Neighborhood greenness and burden of non-communicable diseases in Sub-Saharan Africa: A multi-country cross-sectional study

Association of greenspace with hypertension in adult: a systematic review and meta-analysis of epidemiological studies

BACKGROUND

Several studies have investigated the relationship of greenspace with blood pressure (BP) and hypertension, but the results were inconsistent. We aimed to assess the relationship of greenspace with BP/hypertension.

METHODS

We searched PubMed, Embase and Web of Science on greenspace and BP/hypertension published before 5 April 2023. The methodological quality and risk of bias were evaluated.

RESULTS

Twenty-seven articles were included. Our results suggested that higher normalized difference vegetation index (NDVI) was associated with lower odds of hypertension and levels of SBP [for every 10% increase of NDVI 500-m and NDVI 1000-m, the ORs were 0.95 (95% CI: 0.90-0.99) and 0.95 (95% CI: 0.90-0.99), the ꞵwas -1.32 (95% CI: -2.18, -0.45) and -1.41 (95% CI: -2.57, -0.25), respectively].

CONCLUSION

This study indicated that higher exposure to greenspace might be associated with lower levels of BP and risk of hypertension. Increase green spaces should be regarded as an important public health intervention..

Residential greenness and lower breast and prostate cancer incidence: Evidence from a retrospective cohort study of 977,644 participants from Israel

BACKGROUND

There is limited evidence on the associations between residential greenness and cancer incidence in longitudinal studies.

OBJECTIVES

The aim of the study was to evaluate the associations between weighted mean residential greenness exposure and cancer incidence.

METHODS

This is a registry based retrospective cohort study of 977,644 participants. The residential greenness exposure was estimated for every participant, as the weighted mean residential greenness exposure. This was based on the mean Normalized Difference Vegetation Index (NDVI) in the residential small geographic area and the duration of the residence in this area. Cancer incidence cases included consecutive newly diagnosed cases of primary cancer. Analyses were conducted for all cancer sites, lung cancer, bladder cancer, breast cancer, prostate cancer and melanoma-skin cancer. Cox regression models were used to evaluate the crude and adjusted associations (hazards ratios (HR) and its 95 % confidence intervals (CIs)) between tertiles of residential greenness and cancer incidence. Further adjusted models to nitrogen oxides (NOx) were estimated.

RESULTS

After adjustment to covariates, exposure to the highest tertile of residential greenness, compared to the lowest, were associated with lower risk for all cancer sites (HR = 0.88, 95 % CI: 0.86-0.90), breast cancer (HR = 0.85, 95 % CI: 0.80-0.89) and prostate cancer (HR = 0.85, 95 % CI: 0.79-0.91). In addition, lower risk were observed for the middle tertile of exposure and all cancer sites (HR = 0.88, 95 % CI: 0.86-0.90), breast cancer (HR = 0.88, 95 % CI: 0.84-0.92) and prostate cancer (HR = 0.83, 95 % CI: 0.79-0.89). There was no evidence for mediation by air pollution (NOx).

DISCUSSION

Residential greenness demonstrated beneficial associations with lower risk for all cancers, breast and prostate cancers. If our observations will be replicated, it may present a useful avenue for public-health intervention to reduce cancer burden through the provision of greenness exposure.

Association of greenspaces exposure with cardiometabolic risk factors: a systematic review and meta-analysis

BACKGROUND

Cardiometabolic conditions are major contributors to the global burden of disease. An emerging body of evidence has associated access to and surrounding public open spaces (POS) and greenspace with cardiometabolic risk factors, including obesity, body mass index (BMI), hypertension (HTN), blood glucose (BG), and lipid profiles. This systematic review aimed to synthesize this evidence.

METHODS

This systematic review was conducted based on the PRISMA guidelines. Four electronic databases including Web of Science, PubMed, Scopus, and Google Scholar were searched for eligible articles published until July 2023. All observational studies which assessed the association of greenspace and POS with cardiometabolic risk factors including obesity, BMI, HTN, BG, and lipid profiles were included and reviewed by two authors independently. Heterogeneity between studies was assessed using the I2 index and Cochrane's Q test. Random/fixed effect meta-analyses were used to combine the association between greenspace exposure with cardiometabolic risk factors.

