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Objective:This study aimed to examine the intrapersonal, interpersonal, environmental and macrosystem influences on dietary behaviours among primary school children in Singapore.Design:A qualitative interpretive approach was used in this study. Focus group discussions guided by the socio-ecological model (sem), of which transcripts were analysed deductively using the sem and inductively using thematic analysis to identify themes at each sem level.Setting:Two co-educational public primary schools in Singapore.Participants:A total of 48 children (n 26 girls) took part in the semi-structured focus group discussions. Their mean age was 10·8 years (sd = 0·9, range 9–12 years), and the majority of the children were Chinese (n 36), along with some Indians (n 8) and Malays (n 4).Results:Children’s knowledge of healthy eating did not necessarily translate into healthy dietary practices and concern for health was a low priority. Instead, food and taste preferences were pivotal influences in their food choices. Parents had a large influence on children with regards to their accessibility to food, their attitudes and values towards food. Parental food restriction led to some children eating in secrecy. Peer influence was not frequently reported by children. Competitions in school incentivised children to consume fruits and vegetables, but reinforcements from teachers were inconsistent. The proximity of fast-food chains in the neighbourhood provided children easy access to less healthy foods. Health advertisements on social media rather than posters worked better in drawing children’s attention.Conclusions:Findings highlighted important factors that should be considered in future nutrition interventions targeting children.

Objective:To evaluate regional differences in factors associated with food insufficiency during the initial months of the COVID-19 pandemic among three major metropolitan regions in California, a state with historically low participation rates in the Supplementation Nutrition Assistance Program, the nation’s largest food assistance programme.Design:Analysis of cross-sectional data from phase 1 (23 April–21 July 2020) of the US Census Household Pulse Survey, a weekly national online survey.Setting:California, and three Californian metropolitan statistical areas (MSA), including San Francisco–Oakland–Berkeley, Los Angeles–Long Beach–Anaheim and Riverside–San Bernardino–Ontario MSA.Participants:Adults aged 18 years and older living in households.Results:Among the three metropolitan areas, food insufficiency rates were lowest in the San Francisco–Oakland–Berkeley MSA. Measures of disadvantage (e.g., having low-income, being unemployed, recent loss of employment income and pre-pandemic food insufficiency) were widely associated with household food insufficiency. However, disadvantaged households in the San Francisco Bay Area, the area with the lowest poverty and unemployment rates, were more likely to be food insufficient compared with those in the Los Angeles–Long Beach–Anaheim and Riverside–San Bernardino–Ontario MSA.Conclusions:Food insufficiency risk among disadvantaged households differed by region. To be effective, governmental response to food insufficiency must address the varied local circumstances that contribute to these disparities.

Background: This study examines how neighborhood socioeconomic status (nSES) and ethnic composition are associated with breast cancer risk for Asian American women. Methods: We linked individual level data from a population-based case–control study of breast cancer among Asian American women with neighborhood level data in the Greater San Francisco Bay Area (cases: n = 118, controls: n = 390). Multivariable logistic regression models examined the association between nSES, ethnic composition, and odds of having breast cancer. Results: Asian American women living in neighborhoods with high nSES and high ethnic composition had the highest odds of breast cancer, compared to those living in neighborhoods with high nSES and low ethnic composition (OR = 0.34, 95% CI [0.16–0.75]) or in neighborhoods with low nSES and high ethnic composition (OR = 0.37, 95% CI [0.17–0.83]). Discussion: Neighborhood socioeconomic and ethnic contexts are associated with breast cancer for Asian American women. We discuss explanations and avenues for future research.

Objective:To determine whether a previously reported association between the Special Supplemental Nutrition Program for Women, Infants and Children (WIC) food package change and reduced child obesity risk among WIC-participating children in Los Angeles County holds across levels of family income and neighbourhood poverty.Design:Analysis of prospectively collected WIC administrative data. The outcome was obesity at age 4 years (BMI-for-age ≥ 95th percentile). Poisson regression was applied to a matched sample (n 79 502) to determine if the association between the WIC food package change and child obesity was modified by family income (100 % but Setting:Los Angeles County, California.Participants:Children who participated in WIC in Los Angeles County between 2003 and 2016; children were grouped as receiving the old WIC food package (2003–2009) or the new WIC food package (2010–2016).Results:Receiving the new WIC food package (i.e., post-2009) was associated with 7–18 % lower obesity risk across all family income categories. Neither family income nor neighbourhood poverty significantly modified the association between the WIC food package and child obesity. However, certain sub-groups seemed to benefit more from the food package change than others. In particular, boys from families with income above poverty but residing in the poorest neighbourhoods experienced the greatest reductions in obesity risk (relative risk = 0·77; 95 % CI 0·66, 0·88).Conclusions:The WIC food package revisions were associated with reduced childhood obesity risk among all WIC-participating families in Los Angeles County, across levels of income eligibility and neighbourhood poverty.

