D. Phuong Do

Circadian rhythm of cortisol and neighborhood characteristics in a population-based sample: The Multi-Ethnic Study of Atherosclerosis

Although stress is often hypothesized to contribute to the effects of neighborhoods on health, very few studies have investigated associations of neighborhood characteristics with stress biomarkers. This study helps address the gap in the literature by examining whether neighborhood characteristics are associated with cortisol profiles. Analyses were based on data from the Multi-Ethnic Study of Atherosclerosis Stress study, which collected multiple measures of salivary cortisol over three days on a population based sample of approximately 800 adults. Multilevel models with splines were used to examine associations of cortisol levels with neighborhood poverty, violence, disorder, and social cohesion. Neighborhood violence was significantly associated with lower cortisol values at wakeup and with a slower decline in cortisol over the earlier part of the day, after sociodemographic controls. Associations were weaker and less consistent for neighborhood poverty, social cohesion, and disorder. Results revealed suggestive, though limited, evidence linking neighborhood contexts to cortisol circadian rhythms.

Neighborhood effects on health: Concentrated advantage and disadvantage

We investigate an alternative conceptualization of neighborhood context and its association with health. Using an index that measures a continuum of concentrated advantage and disadvantage, we examine whether the relationship between neighborhood conditions and health varies by socio-economic status. Using NHANES III data geocoded to census tracts, we find that while largely uneducated neighborhoods are universally deleterious, individuals with more education benefit from living in highly educated neighborhoods to a greater degree than individuals with lower levels of education.

Does mental health history explain gender disparities in insomnia symptoms among young adults

BACKGROUND Insomnia is the most commonly reported sleep disorder, characterized by trouble falling asleep, staying asleep, or waking up too early. Previous epidemiological data reveal that women are more likely than men to suffer from insomnia symptoms. We investigate the role that mental health history plays in explaining the gender disparity in insomnia symptoms. METHODS Using logistic regression, we analyze National Health and Nutritional Examination Survey (NHANES) III interview and laboratory data, merged with data on sociodemographic characteristics of the residential census tract of respondents. Our sample includes 5469 young adults (ages 20-39) from 1429 census tracts. RESULTS Consistent with previous research, we find that women are more likely to report insomnia symptoms compared to men (16.7% vs. 9.2%). However, in contrast to previous work, we show that the difference between womens and mens odds of insomnia becomes statistically insignificant after adjusting for history of mental health conditions (OR=1.08, p>.05). CONCLUSIONS The gender disparity in insomnia symptoms may be driven by higher prevalence of affective disorders among women. This finding has implications for clinical treatment of both insomnia and depression, especially among women.

The relationship between height and neighborhood context across racial/ethnic groups: a multi-level analysis of the 1999-2004 U.S. National Health and Nutrition Examination Survey.

While a growing literature has documented a link between neighborhood context and health outcomes, little is known about the relationship between neighborhood characteristics and height. Using individual data from the 1999-2004 U.S. National Health and Nutrition Examination Survey merged with tract-level data from the U.S. Census, we investigate several neighborhood characteristics, including neighborhood socioeconomic status (NSES), education index of concentration at the extremes (ICE), and population density, as potential predictors of height. Employing a series of two-level random intercept models, we find a one standard deviation increase in NSES to be associated with a 0.6-1.4 cm height advantage for white and foreign-born Mexican-American females and for U.S. born Mexican-American males, net of individual-level controls. Similarly, a 10 point increase in neighborhood education ICE was associated with 0.23-0.32 cm greater height for white and foreign-born Mexican-American females and U.S. born Mexican-American males. Population density was nominally negatively associated with height for foreign-born Mexican-American females. Our findings reveal that lower physical stature for some ethnic and gender groups is clustered within neighborhoods of low SES and education, suggesting that contextual factors may play a role in influencing height above individual-level attributes.

Hispanic Segregation and Poor Health: It's Not Just Black and White

Despite the importance of understanding the fundamental determinants of Hispanic health, few studies have investigated how metropolitan segregation shapes the health of the fastest-growing population in the United States. Using 2006-2013 data from the National Health Interview Survey, we 1) examined the relationship between Hispanic metropolitan segregation and respondent-rated health for US-born and foreign-born Hispanics and 2) assessed whether neighborhood poverty mediated this relationship. Results indicated that segregation has a consistent, detrimental effect on the health of US-born Hispanics, comparable to findings for blacks and black-white segregation. In contrast, segregation was salutary (though not always significant) for foreign-born Hispanics. We also found that neighborhood poverty mediates some, but not all, of the associations between segregation and poor health. Our finding of divergent associations between health and segregation by nativity points to the wide range of experiences within the diverse Hispanic population and suggests that socioeconomic status and structural factors, such as residential segregation, come into play in determining Hispanic health for the US-born in a way that does not occur among the foreign-born.