Emma V. Sanchez-Vaznaugh

Differential effect of birthplace and length of residence on body mass index (BMI) by education, gender and race/ethnicity.

Although birthplace and length of residence have been found to be associated with Body Mass Index (BMI)/obesity in the USA, their effects may not be the same across groups defined by education, gender and race/ethnicity. Using cross-sectional population based data from the 2001 California Health Interview Survey, we investigated the associations of birthplace and US length of residence with BMI, and whether the influence of birthplace-US length of residence on BMI varied by education, gender and race/ethnicity. Our sample included 37,350 adults aged 25-64 years. Self-reported weight and height were used to calculate BMI. Birthplace and length of residence were combined into a single variable divided into five levels: US-born, foreign-born living in the United States for more than 15, 10-14, 5-9, and less than 5 years. Controlling for age, gender, marital status, race/ethnicity, education, income, fruit and vegetable consumption, current smoking and alcohol use, we found that: (1) foreign-born adults had lower BMI than US-born adults; (2) among foreign-born adults, longer residence in the United States was associated with higher BMI; and (3) the effect of birthplace-length of US residence on BMI differed by education level, gender and race/ethnicity. Specifically, longer residence in the United States was associated with the greatest percent increases in BMI among the lowest educated groups than higher educated groups, among women (vs. men) and among Hispanics (vs. other racial/ethnic groups). These findings suggest that a protective effect of foreign birthplace on BMI appears to attenuate with length of residence in the United States, and also reveal that BMI/obesity trajectories associated with length of US residence vary by education, gender and race/ethnicity. Immigrant status, independently and in combination with education, gender and race/ethnicity should be considered in future obesity prevention and reduction efforts.

Do Socioeconomic Gradients in Body Mass Index Vary by Race/Ethnicity, Gender, and Birthplace?

Despite the well-documented negative socioeconomic status (SES) gradient in body mass index (BMI; weight (kg)/height (m)(2)) among women in developed societies, the presence and strength of the gradient is less consistent among men. Far less clear is the SES patterning of BMI among racial/ethnic minorities and immigrants. Using data from the 2001 California Health Interview Survey, a cross-sectional representative sample of California adults, the authors examined whether the SES patterning of BMI varied across 4 major US racial/ethnic groups (n = 37,150) by gender and birthplace. The shape and strength of the relation between SES and BMI differed markedly by race/ethnicity; and within racial/ethnic groups, it varied by gender. Irrespective of race/ethnicity, there were negative income and education gradients in BMI among women; however, there was considerable variation among men. The effect of education on BMI differed by birthplace in some groups. A clear education gradient in BMI was found among all US-born participants, a quadratic education pattern in BMI was found among foreign-born Asian men, a flat pattern was found among foreign-born Asian women, and no clear pattern was found in the remaining foreign-born groups. There is substantial heterogeneity in the contemporaneous SES gradient in BMI. US social disparities in BMI require simultaneous consideration of race/ethnicity and SES, but also birthplace.

'Competitive' food and beverage policies: are they influencing childhood overweight trends?

We examined whether new policies restricting sales in schools of so-called competitive foods and beverages-those that fall outside of what is served through federally reimbursed school meal programs-influenced increasing rates of overweight children in the Los Angeles Unified School District and the rest of California. After these policies, which set stricter nutrition standards for certain food and beverages sold to students, took effect, the rate of increase in overweight children significantly diminished among fifth graders in Los Angeles and among fifth-grade boys and seventh graders in the rest of California. The extent to which the new nutritional policies contributed to the change is unclear. This is one of the first studies examining the postulated population-level influence of recently implemented policies aimed at sales of competitive foods and beverages in schools.

Physical Education Policy Compliance and Children's Physical Fitness

BACKGROUND Physical education policies have received increased attention as a means for improving physical activity levels, enhancing physical fitness, and contributing to childhood obesity prevention. Although compliance at the school and district levels is likely to be critical for the success of physical education policies, few published studies have focused on this issue. PURPOSE This study investigated whether school district-level compliance with California physical education policies was associated with physical fitness among 5th-grade public-school students in California. METHODS Cross-sectional data from FITNESSGRAM(®) 2004-2006, district-level compliance with state physical education requirements for 2004-2006, school- and district-level information, and 2000 U.S. Census data were combined to examine the association between district-level compliance with physical education policies and childrens fitness levels. The analysis was completed in 2010. RESULTS Of the 55 districts with compliance data, 28 (50%) were in compliance with state physical education mandates; these districts represented 21% (216) of schools and 18% (n=16,571) of students in the overall study sample. Controlling for other student-, school-, and district-level characteristics, students in policy-compliant districts were more likely than students in noncompliant districts to meet or exceed physical fitness standards (AOR=1.29, 95% CI=1.03, 1.61). CONCLUSIONS Policy mandates for physical education in schools may contribute to improvements in childrens fitness levels, but their success is likely to depend on mechanisms to ensure compliance.