Background We estimated longitudinal trajectories of body mass index (BMI) z-score and percentile, weight for height (WFH) z-score and percentile, and percentage of the 95th BMI percentile (BMIp95) among low-income Hispanic children ages 2–5 years to provide normative data for this population and compare the behavior of different measures. Methods Longitudinal height and weight measurements obtained from 18,072 Hispanic children aged 2–5 years enrolled in the Special Supplemental Nutrition Program for Women, Infants and Children in Los Angeles County were analyzed. Trajectories of adiposity-related measures were estimated using mixed models, stratified by sex and BMI percentile at age 2 years. Results For children in the 5th–85th BMI percentile at age 2 years, all adiposity-related measures rose during ages 2–3.5 years; during ages 3.5–5 years, BMI-based measures increased, BMIp95 decreased, and WFH-based measures were stable. For children exceeding the 85th BMI percentile at age 2 years, measures generally trended downward during ages 2–5 years, except for BMIp95, which had variable trends. Conclusions Adiposity measures changed at different rates as children grew during ages 2–3.5 years compared to ages 3.5–5 years, and different measures displayed different trends. Studies should consider examining multiple measures and focusing on change relative to a comparison group. Impact To address the childhood obesity epidemic, information on normative trajectories of adiposity-related measures in at-risk populations of young children is needed. Longitudinal analysis of data collected from low-income Hispanic children during ages 2–5 years revealed different patterns for different adiposity measures and for ages 2–3.5 years versus 3.5–5 years. Child obesity studies should consider examining multiple adiposity measures and focus on change relative to a comparison group to avoid misinterpreting longitudinal patterns.

Background Food packages provided by the Special Supplemental Nutrition Program for Women, Infants and Children (WIC) were revised in 2009 to better align them with the Dietary Guidelines for Americans. This study was conducted to evaluate whether the effect of the food package change on childhood obesity varied by the food environment in the neighborhoods where WIC-participating children live. Methods Administrative data from participating children in Los Angeles County, California (2003–2016) were merged with geocoded food vendor information by neighborhood of residence. Obesity risk at age 4 was compared between children receiving old (2003–2009) and new (2010–2016) WIC food packages using sex-stratified Poisson regression models, with interaction terms between WIC package and neighborhood density (number per square mile) of healthy and unhealthy food outlets. Results The new food package was associated with a significant decrease in obesity risk. Among boys, the new food package was associated with 8 to 18% lower obesity risk at all healthy and unhealthy food outlet densities, and the association was not modified by neighborhood food outlet density. Among girls, the association of the new food package with obesity risk was protective in neighborhoods with high healthy and low unhealthy food outlet densities, and adverse in neighborhoods with high unhealthy and low healthy food outlet densities. The effect of the new food package among girls was modified by unhealthy food outlet density, with significantly smaller (p-value = 0.004) decreases in obesity risk observed in neighborhoods with higher unhealthy food outlet density. Conclusions The impact of the food package change was modified by the neighborhood food environment among girls only. Future policy changes should incorporate consideration of ways to mitigate potentially inequitable geographic distribution of the health benefits of policy changes.

Background The Special Supplemental Nutrition Program for Women, Infants and Children (WIC) changed the food packages provided to its participants in 2009, to better align them with the Dietary Guidelines for Americans. Previous research found that the 2009 WIC food package change was associated with reduced obesity risk, particularly among breastfed infants but also among those who were never breastfed. The objective of this study was to determine if the new child food package introduced in 2009, including more produce and whole grains for 1–4-year old children, was associated with healthier growth trajectories and reduced obesity risk at age 4 years among children who were exclusively formula fed during infancy. Methods Administrative data on WIC-participating children in Los Angeles County, 2003–2016, were used (N = 74,871), including repeated measures of weight and length (or height); child’s age, gender, and race/ethnicity; maternal education and language; and family poverty. Gender-stratified spline mixed models were used to examine weight-for-height z-score (WHZ) growth trajectories from 0 to 4 years and Poisson regression models were used to assess obesity (BMI-for-age > 95th percentile) at age 4. The main independent variable was duration of receipt (dose) of the new child package, categorized as 0, > 0 to Results WHZ growth trajectories were similar for children across new child package dose groups. Boys and girls who were fully formula fed during infancy but received the new child food package for 4 years had a 7% (RR = 0.93; 95%CI = 0.89–0.98) and a 6% (RR = 0.94; 95%CI = 0.89–0.99) lower obesity risk, respectively, compared to children who received the new child food package for 0 years. There were no differences in obesity risk for children receiving child package vs. 0 years. Conclusions Providing healthy foods during childhood to children who were exclusively formula fed as infants was associated with modest improvements in obesity outcomes. While breastfeeding promotion should still be prioritized among WIC participants, providing healthy foods during childhood may provide health benefits to formula fed children, who comprise a sizeable proportion of children served by WIC.

Background:The Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) provides nutrition assistance to half of infants born in the United States. The nationally representative WIC Infants and Toddler Feeding Practices Study-2 (ITFPS-2) reported a caloric deficit at 7 months among infants receiving WIC mixed feeding packages, suggesting these infants may be at risk for growth deceleration/faltering.Methods:Longitudinal administrative data collected prospectively from WIC participants in Southern California between 2010 and 2019 were used (n= 16,255). Infant lengths and weights were used to calculate weight-for-length (WLZ), weight-for-age (WAZ) and length-for-age (LAZ) z-scores at different time points. Growth deceleration/faltering was determined at 9, 12, 18, and 24 months by the change in z-score from the last measurement taken ≤ 6 months of age. Infant feeding was categorized by the food package (breastfeeding, mixed feeding, and formula feeding) infants received from WIC at 7 months. Poisson regression models were used to evaluate the association between WIC infant package at 7 months and deceleration/faltering at 9, 12, 18, and 24 months.Results:The proportion of infants displaying decelerated/faltering growth was low for all infant food package groups. Receiving the WIC mixed feeding package at 7 months of age was not associated with WLZ, WAZ, and LAZ deceleration/faltering growth.Conclusions:Growth deceleration/faltering rates were very low among WIC participating children in Southern California, highlighting the critical role of nutrition assistance in supporting adequate growth in early childhood.