RESULTS

Overall, 118 relevant articles were included in our review. The majority of the articles were conducted in North America or Europe. In qualitative synthesis, access or proximity to greenspaces or POS impacts BMI and blood pressure or HTN, BG, and lipid profiles via various mechanisms. According to the random effect meta-analysis, more access to greenspace was significantly associated with lower odds of HTN (odds ratio (OR): 0.81, 95% confidence intervals (CIs): 0.61-0.99), obesity (OR: 0.83, 95% CIs: 0.77-0.90), and diabetes (OR:0.79, 95% CI: 0.67,0.90).

CONCLUSIONS

Findings of this systematic review and meta-analysis suggested that greenspace accessibility is associated with some cardiometabolic risk factors. Improving greenspace accessibility could be considered as one of the main strategies to reduce cardiometabolic risk factors at population level.

Association between Residential Greenness and Allostatic Load: A Cohort Study

The association between residential greenness and allostatic load (AL), a marker of composite physiological burden and predictor of chronic disease, remains understudied. This study comprised 212,600 UK Biobank participants recruited over 2007 and 2010 at the baseline. Residential greenness was modeled as the normalized difference vegetation index (NDVI) from high spatial resolution (0.50 m) color infrared imagery and measured within a 0.5 km radial catchment. AL was measured as a composite index from 13 biomarkers comprising three physiological systems (metabolic, cardiovascular, and inflammatory systems) and two organ systems (liver and kidney). Multilevel mixed-effects generalized linear models with a random intercept for UK Biobank assessment centers were employed to examine the association between residential greenness and AL. Each interquartile range (IQR = 0.24) increment in NDVI greenness was associated with lower AL (beta (β) = -0.28, 95% confidence interval (CI) = -0.55, -0.01). Consistently, relative to the lowest NDVI greenness quintile, participants in the highest quintile had lower AL (β = -0.64, 95% CI = -1.02, -0.26). The proportion of the association between greenness and AL mediated by the physical activity was 3.2%. In conclusion, residential greenness was protectively associated with AL, a composite marker of wear and tear and general health.

Exposure to Neighborhood Greenness and Hypertension Incidence in Adults: A Longitudinal Cohort Study in Taiwan

BACKGROUND

There are few studies on the health effects of long-term exposure to neighborhood greenness in a longitudinal setting, especially in Asian countries with high population densities.

OBJECTIVES

This study investigates the association between long-term exposure to neighborhood greenness and hypertension among adults in Taiwan.

METHODS

We selected 125,537 participants (≥ 18  years of age) without hypertension from Taiwan who had joined the standard medical examination program between 2001 and 2016. Neighborhood greenness was estimated using the normalized difference vegetation index (NDVI), derived from satellite images at a resolution of 250   m 2 . The 2-y average NDVI value within a 500 -m circular buffer around participants' residences was calculated. A time-varying Cox regression model was used to investigate the association between neighborhood greenness and incident hypertension. Mediation analyses were performed to examine whether the association was explained by air pollution, leisure-time physical exercise, or body mass index (BMI).

RESULTS

Compared with living in areas within the first quartile of neighborhood greenness, living in areas within the second, third, and fourth quartiles of neighborhood greenness was found to be associated with a lower risk of hypertension, with hazard ratios (HRs) and 95% confidence intervals (CIs) of 0.95 (95% CI: 0.91, 1.00), 0.95 (95% CI: 0.90, 0.99), and 0.93 (95% CI: 0.88, 0.97), respectively. Each 0.1-unit increase in the NDVI was associated with a 24% lower risk of developing hypertension (HR = 0.76; 95% CI: 0.66, 0.87), with this associations being stronger among males and those with higher education levels. This association was slightly mediated by BMI but not by air pollution or leisure-time physical exercise.

DISCUSSION

Our findings suggest the protective effects of neighborhood greenness on hypertension development, especially in males and well-educated individuals. Our results reinforced the importance of neighborhood greenness for supporting health. https://doi.org/10.1289/EHP13071.

The impact of environmental conditions on non-communicable diseases in sub-Saharan Africa: A scoping review of epidemiologic evidence

Background

The burden of non-communicable diseases (NCDs) in sub-Saharan Africa (SSA) is increasing. Environmental conditions such as heavy metals and air pollution have been linked with the incidence and mortality of chronic diseases such as cancer, as well as cardiovascular and respiratory diseases. We aimed to scope the current state of evidence on the impact of environmental conditions on NCDs in SSA.

Methods

We conducted a scoping review to identify environmental conditions linked with NCDs in SSA by identifying studies published from January 1986 through February 2023. We searched African Index Medicus, Ovid Medline, Scopus, Web of Science, and Greenfile. Using the PICOS study selection criteria, we identified studies conducted in SSA focussed on physical environmental exposures and incidence, prevalence, and mortality of NCDs. We included only epidemiologic or quantitative studies.

