Kristen M. Malecki

Exposure to neighborhood green space and mental health: evidence from the survey of the health of Wisconsin

Green space is now widely viewed as a health-promoting characteristic of residential environments, and has been linked to mental health benefits such as recovery from mental fatigue and reduced stress, particularly through experimental work in environmental psychology. Few population level studies have examined the relationships between green space and mental health. Further, few studies have considered the role of green space in non-urban settings. This study contributes a population-level perspective from the United States to examine the relationship between environmental green space and mental health outcomes in a study area that includes a spectrum of urban to rural environments. Multivariate survey regression analyses examine the association between green space and mental health using the unique, population-based Survey of the Health of Wisconsin database. Analyses were adjusted for length of residence in the neighborhood to reduce the impact of neighborhood selection bias. Higher levels of neighborhood green space were associated with significantly lower levels of symptomology for depression, anxiety and stress, after controlling for a wide range of confounding factors. Results suggest that “greening” could be a potential population mental health improvement strategy in the United States.

Perceived neighborhood quality, sleep quality, and health status: Evidence from the Survey of the Health of Wisconsin

Why does living in a disadvantaged neighborhood predict poorer mental and physical health? Recent research focusing on the Southwestern United States suggests that disadvantaged neighborhoods favor poor health, in part, because they undermine sleep quality. Building on previous research, we test whether this process extends to the Midwestern United States. Specifically, we use cross-sectional data from the Survey of the Health of Wisconsin (SHOW), a statewide probability sample of Wisconsin adults, to examine whether associations among perceived neighborhood quality (e.g., perceptions of crime, litter, and pleasantness in the neighborhood) and health status (overall self-rated health and depression) are mediated by overall sleep quality (measured as self-rated sleep quality and physician diagnosis of sleep apnea). We find that perceptions of low neighborhood quality are associated with poorer self-rated sleep quality, poorer self-rated health, and more depressive symptoms. We also observe that poorer self-rated sleep quality is associated with poorer self-rated health and more depressive symptoms. Our mediation analyses indicate that self-rated sleep quality partially mediates the link between perceived neighborhood quality and health status. Specifically, self-rated sleep quality explains approximately 20% of the association between neighborhood quality and self-rated health and nearly 19% of the association between neighborhood quality and depression. Taken together, these results confirm previous research and extend the generalizability of the indirect effect of perceived neighborhood context on health status through sleep quality.

The association of dietary inflammatory potential with depression and mental well-being among U.S. adults

Current treatment for depression is not considered effective among all cases and, thus far, nutritional protocols are minimal within depression treatment guidelines. Recently, there has been increasing interest in a possible protective and modifiable role of diet in common mental disorders, including depression, due to pro- and anti-inflammatory properties of nutrients. This study aims to investigate whether the Dietary Inflammatory Index (DII), designed to estimate the inflammatory potential of diet, is associated with depression and other measures of mental health. In a representative sample of U.S. adults (≥20years of age, N=11,592), the distribution of DII score is assessed. Multivariate logistic regression models determine the association between DII quintile and depression. Associations of DII quintile with frequent distress and frequent anxiety are also evaluated. In fully adjusted models, higher DII score is associated with over a two-fold higher odds of depression (OR (95% CI)=2.26 (1.60, 3.20) for highest vs. lowest quintile, Type III p-value≤0.0001). DII score is also associated with higher odds of frequent distress (OR (95% CI)=1.81 (1.20, 2.71) for highest vs. lowest quintile, Type III p-value=0.0167). This association was not significant for frequent anxiety (Type III p-value=0.12). Results of this study indicate that dietary inflammatory potential is associated with depression. These results are consistent with existing hypotheses that inflammatory pathways play a role in the etiology of depression. Further research examining the underlying biological and cellular mechanisms of depression is warranted.