There is growing evidence that prenatal participation in the Special Supplemental Nutrition Program for Women, Infants and Children (WIC) reduces the risk of adverse birth outcomes. With recent changes in health care, rising health care costs, and increasing rates of prematurity in the U.S., there is urgency to estimate the potential cost savings associated with prenatal WIC participation. A cost-benefit analysis from a societal perspective with a time horizon over the newborn’s life course for a hypothetical cohort of 500,000 Californian pregnant women was conducted in 2017. A universal coverage, a status quo (‘business as usual’) and a reference scenario (absence of WIC) were compared. Total societal costs, incremental cost savings, return on investment, number of preterm births prevented, and incremental net monetary benefits were reported. WIC resulted in cost-savings of about $349 million and the prevention of 7,575 preterm births and would save more if it were universal. Spending $1 on prenatal WIC resulted in mean savings of $2.48 (range: $1.24 to $6.83). Decreasing prenatal WIC enrollment by 10% would incur additional costs (i.e. loss) of about $45.3 million to treat the resulting 981 preterm babies. In contrast, a 10% increase in prenatal WIC enrollment would prevent 141 preterm births and achieve additional cost-savings of $6.5 million. The findings confirm evaluations from the early 1990s that prenatal WIC participation is cost-saving and cost-effective. Further savings could be achieved if all eligible women were enrolled in WIC. Substantial preterm birth-related costs would result from reductions in WIC participation.

Objective: Evidence for effective food environment interventions to improve the quality of out-of-home foods is limited in Asia. The Healthier Dining Programme (HDP) is a voluntary government programme designed to increase the availability and accessibility of healthier foods and beverages at eateries in Singapore, a multi-ethnic, urbanized and developed nation. The objective of our study was to evaluate effects of the HDP on the out-of-home dietary intakes of consumers at an institute of higher learning. Design/Setting: We used a cluster-randomized trial design. Six food centers (two food courts and four canteens) at a large university campus were randomly assigned to the intervention or control arm. Participants were university students or staff aged ≥18 years (n=408) who frequently dined at these six food centers. Relevant data were gathered by interview and a 7-day food diary before and after 10 weeks of the intervention. Generalized estimating equations for logistic and linear regression were used to assess the difference in intake of out-of-home healthier dishes between the two study arms. Results: Participants in the intervention arm were more likely to have at least one healthier out-of-home dish per week as compared to those in the control arm (84% vs. 65%, unadjusted OR: 2.79 95% CI: 1.59, 4.88). This was due mainly to the higher consumption of dishes prepared with healthier oil blends (unadjusted OR: 3.24 95% CI: 1.95, 5.38) and lower-sodium salt (unadjusted OR: 4.36 95% CI: 1.64, 11.58) in the intervention arm. Whilst saturated and polyunsaturated fat intake in the two arms were comparable, participants in the intervention arm had lower total fat (-1.27 g/1000 kcal, 95% CI: -2.48, -0.06) and monounsaturated fat intakes (-0.50 g/1000 kcal, 95% CI: -0.94, -0.06), from out-of-home dishes as compared with the control arm. Conclusions: These findings suggest that environmental interventions at institutes of higher learning to increase healthier food availability and accessibility can improve dietary intake from out-of-home foods.Trial registration: ClinicalTrial.gov, NCT02435264. Registered 5 May 2015 - Retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT02435264NUS Institutional Review Board approval number: 11-137

Despite high rates of housing-cost burden in the United States, little is known regarding its impact on childhood obesity. In this article, we determine whether low-income 2–5-year-olds living in housing-cost burdened households are more likely to be obese and examine the potential moderators and behavioral and psychosocial mediators of this relationship. We used data from a triennial survey (2011, 2014) of a random sample of Los Angeles County participants of the Special Supplemental Nutrition Program for Women, Infants and Children (n = 2307). Logistic regression was used to examine the association between child's obesity status (Body Mass Index for age and sex ≥ 95th percentile) and severe housing-cost burden (finding it very difficult to pay for housing). Mother's depressive symptoms and child's diet and screen time were tested for mediation. We found that 16% of children lived in severe housing-cost burdened households. Severe housing-cost burden was associated with an increase in the odds of childhood obesity [aOR (95%CI) = 1.33 (1.00, 1.78)] and household size moderated this relationship. Child's diet and screen time and mother's depressive symptoms were not mediators. Given the high and vacillating rates of early childhood obesity and the increasing burden of housing costs in low-income populations, there is an urgency to better understand the role of housing-cost burden in epidemiologic investigations of early childhood obesity., Highlights • Children in severe housing-cost burdened households had more chronic stressors. • Severe housing-cost burden was associated with greater odds of childhood obesity. • Child's behavior and mother's mental well-being were not mediators of the relationship.

The recognition of the role of the environment in contributing to the obesity epidemic has led to increasing efforts to address obesity through environmental or place-based approaches in the past decade. This has challenged the use of the quasi-experimental design for evaluating community interventions. The objective of this study is to describe the development of an index of dose of exposure to community interventions that impact early childhood obesity. The goal is to provide an alternative means for evaluating the impact of multiple intervention strategies that target the same community at the same time. Two workgroups developed domains, constructs and protocols for estimating a "community intervention dose index" (CIDI). Information used to develop the protocol came from multiple sources including databases and reports of major funding organizations on obesity-related interventions implemented in Los Angeles County from 2005 to 2015, key informant interviews, and published literature. The workgroups identified five domains relevant to the consideration of dose of exposure to interventions: physical resources, social resources, context, capacity development, and programs and policies; developed a system for classifying programs and policies into macro- and micro-level intervention strategies; and sought ratings of strategy effectiveness from a panel of 13 experts using the Delphi technique, to develop an algorithm for calculating CIDI that considers intervention strength, reach and fidelity. This CIDI can be estimated for each community and used to evaluate the impact of multiple programs that use a myriad of intervention strategies for addressing a defined health outcome.

