Ethnic density and obesity: evidence from fixed-effects models

Associations of peer generational status on adolescent weight across Hispanic immigrant generations: A social network analysis

BACKGROUND

Childhood obesity disproportionately impacts Hispanics in the United States (US), the nation's largest ethnic minority population. However, even among Hispanic children, those born in the US are at increased risk of developing obesity than those not born in the US (i.e. first-generation Hispanics). The objective of this study is to assess whether ethnic and generational differences in the friend networks of Hispanic adolescents moderate the association between immigrant generation and weight.

METHODS

We analyzed data from first-generation, second-generation, and third-generation Hispanic 12 to 19 year-old participants in Wave 1 of the Longitudinal Study of Adolescent to Adult Health (Add Health). Using multivariable linear regression, we examined the association between generational status and body mass index (BMI), and whether the ethnic and generational composition of friends moderated that association.

RESULTS

Higher generational status was associated with higher BMI. The ethnic and generational composition of friends was not independently associated with BMI among Hispanic adolescents. However, a social network with a greater proportion of second-generation Hispanics was positively associated with BMI among first-generation Hispanics, and negatively associated with BMI among second-generation Hispanics.

CONCLUSIONS

The generational status of peers in Hispanic adolescents' social networks, particularly the proportion that are second-generation Hispanic, moderates the positive association between immigrant generation and BMI. Moreover, this moderation effect is different across immigrant generations so that the proportion of second-generation adolescents within a social network is associated with higher BMI in first-generation Hispanic adolescents, but with lower BMI among those who are second-generation. These results were confirmed in sensitivity analyses. Our findings suggest that the generational composition of social networks alters the association between the generational status and weight of Hispanic adolescents, and thus that social factors within those networks may contribute to those associations.

Ethnic density and area-deprivation effects on central obesity among ethnic minority people in England-A cross-sectional, multi-level analysis

Background

Central obesity is a risk factor for many health conditions, and it disproportionately affects some ethnic minority groups. Research has shown that there is an association between area environments and obesity, but no studies have explored the association between co-ethnic density and central obesity in the UK (United Kingdom). This paper addresses the following research question: Does the relationship between co-ethnic density/area deprivation and waist circumference differ by ethnic group in England?

Methods

Data come from 4 years of the cross-sectional Health Survey for England (1998, 1999, 2003, 2004) and linked area-level data from the 2001 Census. More recent data on objectively measured central obesity for a nationally representative sample of ethnic minorities does not exist. Multi-level modeling methods account for individual-level and area-level factors. Interaction models test the effect of area deprivation and co-ethnic density for each ethnic group compared with the White reference group.

Results

For women, the relationship between area deprivation and waist circumference does not vary by ethnic group. For Indian and Bangladeshi men there is a decrease in waist circumference as area deprivation increases. There is an increase in waist circumference as co-ethnic density increases for Black Caribbean women. For Indian men there is a decrease in waist circumference as co-ethnic density increases.

Conclusions

Further research is needed to understand the mechanisms through which (1) increasing area-deprivation is protective for Indian and Bangladeshi men and (2) increasing co-ethnic density is associated with an increase in waist circumference for Black Caribbean women but a decrease in waist circumference among Indian men. Each of these results are important because (1) Indian and Bangladeshi men have an increased risk of the metabolic syndrome, which is linked to central obesity, and (2) Black Caribbean women have a higher risk of central obesity than the general population in England.

The Diverging Impacts of Segregation on Obesity Risk by Nativity and Neighborhood Poverty Among Hispanic Americans

While racial residential segregation is frequently cited as a fundamental cause of racial health disparities, its health impacts for Hispanic Americans remain unclear. We argue that several shortcomings have limited our understanding of how segregation influences Hispanic health outcomes, most notably a failure to assess the possible diverging impacts of segregation by neighborhood poverty level and the conflation of segregation with ethnic enclaves. We use multiple years of restricted geocoded data from a nationally representative sample of the US population (2006-2013 National Health Interview Survey) to investigate the association between metropolitan-level Hispanic segregation and obesity by nativity and neighborhood poverty level. We find segregation to be protective against obesity for Hispanic immigrants who reside in low poverty neighborhoods. For Hispanic immigrants residing in higher neighborhood poverty, no association between segregation and obesity was found. Among US-born Hispanics, we observe an increased risk of obesity-but only for those in high poverty neighborhoods. No association was found for those in low and medium neighborhood poverty. Results provide evidence to indicate that the relationship between segregation and health for Hispanics is not uniform within a metropolitan area. In the case of obesity, the consequences of metropolitan Hispanic segregation can be either protective, null, or deleterious depending not only on local neighborhood context but also on nativity.