Allergic disease associations with regional and localized estimates of air pollution

Background: Exposure to multiple types of air pollution may contribute to and exacerbate allergic diseases including asthma and wheezing. However, few studies have examined chronic air pollution exposure and allergic disease outcomes among an adult population. Associations between potential estimates of annual average fine particulate matter (PM2.5), traffic related air pollution, and industrial source air emissions and three allergic disease outcomes (asthma, allergies and wheezing) were examined in a state‐wide general population of adults. Methods: The study includes a representative sample of 3381 adult Wisconsin residents who participated in the 2008–2013 Survey of the Health of Wisconsin (SHOW) program. Participant data were geographically linked to The United States Environmental Protection Agency (USEPA) Baysian space‐time downscaler air pollution model for PM2.5, the United States Census roadway, and USEPAs Toxic Release Inventory data. Self‐report and lung function (FEV1) estimates were used to define prevalence of asthma, allergies and wheezing symptoms. Results: Annual mean exposure to fine particulate matter (PM2.5) was between 6.59 and 15.14 &mgr;g/m3. An increase of 5 &mgr;g/m3 in the annual mean PM2.5 resulted in a 3.58 (2.36, 5.43) increase in the adjusted odds (95% CI) of having asthma. Exposure to vehicle traffic increased the odds of both current allergies [OR (95% CI)=1.35 (1.07, 1.35)] and current asthma [OR (95% CI)=1.51 (1.14, 2.00)]. Living within 300 m of an Interstate roadway was associated with a 3‐fold increase in the odds of asthma. Those living within 800 m of an industrial site were 47% more likely to have asthma. No significant associations were seen with wheezing. Conclusions: Within this population exposed to overall annual average levels of estimated low level chronic exposure to fine particulate matter (PM2.5) at or near 12 &mgr;g/m3, the USEPA standard for air quality, significant association between both modeled PM2.5 exposure and proximity to roadways with asthma and allergies but not wheezing were found. Industrial source emissions were not associated with any allergic disease outcomes. HighlightsAir pollution and allergic disease associations vary by exposure source and outcome.Low level regional air pollution is marginally associated with asthma and allergies.Proximity to roadways and industrial sites are associated with asthma and allergies.Areas with low level regional pollution should focus on reducing local emissions.

Private-well stewardship among a general population based sample of private well-owners

Private well stewardship, including on-going testing and treatment, can ensure private well users are able to maintain source-water quality and prevent exposures to potentially harmful constituents in primary drinking water supplies. Unlike municipal water supplies, private well users are largely responsible for their own testing and treatment and well stewardship is often minimal. The importance of factors influencing regular testing, and treatment behaviors, including knowledge, risk perception, convenience and social norms, can vary by geography and population characteristics. The primary goals of this study were to survey a general statewide population of private well users in Wisconsin in order to quantify testing and treatment patterns and gather data on motivations and barriers to well stewardship. The majority of respondents reported using and drinking well water daily but only about one half of respondents reported testing their wells in the last ten years and of these, only 10% reported testing in the last 12months. Bacteria and nitrates were contaminants most often tested; and, a private laboratory most often conducted testing. The most commonly reported water treatment was a water softener. Living in a particular geographic region and income were the most significant predictors of water testing and treatment. Iron and hardness, which influence water aesthetics but not always safety, were the most commonly reported water quality problems. Health concerns or perceived lack thereof were, respectively, motivators and barriers to testing and treatment. Limited knowledge of testing and treatment options were also identified as barriers. Results confirm previous findings that well stewardship practices are minimal and often context specific. Understanding the target populations perceptions of risk and knowledge are important elements to consider in identifying vulnerable populations and developing education and policy efforts to improve well stewardship.

Exposure to neighborhood green space and sleep: evidence from the Survey of the Health of Wisconsin