ObjectiveWhile economic crises can increase socio-economic disparities in health, little is known about the impact of the 2008–09 Great Recession on obesity prevalence among children, especially low-income children. The present study examined whether socio-economic disparities in obesity among children of pre-school age participating in a federal nutrition assistance programme have changed since the recession.DesignA pre–post observational study using administrative data of pre-school-aged programme participants from 2003 to 2014. Logistic regression was used to examine whether the relationship between obesity prevalence (BMI≥95th percentile of the Centers for Disease Control and Prevention’s growth charts) and three measures of socio-economic status (household income, household educational attainment, neighbourhood-level median household income) changed after the recession by examining the interaction between each socio-economic status measure and a 5-year time-period variable (2003–07 v. 2010–14), stratified by child’s age and adjusted for child’s sociodemographic characteristics.SettingLos Angeles County, California, USA.SubjectsChildren aged 2–4 years (n 1 637 788) participating in the Special Supplemental Nutrition Program for Women, Infants, and Children.ResultsThe magnitude of the association of household income and household education with obesity increased after 2008–09 among 3- and 4-year-olds and 2- and 3-year-olds, respectively. However, the magnitude of the association of neighbourhood-level median household income with obesity did not change after 2008–09.ConclusionsDisparities in obesity by household-level socio-economic status widened after the recession, while disparities by neighbourhood-level socio-economic status remained the same. The widening household-level socio-economic disparities suggest that obesity prevention efforts should target the most vulnerable low-income children.

BackgroundBreastfeeding has clear benefits. Yet, breastfeeding practices fall short of recommendations in low-income populations including participants of the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC). To promote breastfeeding, it is important to understand breastfeeding-related behaviors such as initiation and maintenance within the context of a complex societal system. For individual women, making choices about infant feeding (whether to breastfeed or formula-feed a newborn, or when to stop breastfeeding) is a dynamic process involving interactions with health professionals, family, peers and workplaces. Integrating behavioral change theories with systems science tools such as agent-based modeling can help illuminate patterns of breastfeeding behaviors, identify key factors affecting breastfeeding behaviors within this complex dynamic system, and estimate the population impact of hypothetical interventions.MethodsAn agent-based model (ABM) was developed to investigate the influences of multiple levels of factors affecting breastfeeding behaviors among WIC participants. Health behavioral change theories were applied and stakeholder input obtained to improve the model, particularly during the conceptual design and model specification steps. The model was then used to identify critical points for intervention and assess the effects of five common interventions (improving knowledge through education, implementing Baby-Friendly Hospital Initiative practices, providing postpartum breastfeeding counselling, strengthening partner support, and fostering supportive workplace environments.).ResultsThe ABM developed in this study produced outcomes (i.e., breastfeeding rates) that were concordant with empirical data. Increasing the coverage of the five selected interventions produced various levels of improvement in breastfeeding practices in the target population. Specifically, improving breastfeeding knowledge had a positive impact on women's intent to breastfeed, while increasing the availability of the Baby-Friendly Hospital Initiative improved breastfeeding initiation rates. However, neither of these two interventions showed a significant impact on breastfeeding maintenance, which was supported by postpartum breastfeeding counseling, partner support and a supportive workplace environment. These three intervention strategies each improved breastfeeding rates at 6 months from 55.6% to 57.1%, 59.5% and 59.3%, respectively. Increasing the coverage of multiple interventions simultaneously had a synergistic effect on breastfeeding maintenance with their effects being greater than the cumulative effects of increasing the coverage of these interventions individually.ConclusionThe ABM we developed was helpful for understanding the dynamic process of decision-making regarding infant feeding modalities in a low-income population, and for evaluating the aggregated population-level impact of breastfeeding promotion interventions.

Little is known about fine particulate matter (PM

Background: The Special Supplemental Nutrition Program for Women, Infants and Children (WIC) is a federal nutrition assistance program which provides supplemental food and nutrition services to children 0-5 years and their mothers, living in low-income households. In October of 2009, WIC food packages were changed to be better aligned to the Dietary Guidelines of Americans. Objective: The objective of this study was to evaluate whether observed differences in children’s BMI z-scores (BMIz) at age 4 years between WIC participants enrolled before and after the 2009 policy change could be attributable to changes in the type of infant feeding package they were exposed to. Methods: Our sample is based on children enrolled in WIC in Los Angeles County, CA between 2003 and 2016, from birth to age 5, with infant package issuance data for 11 or more of the first 13 months of life. Infant package exposure was quantified by the number of months receiving the fully breastfeeding infant package (a proxy for exclusive breastfeeding). A mediation analysis was performed in which BMIz at age 4 was the outcome, WIC package (new vs. old) was the exposure, and the number of months receiving the fully breastfeeding infant package was the mediator. Mediation was assessed by a product of coefficients method, and confidence limits for the mediated effect were based on the non-normal distribution of the mediated effect, using the PRODCLIN program in SAS. Models were gender-stratified and adjusted for child race/ethnicity, maternal education and language preference, household poverty status, initial weight status, and whether the child had a sibling in the sample. Results: The sample consisted of 140,204 children. Boys and girls exposed to the new WIC package received the fully breastfeeding infant package for 1.40 and 1.45 months longer than boys and girls exposed to the old WIC package. Among boys, the new WIC package was associated with a 0.12 standard deviation lower BMIz at age 4 (SE 0.01, p fully breastfeeding infant package partially mediated the association between exposure to the new WIC food package (vs. old) and BMIz at age 4, explaining 22.1% of the total effect (95% CI 19.1-25.1) for boys and 34.4% of the total effect (95% CI 29.9-38.9) for girls. Conclusions: Longer exposure to the fully breastfeeding infant package seemed to explain part of the association between BMIz at age 4 and receiving the new (vs. old) WIC food package. The percent of the total effect mediated by months of fully breastfeeding exposure was greater in girls than in boys. Future revisions to the WIC packages that continue to support women to fully breastfeed are likely to have significant effects on childhood obesity.

