Peter James

Harvard Medical School and Harvard Pilgrim Health Care Institute · Population Medicine

Background: Emerging evidence has suggested lifestyle and behavioral factors such as physical activity, diet, and sleep may be associated with cardiometabolic health outcomes in US adults. However, these studies typically have limited temporal or spatial coverage. The current study aimed to fill in this gap by applying smartphone-based digital phen...

Unlabelled: Green spaces may be protective against COVID-19 incidence. They may provide outdoor, ventilated, settings for physical and social activities and therefore decrease transmission risk. We examined the association between neighborhood greenness and COVID-19-like illness incidence using individual-level data. Methods: The study populatio...

Background: Several studies have evaluated whether the distribution of natural environments differs between marginalized and privileged neighborhoods. However, most studies restricted their analyses to a single or handful of cities and used different natural environment measures. Objectives: We evaluated whether natural environments are inequita...

Importance Exposure to natural environments has been associated with health outcomes related to neurological diseases. However, the few studies that have examined associations of natural environments with neurological diseases report mixed findings. Objective To evaluate associations of natural environments with hospital admissions for Alzheimer d...

Most spatial epidemiological studies of nature-health relationships use generalized greenspace measures. For instance, coarse-resolution spatial data containing normalized difference vegetative index (NDVI) values are prominent despite criticisms, such as the inability to restrain exposure estimates to public and private land. Non-threatening natur...

Unlabelled: Few studies have prospectively examined long-term associations between neighborhood socioeconomic status (nSES) and mortality risk, independent of demographic and lifestyle risk factors. Methods: We assessed associations between nSES and all-cause, nonaccidental mortality among women in the Nurses' Health Study (NHS) 1986-2014 (N = 1...

Importance: Physical and social neighborhood attributes may have implications for children's growth and development patterns. The extent to which these attributes are associated with body mass index (BMI) trajectories and obesity risk from childhood to adolescence remains understudied. Objective: To examine associations of neighborhood-level mea...

Introduction The burden of Alzheimer’s disease (AD) and AD-related dementias (ADRD) is increasing nationally and globally, with disproportionate impacts on lower-income, lower education and systematically marginalised older adults. Presence of inequalities in neighbourhood factors (eg, social context, physical and built environments) may affect ris...

Background Short-term exposure to high or low temperatures is associated with increased mortality and morbidity. Less is known about effects of long-term exposure to high or low temperatures. Prolonged exposure to high or low temperatures might contribute to pathophysiological mechanisms, thereby influencing the development of diseases. Our aim was...

Purpose: Outdoor light at night (LAN) can result in circadian disruption and hormone dysregulation and is a suspected risk factor for some cancers. Our study is the first to evaluate the association between LAN and risk of endometrial cancer, a malignancy with known relationship to circulating estrogen levels. Methods: We linked enrollment addre...

Background: Previous studies have linked environmental exposures with anti-Müllerian hormone (AMH), a marker of ovarian reserve. However, associations with multiple environment factors has to our knowledge not been addressed. Methods: We included a total of 2,447 premenopausal women in the Nurses' Health Study II (NHSII) who provided blood sampl...

Background Light at night (LAN) may alter estrogen regulation through circadian disruption. High levels of outdoor LAN may increase breast cancer risk, but studies have largely not considered possible residual confounding from correlated environmental exposures. We evaluated the association between indoor and outdoor LAN and incident breast cancer....

Most spatial epidemiological studies of nature-health relationships use generalized green space measures. For instance, the normalized difference vegetative index (NDVI) is prominent despite its criticisms, such as its inability to differentiate more public (accessible) vs. private (largely inaccessible) land. Green space’s capacity to improve heal...

Particulate matter with aerodynamic diameter less than 2.5 µm (PM2.5) is a multi-million human silent killer worldwide, and contains many trace elements (TEs). Understanding the relative toxicity is largely limited by lack of data. Ensembles of machine learning models were used to generate ~163 billion predictions estimating annual mean PM2.5 TEs,...

Particulate matter with aerodynamic diameter less than 2.5 μm (PM2.5) increases mortality and morbidity. PM2.5 is composed of a mixture of chemical components that vary across space and time. Due to limited hyperlocal data availability, less is known about health risks of PM2.5 components, their US-wide exposure disparities, or which species are dr...

Exposure to natural greenspace benefits health through direct and indirect pathways: increasing physical activity, improving mental health, relieving social isolation, reducing exposure to extreme temperature, noise, and air pollution. Understanding the etiologic pathway of greenspace and health is needed. Here, we used a large cohort follow-up dat...

