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Twin studies have seldom addressed ethnicity as one of the possible factors that create unique combinations of genetic and environmental influences. The major objective of the Carolina African American Twin Study of Aging is to identify the proportion of the genetic and environmental sources of individual variation in measures of health and behavioral factors in a sample of adult African Americans. Drawn from birth records from the State of North Carolina, this in-person study used public records to identify a cohort of twins between 22 and 92 years of age (X = 49.82 yrs, SD = 14.62), 39.7% of which were men. Members of non-intact twin pairs and siblings were also recruited to explore alternative models to the classic twin design. To date, the project has contributed to knowledge about blood pressure, forced expiratory volume, chronic illness, body mass index, and waist-hip ratio memory, personality, social, and demographic factors, mortality, and mental health.

<p><em>Ethn Dis. </em>2017;27(1):1-2; doi: 10.18865/ed.27.1.1</p>

Objective Research shows that education favors mental health, in part, because it helps to develop a greater sense of control. To this point, however, it is unclear whether this process varies according to race and ethnicity. Methods Building on previous research, we use data collected from a large probability sample of Texas adults to test the extent to which the education-control-distress (E-C-D) model varies across three race and ethnic groups, including whites, blacks, and Mexican Americans. Results The results of our simple mediation analyses validate the E-C-D model for each race/ethnic group. Our moderated mediation analyses suggest that the indirect effect of education on psychological distress through the sense of control is comparable across race/ethnic groups. Conclusion The mediating influence of the sense of control does not appear to vary according to the three race/ethnic groups included in the study. Adapted from the source document.

ObjectiveResearch shows that education favors mental health, in part, because it helps to develop a greater sense of control. To this point, however, it is unclear whether this process varies according to race and ethnicity.MethodsBuilding on previous research, we use data collected from a large probability sample of Texas adults to test the extent to which the education‐control‐distress (E‐C‐D) model varies across three race and ethnic groups, including whites, blacks, and Mexican Americans.ResultsThe results of our simple mediation analyses validate the E‐C‐D model for each race/ethnic group. Our moderated mediation analyses suggest that the indirect effect of education on psychological distress through the sense of control is comparable across race/ethnic groups.ConclusionThe mediating influence of the sense of control does not appear to vary according to the three race/ethnic groups included in the study.

Objectives
We investigated the associations of lifetime and everyday discrimination with cognitive function.


Methods
Data were from the Chicago Community Adult Health Study (n=2952, mean age=43 years [SD=17]). We fitted multivariable linear regression models to quantify the discrimination-cognition associations.


Results
Major lifetime (β1 vs 0 episodes of discrimination = 0.56; 95% CI, 0.15-0.96; β2+ vs 0 episodes of discrimination = 0.64, 95% CI, 0.31-0.97) and everyday (β=0.10, 95% CI, 0.06-0.14) discrimination were positively associated with cognition, and these associations did not differ by race/ethnicity. Among older adults, major lifetime discrimination, but not everyday discrimination, was positively associated with cognition (β2+ vs 0 episodes of discrimination=1.79; 95% CI, 0.79-2.79).


Discussion
Measurement and selection bias may partially explain the counterintuitive study findings. We call for longitudinal research to further investigate the discrimination-cognition relationship.

AbstractThe Interplay of Genes and Environment across Multiple Studies (IGEMS) is a consortium of 18 twin studies from 5 different countries (Sweden, Denmark, Finland, United States, and Australia) established to explore the nature of gene–environment (GE) interplay in functioning across the adult lifespan. Fifteen of the studies are longitudinal, with follow-up as long as 59 years after baseline. The combined data from over 76,000 participants aged 14–103 at intake (including over 10,000 monozygotic and over 17,000 dizygotic twin pairs) support two primary research emphases: (1) investigation of models of GE interplay of early life adversity, and social factors at micro and macro environmental levels and with diverse outcomes, including mortality, physical functioning and psychological functioning; and (2) improved understanding of risk and protective factors for dementia by incorporating unmeasured and measured genetic factors with a wide range of exposures measured in young adulthood, midlife and later life.

We analyzed birth order differences in means and variances of height and body mass index (BMI) in monozygotic (MZ) and dizygotic (DZ) twins from infancy to old age. The data were derived from the international CODATwins database. The total number of height and BMI measures from 0.5 to 79.5 years of age was 397,466. As expected, first-born twins had greater birth weight than second-born twins. With respect to height, first-born twins were slightly taller than second-born twins in childhood. After adjusting the results for birth weight, the birth order differences decreased and were no longer statistically significant. First-born twins had greater BMI than the second-born twins over childhood and adolescence. After adjusting the results for birth weight, birth order was still associated with BMI until 12 years of age. No interaction effect between birth order and zygosity was found. Only limited evidence was found that birth order influenced variances of height or BMI. The results were similar among boys and girls and also in MZ and DZ twins. Overall, the differences in height and BMI between first- and second-born twins were modest even in early childhood, while adjustment for birth weight reduced the birth order differences but did not remove them for BMI.