Summary Background It is difficult to evaluate the effectiveness of interventions aimed at reducing early childhood obesity using randomized trials. Objective To illustrate how observational data can be analysed using causal inference methods to estimate the potential impact of behavioural ‘interventions’ on early childhood adiposity. Methods We used longitudinal data from 1054 children 1–5 years old enrolled in the Special Supplemental Nutrition Program for Women, Infants and Children and followed (WIC) from 2008 to 2010 for a mean duration of 23 months. The data came from a random sample of WIC families living in Los Angeles County in 2008. We used the parametric g-formula to estimate the impact of various hypothetical behavioural interventions. Results Adjusted mean weight-for-height Z score at the end of follow-up was 0.73 (95% CI 0.65, 0.81) under no intervention and 0.63 (95% CI 0.38, 0.87) for all interventions given jointly. Exclusive breastfeeding for 6 months or longer was the most effective intervention [population mean difference = −0.11 (95% CI −0.22, 0.01)]. Other interventions had little or no effect. Conclusions Compared with interventions promoting healthy eating and physical activity behaviours, breastfeeding was more effective in reducing obesity risk in children aged 1–5 years. When carefully applied, causal inference methods may offer viable alternatives to randomized trials in etiologic and evaluation research.

Background: Dietary patterns affect both human health and environmental sustainability. Prior research found a ten-unit course on food systems and environmental sustainability shifted dietary intake and reduced dietary carbon footprint among college students. This research evaluated the impact of a similar, more scalable one-unit Foodprint seminar taught at multiple universities. Methods: We used a quasi-experimental pre-post nonequivalent comparison group design (n = 176). As part of the Menus of Change University Research Collaborative, research was conducted at three university campuses in California over four academic terms. All campuses used the same curriculum, which incorporates academic readings, group discussions, and skills-based exercises to evaluate the environmental footprint of different foods. The comparison group comprised students taking unrelated one-unit courses at the same universities. A questionnaire was administered at the beginning and end of each term. Results: Students who took the Foodprint seminar significantly improved their reported vegetable intake by 4.7 weekly servings relative to the comparison group. They also reported significantly decreasing intake of ruminant meat and sugar-sweetened beverages. As a result of dietary shifts, Foodprint seminar students were estimated to have significantly decreased their dietary carbon footprint by 14%. Conclusions: A scalable, one-unit Foodprint seminar may simultaneously promote environmental sustainability and human health.

Little is known about fine particulate matter (PM2.5) exposure among pregnant women in rural China. This study aims to characterize exposure to PM2.5 among pregnant women in rural China, and investigate potential risk factors of personal exposure to PM2.5. The data were obtained from a birth cohort study that enrolled 606 pregnant women in Xuanwei, a county known for its high rates of lung cancer. The personal exposure to PM2.5 was measured using small portable particulate monitors during each trimester of pregnancy. Participants were interviewed using structured questionnaires that sought information on risk factors of PM2.5 exposure. The daily exposure to PM2.5 among the pregnant women ranged from 19.68 to 97.08 μg/m3 (median = 26.08). Exposure to PM2.5 was higher in winter and autumn than other seasons (p

Background In 2009, for the first time since the program's inception in 1974, the Special Supplemental Nutrition Program for Women, Infants and Children (WIC) changed their food packages, providing food options better aligned with the 2005 Dietary Guidelines for Americans. Objective The aim of this study was to evaluate whether the 2009 WIC food package change was associated with changes in growth trajectories from age 0 to 4 y or obesity at age 4 among children who participated in WIC in Los Angeles County between 2003 and 2016. Methods Children were grouped into 1 of 4 exposure groups: full-dose, new food package group (participating in WIC from birth to age 4, post 2009, N = 70,120), full-dose, old food package group (participating from birth to age 4, pre 2009, N = 85,871), late-dose, new food package group (participating from age 2 to 4 y, post 2009, N = 8386), and late-dose, old food package group (participating from age 2 to 4 y, pre 2009, N = 18,241). Children were matched across groups on gender, race/ethnicity, maternal education and language, family income, and initial weight status, and matched analyses were performed. Longitudinal growth trajectories were modeled using piecewise linear spline mixed models, and differences in obesity at age 4 were compared using Poisson regression models. Results Children receiving a full dose of the new food package had healthier growth trajectories and a lower obesity risk at age 4 than children receiving a full dose of the old food package (RR [95% CI]: 0.88 [0.86, 0.91] for boys, 0.90 [0.87, 0.93] for girls). Boys, but not girls, in the late-dose, new food package group had a lower obesity risk at age 4 compared with boys in the late-dose, old food package group (RR = 0.89, 95% CI = 0.81, 0.98). Conclusions The WIC food package change appears to be associated with improved childhood obesity outcomes. These findings are important in informing policymakers considering further improvements to the WIC food packages.