Introduction: Adequate sleep duration and quality are protective against many adverse health outcomes. Many individual‐level predictors of poor sleep have been examined, but few studies have examined neighborhood‐level influences. Despite known associations between neighborhood green space and sleep influencing factors (eg, physical activity, mental health), few studies have examined green space and sleeps relationship. Furthermore, little work has examined the relationship between the magnitude and type of neighborhood sounds and sleep. Study methods: We analyzed data from the Survey of the Health of Wisconsin database (n = 2712) for 2008‐2013, a representative sample of Wisconsin residents ages 21‐74. Outcomes included weekday and weekend sleep duration and self‐rated sleep quality. Primary predictors were the proportion tree canopy (National Land Cover Database) and mean decibel levels of outdoor sound (US National Park Service) at the census block group level. Survey regression analysis was used to examine statistical associations, controlling for individual and neighborhood‐level covariates. Results: Models suggest a significant relationship (P < .05) between weekday sleep duration and green space, and between weekend/day sleep duration and human‐made and total neighborhood sound. Increased percent tree canopy in a census block group was associated with lower odds of short weekday sleep (<6 hours) (OR 0.76 [0.58‐0.98]). Increased human‐made and total mean decibel levels were associated with increased instances of short weekend and weekday sleep (OR 1.05 [1.01‐1.08] and 1.03 [1.01‐1.06] respectively). Conclusions: Neighborhood tree canopy and sound levels may influence sleep duration and are potential targets for neighborhood‐level interventions to improve sleep.

Associations between Food Security Status and Dietary Inflammatory Potential within Lower-Income Adults from the United States National Health and Nutrition Examination Survey, Cycles 2007 to 2014

BACKGROUND Evidence suggests both that chronic inflammation mediates the association of food insecurity with adverse health outcomes and that diet may be a significant source of inflammation among food insecure individuals. OBJECTIVE To examine whether food security status is associated with dietary inflammatory potential. DESIGN AND PARTICIPANTS Cross-sectional data came from the National Health and Nutrition Examination Survey (NHANES), cycles 2007 to 2014 (n=10,630). The analysis sample is representative of noninstitutionalized US adults with an income-to-poverty ratio ≤3.00. MAIN OUTCOME Dietary Inflammatory Index (DII) score, calculated using the average of two 24-hour dietary recalls, was the main outcome measure. STATISTICAL ANALYSIS Type III F tests or χ2 tests compared population characteristics by food security status, defined using the US Food Security Survey Module. Multivariable linear regression was used to estimate the association between food security status and the DII score and moderation by demographic factors. Survey weighting procedures accounted for the effects of stratification and clustering used in the NHANES study design. RESULTS When accounting for socioeconomic status, demographic factors, and health status, DII score was higher at greater levels of food insecurity (P=0.0033). Those with very low food security had a 0.31 (95% CI=0.12 to 0.49) higher DII score than those with high food security. Age moderated the association between food security status and DII score (interaction P=0.0103), where the magnitude of the association between DII score and severity of food insecurity was higher for those >65 years than for younger age groups. CONCLUSION Food security status may be associated with dietary inflammatory potential, which is hypothesized to play a role in multiple chronic health conditions. Further research is needed to determine the causal nature of this relationship and evaluate how best to implement programs designed to address health disparities within food insecure populations.

Heavy metal exposure and nasal Staphylococcus aureus colonization: analysis of the National Health and Nutrition Examination Survey (NHANES)

BackgroundHeavy metals including lead and cadmium can disrupt the immune system and the human microbiota. and are increasingly of concern with respect to the propogation of antibiotic-resistence. Infection by methicillin-resistant Staphylococcus aureus (MRSA) is a major cause of global morbidity and mortality. Heavy metal exposure may be associated with increased MRSA colonization and infection, and a decrease in methicillin-susceptible Staphylococcus aureus (MSSA) through co-selection mechanisms and natural selection of antibiotic resistance in the presence of heavy metals. This study examines the association between blood lead (Pb) and cadmium (Cd) level, and MRSA and MSSA nasal colonization.MethodsAll data used for this analysis came from the 2001–2004 National Health and Nutrition Examination Survey (NHANES). The analytical sample consisted of 18,626 participants aged 1 year and older. Multivariate logistic regression, including adjustment for demographic and dietary factors, was used to analyze the association between blood Pb and Cd, and nasal colonization by MRSA and MSSA.ResultsPrevalence of MRSA and MSSA carriage were 1.2%, and 29.3% respectively. MRSA was highest in women, individuals age 70 and older, who self-identified as black, had only a high school diploma, lived below 200% of the Federal Poverty Level, and had a history of smoking. While not significantly different from those colonized with MSSA, geometric mean blood Pb (1.74 μg/dL) and blood Cd (0.31 μg/L) were highest in those colonized with MRSA. Associations with MRSA colonization appeared to increase in a dose-dependent manner with increasing quartile of blood Pb level. Blood Cd level in the fourth quartile was also significantly associated with lower odds of MRSA colonization. Both metals were associated with lower odds of MSSA colonization.ConclusionsBoth MRSA and MSSA results suggest that general population levels of blood Pb but not Cd are associated with differences in nasal carriage of S. aureus. While further research is needed, reduction in heavy metal exposures such as lead, concurrently with maintaining a healthy microbiota may be two modifiable options to consider in the fight against antibiotic-resistance.

