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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.

The complex multifactorial nature of childhood obesity makes community interventions difficult to evaluate using traditional approaches; innovative methods are needed.To evaluate the impact of various interventions targeting childhood obesity-related behaviours, and classified as using a micro-level (e.g., home visitation programs) or macro-level (e.g., business practices) strategy, on obesity among children enrolled in the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC).We simulated a population of 1500 children enrolled in WIC, with specific diet, physical activity, breastfeeding behaviours and body mass index z-scores (BMIz), following them from age 2 to 5 years.Combined interventions targeting breastfeeding appeared to be moderately effective, reducing BMIz by 0.03 (95% CI -005, -0.01). Two strategy-specific interventions, home visitation programs and business practices targeting obesity-related behaviours, appeared to be moderately effective at reducing BMIz by 0.04 (95% CI -0.06, -0.02) and 0.02 (95% CI -0.04, 0.00), respectively. Contrary to expectation, combining all micro and macro interventions appeared to have no impact or moderately increased the proportion of obesity/overweight among children.Interventions targeting breastfeeding behaviour were most effective when both micro and macro strategies were implemented. Interventions targeting obesity-related behaviours in general were effective for two strategies, home visitation and business practices.

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.

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.

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.

Background In 2009, the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) food packages were updated. WIC-participating children in Los Angeles County receiving the new food package, compared with the old, had lower obesity risk at age 4. Objective To determine if the association between the new WIC food package and obesity varies by type of infant WIC food package received. Design Longitudinal study using administrative data on children participating in WIC in Los Angeles County continuously from birth until age 4. Children were compared across periods: Before (period 1: born 2003-2004), straddling (period 2: born 2005-2008), and after (period 3: born 2009-2011) the food package change. Children were further grouped as Fully Breastfed, Mostly Breastfed, Mostly Formula Fed, and Fully Formula Fed based on the type of food packages received during the first year of life. Participants/setting WIC-participating children in Los Angeles County between 2003 and 2016 (N=116,991). Main outcome measures Weight-for-height z-score growth trajectories from 0 to 4 years and obesity (body mass index-for-age≥95th percentile) at age 4. Statistical analyses performed Children were matched across periods on infant feeding group; age, sex, race or ethnicity, and initial weight status; maternal education and language; and family poverty. Sex-stratified piecewise linear spline mixed models and Poisson regression models were fit to the data. Results No differences across periods were observed for children in the Fully Breastfed group. Boys in the Mostly Breastfed (relative risk [RR]=1.27, 95% CI=1.17 to 1.38), Mostly Formula Fed (RR=1.07, 95% CI=1.02 to 1.13), and Fully Formula Fed (RR=1.13, 95% CI=1.06 to 1.20) groups in period 1 had higher obesity risk than their counterparts in period 3; girls in the Mostly Breastfed group in period 1 had a higher obesity risk than those in period 3 (RR=1.17, 95% CI=1.07 to 1.28). Conclusions The association between the WIC food package change and obesity varied by type of infant food package received, with the strongest associations observed for those who were mostly breastfed.

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.

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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.

OBJECTIVE To assess whether the effect of the 2009 women, infants, and children (WIC) food package change on obesity outcomes varies by initial weight status and gender. METHODS Using 2003 to 2016 data from Los Angeles County, we compared growth trajectories and obesity at age 4 years among children exposed to WIC after the food package change (n = 53 075) vs children exposed before (n = 53 075). Analyses were stratified by gender and initial weight status: low weight-for-height z-score (WHZ ≤ 25th percentile), average WHZ (25th

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: Breastfeeding rates among low-income infants lag behind national rates. Policies such as the Baby-Friendly Hospital Initiative (BFHI) improve breastfeeding and may benefit low-income populations such as those who participate in the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC). A recent effort exists to increase the number of Baby-Friendly designated hospitals in Los Angeles County (LAC). Research aim: This study aimed to determine whether the BFHI effort has had a beneficial effect on Baby-Friendly hospital practices in LAC hospitals and to determine if birthing hospitals’ Baby-Friendly designation status is associated with breastfeeding outcomes among WIC-participating children in LAC. Methods: Data came from the Los Angeles County WIC Survey (2008, 2011, 2014), which is conducted on a random sample of approximately 5,000 WIC families living in LAC. The prevalence of three Baby-Friendly hospital practices was examined between 2008 and 2014. Logistic regression was used to examine the association of birthing hospitals’ Baby-Friendly designation status with any breastfeeding and exclusive breastfeeding at 1, 3, and 6 months. Results: The rates of Baby-Friendly hospital practices have improved since 2008. Although no association existed with rates of any breastfeeding, being born in a hospital designated Baby-Friendly or in the process of obtaining this designation was significantly associated with an increased odds of exclusive breastfeeding at 1 and 3 months. Conclusion: The BFHI may help achieve recommended exclusive breastfeeding rates, especially for low-income populations. Additional strategies are needed to support low-income mothers in LAC with all levels of breastfeeding.