Does the ethnic density effect extend to obesity? A cross-sectional study of 415 166 adults in east London

OBJECTIVES

To examine the prevalence of obesity by ethnic group and to examine the association between ethnic density and obesity prevalence.

DESIGN AND SETTING

Cross-sectional study utilising electronic primary care records of 128 practices in a multiethnic population of east London.

PARTICIPANTS

Electronic primary care records of 415 166 adults with a body mass index recorded in the previous 3 years.

OUTCOME MEASURES

(1) Odds of obesity for different ethnic groups compared with white British. (2) Prevalence of obesity associated with each 10% increase in own-group ethnic density, by ethnic group.

RESULTS

Using multilevel logistic regression models, we find that compared with white British/Irish males, the odds of obesity were significantly higher among black ethnic groups and significantly lower among Asian and white other groups. Among females, all ethnic groups except Chinese and white other were at increased odds of obesity compared with white British/Irish. There was no association between increasing ethnic density and obesity prevalence, except among black Africans and Indian females. A 10% increase in black ethnic density was associated with a 15% increase in odds of obesity among black African males (95% CI 1.07 to 1.24) and 18% among black African females (95% CI 1.08 to 1.30). Among Indian females, a 10% increase in Indian ethnic density was associated with a 7% decrease in odds of obesity (95% CI 0.88 to 0.99).

CONCLUSION

Wider environmental factors play a greater role in determining obesity than the ethnic composition of the area for most ethnic groups. Further research is needed to understand the mechanism through which increasing ethnic density is associated with increased odds of obesity among black Africans and decreased odds of obesity among Indian females.

Pathways to ethnic differences in obesity: The role of migration, culture and socio-economic position in the UK

Previous research has identified ethnic differences in abdominal obesity but has not fully explored the pathways that explain these ethnic differences, which may relate to individual and contextual characteristics. This research identifies ethnic differences in waist circumference for eight ethnic groups in England, before and after accounting for a range of individual-level and area-level factors. Three key pathways to obesity are explored: migration status, cultural characteristics, and socio-economic characteristics. Data come from four years of the Health Survey for England (1998, 1999, 2003 and 2004) and linked area-level data from the 2001 Census. The total sample size is 27,946. Multi-level modelling methods are used to account for individual-level and area-level factors. The results show that migration status has a strong association with ethnic differences in waist circumference - in particular, waist circumference increases with length of time since migration to the UK. Cultural characteristics and socio-economic characteristics are also associated with ethnic differences in waist circumference, but not to the same extent as migration status. The strong association between migration status and waist circumference is partly attenuated by cultural characteristics and partly by socio-economic inequality. However, there is still a strong association between migrant status and waist circumference that remains unexplained.

Neighborhood effects on body mass: Temporal and spatial dimensions

Research examining the effects of neighborhood characteristics on obesity and excess body weight has generally neglected the influence of both life-course exposure and geographically-proximate communities. Using data on 9357 respondents to the National Longitudinal Survey of Youth, 1979 Cohort, in conjunction with tract-level data from the 1980-2010 U.S. censuses, this study examines how black, Hispanic, and white individuals' cumulative exposure to varying levels of neighborhood poverty and co-ethnic density from their mid-teens through mid-adulthood, as well as the levels of poverty and co-ethnic density in nearby, or "extralocal," neighborhoods, are associated with their body mass index (BMI). Fixed-effect regression models show that, among Hispanics and whites, cumulative exposure to co-ethnic neighbors is a stronger positive predictor of BMI than the co-ethnic density of the immediate, point-in-time neighborhood. Among whites, cumulative exposure to neighborhood poverty is a stronger positive predictor of BMI than is the poverty rate of the current neighborhood of residence. And among both blacks and whites, the distance-weighted poverty rate of extralocal neighborhoods is significantly and inversely related to BMI, suggesting that relative affluence in nearby neighborhoods engenders relative deprivation among residents of the focal neighborhood, leading to increased BMI. Overall, the results suggest that greater attention to both the temporal and spatial dimensions of neighborhood effects has the potential to enhance our understanding of how neighborhoods affect obesity and related health outcomes.