Transcriptional differences between smokers and non-smokers and variance by obesity as a risk factor for human sensitivity to environmental exposures

BACKGROUND Obesity has been shown to alter response to air pollution and smoking but underlying biological mechanisms are largely unknown and few studies have explored mechanisms by which obesity increases human sensitivity to environmental exposures. OBJECTIVE Overall study goals were to investigate whole blood gene expression in smokers and non-smokers to examine associations between cigarette smoke and changes in gene expression by obesity status and test for effect modification. METHODS Relative fold-change in mRNA expression levels of 84 genes were analyzed using a Toxicity and Stress PCR array among 50 21-54 year old adults. Data on smoking status was confirmed using urinary cotinine levels. Adjusted models included age, gender, white blood cell count and body-mass index. RESULTS Models comparing gene expression of smokers vs. non-smokers identified six differentially expressed genes associated with smoking after adjustments for covariates. Obesity was associated with 29 genes differentially expressed compared to non-obese. We also identified 9 genes with significant smoking/obesity interactions influencing mRNA levels in adjusted models comparing expression between smokers vs non-smokers for four DNA damage related genes (GADD45A, DDB2, RAD51 and P53), two oxidative stress genes (FTH1, TXN), two hypoxia response genes (BN1P3lL, ARNT), and one gene associated with unfolded protein response (ATF6B). CONCLUSIONS Findings suggest that obesity alters human sensitivity to smoke exposures through several biological pathways by modifying gene expression. Additional studies are needed to fully understand the clinical impact of these effects, but risk assessments should consider underlying phenotypes, such as obesity, that may modulate sensitivity of vulnerable populations to environmental exposures.

Wisconsin microbiome study, a cross-sectional investigation of dietary fibre, microbiome composition and antibiotic-resistant organisms: rationale and methods

Introduction Prevention of multidrug-resistant organism (MDRO) infections, such as those caused by methicillin-resistant Staphylococcus aureus, vancomycin-resistant enterococci, fluoroquinolone-resistant Gram-negative bacteria and Clostridium difficile is crucial. Evidence suggests that dietary fibre increases gut microbial diversity, which may help prevent colonisation and subsequent infection by MDROs. The aim of the Winning the War on Antibiotic Resistance (WARRIOR) project is to examine associations of dietary fibre consumption with the composition of the gut microbiota and gut colonisation by MDROs. The secondary purpose of the study is to create a biorepository of multiple body site specimens for future microbiota research. Methods and analysis The WARRIOR project collects biological specimens, including nasal, oral and skin swabs and saliva and stool samples, along with extensive data on diet and MDRO risk factors, as an ancillary study of the Survey of the Health of Wisconsin (SHOW). The SHOW is a population-based health survey collecting data on several different health determinants and outcomes, as well as objective body measurements and biological specimens. WARRIOR participants include 600 randomly selected Wisconsin residents age 18 and over. Specimens are screened for MDRO colonisation and DNA is extracted for 16S ribosomal RNA-based microbiota sequencing. Data will be analysed to assess the relationship between dietary fibre, the gut microbiota composition and gut MDRO colonisation. Ethics and dissemination The WARRIOR project is approved by the University of Wisconsin Institutional Review Board. The main results of this study will be published in a peer-reviewed scientific journal.