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.

Background Although increasing access to electronic benefit transfer (EBT) at farmers' markets has become a popular strategy for encouraging healthy eating, its relationships to a number of dietary behaviors in low-income populations are not well understood. Objective To describe the frequency of and relationships between EBT access, fruit and vegetable intake, and sugar-sweetened beverage (SSB) consumption among public health center (PHC) clients with access to EBT at farmers' markets during 2011-2012. Design Cross-sectional. Participants/setting Low-income participants recruited from the waiting rooms of five multipurpose PHCs operated by the Los Angeles County Department of Public Health. Main outcome measures Fruit and vegetable and SSB consumption (number per week). Statistical analysis Data from the 2012 Los Angeles County Health and Nutrition Examination Survey were analyzed using multivariable regressions, with EBT access at farmers' markets as the primary independent variable. Covariates included EBT use, transportation behaviors, neighborhood attributes, and sociodemographic characteristics. Results A total of 1,503 adults participated in the survey (response rate=69%). Of these, 529 reported receiving EBT benefits. Among these benefits recipients, 64% were women, 54% were aged 25 to 44 years, 62% were black, and 75% were unemployed or part-time employed. In multivariable regression analyses, EBT access at farmers' markets was positively associated with higher fruit and vegetable consumption; however, an association to SSB consumption was not demonstrated. Conclusions EBT access at farmers' markets is related to higher fruit and vegetable consumption among PHC clients in Los Angeles County. However, the finding of no association to SSB consumption raises important questions about the need for strategies to discourage EBT recipients' purchase of foods of minimal nutritional value in other venues that accept nutrition assistance program benefits.

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.

Although obesity is associated with increased risk of many chronic diseases including cardiovascular disease, diabetes, hypertension, and cancer, there is little evidence to suggest that obesity increases risk of osteoporosis. In fact, both weight and body mass index (BMI) are positive predictors of bone mass in adults, suggesting that those who are overweight or obese may be at lower risk of osteoporosis. However, recent evidence suggests that in children and adolescents, obesity may be associated with lower rather than higher bone mass. To understand the relation of fat mass to bone mass, we examined data gathered from an ethnically diverse group of 921 young women, aged 20-25 years (317 African Americans, 154 Asians, 322 Caucasians, and 128 Latinas) to determine how fat mass (FM) as well as lean tissue mass (LTM) is associated with bone mass. Bone mass, FM, and LTM were measured using dual energy X-ray absorptiometry (GE Lunar Corp, Madison, WI). Bone mass was expressed as bone mineral density (BMD; g/cm2) and bone mineral apparent density (BMAD; g/cm3) for the spine and femoral neck, and as BMD and bone mineral content (BMC; g) for the whole body. Regression techniques were used to examine the following: (1) in separate equations, the associations of LTM and FM with each bone mass parameter; and (2) in the same equation, the independent contributions of LTM and FM to bone mass. LTM and FM were positively correlated with BMD at all skeletal sites. When the contributions of FM and LTM were examined simultaneously, both FM and LTM continued to be positively associated with bone mass parameters but the effect of FM was noted to be smaller than that of LTM. We conclude that in young women, LTM has a greater effect than fat mass on bone density per kg of tissue mass.

Dear Editors We are pleased that our paper has been deemed thought-provoking. Regarding the issues brought by Joe Brew, we would like to respond as follows: 1. Brew suggests that we should have used body mass index (BMI) percentiles instead of weight-for-height z-scores (WHZ). We disagree and stand behind our original statement that WHZ is a more appropriate measure for longitudinally assessing adiposity among young children. In the paper cited by Brew1 as justification for his argument, …

As countries develop economically and increasing numbers of women enter the workforce, children are partly being cared for by someone other than their mother. Little is known about the impact of this shift in child-care provider on children’s nutrition. This study presents findings from a case study of Singapore, a small country that has experienced phenomenal economic growth. Focus groups were conducted with 130 women of varying educational levels and ethnicities to learn about food decisions in their families. The findings showed that Singaporean working women cook infrequently, families eat out frequently, and children exert considerable influence on food choices. Implications for work–family policies and child health are discussed.

