Andrew Rundle

Short Sleep Duration as a Risk Factor for Hypertension Analyses of the First National Health and Nutrition Examination Survey

Depriving healthy subjects of sleep has been shown to acutely increase blood pressure and sympathetic nervous system activity. Prolonged short sleep durations could lead to hypertension through extended exposure to raised 24-hour blood pressure and heart rate, elevated sympathetic nervous system activity, and increased salt retention. Such forces could lead to structural adaptations and the entrainment of the cardiovascular system to operate at an elevated pressure equilibrium. Sleep disorders are associated with cardiovascular disease, but we are not aware of any published prospective population studies that have shown a link between short sleep duration and the incidence of hypertension in subjects without apparent sleep disorders. We assessed whether short sleep duration would increase the risk for hypertension incidence by conducting longitudinal analyses of the first National Health and Nutrition Examination Survey (n=4810) using Cox proportional hazards models and controlling for covariates. Hypertension incidence (n=647) was determined by physician diagnosis, hospital record, or cause of death over the 8- to 10-year follow-up period between 1982 and 1992. Sleep durations of ≤5 hours per night were associated with a significantly increased risk of hypertension (hazard ratio, 2.10; 95% CI, 1.58 to 2.79) in subjects between the ages of 32 and 59 years, and controlling for the potential confounding variables only partially attenuated this relationship. The increased risk continued to be significant after controlling for obesity and diabetes, which was consistent with the hypothesis that these variables would act as partial mediators. Short sleep duration could, therefore, be a significant risk factor for hypertension.

Neighborhood food environment and walkability predict obesity in New York City.

Background Differences in the neighborhood food environment may contribute to disparities in obesity. Objectives The purpose of this study was to examine the association of neighborhood food environments with body mass index (BMI) and obesity after control for neighborhood walkability. Methods This study employed a cross-sectional, multilevel analysis of BMI and obesity among 13,102 adult residents of New York City. We constructed measures of the food environment and walkability for the neighborhood, defined as a half-mile buffer around the study subject’s home address. Results Density of BMI-healthy food outlets (supermarkets, fruit and vegetable markets, and natural food stores) was inversely associated with BMI. Mean adjusted BMI was similar in the first two quintiles of healthy food density (0 and 1.13 stores/km2, respectively), but declined across the three higher quintiles and was 0.80 units lower [95% confidence interval (CI), 0.27–1.32] in the fifth quintile (10.98 stores/km2) than in the first. The prevalence ratio for obesity comparing the fifth quintile of healthy food density with the lowest two quintiles combined was 0.87 (95% CI, 0.78–0.97). These associations remained after control for two neighborhood walkability measures, population density and land-use mix. The prevalence ratio for obesity for the fourth versus first quartile of population density was 0.84 (95% CI, 0.73–0.96) and for land-use mix was 0.91 (95% CI, 0.86–0.97). Increasing density of food outlets categorized as BMI-unhealthy was not significantly associated with BMI or obesity. Conclusions Access to BMI-healthy food stores is associated with lower BMI and lower prevalence of obesity.

The Urban Built Environment and Obesity in New York City: A Multilevel Analysis:

Purpose. To examine whether urban form is associated with body size within a densely-settled city. Design. Cross-sectional analysis using multilevel modeling to relate body mass index (BMI) to built environment resources. Setting. Census tracts (n = 1989) within the five boroughs of New York City. Subjects. Adult volunteers (n = 13,102) from the five boroughs of New York City recruited between January 2000 and December 2002. Measures. The dependent variable was objectively-measured BMI. Independent variables included land use mix; bus and subway stop density; population density; and intersection density. Covariates included age, gender, race, education, and census tract–level poverty and race/ethnicity. Analysis. Cross-sectional multilevel analyses. Results. Mixed land use (Beta = 2.55, p < .01), density of bus stops (Beta = −.01, p < .01) and subway stops (Beta = −.06, p < .01), and population density (Beta = −.25, p < .001), but not intersection density (Beta = −.002) were significantly inversely associated with BMI after adjustment for individual- and neighborhood-level sociodemographic characteristics. Comparing the 90th to the 10th percentile of each built environment variable, the predicted adjusted difference in BMI with increased mixed land use was −.41 units, with bus stop density was −.33 units, with subway stop density was −.34 units, and with population density was −.86 units. Conclusion. BMI is associated with built environment characteristics in New York City.