How Incarceration Influences Native-Born Black Men's Risk of Obesity

Objective

To build upon research that investigates the health significance of familial and former incarceration with special emphasis on obesity risk among native-born Black (ie, African American) men.

Methods

We analyzed data from the 2001-2003 National Survey of American Life (NSAL), focusing on native-born Black men (n=1140), the demographic group that bears the brunt of mass incarceration. The outcome of interest was obesity as measured by body mass index (BMI)>30. Principal predictors were familial and former incarceration, and their statistical interaction.

Results

In survey-adjusted binomial logistic regression models, familial incarceration appeared an unimportant predictor; whereas, former incarceration associated with a lower risk of obesity. However, former incarceration modifies the association between familial incarceration and obesity, such that native-born Black men experiencing both familial and former incarceration were significantly more likely to be obese.

Conclusions

Public health researchers should treat former incarceration with greater care in studies including native-born Black men because time spent incarcerated has lingering physical health significance.

Race-Ethnicity, Union Status, and Change in Body Mass Index in Young Adulthood

This study used data from three waves of the National Longitudinal Study of Adolescent to Adult Health (Add Health) and fixed-effects regression to consider whether associations between change in union status and change in BMI were moderated by race/ethnicity. The results indicated that intimate unions were differentially associated with gains in BMI along race/ethnic lines, especially for women. Compared to White women, marriage was associated with larger increases in BMI for Black, Hispanic and Multiracial women, and cohabitation was associated with larger increases for Black and Hispanic women. In contrast, both marriage and cohabitation were associated with less weight gain for Asian compared to White women. Among men, racial/ethnic differences in the relationship between union status and BMI were similarly patterned but less pronounced. The results suggest that, particularly for women, marital status-already its own source of stratification, further exacerbates racial/ethnic disparities in BMI from adolescence to young adulthood.

Neighbourhood disadvantage, geographic remoteness and body mass index among immigrants to Australia: A national cohort study 2006-2014

Obesity is socioeconomically, geographically and ethnically patterned. Understanding these elements of disadvantage is vital in understanding population obesity trends and the development of effective and equitable interventions. This study examined the relationship between neighbourhood socioeconomic disadvantage and geographic remoteness with prospective trends in mean body mass index (BMI) among immigrants to Australia. Longitudinal data (2006–2014) from a national panel survey of Australian adults was divided into an immigrant-only sample (n = 4,293, 52.6% women and 19,404 person-year observations). The data were analysed using multi-level random effects linear regression modelling that controlled for individual socioeconomic and demographic factors. Male immigrants living in the most disadvantaged neighbourhoods had significantly higher mean BMI compared with those living in the least disadvantaged. Over time, mean BMI increased for all groups except for men living in the least disadvantaged neighbourhoods, for whom mean BMI remained almost static (0.1 kg/m² increase from 2006 to 2014), effectively widening neighbourhood inequalities. Among women, mean BMI was also significantly higher in the most compared with the least, disadvantaged neighbourhoods (β = 2.08 kg/m²; 95%CI: 1.48, 2.68). Neighbourhood inequalities were maintained over time as mean BMI increased for all groups at a similar rate. Male and female immigrants residing in outer regional areas had significantly higher mean BMI compared with those living in major cities; however, differences were attenuated and no longer significant following adjustment for ethnicity, individual socioeconomic position and neighbourhood disadvantage. Over time, mean BMI increased in all male and female groups with no differences based on geographic remoteness. Obesity prevention policy targeted at immigrant cohorts needs to include area-level interventions that address inequalities in BMI arising from neighbourhood disadvantage, and be inclusive of immigrants living outside Australia’s major cities.