Results

We identified 6754 articles from electronic database searches; only 36 met our inclusion criteria and were qualitatively synthesised. Two studies were conducted in multiple SSA countries, while 34 were conducted across ten countries in SSA. Air pollution (58.3%) was the most common type of environmental exposure reported, followed by exposure to dust (19.4%), meteorological variables (13.8%), heavy metals (2.7%), soil radioactivity (2.7%), and neighbourhood greenness (2.7%). The examined NCDs included respiratory diseases (69.4%), cancer (2.7%), stroke (5.5%), diabetes (2.7%), and two or more chronic diseases (19.4%). The study results suggest an association between environmental exposures and NCDs, particularly for respiratory diseases. Only seven studies found a null association between environmental conditions and chronic diseases.

Conclusions

There is a growing body of research on environmental conditions and chronic diseases in the SSA region. Although some cities in SSA have started implementing environmental monitoring and control measures, there remain high levels of environmental pollution. Investment can focus on improving environmental control measures and disease surveillance.

Green space modified the association between air pollutants and hypertension in China

Evidence regarding the combined effects of green space and air pollutants on hypertension remains limited and complex. This study aims to investigate the varying effects of greenness under different air pollution levels in China, using data from the wave 2018 China Health and Retirement Longitudinal Study (CHARLS) involving 17 468 adults (aged ≥ 45 years). As a result, the prevalence rate of hypertension was 42.04%. Logistic regression analyses revealed the positive associations between air pollution concentrations at the city level and prevalent hypertension and the negative associations between NDVI and prevalent hypertension, all of which were more prominent in the populations of the eastern and rural regions. Notably, the negative effect of green space was greater at the lowest quartiles of each air pollutant (OR for PM2.5 quartiles = 0.724, 0.792, 0.740, and 0.931)  . Improving air quality and greenness could potentially reduce hypertension risk, and minimizing air pollution might optimize the protective effects of greenness.

Does the quality of street greenspace matter? Examining the associations between multiple greenspace exposures and chronic health conditions of urban residents in a rapidly urbanising Chinese city

BACKGROUND

Numerous studies have demonstrated that greenspace(GS) exposure is associated with health improvements in individuals with hypertension and diabetes. However, studies examining the associations between multiple GS exposures and chronic health conditions in developing countries are limited.

METHODS

Geospatial data and spatial analysis were employed to objectively measure the total neighbourhood vegetative cover (mean value of normalised difference vegetation index [NDVI] within specific buffer zone) and proximity to park-based GS (network distance from home to the entrance of park-based GS). Street view imagery and machine learning techniques were used to measure the subjective perceptions of street GS quality. A multiple linear regression model was applied to examine the associations between multiple GS exposures and the prevalence of hypertension and diabetes in neighbourhoods located in Qingdao, China.

RESULTS

The model explained 29.8% and 28.2% of the prevalence of hypertension and diabetes, respectively. The results suggested that: 1) the total vegetative cover of the neighbourhood was inversely correlated with the prevalence of hypertension (β = -0.272, p = 0.013, 95% confidence interval (CI): [-1.332, -0.162]) and diabetes (β = -0.230, p = 0.037, 95% CI: [-0.720, -0.008]). 2) The street GS quality was negatively correlated with the prevalence of hypertension (β = -0.303, p = 0.007, 95% CI: [-2.981, -0.491]) and diabetes (β = -0.309, p = 0.006, 95% CI: [-1.839, -0.314]). 3) Proximity to park-based GS and the prevalence of hypertension and diabetes mellitus were not significantly correlated.

CONCLUSIONS

This study used subjective and objective methods to comprehensively assess the greenspace exposure from overhead to eye level, from quantity, proximity to quality. The results demonstrated the beneficial relationships between street GS quality, total vegetative cover, and chronic health in a rapidly urbanising Chinese city. Furthermore. the effect of street GS quality was more pronounced in potentially mitigating chronic health problems, and improving the quality of street GS might be an efficient and effective intervention pathway for addressing chronic health issues in densely populated cities.

Association between greenness and cardiovascular risk factors: Results from a large cohort study in Thailand

BACKGROUND

The risk of cardiovascular diseases may be reduced by residing in green environments. However, there are relatively few longitudinal cohort studies, especially in Southeast Asia, that focused on the health benefits of long-term greenness exposure in young adults. The present study examined the association between long-term exposure to residential greenness and self-reported morbidities in participants of the Thai Cohort Study (TCS) in Thailand from 2005 to 2013.