Natural environments have been linked to decreased risk of cardiovascular disease (CVD) and respiratory disease (RSD) mortality. However, few cohort studies have looked at associations of natural environments with CVD or RSD hospitalization. The aim of this study was to evaluate these associations in a cohort of U.S. Medicare beneficiaries (∼63 mil...

The concept of the exposome encompasses the totality of exposures from a variety of external and internal sources across an individual’s life course. The wealth of existing spatial and contextual data makes it appealing to characterize individuals’ external exposome to advance our understanding of environmental determinants of health. However, the...

Inverse associations between natural vegetation exposure (i.e., greenness) and breast cancer risk have been reported; however, it remains unknown whether greenness affects breast tissue development or operates through other mechanisms (e.g., body mass index [BMI] or physical activity). We examined the association between greenness and mammographic...

Individual-level studies with adjustment for important COVID-19 risk factors suggest positive associations of long-term air pollution exposure (particulate matter and nitrogen dioxide) with COVID-19 infection, hospitalisations and mortality. The evidence, however, remains limited and mechanisms unclear. We aimed to investigate these associations wi...

Particulate matter with aerodynamic diameter less than 2.5 μm (PM2.5) increases mortality and morbidity.1,2 PM2.5 is composed of a mixture of chemical components that vary across space and time.3 Due to limited hyperlocal data availability, less is known about health risks of PM2.5 components, their US-wide exposure disparities, or which species ar...

Particulate matter with aerodynamic diameter less than 2.5 μm (PM2.5) increases mortality and morbidity.1,2 PM2.5 is composed of a mixture of chemical components that vary across space and time.3 Due to limited hyperlocal data availability, less is known about health risks of PM2.5 components, their US-wide exposure disparities, or which species ar...

Background: Research has suggested optimism is associated with healthy aging and exceptional longevity, but most studies were conducted among non-Hispanic White populations. We examined associations of optimism to longevity across racial and ethnic groups and assessed healthy lifestyle as a possible mediating pathway. Methods: Participants from...

Greenspace may benefit sleep by enhancing physical activity, reducing stress or air pollution exposure. Studies on greenspace and children's sleep are limited, and most use satellite-derived measures that do not capture ground-level exposures that may be important for sleep. We examined associations of street view imagery (SVI)-based greenspace wit...

Across the United States, cities are creating sustainability and climate action plans (CAPs) that call to increase local vegetation. These greening initiatives have the potential to not only benefit the environment but also human health. In epidemiologic literature, greenness has a protective effect on mortality through various direct and indirect...

Introduction Built and natural environments may provide opportunities for physical activity. However, studies are limited by primarily using residential addresses to define exposure and self-report to measure physical activity. We quantified associations between global positioning systems (GPS)-based activity space measures of environmental exposur...

Background Neighborhood deprivation is linked with inflammation, which may explain poorer health across populations. Behavioral risk factors are assumed to largely mediate these relationships, but few studies have examined this. We examined three neighborhood contextual factors that could exert direct effects on inflammation: (1) neighborhood socio...

While COVID-19 lockdowns have slowed coronavirus transmission, such structural measures also have unintended consequences on mental and physical health. Growing evidence shows that exposure to the natural environment (e.g., blue-green spaces) can improve human health and wellbeing. In this narrative review, we synthesized the evidence about nature'...

Importance: Green space can decelerate cognitive decline by supporting physical activity, psychological restoration, or reducing exposure to air pollution. However, existing studies on the association of green space with cognitive decline are limited. Objective: To examine whether residential green space was associated with cognitive function in...

Objectives: Growing evidence supports optimism as a health asset, yet how optimism influences well-being and health remains uncertain. We evaluated 1 potential pathway-the association of optimism with daily stress processes-and tested 2 hypotheses. The stressor exposure hypothesis posits that optimism would preserve emotional well-being by limitin...

Background: Higher optimism is associated with maintaining favorable cardiovascular health (FCH) among White adults, but evidence for this relationship is limited among African American adults, whose cardiovascular disease risk is higher than Whites. We investigated whether higher optimism is associated with more FCH over ~12 years among African Am...

Background: Communities with lower socioeconomic status and higher prevalence of racial/ethnic minority populations are often more exposed to environmental pollutants. Although studies have shown associations between aircraft noise and property values and various health outcomes, little is known about how aircraft noise exposures are sociodemograp...