Association Between Competitive Food and Beverage Policies in Elementary Schools and Childhood Overweight/Obesity Trends: Differences by Neighborhood Socioeconomic Resources

IMPORTANCE To our knowledge, few published studies have examined the influence of competitive food and beverage (CF&B) policies on student weight outcomes; none have investigated disparities in the influence of CF&B policies on childrens body weight by school neighborhood socioeconomic resources. OBJECTIVE To investigate whether the association between CF&B policies and population-level trends in childhood overweight/obesity differed by school neighborhood income and education levels. DESIGN, SETTING, AND PARTICIPANTS This cross-sectional study, from July 2013 to October 2014, compared overweight/obesity prevalence trends before (2001-2005) and after (2006-2010) implementation of CF&B policies in public elementary schools in California. The study included 2 700 880 fifth-grade students in 5362 public schools from 2001 to 2010. EXPOSURES California CF&B policies (effective July 1, 2004, and July 1, 2007) and school neighborhood income and education levels. MAIN OUTCOMES AND MEASURES Overweight/obesity defined as a body mass index at or greater than the 85th percentile for age and sex. RESULTS Overall rates of overweight/obesity ranged from 43.5% in 2001 to 45.8% in 2010. Compared with the period before the introduction of CF&B policies, overweight/obesity trends changed in a favorable direction after the policies took effect (2005-2010); these changes occurred for all children across all school neighborhood socioeconomic levels. In the postpolicy period, these trends differed by school neighborhood socioeconomic advantage. From 2005-2010, trends in overweight/obesity prevalence leveled off among students at schools in socioeconomically disadvantaged neighborhoods but declined in socioeconomically advantaged neighborhoods. Students in the lowest-income neighborhoods experienced zero or near zero change in the odds of overweight/obesity over time: the annual percentage change in overweight/obesity odds was 0.1% for females (95% CI, -0.7 to 0.9) and -0.3% for males (95% CI, -1.1 to 0.5). In contrast, in the highest-income neighborhoods, the annual percentage decline in the odds of overweight was 1.2% for females (95% CI, 0.4 to 1.9) and 1.0% for males (95% CI, 0.3 to 1.8). Findings were similar for school neighborhood education. CONCLUSIONS AND RELEVANCE Our study found population-level improvements in the prevalence of childhood overweight/obesity that coincided with the period following implementation of statewide CF&B policies (2005-2010). However, these improvements were greatest at schools in the most advantaged neighborhoods. This suggests that CF&B policies may help prevent child obesity; however, the degree of their effectiveness is likely to depend on socioeconomic and other contextual factors in school neighborhoods. To reduce disparities and prevent obesity, school policies and environmental interventions must address relevant contextual factors in school neighborhoods.

Distributed Lag Models: Examining Associations Between the Built Environment and Health.

Built environment factors constrain individual level behaviors and choices, and thus are receiving increasing attention to assess their influence on health. Traditional regression methods have been widely used to examine associations between built environment measures and health outcomes, where a fixed, prespecified spatial scale (e.g., 1 mile buffer) is used to construct environment measures. However, the spatial scale for these associations remains largely unknown and misspecifying it introduces bias. We propose the use of distributed lag models (DLMs) to describe the association between built environment features and health as a function of distance from the locations of interest and circumvent a-priori selection of a spatial scale. Based on simulation studies, we demonstrate that traditional regression models produce associations biased away from the null when there is spatial correlation among the built environment features. Inference based on DLMs is robust under a range of scenarios of the built environment. We use this innovative application of DLMs to examine the association between the availability of convenience stores near California public schools, which may affect children’s dietary choices both through direct access to junk food and exposure to advertisement, and children’s body mass index z scores.

Latina Birth Outcomes in California: Not so Paradoxical.

