Shortcomings of the normalized difference vegetation index as an exposure metric.

The health benefits of exposure to trees and plants is a rapidly expanding field of study. Research has shown that exposure is associated with improvements in a wide range of health outcomes including cardiovascular disease, birth outcomes, respiratory disease, cancer, mental health and all-cause mortality1. One of the challenges that these studies face is characterizing participants' exposure to trees and plants. A common approach is to use the normalized difference vegetation index, a greenness index typically derived from satellite imagery. Reliance on the normalized difference vegetation index is understandable; for decades, the imagery required to calculate the normalized difference vegetation index has been available for the entire Earth's surface and is updated at regular intervals. However, the normalized difference vegetation index may do a poor job of fully characterizing the human experience of being exposed to trees and plants, because scenes with the same normalized difference vegetation index value can appear different to the human eye. We demonstrate this phenomenon by identifying sites in Portland, Oregon that have the same normalized difference vegetation index value as a large, culturally significant elm tree. These sites are strikingly different aesthetically, suggesting that use of the normalized difference vegetation index may lead to exposure misclassification. Where possible, the normalized difference vegetation index should be supplemented with other exposure metrics.

Using high-resolution residential greenspace measures in an urban environment to assess risks of allergy outcomes in children.

Despite reported health benefits of urban greenspace (gs), the epidemiological evidence is less clear for allergic disease. To address a limitation of previous research, we examined the associations of medium- and high-resolution residential gs measures and tree and/or grass canopies with allergic outcomes for children enrolled in the longitudinal cincinnati childhood allergy and air pollution study (ccaaps). We estimated residential gs based on 400 m radial buffers around participant addresses (n = 478) using the normalized differential vegetation index (ndvi) and land cover-derived urban greenspace (ugs) (tree and grass coverage, combined and separate) at 30 m and 1.5-2.5 m resolution, respectively. Associations between outdoor aeroallergen sensitization and allergic rhinitis at age 7 and residential gs measures at different exposure windows were examined using multivariable logistic regression models. A 10% increase in ugs-derived grass coverage was associated with an increased risk of sensitization to grass pollens (adjusted odds ratio [aor]: 1.27; 95% confidence interval = 1.02-1.58). For each 10% increase in ugs-derived tree canopy coverage, nonstatistically significant decreased odds were found for grass pollen sensitization, tree pollen sensitization, and sensitization to either (aor range = 0.87-0.94). Results similar in magnitude to ugs-tree canopy coverage were detected for ndvi and allergic sensitizations. High-resolution (down to 1.5 m) gs measures of grass- and tree-covered areas showed associations in opposite directions for different allergy outcomes. These data suggest that measures strongly correlated with tree canopy (e.g., ndvi) may be insufficient to detect health effects associated with proximity to different types of vegetation or help elucidate mechanisms related to specific gs exposure pathways.

Interventions to Prevent Falls in Older Adults: Updated Evidence Report and Systematic Review for the US Preventive Services Task Force.