Background Given the rapid pace of urbanization and Westernization and the increasing prevalence of obesity, there is a need for research to better understand the influence of the built environment on overweight and obesity in world’s developing regions. Culturally-specific food environment survey instruments are important tools for studying changing food availability and pricing. Here, we present findings from an effort to develop and evaluate food environment survey instruments for use in a rapidly developing city in southwest China. Methods We developed two survey instruments (for stores and restaurants), each designed to be completed within 10 minutes. Two pairs of researchers surveyed a pre-selected 1-km stretch of street in each of three socio-demographically different neighborhoods to assess inter-rater reliability. Construct validity was assessed by comparing the food environments of the neighborhoods to cross-sectional height and weight data obtained on 575 adolescents in the corresponding regions of the city. Results 273 food establishments (163 restaurants and 110 stores) were surveyed. Sit-down, take-out, and fast food restaurants accounted for 40%, 21% and 19% of all restaurants surveyed. Tobacco and alcohol shops, convenience stores and supermarkets accounted for 25%, 12% and 11%, respectively, of all stores surveyed. We found a high percentage of agreement between teams (>75%) for all categorical variables with moderate kappa scores (0.4-0.6), and no statistically significant differences between teams for any of the continuous variables. More developed inner city neighborhoods had a higher number of fast food restaurants and convenience stores than surrounding neighborhoods. Adolescents who lived in the more developed inner neighborhoods also had a higher percentage of overweight, indicating well-founded construct validity. Depending on the cutoff used, 19% to 36% of male and 10% to 22% of female 16-year old adolescents were found to be overweight. Conclusions The prevalence of overweight Chinese adolescents, and the food environments they are exposed to, deserve immediate attention. To our knowledge, these are the first food environment surveys developed specifically to assess changing food availability, accessibility, and pricing in China. These instruments may be useful in future systematic longitudinal assessments of the changing food environment and its health impact in China.

The primary objective of this analysis was to examine the burden of diabetes among Asians and Asian subgroups in Los Angeles County, which has the largest county population of Asians in the U.S.Data were analyzed from 6cycles of the Los Angeles County Health Survey, 1997-2011 (n=47,282). Asian adults (n=4672) were categorized into the following ethnic subgroups: Chinese, Filipino, Korean, Japanese, Vietnamese, South Asian, and Other Asian. Descriptive and multivariable logistic regression analyses were conducted to examine trends in prevalence, prevalence among Asian subgroups, and factors associated with diabetes.In 2005, we observed a rapid increase in diabetes prevalence among Asians compared to whites despite consistently lower BMI relative to other racial/ethnic groups. Diabetes prevalence was significantly higher among Filipinos and South Asians (10%) compared to East Asians and Vietnamese (7%). After adjusting for all covariates, Asians who were older, non-drinkers, insured, and overweight or obese were found to have increased odds of diabetes.Diabetes prevalence is increasing more rapidly among Asians compared to whites despite overall lower BMI. The significant heterogeneity among Asian subgroups highlights the need for disaggregated data and additional research to develop culturally appropriate interventions for diabetes prevention and control.

This study examines responses to questions regarding food choices and decisions from 18 focus groups of women ( n = 130) age 30–55 years living in Singapore. Focusing on the responses to the questions in the interview protocol closely associated with decision making identified several themes. Food choices and eating decisions are composite phenomenon. These composite food decisions reflect flexible, open systems we refer to here as idiosyncratic regimes in which environmental, social, and intra-personal streams of influence are prioritized as individuals generate possible food decisions. Food decisions represent the imagined and actual presence of the “family” and differing inter-generational food preferences. As women attempt to create harmony from the diversity of food preferences they generate idiosyncratic regimes of food and eating reflecting “triadic streams of influence” manifest in the context of everyday contingencies of family and individual life. Recent concern in Singapore on the part of the Health Promotion Board and the Saw Swee Hock School of Public Health at the National University of Singapore regarding the increasing prevalence of diet-related diseases and obesity among Singaporeans provided the impetus for conducting this qualitative study of food and eating among Singaporean women.

This pilot study explores the roles of family socioeconomic status (SES) in influencing dietary consumption patterns in 60 Chinese elementary school-aged children (ages 6-11) in Chengdu, China. Two interviewer-administered questionnaires were specially developed to gather sociodemographic and food frequency data. Children from low SES families consumed rice and traditional staples, and high calcium drinks more frequently, and western fast food less frequently than children from higher SES families. After controlling for family SES, children who were primarily cared for by their mothers or grandparents consumed less healthy snacks less frequently than children who were primarily cared for by other adults (including fathers).

