Relationship of Neighborhood Greenness to Alzheimer's Disease and Non-Alzheimer's Dementia Among 249,405 U.S. Medicare Beneficiaries.

BACKGROUND: Neighborhood greenness (vegetative presence) has been linked to multiple health outcomes, but its relationship to Alzheimer's disease (AD) and non-Alzheimer's (non-AD) dementia has been less studied. OBJECTIVE: This study examines the relationship of greenness to both AD and non-AD dementia in a population-based sample of Medicare beneficiaries. METHODS: Participants were 249,405 US Medicare beneficiaries aged > 65 years living in Miami-Dade County, FL, from 2010 to 2011. Multi-level analyses examined the relationship of greenness, assessed by mean Census block level Normalized Difference Vegetation Index (NDVI), to odds of each of AD, Alzheimer's disease and related dementias (ADRD), and non-AD dementia, respectively. Covariates included age, gender, race/ethnicity, number of comorbid health conditions, and neighborhood income. RESULTS: Higher greenness was associated with reduced risk of AD, ADRD, and non-AD dementia, respectively, adjusting for individual and neighborhood sociodemographics. Compared to the lowest greenness tertile, the highest greenness tertile was associated with reduced odds of AD by 20%(odds ratio, 0.80; 95%CI, 0.75-0.85), ADRD by 18%(odds ratio, 0.82; 95%CI, 0.77-0.86), and non-AD dementia by 11%(odds ratio, 0.89; 95%CI, 0.82-0.96). After further adjusting for number of comorbidities, compared to the lowest greenness tertile, the highest greenness tertile was associated with reduced odds of AD (OR, 0.94; 95%CI, 0.88-1.00) and ADRD (OR, 0.93; 95%CI, 0.88-0.99), but not non-AD dementia (OR, 1.01; 95%CI, 0.93-1.08). CONCLUSION: High neighborhood greenness may be associated with lower odds of AD and ADRD. Environmental improvements, such as increasing neighborhood vegetation, may be a strategy to reduce risk for AD and possibly other dementias.

Neighbourhood greenness and depression among older adults.

BACKGROUND: Neighbourhood greenness or vegetative presence has been associated with indicators of health and well-being, but its relationship to depression in older adults has been less studied. Understanding the role of environmental factors in depression may inform and complement traditional depression interventions, including both prevention and treatment.AimsThis study examines the relationship between neighbourhood greenness and depression diagnoses among older adults in Miami-Dade County, Florida, USA. METHOD: Analyses examined 249 405 beneficiaries enrolled in Medicare, a USA federal health insurance programme for older adults. Participants were 65 years and older, living in the same Miami location across 2 years (2010-2011). Multilevel analyses assessed the relationship between neighbourhood greenness, assessed by average block-level normalised difference vegetative index via satellite imagery, and depression diagnosis using USA Medicare claims data. Covariates were individual age, gender, race/ethnicity, number of comorbid health conditions and neighbourhood median household income. RESULTS: Over 9% of beneficiaries had a depression diagnosis. Higher levels of greenness were associated with lower odds of depression, even after adjusting for demographics and health comorbidities. When compared with individuals residing in the lowest tertile of greenness, individuals from the middle tertile (medium greenness) had 8% lower odds of depression (odds ratio 0.92; 95% CI 0.88, 0.96; P = 0.0004) and those from the high tertile (high greenness) had 16% lower odds of depression (odds ratio 0.84; 95% CI 0.79, 0.88; P < 0.0001). CONCLUSIONS: Higher levels of greenness may reduce depression odds among older adults. Increasing greenery - even to moderate levels - may enhance individual-level approaches to promoting wellness.Declaration of interestNone.

Relationship of Neighborhood Greenness to Heart Disease in 249 405 US Medicare Beneficiaries.