Importance: Falls are the most common cause of injury-related morbidity and mortality among older adults. Objective: To systematically review literature on the effectiveness and harms of fall prevention interventions in community-dwelling older adults to inform the US Preventive Services Task Force. Data Sources: MEDLINE, PubMed, Cumulative Index for Nursing and Allied Health Literature, and Cochrane Central Register of Controlled Trials for relevant English-language literature published through August 2016, with ongoing surveillance through February 7, 2018. Study Selection: Randomized clinical trials of interventions to prevent falls in community-dwelling adults 65 years and older. Data Extraction and Synthesis: Independent critical appraisal and data abstraction by 2 reviewers. Random-effects meta-analyses using the method of DerSimonian and Laird. Main Outcomes and Measures: Number of falls (number of unexpected events in which a person comes to rest on the ground, floor, or lower level), people experiencing 1 or more falls, injurious falls, people experiencing injurious falls, fractures, people experiencing fractures, mortality, hospitalizations, institutionalizations, changes in disability, and treatment harms. Results: Sixty-two randomized clinical trials (N = 35 058) examining 7 fall prevention intervention types were identified. This article focused on the 3 most commonly studied intervention types: multifactorial (customized interventions based on initial comprehensive individualized falls risk assessment) (26 trials [n = 15 506]), exercise (21 trials [n = 7297]), and vitamin D supplementation (7 trials [n = 7531]). Multifactorial intervention trials were associated with a reduction in falls (incidence rate ratio [IRR], 0.79 [95% CI, 0.68-0.91]) but were not associated with a reduction in other fall-related morbidity and mortality outcomes. Exercise trials were associated with statistically significant reductions in people experiencing a fall (relative risk, 0.89 [95% 13 CI, 0.81-0.97]) and injurious falls (IRR, 0.81 [95% CI, 0.73-0.90]) and with a statistically nonsignificant reduction in falls (IRR, 0.87 [95% CI, 0.75-1.00]) but showed no association with mortality. Few exercise trials reported fall-related fractures. Seven heterogeneous trials of vitamin D formulations (with or without calcium) showed mixed results. One trial of annual high-dose cholecalciferol (500 000 IU), which has not been replicated, showed an increase in falls, people experiencing a fall, and injuries, while 1 trial of calcitriol showed a reduction in falls and people experiencing a fall; the remaining 5 trials showed no significant difference in falls, people experiencing a fall, or injuries. Harms of multifactorial and exercise trials were rarely reported but generally included minor musculoskeletal injuries. Conclusions and Relevance: Multifactorial and exercise interventions were associated with fall-related benefit, but evidence was most consistent across multiple fall-related outcomes for exercise. Vitamin D supplementation interventions had mixed results, with a high dose being associated with higher rates of fall-related outcomes.

Vitamin D levels and menopause-related symptoms.

OBJECTIVE: This study aims to determine whether vitamin D levels are associated with menopause-related symptoms in older women. METHODS: A randomly selected subset of 1,407 women, among 26,104 potentially eligible participants of the Women's Health Initiative Calcium and Vitamin D trial of postmenopausal women aged 51 to 80 years, had 25-hydroxyvitamin D [25(OH)D] levels measured at the Women's Health Initiative Calcium and Vitamin D trial baseline visit. Information about menopause-related symptoms at baseline was obtained by questionnaire and included overall number of symptoms and composite measures of sleep disturbance, emotional well-being, and energy/fatigue, as well as individual symptoms. After exclusions for missing data, 530 women (mean [SD] age, 66.2 [6.8] y) were included in these analyses. RESULTS: Borderline significant associations between 25(OH)D levels and total number of menopausal symptoms were observed (with P values ranging from 0.05 to 0.06 for fully adjusted models); however, the effect was clinically insignificant and disappeared with correction for multiple testing. No associations between 25(OH)D levels and composite measures of sleep disturbance, emotional well-being, or energy/fatigue were observed (P's > 0.10 for fully adjusted models). CONCLUSIONS: There is no evidence for a clinically important association between serum 25(OH)D levels and menopause-related symptoms in postmenopausal women.

Vitamin D supplementation and depression in the women's health initiative calcium and vitamin D trial.

While observational studies have suggested that vitamin D deficiency increases risk of depression, few clinical trials have tested whether vitamin D supplementation affects the occurrence of depression symptoms. The authors evaluated the impact of daily supplementation with 400 IU of vitamin D(3) combined with 1,000 mg of elemental calcium on measures of depression in a randomized, double-blinded US trial comprising 36,282 postmenopausal women. The Burnam scale and current use of antidepressant medication were used to assess depressive symptoms at randomization (1995-2000). Two years later, women again reported on their antidepressant use, and 2,263 completed a second Burnam scale. After 2 years, women randomized to receive vitamin D and calcium had an odds ratio for experiencing depressive symptoms (Burnam score ≥0.06) of 1.16 (95% confidence interval: 0.86, 1.56) compared with women in the placebo group. Supplementation was not associated with antidepressant use (odds ratio = 1.01, 95% confidence interval: 0.92, 1.12) or continuous depressive symptom score. Results stratified by baseline vitamin D and calcium intake, solar irradiance, and other factors were similar. The findings do not support a relation between supplementation with 400 IU/day of vitamin D(3) along with calcium and depression in older women. Additional trials testing higher doses of vitamin D are needed to determine whether this nutrient may help prevent or treat depression.