To investigate differences in childhood overweight and obesity prevalence among Asian/Pacific Islander (API) subgroups.Cross-sectional secondary data analysis.California public school children participating in an annual state-mandated physical fitness testing program which included measured height and weight.5th, 7th and 9th grade students attending public schools in Los Angeles County (LAC) in 2006 and 2007 (n=670,352).Overweight and obesity prevalence, where overweight is categorized between the 85th to95th BMI-forage percentile, and obese is defined at the 95th BMI-for-age percentile and above according to the Centers for Disease Control and Prevention Growth Charts.The overall prevalence of obesity among LAC students was 22.9%, and was 19.4% for overweight. For API students, the prevalence of obesity was markedly different between Asians and Pacific Islanders (PIs) (12.1% vs. 35.6%, P0.01). Obesity also differed noticeably among ethnic subgroups, ranging from 8.4% to 17.5% among Asians, and from 17.2% to 48.6% among PIs. The prevalence of overweight students ranged from 12.8% to 17.3% among Asians and from 16.4% to 21.1% among PIs.Childhood obesity and overweight prevalence in the API population varies widely among ethnic subgroups, strongly indicating a need for disaggregating data relating to APIs. Recognizing the heterogeneity of the API population will allow more effective prioritization of community intervention and outreach efforts within API communities and improve recognition and treatment by healthcare providers of API children who may be at higher risk for obesity.

The current epidemic of childhood overweight has launched a variety of school-based efforts to address the issue. This study reports on the first 2 years of a 3-year evaluation of one school district's comprehensive intervention to transform school foodservices and dining experiences, offer cooking and gardening programs, and integrate nutrition and food systems concepts into the academic curriculum.This 3-year prospective study enrolled 327 4th and 5th graders in a mid-sized school district in California, and followed them into middle school. Intervention exposure was determined through interviews with school staff and student surveys. Student knowledge and attitudes were assessed annually by questionnaire, and student behavior was assessed annually by 3-day food diary. Household information was gathered by parent questionnaire. Changes in knowledge, attitudes, and behavior were compared by level of intervention exposure using analysis of covariance; pairwise differences were evaluated using Bonferroni's test at a procedure-wise error rate of 5%.After controlling for family sociodemographic background, students most exposed to the intervention increased their consumption of fruits and vegetables by nearly 0.5 cups (one standard serving), whereas students least exposed decreased their consumption by 0.3 cups (p.05). Students most exposed to the programming also showed a significantly greater increase in preference for fruit and green leafy vegetables, compared to students least exposed to the programming (p.05).Future research is needed to better understand the relative importance of the different components of such a program, and their cost-benefits as well as health impacts.

Objective Early menarche is a risk factor for breast cancer. We investigated the variation in age at menarche by socioeconomic status (SES) and race. Methods A cohort study was conducted on 1,091 black and 986 white girls from the three sites in the United States as part of the NHLBI Growth and Health Study (NGHS), who were aged 9–10 years at baseline and followed through adolescence over a 10-year period with annual exams. Using logistic regression models, we evaluated the nature and strength of associations between two socioeconomic indicators (household income and parental education) and early menarche (\12 years old) unadjusted and adjusted for anthropometry and maternal age at menarche. Results Proportionately, more black girls were menarcheal before 12 years of age compared to their white counterparts (46%, n = 468 vs. 26%, n = 240, respectively, p \ 0.0001). Parental education was not a significant predictor of early menarche. The graded association between household income and age at menarche was strong and significant among black girls but less clear among white girls. Compared with those in the lowest quartile of household income, white girls in the highest quartile were at a significantly lower risk of early menarche [adjusted odds ratio (OR) = 0.37, 95% confidence intervals (CIs) 0.18–0.80]. The inverse was true for black girls: those in the highest quartile of household income were at an increased risk of early menarche (adjusted OR = 2.15, 95% CI 1.27–3.63) Conclusion The SES factor selected (household income versus parental education) affected the findings regarding racial differences in the timing of menarche. It will be important for future studies to elucidate the link between household income and age at menarche in developed countries.