METHODS

The self-reported outcomes, including high blood pressure, high blood cholesterol, and diabetes, were reported in 2005, 2009, and 2013, where the study participants provided the exact year of disease occurrence. Greenness was assessed by the satellite-based Normalized Difference Vegetation Index (NDVI) and Enhanced Vegetation Index (EVI), with a spatial resolution of 250 m. Long-term exposure to NDVI and EVI of each participant's sub-district was averaged over the period of person-time. We used Cox proportional hazards models to examine the association between greenness and health outcomes. Associations with self-reported morbidity were measured using hazard ratios (HRs) per interquartile range (IQR) increase in NDVI and EVI.

RESULTS

After adjusting for potential confounders, we observed that an IQR increase in NDVI was associated with lower incidence of high blood pressure (HR = 0.92, 95% CI: 0.89, 0.97) and high blood cholesterol (HR = 0.89, 95%CI: 0.87, 0.92), but not significantly associated with diabetes (HR = 0.93, 95%CI: 0.85, 1.01). EVI was also inversely associated with self-reported high blood pressure (HR = 0.92, 95%CI: 0.88, 0.96), high blood cholesterol (HR = 0.89, 95%CI: 0.87, 0.91), and diabetes (HR = 0.92, 95%CI: 0.85, 0.99).

CONCLUSIONS

Long-term exposure to residential greenness was inversely associated with self-reported high blood pressure, high blood cholesterol, and diabetes in participants of TCS. Our study provides evidence that greenness exposure may reduce cardiovascular disease risk factors in adult population.

Residential greenness associated with decreased risk of metabolic- dysfunction-associated fatty liver disease: Evidence from a large population-based epidemiological study

BACKGROUND

Numerous studies have shown that residential greenness positively correlates with enhanced health. Metabolic dysfunction-associated fatty liver disease (MAFLD) affects about a quarter of the population while lacking specific treatments. Given that the association between green space and MAFLD is still unknown, we explored the association between residential greenness and MAFLD as well as the potential mechanisms based on the baseline survey of the China Multi-Ethnic Cohort (CMEC).

METHODS

Residential greenness was expressed as normalized difference vegetation index (NDVI) and enhanced vegetation index (EVI). MAFLD was assessed through hepatic steatosis, the presence of overweight/obesity, type 2 diabetes mellitus, and evidence of metabolic dysregulation. We used logistic regression to examine the association between NDVI/EVI and the prevalence of MAFLD. Moreover, we utilized causal mediation analyses to explore the role of physical activity and ambient particulate matters (PM₁, PM_2.5, and PM₁₀) on the association between residential greenness and MAFLD.

RESULTS

We included 72,368 participants from the CMEC and found that residential greenness was negatively associated with the prevalence of MAFLD. For an interquartile range (IQR) increase in NDVI_500 m and EVI_500 m, the odds ratio (OR) of MAFLD were 0.78 (95 %CI: 0.75, 0.81) and 0.81 (95 %CI: 0.78, 0.84), respectively. Greater association between residential greenness and MAFLD was observed among males. Air pollutants and physical activity could mediate a partial effect (8.5-22.9 %) of residential greenness on MAFLD.

CONCLUSION

Higher residential greenness was associated with decreased risk of MAFLD. Moreover, the association was greater among males. The protective effects of residential greenness may be achieved by mitigating the hazardous effects of air pollutants and encouraging physical activity.

Understanding perceptions of neighborhood health and non-communicable disease risk in urban contexts in Ghana

Global health surveillance reports show Africa's epidemiologic transition from one dominated by higher burdens of nutritional, maternal, and communicable diseases to one increasingly dominated by non-communicable diseases (NCDs). Debates on the increasing cases of NCDs in the African context have focused on individualistic risk factors to the neglect of other similar important determinants such as the living environment. Drawing on theoretical tenets of the protection motivation theory and using cross-sectional data, we examined neighborhood risk perceptions and self-rated risk of developing NCDs in Ghana. The dependent variable 'self-rated risk of developing NCDs' was measured as a binary outcome and the focal independent variable - perceived neighborhood health risk - as an index. We fitted multivariate multilevel regression models to a sample of 1376 individuals across 9 neighborhoods. Results show that respondents who perceived their neighborhoods as risky were more likely to rate their risk of developing NCDs high. A unit increase in neighborhood violence was associated with 8% likelihood of self-rated risk of developing NCDs. However, a unit increase in the aesthetic quality of respondent's neighborhood was associated with lower likelihood of self-rated risk of developing NCDs. Engaging in regular physical activity, and non-tobacco use were associated with a lower likelihood of perceived NCDs risk. We suggest policy agendas intended for reducing the burden of NCDs in Ghana and other LMICs could incorporate programs that target improving environmental characteristics to minimize risks and offer people the opportunity to make healthy choices.