Using google street view to audit neighborhood environments

BACKGROUND Research indicates that neighborhood environment characteristics such as physical disorder influence health and health behavior. In-person audit of neighborhood environments is costly and time-consuming. Google Street View may allow auditing of neighborhood environments more easily and at lower cost, but little is known about the feasibility of such data collection. PURPOSE To assess the feasibility of using Google Street View to audit neighborhood environments. METHODS This study compared neighborhood measurements coded in 2008 using Street View with neighborhood audit data collected in 2007. The sample included 37 block faces in high-walkability neighborhoods in New York City. Field audit and Street View data were collected for 143 items associated with seven neighborhood environment constructions: aesthetics, physical disorder, pedestrian safety, motorized traffic and parking, infrastructure for active travel, sidewalk amenities, and social and commercial activity. To measure concordance between field audit and Street View data, percentage agreement was used for categoric measures and Spearman rank-order correlations were used for continuous measures. RESULTS The analyses, conducted in 2009, found high levels of concordance (≥80% agreement or ≥0.60 Spearman rank-order correlation) for 54.3% of the items. Measures of pedestrian safety, motorized traffic and parking, and infrastructure for active travel had relatively high levels of concordance, whereas measures of physical disorder had low levels. Features that are small or that typically exhibit temporal variability had lower levels of concordance. CONCLUSIONS This exploratory study indicates that Google Street View can be used to audit neighborhood environments.

Prenatal exposure to antibiotics, cesarean section and risk of childhood obesity

Background/Objectives:Cesarean section (CS) and antibiotic use during pregnancy may alter normal maternal-offspring microbiota exchange, thereby contributing to aberrant microbial colonization of the infant gut and increased susceptibility to obesity later in life. We hypothesized that (i) maternal use of antibiotics in the second or third trimester of pregnancy and (ii) CS are independently associated with higher risk of childhood obesity in the offspring.Subjects/Methods:Of the 727 mothers enrolled in the Northern Manhattan Mothers and Children Study, we analyzed the 436 mother–child dyads followed until 7 years of age with complete data. We ascertained prenatal antibiotic use by a questionnaire administered late in the third trimester, and delivery mode by medical record. We derived age- and sex-specific body mass index (BMI) z-scores using the CDC SAS Macro, and defined obesity as BMI z⩾95th percentile. We used binary regression with robust variance and linear regression models adjusted for maternal age, ethnicity, pre-gravid BMI, maternal receipt of public assistance, birth weight, sex, breastfeeding in the first year and gestational antibiotics or delivery mode.Results:Compared with children not exposed to antibiotics during the second or third trimester, those exposed had 84% (33–154%) higher risk of obesity, after multivariable adjustment. Second or third trimester antibiotic exposure was also positively associated with BMI z-scores, waist circumference and % body fat (all P<0.05). Independent of prenatal antibiotic usage, CS was associated with 46% (8–98%) higher offspring risk of childhood obesity. Associations were similar for elective and non-elective CS.Conclusions:In our cohort, CS and exposure to antibiotics in the second or third trimester were associated with higher offspring risk of childhood obesity. Future studies that address the limitations of our study are warranted to determine if prenatal antibiotic use is associated with offspring obesity. Research is also needed to determine if alterations in neonatal gut microbiota underlie the observed associations.

Children living in areas with more street trees have lower prevalence of asthma

Background: The prevalence of childhood asthma in the USA increased by 50% from 1980 to 2000, with especially high prevalence in poor urban communities. Methods: Data on the prevalence of asthma among children aged 4–5 years and on hospitalisations for asthma among children less than 15 years old were available for 42 health service catchment areas within New York City. Street tree counts were provided by the New York City Department of Parks and Recreation. The proximity to pollution sources, sociodemographic characteristics and population density for each area were also measured. Results: Controlling for potential confounders, an increase in tree density of 1 standard deviation (SD, 343 trees/km2) was associated with a lower prevalence of asthma (RR, 0.71 per SD of tree density; 95% CI, 0.64 to 0.79), but not with hospitalisations for asthma (RR, 0.89 per SD of tree density; 95% CI, 0.75 to 1.06). Conclusions: Street trees were associated with a lower prevalence of early childhood asthma. This study does not permit inference that trees are causally related to asthma at the individual level. The PlaNYC sustainability initiative, which includes a commitment to plant one million trees by the year 2017, offers an opportunity for a large prospective evaluation.

Disparities in urban neighborhood conditions: evidence from GIS measures and field observation in New York City.

Although many low-income urban areas are highly walkable by conventional measures such as population density or land use mix, chronic diseases related to lack of physical activity are more common among residents of these areas. Disparities in neighborhood conditions may make poor areas less attractive environments for walking, offsetting the advantages of density and land use mix. This study compared poor and nonpoor neighborhoods in New York City, using geographic information systems measures constructed from public data for US census tracts within New York City (N=2,172) as well as field observation of a matched-pair sample of 76 block faces on commercial streets in poor and nonpoor neighborhoods. Poor census tracts had significantly fewer street trees, landmarked buildings, clean streets, and sidewalk cafes, and higher rates of felony complaints, narcotics arrests, and vehicular crashes. The field observation showed similar results. Improving aesthetic and safety conditions in poor neighborhoods may help reduce disparities in physical activity among urban residents.

