The effects of socioeconomic status and indices of physical environment on reduced birth weight and preterm births in Eastern Massachusetts

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.Background: Air pollution and social characteristics have been shown to affect indicators of health. While use of spatial methods to estimate exposure to air pollution has increased the power to detect effects, questions have been raised about potential for confounding by social factors.Methods: A study of singleton births in Eastern Massachusetts was conducted between 1996 and 2002 to examine the association between indicators of traffic, land use, individual and area-based socioeconomic measures (SEM), and birth outcomes ( birth weight, small for gestational age and preterm births), in a two-level hierarchical model.Results: We found effects of both individual ( education, race, prenatal care index) and area-based ( median household income) SEM with all birth outcomes. The associations for traffic and land use variables were mainly seen with birth weight, with an exception for an effect of cumulative traffic density on small for gestational age. Race/ethnicity of mother was an important predictor of birth outcomes and a strong confounder for both area-based SEM and indices of physical environment. The effects of traffic and land use differed by level of education and median household income.Conclusion: Overall, the findings of the study suggested greater likelihood of reduced birth weight and preterm births among the more socially disadvantaged, and a greater risk of reduced birth weight associated with traffic exposures. Results revealed the importance of controlling simultaneously for SEM and environmental exposures as the way to better understand determinants of health.This work is supported by the Harvard Environmental Protection Agency (EPA) Center, Grants R827353 and R-832416, and National Institute for Environmental Health Science (NIEHS) ES-0002

Modifiers of short-term effects of ozone on mortality in eastern Massachusetts - A case-crossover analysis at individual level

<p>Abstract</p> <p>Background</p> <p>Substantial epidemiological studies demonstrate associations between exposure to ambient ozone and mortality. A few studies simply examine the modification of this ozone effect by individual characteristics and socioeconomic status, but socioeconomic status was usually coded at the city level.</p> <p>Methods</p> <p>This study used a case-crossover design to examine whether impacts of ozone on mortality were modified by socioeconomic status coded at the tract or characteristics at an individual level in eastern Massachusetts, US for a period May-September, 1995-2002, with a total of 157,197 non-accident deaths aging 35 years or older. We used moving averages of maximal 8-hour concentrations of ozone monitored at 8 stationary stations as personal exposure.</p> <p>Results</p> <p>A 10 ppb increase in the four-day moving average of maximal 8-hour ozone was associated with 1.68% (95% confidence interval (CI): 0.51%, 2.87%), 1.96% (95% CI: -1.83%, 5.90%), 8.28% (95% CI: 0.66%, 16.48%), 0.44% (95% CI: -1.45%, 2.37%), -0.83% (95% CI: -2.94%, 1.32%), -1.09% (95% CI: -4.27%, 2.19%) and 6.5% (95% CI: 1.74%, 11.49%) changes in all natural deaths, respiratory disorders, diabetes, cardiovascular diseases, heart diseases, acute myocardial infarction and stroke, respectively. We did not find any evidence that the associations were significantly modified by socioeconomic status or individual characteristics although small differences of estimates across subpopulations were demonstrated.</p> <p>Conclusions</p> <p>Exposure to ozone was associated with specific cause mortality in Eastern Massachusetts during May-September, 1995-2002. There was no evidence that effects of ozone on mortality were significantly modified by socioeconomic status and individual characteristics.</p

Exploratory Study of Environmental Effects on Physical Activity and Overweight in Older Women: Research Update

Background: Physical inactivity and obesity are major public health issues. Recent studies have provided evidence that attributes of the built environment influence physical activity among adults and that factors such as greater urban sprawl are related to overweight and obesity. Few studies have developed objective individual-level measures of the built environment, a geographic scale that may be more relevant to certain types of physical activity, such as walking. In addition, further research is needed to assess the associations of both objective and perceived environmental factors with physical activity. In this 2-year exploratory study funded by the National Cancer Institute, we are addressing these research gaps. Purpose: The purpose of this poster presentation is to provide a brief overview of progress to date on a major component of this study, which is to develop objective measures of the built environment for approximately 30,000 women in the Nurses’ Health Study (NHS) using Geographic Information Systems (GIS) techniques and to examine associations with physical activity and weight-related outcomes. In particular, we will briefly summarize pilot work focused on development and testing of built environment variables. Methods: A sample of 300 NHS participants from six counties in Massachusetts, Pennsylvania, and California were selected for the pilot GIS work. Geocoded home addresses, U.S. Census population data, an InfoUSA facilities database, and street network files were loaded into ArcGIS 9.3. GIS methods were used to derive variables in three domains: 1) street connectivity, 2) land use mix, and 3) population density. For each domain at least two variables were created using different operational definitions. We also created variables using 400, 800, and 1200 m network buffers. We merged the built environment data with NHS survey data. Statistical analyses included calculating mean values for environmental variables, both overall and at the county level, and running correlations between environmental variables and physical activity outcomes. Next steps: A next step in the project is to create environmental variables for the full sample of NHS participants living in the three states (n≈30,000) and merge these data with NHS survey data. In addition, we are conducting a small validation study with the InfoUSA data. During November, we are also implementing a supplemental survey with a sub-sample (n≈3,800) of NHS participants to assess perceptions of the neighborhood environment and to collect detailed information on physical activity. In another component of the study, we are testing the use of available tools such as Google Map/Earth, Google Street View, and Microsoft Visual Oblique to develop micro-scale measures of the built environment, such as the presence of sidewalks availability and their condition