Background: Television watching, a sedentary activity, has been associated with overweight in children. While the family environment is known to influence television watching, little is known about the influence of the neighbourhood environment. This study is an exploratory examination of the association of socioeconomic characteristics of the neighbourhood environment with television watching among 9–10 year old girls. Methods: Data collected by the Berkeley site of the National Heart, Lung and Blood Institute Growth and Health Study (NGHS) in 1987–8 from 787 girls who had a complete set of measurements relevant to the analysis were used. These measures included parental education, household income, race and weekly hours spent watching television. Addresses of the girls were geocoded and the median household income for the census tracts in which they lived was used to indicate neighbourhood socioeconomic characteristics. Multilevel modelling procedures were used to estimate fixed effect coefficients for individual and neighbourhood level variables. Results: Living in high income areas was associated with less television watching, a finding that held even when controlling for parental education, household income and race. Race and parental education were also associated with television watching. Conclusion: Television watching among girls was associated not only with the socioeconomic characteristics of their households, but also of their neighbourhoods. Future studies should explore the mechanisms that mediate this relation and determine if these results are generalisable to other populations.

Childhood obesity may be seen as a marker for high-risk dietary and physical inactivity practices. Recent increases in the prevalence of overweight and obesity among American children are not limited to one age, gender, or ethnic group, which suggests that unique behaviors of the members of various racial or ethnic subgroups of the population are unlikely to be the major contributing factors. Rather, it seems that environmental changes promoting increased energy intake and decreased energy output are occurring and have widespread impact on children from various backgrounds. Although no ethnic group is immune from the current shift in energy balance, differential rates of overweight seem to exist among ethnic groups. National probability samples of African-American, Hispanic, and white children in the United States provide clear evidence that white children are at lower risk for childhood overweight than are African-American or Hispanic children. Of concern is the lack of national data on the prevalence of overweight and obesity for Native-American and Asian-American groups. Also of concern is the aggregation of racial and ethnic subgroups, which may render prevalence rates meaningless. This possibility is clearly true with some surveys of weight status that combine diverse populations, such as Asians and Pacific Islanders, into one group. The high rates of obesity in African-American, Hispanic, and Native-American children are of concern. Although parental SES is associated inversely with childhood obesity among whites, higher SES does not seem to protect African-American and Hispanic children against obesity. In these groups, childhood obesity does not seem to be associated significantly with parental income and education. Health consequences of childhood obesity include a higher prevalence of type 2 diabetes and an increased risk for adverse levels of lipids, lipoproteins, and blood pressure. The effects of recently reported unprecedented levels of childhood overweight on subsequent risk for obesity in middle age are not known until future longitudinal data can be collected. It seems likely, however, that future health consequences of current early and severe childhood obesity will be staggering. Funding for adult follow-up of longitudinal studies of high-risk African American, Hispanic, and Native-American children is needed urgently to provide information on the long-term effects of childhood obesity. Halting the obesity epidemic is a formidable task, but the success in recent decades of drastically reducing childhood undernutrition offers hope and should spur similar action and leadership efforts. Promotion of efforts to reduce excess caloric intake with efforts to increase energy expenditure should receive paramount attention in the design of health programs. Given the relatively few published obesity-prevention and treatment studies that are designed to address specific cultural issues, it is important to promote the development of culturally appropriate intervention strategies that are shown to be effective among youth of diverse backgrounds. Although the dietary and activity goals will be similar, parental, family, and community messages and techniques grounded in cultural traditions and norms will be different for each ethnic group. This approach is crucial in the United States, a country with an increasingly diverse population.

Nongenetic determinants of quantitative ultrasound (QUS) properties of the bone remain to be identified. The purpose of this study was to determine relationships between early adolescent diet and QUS bone measurements taken in young adulthood. Subjects were participants in the 10-year longitudinal National Heart, Lung, and Blood Institute Growth and Health Study (NGHS). QUS parameters measured at the calcaneus in a convenience subsample of 63 18- to 19-year-old black and white women were correlated with dietary data collected when the subjects were aged 9-11 years. We hypothesized that pre-adolescent intake of calcium, magnesium, vitamin C and protein, nutrients known to be associated with bone development, would be associated with QUS measurements in young women. Stepwise multiple regression analysis, controlling for race, height and weight, demonstrated that pre-adolescent intake of calcium and magnesium were positively related to QUS parameters (calcium with broadband ultrasound attenuation, and magnesium with speed of sound and bone velocity). Our findings suggest that pre-adolescent diet may be associated with bone properties as measured by ultrasound. Further investigations of this relationship may yield a deeper understanding of the impact of diet on skeletal development. The small size of the convenience sample used for the analysis precludes stronger inferences at this time.