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Arnold School studies cover topics of national, international significance
September 7, 2010
Jim Thrasher
Katrina Waslemann
The Department of Health Promotion, Education, and Behavior at the Arnold School of Public Health is represented in two studies published in the September issue of the American Journal of Public Health. Dr. Jim Thrasher’s research on smoking policies in Mexico and Dr. Katrina Walsemann’s study on the impact of segregation on adolescent behavior are featured in the AJPH “Research and Practice” Section. Below are highlights of these studies.
New laws benefit smoke-free environment in Mexico City
Surveys led by Dr. Jim Thrasher of the Arnold School find that Mexico City residents are less exposed to toxic cigarette smoke and show high and increasing support for the municipality’s tough, two-year-old smoke-free law.
Mexico City officials implemented the smoking ban in April 2008, requiring all enclosed public places and workplaces, including public transport, restaurants and bars, to be 100 percent smoke free. This made Mexico City the largest city in Latin America to have implemented such a comprehensive policy.
Thrasher and his colleagues at USC and the Mexican National Institute of Public Health conducted three surveys of city residents about their attitudes and beliefs about smoke-free laws, compliance with those laws, and exposure to secondhand smoke.
The first sample involved 800 participants surveyed two weeks before the law was implemented. Four months after the law was implemented, 961 participants were surveyed. A final survey was conducted among 761 participants eight months after implementation.
“Results indicated high support for 100 percent smoke-free policies, and this support increased further after the policy was implemented,” Thrasher said.
“This pattern of increasing acceptance of smoke-free policies has been found for high-income, Western countries, as we have found here in South Carolina, as well,” he said. “Our study aimed to document this phenomenon in a middle-income country with a different cultural tradition, where some have argued that this kind of policy would be less successful.”
The research team also found that exposure to secondhand smoke declined dramatically across all venues. When surveyed, people who reported that they did not breathe toxic secondhand smoke in the previous month more than doubled, from 19 percent to 44 percent, while those who breathed secondhand smoke daily was cut in half, from 28 percent to 14 percent.
This change will translate into significantly better health for Mexico City residents,” Thrasher said.
In addition to Thrasher, others who participated in the study were Rosaura Pérez-Hernández and Edna Arillo-Santillán, both from the Department of Tobacco Research, Mexican National Institute of Public Health, Cuernavaca, Mexico; Dr. Matteo Bottai of the Arnold School’s Department of Epidemiology and Biostatistics; and Kamala Swayampakala, a research associate at the S.C. Public Health Consortium.
Study finds segregation impacts student behavior
Smoking, drinking, and educational aspirations of students can be influenced by the level of racial segregation within their school, according to a study by USC researchers Dr. Katrina Walsemann of the Arnold School and Dr. Bethany A. Bell of the Department of Educational Psychology, Research, and Foundations in the College of Education.
The study was based on an analysis of data from 2,731 black and 3,158 white students who were interviewed as part of the National Longitudinal Study of Adolescent Health, a nationally representative sample of adolescents in grades 7-12 in the United States during the 1994 - 95 school year.
Walsemann and Bell found that racial health disparities as a consequence of residential segregation has long been studied, but little research has been focused on schools where racial inequities are sometimes perpetuated. The results, the scientists said, suggest that within-school segregation, as measured by the uneven distribution of black and white adolescents across levels of the English curriculum (advanced placement – international baccalaureate – honors, general, remedial, or no English), has consequences for black adolescents’ health behaviors and educational aspirations.
The study found that white female students had higher predicted probabilities of smoking or drinking than did black female students. The largest differences were in schools with high levels of within-school segregation.
“Prior research demonstrates that assigning students to less rigorous coursework reduces these students’ chances of graduating from high school and attending college,” Waslemann said.
“Because lower educational attainment is associated with greater odds of smoking and heavy drinking in adulthood, within-school segregation may protect black girls from the risky behavior of their white peers during adolescence by fostering same-race friendships or engagement in other resiliency strategies, but may in the long-run increase their risk of smoking or drinking by reducing their odds of attaining a college degree,” she said.
Although black males typically report higher educational aspirations than their white peers during adolescence, the study found that the black-white gap in educational aspirations was diminished in schools with moderate and high levels of within-school segregation.
“Like our findings for females, this result suggests that high school environments may have long-term ramifications for population health, particularly since educational aspirations are associated with educational attainment in adulthood,” Walsemann said.