Background Nature exposures may be associated with reduced risk of heart disease. The present study examines the relationship between objective measures of neighborhood greenness (vegetative presence) and 4 heart disease diagnoses (acute myocardial infarction, ischemic heart disease, heart failure, and atrial fibrillation) in a population-based sample of Medicare beneficiaries. Methods and Results The sample included 249 405 Medicare beneficiaries aged 65 years and older whose location ( ZIP +4) in Miami-Dade County, Florida, did not change from 2010 to 2011. Analyses examined relationships between greenness, measured by mean block-level normalized difference vegetation index from satellite imagery, and 4 heart disease diagnoses. Hierarchical regression analyses, in a multilevel framework, assessed the relationship of greenness to each heart disease diagnosis, adjusting successively for individual sociodemographics, neighborhood income, and biological risk factors (diabetes mellitus, hypertension, and hyperlipidemia). Higher greenness was associated with reduced heart disease risk, adjusting for individual sociodemographics and neighborhood income. Compared with the lowest tertile of greenness, the highest tertile of greenness was associated with reduced odds of acute myocardial infarction by 25% (odds ratio, 0.75; 95% CI , 0.63-0.90), ischemic heart disease by 20% (odds ratio, 0.80; 95% CI , 0.77-0.83), heart failure by 16% (odds ratio, 0.84; 95% CI , 0.80-0.88), and atrial fibrillation by 6% (odds ratio, 0.94; 95% CI , 0.87-1.00). Associations were attenuated after adjusting for biological risk factors, suggesting that cardiometabolic risk factors may partly mediate the greenness to heart disease relationships. Conclusions Neighborhood greenness may be associated with reduced heart disease risk. Strategies to increase area greenness may be a future means of reducing heart disease at the population level.

Health Disparities in the Relationship of Neighborhood Greenness to Mental Health Outcomes in 249,405 U.S. Medicare Beneficiaries.

Prior studies suggest that exposure to the natural environment may be important for optimal mental health. The present study examines the association between block-level greenness (vegetative presence) and mental health outcomes, in a population-based sample of 249,405 U.S. Medicare beneficiaries aged ≥65 years living in Miami-Dade County, Florida, USA, whose location did not change from 2010 to 2011. Multilevel analyses examined relationships between greenness, as measured by mean Normalized Difference Vegetation Index from satellite imagery at the Census block level, and each of two mental health outcomes; Alzheimer's disease and depression, respectively, after statistically adjusting for age, gender, race/ethnicity, and neighborhood income level of the individuals. Higher block-level greenness was linked to better mental health outcomes: There was a reduced risk of Alzheimer's disease (by 18%) and depression (by 28%) for beneficiaries living in blocks that were 1 SD above the mean for greenness, as compared to blocks that were 1 SD below the mean. Planned post-hoc analyses revealed that higher levels of greenness were associated with even greater mental health benefits in low-income neighborhoods: An increase in greenness from 1 SD below to 1 SD above the mean was associated with 37% lower odds of depression in low-income neighborhoods, compared to 27% and 21% lower odds of depression in medium- and high-income neighborhoods, respectively. Greenness may be effective in promoting mental health in older adults, particularly in low-income neighborhoods, possibly as a result of the increased opportunities for physical activity, social interaction, or stress mitigation.

Neighborhood Greenness and Chronic Health Conditions in Medicare Beneficiaries.

INTRODUCTION: Prior studies suggest that exposure to the natural environment may impact health. The present study examines the association between objective measures of block-level greenness (vegetative presence) and chronic medical conditions, including cardiometabolic conditions, in a large population-based sample of Medicare beneficiaries in Miami-Dade County, Florida. METHODS: The sample included 249,405 Medicare beneficiaries aged ≥65 years whose location (ZIP+4) within Miami-Dade County, Florida, did not change, from 2010 to 2011. Data were obtained in 2013 and multilevel analyses conducted in 2014 to examine relationships between greenness, measured by mean Normalized Difference Vegetation Index from satellite imagery at the Census block level, and chronic health conditions in 2011, adjusting for neighborhood median household income, individual age, gender, race, and ethnicity. RESULTS: Higher greenness was significantly associated with better health, adjusting for covariates: An increase in mean block-level Normalized Difference Vegetation Index from 1 SD less to 1 SD more than the mean was associated with 49 fewer chronic conditions per 1,000 individuals, which is approximately similar to a reduction in age of the overall study population by 3 years. This same level of increase in mean Normalized Difference Vegetation Index was associated with a reduced risk of diabetes by 14%, hypertension by 13%, and hyperlipidemia by 10%. Planned post-hoc analyses revealed stronger and more consistently positive relationships between greenness and health in lower- than higher-income neighborhoods. CONCLUSIONS: Greenness or vegetative presence may be effective in promoting health in older populations, particularly in poor neighborhoods, possibly due to increased time outdoors, physical activity, or stress mitigation.