Background Immigrants to the United States are usually healthier than their U.S.-born counterparts, yet the health of immigrants declines with duration of stay in the U.S. This pattern is often seen for numerous health problems such as obesity, and is usually attributed to acculturation (the adoption of “American” behaviors and norms). However, an alternative explanation is secular trends, given that rates of obesity have been rising globally. Few studies of immigrants are designed to distinguish the effects of acculturation versus secular trends, in part because most studies of immigrants are cross-sectional, lack baseline data prior to migration, and do not have a comparison group of non-migrants in the country of origin. This paper describes the Health of Philippine Emigrants Study (HoPES), a study designed to address many of these limitations. Methods HoPES is a dual-cohort, longitudinal, transnational study. The first cohort consisted of Filipinos migrating to the United States (n = 832). The second cohort consisted of non-migrant Filipinos who planned to remain in the Philippines (n = 805). Baseline data were collected from both cohorts in 2017 in the Philippines, with follow-up data collection planned over 3 years in either the U.S. for the migrant cohort or the Philippines for the non-migrant cohort. At baseline, interviewers administered semi-structured questionnaires that assessed demographic characteristics, diet, physical activity, stress, and immigration experiences. Interviewers also measured weight, height, waist and hip circumferences, blood pressure, and collected dried blood spot samples. Discussion Migrants enrolled in the study appear to be representative of recent Filipino migrants to the U.S. Additionally, migrant and non-migrant study participants are comparable on several characteristics that we attempted to balance at baseline, including age, gender, and education. HoPES is a unique study that approximates a natural experiment from which to study the effects of immigration on obesity and other health problems. A number of innovative methodological strategies were pursued to expand the boundaries of current immigrant health research. Key to accomplishing this research was investment in building collaborative relationships with stakeholders across the U.S. and the Philippines with shared interest in the health of migrants.

Background: Obesity prevalence among low-income preschool-aged children in the United States decreased between 2010 and 2014. However, this decreasing trend may be varied across socioeconomic subgroups. This study examined trends in obesity prevalence among low-income children from 2003 to 2014 by child's age and household and neighborhood socioeconomic status (SES). Methods: This study used administrative data for all children, aged 2–4 years, participating in the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) in Los Angeles County (LAC) during the years 2003–2014. Obesity was defined as having a BMI ≥95th percentile of CDC's age- and sex-specific growth charts. Household income and household educational attainment were indicators of household SES. Neighborhood median household income was an indicator of neighborhood SES. Results: Childhood obesity prevalence increased sharply from 15.7% in 2003 to 19.1% in 2005, and remained constant until 2010, when it started decreasing. During most years, the prevalence of obesity was higher among the lowest SES groups. Despite the recent decreasing trend, the 2014 estimates were still generally higher than the 2003 levels except among some low-income children living in less-poor and more-educated households. Conclusions: The decreasing trend between 2010 and 2014 among WIC-participating children in LAC is encouraging and mirrors national trends among WIC-participating children. However, continued efforts should be made to focus obesity prevention efforts on low-income children, especially those who are the most vulnerable as they have experienced significant gains in obesity since 2003.

Although many studies have examined the relationship of adiposity with neighborhood socioeconomic context in adults, few studies have investigated this relationship during adolescence. Using 10-year annual measurements of body mass index, expressed as z-scores (BMIz), obtained from 775 black and white participants of the National Heart, Lung, and Blood Institute Growth and Health Study, a prospective cohort study of girls from pre- to postadolescence, we used multilevel modeling to investigate whether family socioeconomic status (SES) and neighborhood socioeconomic characteristics (measured by census-tract median family income) explain variation in BMIz trajectory parameters. Analyses controlled for pubertal maturation. We found that lower SES was associated with higher overall levels of BMIz for both white and black girls. Additionally, lower-SES black girls had a more sustained increase in BMIz during early adolescence and reached a higher peak compared to higher-SES black girls and to white girls. Neighborhood income was associated with BMIz trajectory for black girls only. Unexpectedly, among black girls, living in higher-income neighborhoods was associated with higher overall levels of BMIz, controlling for SES. Our findings suggest that neighborhood socioeconomic characteristics may affect adolescent BMIz trajectories differently in different racial/ethnic groups.

Background Participation in the Supplemental Nutrition Assistance Program (SNAP) has been linked to an increased risk of obesity, but not much is known about the mechanisms behind this association. The objective of this study was to determine if the neighborhood density of unhealthy food outlets modifies the association between obesity and participation in SNAP. Methods Data comes from the first wave of the Los Angeles Family and Neighborhood Survey; included are a subsample of adults (18+ years) who were SNAP participants or eligible non-participants (N = 1,176). We carried out multilevel analyses with obesity (BMI ≥ 30 Kg/m2), SNAP participation, and the neighborhood density of unhealthy food outlets as dependent, independent and modifying variables, respectively, controlling for age, gender, race/ethnicity, marital status, working status, mental health, and neighborhood poverty. Results SNAP participants had double the odds of obesity compared to eligible non-participants (OR = 2.02; 95%CI = 1.44-2.83). However, the neighborhood density of unhealthy food outlets did not modify this association. Conclusions SNAP participation was associated with higher odds of obesity in our primarily Hispanic sample in Los Angeles County, with no effect modification found for the unhealthy portion of the food environment. More research is needed with additional food environment measures to confirm our null findings. Additional research is needed to elucidate the mechanisms linking SNAP participation and obesity as they remain unclear.

This study examined the relationship between racial/ethnic residential segregation and access to health care in rural areas. Data from the Medical Expenditure Panel Survey were merged with the American Community Survey and the Area Health Resources Files. Segregation was operationalized using the isolation index separately for African Americans and Hispanics. Multi-level logistic regression with random intercepts estimated four outcomes. In rural areas, segregation contributed to worse access to a usual source of health care but higher reports of health care needs being met among African Americans (Adjusted Odds Ratio [AOR]: 1.42, CI: 0.96-2.10) and Hispanics (AOR: 1.25, CI: 1.05-1.49). By broadening the spatial scale of segregation beyond urban areas, findings showed the complex interaction between social and spatial factors in rural areas.