Contrasting Hygiene-Related Gastrointestinal Infections and Stress-Related Diseases at a Primary Health Care Facility within a Sub-Saharan African City: Before and during the COVID-19 Pandemic

BACKGROUND

With the advent of the COVID-19 pandemic caused by SARS-CoV-2, protocols such as social distancing and upscaling of hygiene practices were implemented to limit the spread of the disease. Meanwhile, along with COVID-19 came stress due to restrictions on movement, trade and transport, and closure of schools, among others.

AIM

This study compared the prevalence of hygiene-related gastrointestinal infections and stress-related diseases before (March 2019-February 2020) and during (March 2020-February 2021) the COVID-19 pandemic.

METHODOLOGY

This was a retrospective single-center review of deidentified patient data from the Korle Bu Polyclinic, Accra, Ghana.

RESULTS

Comparing the pre-COVID-19 era to the COVID-19 era, there was a statistically nonsignificant change in the number of cases and prevalence of gastroenteritis and enteric fever (p = 0.084 and 0.081, respectively), although for gastroenteritis, the prevalence was higher for the pre-COVID-19 era compared to during COVID-19 by 1.8 per 1000 cases, while that of enteric fever was higher during the COVID-19 era compared to the pre-COVID-19 era by 1.0 per 1000 cases. Of the stress-related diseases, statistically significant increases in the prevalence of anxiety disorders (p = 0.028), insomnia (p = 0.001), and headache (p = 0.010), were noted, with 2.3, 5.5, and 2.4 per 1000 cases, respectively. There were more female cases than male cases recorded for depression (p = 0.001), headache (p = 0.010), and hypertension (p = 0.001) during the pandemic, and these were statistically significant.

CONCLUSION

During the pandemic, a significant increase in the prevalence of stress-related diseases was observed. However, a statistically nonsignificant change was recorded for gastrointestinal infections, with females reporting more of these disorders. Consequently, it is important to strengthen the capacity for managing stress-related conditions alongside diseases that cause pandemics when they arise.

Associations of residential greenness with obesity and BMI level among Chinese rural population: findings from the Henan Rural Cohort Study

In recent years, increasing evidence supports the notion that obesity risk is affected by residential greenness. However, limited studies have been established in low- and middle-income countries, especially in China. The study aimed to evaluate the associations of residential greenness with obesity and body mass index (BMI) level in Chinese rural-dwelling adults. A total of 39,259 adults from the Henan Rural Cohort Study (HRCS) were included in the analyses. According to the guideline for prevention and control of overweight and obesity in Chinese adults, obesity was defined as BMI ≥ 28 kg/m². Residential greenness was measured by satellite-based normalized difference vegetation index (NDVI) and enhanced vegetation index (EVI). Generalized linear mixed models were used to study the associations between exposure to residential greenness with obesity and BMI level. Higher residential greenness was significantly correlated with lower odds of obesity and BMI level. For example, in the full-adjusted analyses, an interquartile range (IQR) increase in EVI_500-m was linked with reduced odds of obesity (OR = 0.77, 95%CI 0.72-0.82) and BMI level (β =  - 0.41 kg/m², 95%CI - 0.48 to - 0.33 kg/m²). Mediation analyses showed air pollution and physical activity could be potential mediators in these associations. Besides, we found that the association of NDVI_500-m with BMI was stronger in females and low-income populations. Higher residential greenness was associated with a lower prevalence of obesity and BMI level, particularly among females and the low-income population. These relationships were partially mediated by reducing air pollution and increasing physical activity.

"Residential greenness and site-specific cancer: A registry based cohort of 144,427 participants with a 21-years of follow-up, Tel-Aviv district, Israel"

BACKGROUND

Few longitudinal studies evaluated the beneficial associations between cumulative residential greenness and site-specific cancer. Our objective was to evaluate the associations between cumulative residential greenness exposure and site-specific cancer incidence (lung, bladder, breast, prostate, and skin cancer) within a registry-based cohort study.

