution), and socioeconomic status (i.e., elderly ratio, medical resources, and economic status) on kidney disease rate. Maximizing land-use mix and green coverage and minimizing urban development intensity, urban sprawl, and industrial levels could help reduce kidney disease rate. Air pollution and high temperature had a mediation effect of built environment on kidney disease rate; with the mediation effect of air pollution was greater than that of high temperature. Furthermore, air pollution, high temperature, and elderly ratio increased kidney disease rate, whereas medical resources decreased kidney disease rate. This study is the first to consider the impact (i.e., direct, indirect, and total effects) and pathways of built environment characteristics on kidney disease rate. The findings revealed that an appropriate urban policy might be a practical strategy and lower kidney disease rate for a healthy city development. Moreover, this study provides a new approach for clarifying complex relationships and identifying crucial factors.