Background Few studies have examined the association between the food environment and adiposity in early childhood, a critical time for obesity prevention. The objective of this study was to examine the longitudinal association between neighbourhood food environment and adiposity among low-income preschool-aged children in a major metropolitan region in the USA. Methods The study sample was 32 172 low-income preschool-aged children in Los Angeles County who had repeated weight and height measurements collected between ages 2 and 5 years through a federal nutrition assistance programme. We conducted multilevel longitudinal analyses to examine how spatial densities of healthy and unhealthy retail food outlets in the children's neighbourhoods were related to adiposity, as measured by weight-for-height z-score (WHZ), while controlling for neighbourhood-level income and education, family income, maternal education, and child's gender and race/ethnicity. Results Density of healthy food outlets was associated with mean WHZ at age 3 in a non-linear fashion, with mean WHZ being lowest for those exposed to approximately 0.7 healthy food outlets per square mile and higher for lesser and greater densities. Density of unhealthy food outlets was not associated with child WHZ. Conclusions We found a non-linear relationship between WHZ and density of healthy food outlets. Research aiming to understand the sociobehavioural mechanisms by which the retail food environment influences early childhood obesity development is complex and must consider contextual settings. © 2014 by the BMJ Publishing Group Ltd.

Recent federal initiatives have used estimates of population reach as a proxy metric for intervention impact, in part to inform resource allocation and programmatic decisions about competing priorities in the community. However, in spite of its utility, population reach as a singular metric of intervention impact may be insufficient for guiding multifaceted program decisions. A more comprehensive, validated approach to measure or forecast dose may complement reach estimates to inform decision makers about optimal ways to use limited resources.

Objectives. We assessed the effect of the new Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) food package, implemented in October 2009, on breastfeeding outcomes among a predominately Latina sample of WIC participants in Los Angeles County, California. Methods. We used data from 5020 WIC participants who were interviewed in a series of repeated cross-sectional surveys conducted in 2005, 2008, and 2011. Participants were randomly selected from Los Angeles County residents who received WIC services during those years. Results. Consistent with the WIC population in Los Angeles, participants were mostly Latina and had low levels of income and education; more than half were foreign-born. We found small but significant increases from pre- to postimplementation of the new WIC food package in prevalence of prenatal intention to breastfeed and breastfeeding initiation, but no changes in any breastfeeding at 3 and 6 months. The prevalence of exclusive breastfeeding at 3 and 6 months roughly doubled, an increase that remained large and significant after adjustment for other factors. Conclusions. The new food package can improve breastfeeding outcomes in a population at high risk for negative breastfeeding outcomes.

Objectives. To examine whether living in a rural versus urban area differentially exposes populations to social conditions associated with disparities in access to health care. Methods. We linked Medical Expenditure Panel Survey (2005–2010) data to geographic data from the American Community Survey (2005–2009) and Area Health Resource File (2010). We categorized census tracts as rural and urban by using the Rural–Urban Commuting Area Codes. Respondent sample sizes ranged from 49 839 to 105 306. Outcomes were access to a usual source of health care, cholesterol screening, cervical screening, dental visit within recommended intervals, and health care needs met. Results. African Americans in rural areas had lower odds of cholesterol screening (odds ratio[OR] = 0.37; 95% confidence interval[CI] = 0.25, 0.57) and cervical screening (OR = 0.48; 95% CI = 0.29, 0.80) than African Americans in urban areas. Whites had fewer screenings and dental visits in rural versus urban areas. There were mixed results for which racial/ethnic group had better access. Conclusions. Rural status confers additional disadvantage for most of the health care use measures, independently of poverty and health care supply.

The Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) serves 50% of infants and 25% of preschool-aged children in the United States and collects height and weight measurements from eligible children every 6 mo, making WIC data a valuable resource for studying childhood growth and obesity. We assessed the accuracy of measurements collected by WIC staff by comparing them to "gold standard" measurements collected by trained research staff.Intraclass correlation coefficients (ICCs) measuring agreement between WIC and research protocol measurements for height, weight, and BMI were 0.96, 0.99, and 0.93, respectively. Although WIC measurements overestimated height by 0.6 cm and weight by 0.05 kg on average, BMI was underestimated by only 0.15 kg/m(2) on average. WIC BMI percentiles classified children as overweight/obese vs. underweight/normal with 86% sensitivity and 92% specificity.We conclude that height, weight, and BMI measurements of children aged 2-5 y collected by trained WIC staff are sufficiently accurate for monitoring and research purposes.At seven WIC clinics in southern California, 287 children aged 2-5 y measured for height and weight by WIC staff using WIC standard protocol were remeasured by research staff using a research protocol (duplicate measurements with shoes and outerwear removed were taken by trained personnel).

ObjectiveThis paper examines trends in the neighbourhood food store environment (defined by the number and geographic density of food stores of each type in a neighbourhood), and in food consumption behaviour and overweight risk of 5779 men and women.DesignThe study used data gathered by the Stanford Heart Disease Prevention Program in four cross-sectional surveys conducted from 1981 to 1990.SettingFour mid-sized cities in agricultural regions of California.SubjectsIn total, 3154 women and 2625 men, aged 25–74 years.ResultsFrom 1981 to 1990, there were large increases in the number and density of neighbourhood stores selling sweets, pizza stores, small grocery stores and fast-food restaurants. During this period, the percentage of women and men who adopted healthy food behaviours increased but so did the percentage who adopted less healthy food behaviours. The percentage who were obese increased by 28% in women and 24% in men.ConclusionFindings point to increases in neighbourhood food stores that generally offer mostly unhealthy foods, and also to the importance of examining other food pattern changes that may have a substantial impact on obesity, such as large increases in portion sizes during the 1980s.