METHODS

This study was based on 144,427 participants who lived in the Tel Aviv district during 1995-2015. The residential greenness exposure was estimated for every participant, as the weighted mean residential greenness exposure, based on the mean Normalized Difference Vegetation Index (NDVI) in the residential area and the duration of the residence in this area. Cox regression models were used to evaluate the unadjusted and adjusted associations between exposure to greenness and cancer incidence during 1998-2015 (Hazard Ratios (HRs) and 95% Confidence Intervals (CIs)). Covariates included in adjusted models were selected based on prior knowledge and directed acyclic graphs. We imputed missing data and further sensitivity analyses were conducted.

RESULTS

After adjustments, beneficial associations between exposure to greenness and cancer incidence were observed. An interquartile range (IQR) increase in NDVI was associated with a lower HRs for lung cancer (HR_adj. = 0.75 95% CI: 0.66-0.85), bladder cancer (HR_adj. = 0.71, 95% CI: 0.62-0.82), breast cancer (HR_adj. = 0.81, 95% CI: 0.74-0.88), prostate cancer (HR_adj. = 0.77, 95% CI: 0.70-0.86) and skin cancer (HR_adj. = 0.78, 95% CI: 0.69-0.88). Generally, the patterns of associations were consistent between complete-case models and imputed models, when estimated for participants aged 16 years or 40 years and older at baseline, when stratified by area level socioeconomic status, when evaluated for non-movers participants and after further adjustment to social determinants of health.

CONCLUSION

Residential greenness may reduce the risk for lung, bladder, breast, prostate, and skin cancers. If our observations will be replicated, it may present a useful avenue for public-health intervention to reduce cancer burden.

Is residential greenness associated with dyslipidemia and lipid levels in Chinese rural-dwelling adults? The Henan rural cohort study

Scarce epidemiologic research examined the associations between residential greenness and dyslipidemia or lipid levels in low/middle-income countries. Baseline statistics (2015-2017) of 39,259 rural-dwelling adults were obtained from a Chinese longitudinal study. The blood lipid level was measured utilizing an enzymatic assay method. According to the 2016 Chinese guidelines on dyslipidemia (revision), patients with dyslipidemia were defined. Participants' exposure to residential greenness was characterized by the satellite-based normalized difference vegetation index (NDVI). Mixed effects logistic regression and mixed effects linear regression were performed to assess the associations of residential greenness with dyslipidemia and lipid levels. The median (interquartile range, IQR) of 3-year average NDVI_1000-m was 0.521 (0.089) units. Each IQR increase in NDVI_1000-m was significantly linked with increased odds of hyperbetalipoproteinemia (OR = 1.33, 95%CI 1.21-1.46). The same increment in NDVI_1000-m was associated with lower total cholesterol (TC) levels and increased low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C) levels. For instance, the %changes in HDL-C levels was 0.71% (95%CI 0.17%-1.26%). The above relationships were partially mediated by reducing air pollution and lowering body mass index (BMI). Interaction effect analysis observed the greenness-lipid association was stronger in males than females (i.e., NDVI_1000-m-TC association). Long-term exposure to residential greenness was associated with odds of dyslipidemia and lipid levels in Chinese rural-dwelling adults, particularly among males. Considering the cross-sectional study design, more longitudinal studies are needed to identify the causal associations.

Associations between residential greenness and self-reported heart disease in Sri Lankan men: A cross-sectional study

Cardiovascular diseases (CVDs) are major contributors to morbidity and mortality in lower-middle-income countries (LMICs). Features of the natural environment, such as greenness, are a potential, modifiable determinant of CVD, yet there is a lack of evidence, particularly in LMICs. Our study investigated associations between residential greenness, measured using the Normalized Difference Vegetation Index (NDVI), and self-reported heart disease in 5268 Sri Lankan men aged 34 to 55 years. Multivariable logistic regression models were fitted to examine associations between mean NDVI within 100 m, 400 m, 800 m, 1600 m, and 2000 m of the residential address, adjusting for age, marital status, income, education, alcohol consumption, smoking and road length. Fully adjusted models showed that a 0.1 increase in mean NDVI was associated with lower odds of heart disease when using the 400 m (OR: 0.80; 95% CI: 0.64, 1.00), 800 m (OR: 0.85; 95% CI: 0.63, 1.14), and 2000 m (OR: 0.74; 95% CI: 0.48, 1.13) buffers. Further research in different contexts, and with improved outcome measures, is needed to confirm relationships between residential greenness and heart disease in rural areas and in LMICs.