Vitamin D intake from foods and supplements and depressive symptoms in a diverse population of older women.

BACKGROUND: Vitamin D may plausibly reduce the occurrence of depression in postmenopausal women; however, epidemiologic evidence is limited, and few prospective studies have been conducted. OBJECTIVE: We conducted a cross-sectional and prospective analysis of vitamin D intake from foods and supplements and risk of depressive symptoms. DESIGN: Study participants were 81,189 members of the Women's Health Initiative (WHI) Observational Study who were aged 50-79 y at baseline. Vitamin D intake at baseline was measured by food-frequency and supplement-use questionnaires. Depressive symptoms at baseline and after 3 y were assessed by using the Burnam scale and current antidepressant medication use. RESULTS: After age, physical activity, and other factors were controlled for, women who reported a total intake of ≥800 IU vitamin D/d had a prevalence OR for depressive symptoms of 0.79 (95% CI: 0.71, 0.89; P-trend < 0.001) compared with women who reported a total intake of <100 IU vitamin D/d. In analyses limited to women without evidence of depression at baseline, an intake of ≥400 compared with <100 IU vitamin D/d from food sources was associated with 20% lower risk of depressive symptoms at year 3 (OR: 0.80; 95% CI: 0.67, 0.95; P-trend = 0.001). The results for supplemental vitamin D were less consistent, as were the results from secondary analyses that included as cases women who were currently using antidepressant medications. CONCLUSIONS: Overall, our findings support a potential inverse association of vitamin D, primarily from food sources, and depressive symptoms in postmenopausal women. Additional prospective studies and randomized trials are essential in establishing whether the improvement of vitamin D status holds promise for the prevention of depression, the treatment of depression, or both.

Primary care-relevant interventions to prevent falling in older adults: a systematic evidence review for the U.S. Preventive Services Task Force.

BACKGROUND: Falls among older adults are both prevalent and preventable. PURPOSE: To describe the benefits and harms of interventions that could be used by primary care practitioners to prevent falling among community-dwelling older adults. DATA SOURCES: The reviewers evaluated trials from a good-quality systematic review published in 2003 and searched MEDLINE, the Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, and CINAHL from the end of that review's search date to February 2010 to identify additional English-language trials. STUDY SELECTION: Two reviewers independently screened 3423 abstracts and 638 articles to identify randomized, controlled trials (RCTs) of primary care-relevant interventions among community-dwelling older adults that reported falls or fallers as an outcome. Trials were independently critically appraised to include only good- or fair-quality trials; discrepancies were resolved by a third reviewer. DATA EXTRACTION: One reviewer abstracted data from 61 articles into standardized evidence tables that were verified by a second reviewer. DATA SYNTHESIS: Overall, the included evidence was of fair quality. In 16 RCTs evaluating exercise or physical therapy, interventions reduced falling (risk ratio, 0.87 [95% CI, 0.81 to 0.94]). In 9 RCTs of vitamin D supplementation, interventions reduced falling (risk ratio, 0.83 [CI, 0.77 to 0.89]). In 19 trials involving multifactorial assessment and management, interventions with comprehensive management seemed to reduce falling, although overall pooled estimates were not statistically significant (risk ratio, 0.94 [CI, 0.87 to 1.02]). Limited evidence suggested that serious clinical harms were no more common for older adults in intervention groups than for those in control groups. LIMITATIONS: Interventions and methods of fall ascertainment were heterogeneous. Data on potential harms of interventions were scant and often not reported. CONCLUSION: Primary care-relevant interventions exist that can reduce falling among community-dwelling older adults. PRIMARY FUNDING SOURCE: Agency for Healthcare Research and Quality.