Objective: To determine whether socioeconomic and food-related physical characteristics of the neighbourhood are associated with body mass index (BMI; kg/m 2 ) independently of individual-level sociodemographic and behavioural characteristics. Design and methods: Observational study using (1) individual-level data previously gathered in five cross-sectional surveys conducted by the Stanford Heart Disease Prevention Program between 1979 and 1990 and (2) neighbourhood-level data from (a) the census to describe socioeconomic characteristics and (b) data obtained from government and commercial sources to describe exposure to different types of retail food stores as measured by store proximity, and count of stores per square mile. Data were analysed using multilevel modelling procedures. The setting was 82 neighbourhoods in agricultural regions of California. Participants: 7595 adults, aged 25–74 years. Results: After adjusting for age, gender, ethnicity, individual-level socioeconomic status, smoking, physical activity and nutrition knowledge, it was found that (1) adults who lived in low socioeconomic neighbourhoods had a higher mean BMI than adults who lived in high socioeconomic neighbourhoods; (2) higher neighbourhood density of small grocery stores was associated with higher BMI among women; and (3) closer proximity to chain supermarkets was associated with higher BMI among women. Conclusion: Living in low socioeconomic neighbourhoods, and in environments where healthy food is not readily available, is found to be associated with increased obesity risk. Unlike other studies which examined populations in other parts of the US, a positive association between living close to supermarkets and reduced obesity risk was not found in this study. A better understanding of the mechanisms by which neighbourhood physical characteristics influence obesity risk is needed.

It is difficult to evaluate the effectiveness of interventions aimed at reducing early childhood obesity using randomized trials. Objective To illustrate how observational data can be analysed using causal inference methods to estimate the potential impact of behavioural 'interventions' on early childhood adiposity. Methods We used longitudinal data from 1054 children 1-5 years old enrolled in the Special Supplemental Nutrition Program for Women, Infants and Children and followed (WIC) from 2008 to 2010 for a mean duration of 23 months. The data came from a random sample of WIC families living in Los Angeles County in 2008. We used the parametric g-formula to estimate the impact of various hypothetical behavioural interventions. Results Adjusted mean weight-for-height Z score at the end of follow-up was 0.73 (95% CI 0.65, 0.81) under no intervention and 0.63 (95% CI 0.38, 0.87) for all interventions given jointly. Exclusive breastfeeding for 6 months or longer was the most effective intervention [population mean difference = -0.11 (95% CI -0.22, 0.01)]. Other interventions had little or no effect. Conclusions Compared with interventions promoting healthy eating and physical activity behaviours, breastfeeding was more effective in reducing obesity risk in children aged 1-5 years. When carefully applied, causal inference methods may offer viable alternatives to randomized trials in etiologic and evaluation research.

A devastating earthquake struck west China in 2008. Reconstruction efforts have focused on urbanization and modernization, hastening economic growth in the area. This rapid growth provides a unique opportunity to explore the potential impact of rapid environmental changes on metabolic disease risk. The study objective was to gather qualitative information from residents of a rapidly changing area in China to determine perceived changes in food- and physical activity-related aspects of the environment and their perceived effects on health. We conducted extensive interviews with 30 residents of an area where towns were rapidly rebuilt after being destroyed by the 2008 Wenchuan earthquake. Findings suggest that a longitudinal investigation of children and their families in this rapidly developing region may identify mechanisms by which environmental factors influence the development of diet-related chronic illnesses.

Most studies of immigrant health are cross-sectional and fail to collect information prior to migration, leading to potential bias and confounding. The present pilot study examines the feasibility of studying migrants prospectively, with baseline data collected before migration. The study followed two cohorts of Filipinos for one year, a migrant cohort (n=27) that emigrated to the U.S. and a second non-migrant cohort (n=26) that remained in the Philippines. The one-year retention rate was 96%. The migrant cohort arrived in the U.S. within two months of their baseline assessment. Migrants and non-migrants did not differ with regard to body mass index, waist circumference, or waist to hip ratio at baseline or at follow-up. It is feasible to conduct a transnational, longitudinal study of two cohorts of Filipinos. This design provides important pre-migration information, is analogous to a natural experiment, can be upscaled, and allows for a rigorous examination of immigrant health.

ObjectivePrevious studies have established that acculturation is associated with dietary intake among Mexican immigrants and their offspring, but few studies have investigated whether food purchasing, food preparation or food-related values act as mechanisms of dietary acculturation. We examine the relationship between language use and a wide range of food behaviours and food-related values among Mexican-American adults.DesignNationally representative probability sample of the US population.Setting2005–2010 National Health and Nutrition Examination Survey.SubjectsMexican-American adults (n 2792) at least 20 years of age.ResultsMexican Americans who speak only or mostly English consume more energy from fast-food and sit-down restaurants and report increased consumption of non-homemade meals, fast-food and pizza meals, frozen meals and ready-to-eat meals relative to Spanish speakers. English speakers prepare one fewer homemade dinner per week and spend less time on meal preparation. English speakers are more likely than Spanish speakers to cite convenience as an important reason why they prefer fast food over cooking at home. There is no relationship between language use and the perceived importance of the nutritional quality, price or taste of fast food.ConclusionsOur results provide evidence that the well-documented relationship between acculturation and diet among Mexican Americans may be just one indicator of a broader pattern characterized by decreased home meal preparation and increased reliance on convenience foods.