Background It remains unclear how changes in human mobility shaped the transmission dynamic of coronavirus disease 2019 (COVID-19) during its first wave in the United States. Methods By coupling a Bayesian hierarchical spatiotemporal model with reported case data and Google mobility data at the county level, we found that changes in movement were...

Increasingly, studies suggest benefits of natural environments or greenness on children's health. However, little is known about cumulative exposure or windows of susceptibility to greenness exposure. Using inverse probability weighting of marginal structural models (IPW/MSM), we estimated effects of greenness exposure from birth through adolescenc...

Optimism is associated with reduced mortality risk among Whites, but evidence for this relationship is limited among African-Americans, whose life expectancy is shorter than Whites. This study examined the association between optimism and mortality rate in African-Americans. Data were from African-American women (n = 2652) and men (n = 1444) in the...

Background: Aircraft noise can affect populations living near airports. Chronic exposure to aircraft noise has been associated with cardiovascular disease, including hypertension. However, previous studies have been limited in their ability to characterize noise exposures over time and to adequately control for confounders. Objectives: The aim o...

Smartphones are now nearly ubiquitous; their numerous built-in sensors enable continuous measurement of activities of daily living, making them especially well-suited for health research. Researchers have proposed various human activity recognition (HAR) systems aimed at translating measurements from smartphones into various types of physical activ...

Green spaces in cities play an important role in people's social, economic and physical well-being. Children spend a large proportion of their time at school, and to date there have been no studies that have investigated the proximity of schools to green spaces. In this work, we conducted a nationwide assessment of the green spaces surrounding 186,...

Multiple systematic reviews on greenspace and health outcomes exist, but the overall evidence base remains unclear. Therefore, we performed an umbrella review to collect and appraise all relevant systematic reviews of epidemiological studies on greenness exposure and health. We searched PubMed, Embase, and Web of Science from inception to June 28,...

BACKGROUND AND AIM: Fine particulate matter (PM2.5) mass is classified as carcinogenic for humans and linked to mortality and morbidity; however, less is known about health risks of PM2.5 components. We aimed to predict PM2.5 components across the contiguous United States. METHODS: Daily mean PM2.5 component data (EC, OC, NO3, NH4, SO4, Br, Ca, Cu,...

[FINAL PUBLISHED VERSION: https://doi.org/10.1016/j.scitotenv.2022.155095 ] While COVID-19 lockdowns have slowed coronavirus transmission, such structural measures also have unintended consequences on mental and physical health. Growing evidence shows that exposure to the natural environment (e.g., blue-green spaces) can improve human health and we...

BACKGROUND Psychological factors (e.g., depression, optimism) and related biological and behavioral responses are associated with numerous physical health outcomes. The majority of research in this area relies on self-reported assessments of psychological factors, which are difficult to scale because they may be expensive to administer and time-con...

Background: Psychological factors (eg, depression) and related biological and behavioral responses are associated with numerous physical health outcomes. Most research in this area relies on self-reported assessments of psychological factors, which are difficult to scale because they may be expensive and time-consuming. Investigators are increasin...

The association between early life greenness and child cognition is not well understood. Using prospective data from Project Viva (n=857) from 1999 to 2010, we examined associations of early life greenness exposure with mid-childhood cognition. We estimated residential greenness at birth, early childhood (median age 3.1y), and mid-childhood (7.8y)...

Urbanization, screen dependency, and the changing nature of childhood and parenting have led to increased time indoors, creating physical and emotional distancing from nature and time spent in natural environments. Substantial evidence from observational and intervention studies indicates that overall time spent in nature leads to increased perceiv...

Background: Studies have observed associations between long-term air pollution and cardiovascular disease hospitalization. Little is known, however, about effect modification of these associations by greenness, temperature and humidity. Methods: We constructed an open cohort consisting of all fee-for-service Medicare beneficiaries, aged ≥ 65, li...

Understanding and responding to adverse human health impacts of global environmental change will be a major priority of 21st century public health professionals. The emerging field of planetary health aims to face this challenge by studying and promoting policies that protect the health of humans and of the Earth's natural systems that support them...

Research into the potential impact of the food environment on liver cancer incidence has been limited, though there is evidence showing that specific foods and nutrients may be potential risk or preventive factors. Data on hepatocellular carcinoma (HCC) cases were obtained from the Surveillance, Epidemiology, and End Results (SEER) cancer registrie...