Effect of Individual or Neighborhood Disadvantage on the Association Between Neighborhood Walkability and Body Mass Index

OBJECTIVES We sought to test whether the association between walkable environments and lower body mass index (BMI) was stronger within disadvantaged groups that may be particularly sensitive to environmental constraints. METHODS We measured height and weight in a diverse sample of 13 102 adults living throughout New York City from 2000-2002. Each participants home address was geocoded and surrounded by a circular buffer with a 1-km radius. The composition and built environment characteristics of these areas were used to predict BMI through the use of generalized estimating equations. Indicators of individual or area disadvantage included low educational attainment, low household income, Black race, and Hispanic ethnicity. RESULTS Higher population density, more mixed land use, and greater transit access were most consistently associated with a lower BMI among those with more education or higher incomes and among non-Hispanic Whites. Significant interactions were observed for education, income, race, and ethnicity. CONCLUSIONS Contrary to expectations, built environment characteristics were less consistently associated with BMI among disadvantaged groups. This pattern may be explained by other barriers to maintaining a healthy weight encountered by disadvantaged groups.

Association of Childhood Obesity With Maternal Exposure to Ambient Air Polycyclic Aromatic Hydrocarbons During Pregnancy

There are concerns that prenatal exposure to endocrine-disrupting chemicals increases childrens risk of obesity. African-American and Hispanic children born in the Bronx or Northern Manhattan, New York (1998-2006), whose mothers underwent personal air monitoring for polycyclic aromatic hydrocarbon (PAH) exposure during pregnancy, were followed up to ages 5 (n = 422) and 7 (n = 341) years. At age 5 years, 21% of the children were obese, as were 25% of those followed to age 7 years. After adjustment for childs sex, age at measurement, ethnicity, and birth weight and maternal receipt of public assistance and prepregnancy obesity, higher prenatal PAH exposures were significantly associated with higher childhood body size. In adjusted analyses, compared with children of mothers in the lowest tertile of PAH exposure, children of mothers in the highest exposure tertile had a 0.39-unit higher body mass index z score (95% confidence interval (CI): 0.08, 0.70) and a relative risk of 1.79 (95% CI: 1.09, 2.96) for obesity at age 5 years, and they had a 0.30-unit higher body mass index z score (95% CI: 0.01, 0.59), a 1.93-unit higher percentage of body fat (95% CI: 0.33, 3.54), and a relative risk of 2.26 (95% CI: 1.28, 4.00) for obesity at age 7 years. The data indicate that prenatal exposure to PAHs is associated with obesity in childhood.

Polymorphisms in the DNA Repair Enzyme XPD are Associated with Increased Levels of PAH–DNA Adducts in a Case-Control Study of Breast Cancer

We present findings on the associations between DNA adduct levels in breast tissue, risk of breast cancer, and polymorphisms in the DNA repair enzyme XPD. Breast cancer cases, benign breast disease (BBD) controls, and healthy controls were enrolled. Polycyclic aromatic hydrocarbons (PAH)–DNA adduct levels were measured by immunohistochemistry in breast tissue samples from cases and BBD controls. XPD polymorphisms at codons 312 and 751 was determined by polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) analysis using white blood cell DNA. Neither of the polymorphisms were associated with case-control status, both in comparisons of cases and BBD controls, and cases and healthy controls. XPD polymorphisms at codons 312 and 751 were associated with higher levels of PAH–DNA in tumor tissue from breast cancer cases. Subjects with an Asp/Asn or Asn/Asn polymorphic genotype in codon 312 of XPD had elevated levels of PAH–DNA adducts compared to subjects with the Asp/Asp genotype (0.55 optical density (OD) v.s. 0.33 OD, p < 0.01). PAH–DNA adducts were associated with increasing copy number of the Gln allele for the codon 751 polymorphism (p for trend <0.01). Among subjects with the Asp/Asn or Asn/Asn genotype at codon 312, adduct levels were higher in tumor tissue compared to tissue from BBD controls (0.55 OD v.s. 0.36 OD, p = 0.003). Among subjects with the Gln/Gln genotype at codon 751 adduct levels were higher in tumor tissue compared to tissue from BBD controls (0.68 OD v.s. 0.40 OD, p = 0.01). The trend of increasing PAH–DNA adduct levels with either the Asn/Asn or Gln/Gln genotype was greater in tumor tissue than the trend in BBD control tissue.