Objectives To investigate Latina-White differences in birth outcomes in California from 2003 to 2010, looking for evidence of the often-cited “Latina paradox” and assessing the possible role of socioeconomic factors in observed differences. MethodsUsing statewide-representative data from the California Maternal and Infant Health Assessment, an annual population-based postpartum survey, we compared rates of preterm birth (PTB) and low birth weight (LBW) in five groups: U.S.-born non-Latina Whites (“Whites”), U.S.-born Mexican–Americans, U.S.-born non-Mexican Latinas, Mexican immigrants, and non-Mexican Latina immigrants. Logistic regression models examined the relative likelihood of PTB and LBW for women in each Latina subgroup compared with Whites, before and after adjustment for socioeconomic and other covariates. Results In unadjusted analyses, women in each Latina subgroup appeared more likely than White women to have PTB and LBW, although the increased likelihood of LBW among Mexican immigrants was statistically non-significant. After adjustment for less favorable socioeconomic characteristics among Latinas compared with Whites, observed differences in the estimated likelihoods of PTB or LBW for Latina subgroups relative to Whites were attenuated and (with the exception of PTB among U.S.-born Mexican Americans) no longer statistically significant. Conclusions We found no evidence of a “Latina paradox” in birth outcomes, which some have cited as evidence that social disadvantage is not always health-damaging. As observed in several previous studies, our findings were non-paradoxical: consistent with their socioeconomic disadvantage, Latinas had worse birth outcomes than non-Latina White women. Policy-makers should not rely on a “Latina paradox” to ensure good birth outcomes among socioeconomically disadvantaged Latina women.

Hierarchical Distributed-Lag Models: Exploring Varying Geographic Scale and Magnitude in Associations Between the Built Environment and Health

It is well known that associations between features of the built environment and health depend on the geographic scale used to construct environmental attributes. In the built environment literature, it has long been argued that geographic scales may vary across study locations. However, this hypothesized variation has not been systematically examined due to a lack of available statistical methods. We propose a hierarchical distributed-lag model (HDLM) for estimating the underlying overall shape of food environment-health associations as a function of distance from locations of interest. This method enables indirect assessment of relevant geographic scales and captures area-level heterogeneity in the magnitudes of associations, along with relevant distances within areas. The proposed model was used to systematically examine area-level variation in the association between availability of convenience stores around schools and childrens weights. For this case study, body mass index (weight kg)/height (m)2) z scores (BMIz) for 7th grade children collected via Californias 2001-2009 FitnessGram testing program were linked to a commercial database that contained locations of food outlets statewide. Findings suggested that convenience store availability may influence BMIz only in some places and at varying distances from schools. Future research should examine localized environmental or policy differences that may explain the heterogeneity in convenience store-BMIz associations.

The relationship between food insecurity and overweight/obesity differs by birthplace and length of US residence

OBJECTIVE To examine whether the cross-sectional association between food insecurity and overweight/obesity varied according to birthplace and length of residence in the USA among California women. DESIGN Using cross-sectional, population-based data from the California Womens Health Survey (CWHS) 2009-2012, we examined whether the association between food insecurity and overweight or obesity varied by birthplace-length of US residence. SETTING California, USA. SUBJECTS Women (n 16 008) aged 18 years or older. RESULTS Among US-born women, very low food security (prevalence ratio (PR)=1·21; 95 % CI 1·11, 1·31) and low food security (PR=1·19; 95 % CI 1·10, 1·28) were significantly associated with higher prevalence of overweight/obesity, after controlling for age, marital status, race/ethnicity, poverty and education. Among immigrant women who lived in the USA for 10 years or longer, very low food security was significantly associated with higher prevalence of overweight/obesity, after controlling for covariates (PR=1·16; 95 % CI 1·07, 1·27). Among immigrant women who had lived in the USA for less than 10 years, low and very low food security were not significantly associated with overweight/obesity, after controlling for covariates. CONCLUSIONS Food insecurity may be an important pathway through which weight may increase with longer US residence among immigrant women. Public health programmes and policies should focus on increasing food security for all women, including immigrant women, as one strategy to reduce the prevalence of overweight/obesity.

Hierarchical multiple informants models: examining food environment contributions to the childhood obesity epidemic

Methods for multiple informants help to estimate the marginal effect of each multiple source predictor and formally compare the strength of their association with an outcome. We extend multiple informant methods to the case of hierarchical data structures to account for within cluster correlation. We apply the proposed method to examine the relationship between features of the food environment near schools and childrens body mass index z-scores (BMIz). Specifically, we compare the associations between two different features of the food environment (fast food restaurants and convenience stores) with BMIz and investigate how the association between the number of fast food restaurants or convenience stores and childs BMIz varies across distance from a school. The newly developed methodology enhances the types of research questions that can be asked by investigators studying effects of environment on childhood obesity and can be applied to other fields.