Association of Adult Socioeconomic Status with Body Mass Index: A Within- and Between-Twin Study.

Adult socioeconomic status (SES) has been consistently associated with body mass index (BMI), but it is unclear whether it is linked to BMI independently of childhood SES or other potentially confounding factors. Twin studies can address this issue by implicitly controlling for childhood SES and unmeasured confounders. This co-twin control study used cross-sectional data from Twins Research Australia's Health and Lifestyle Questionnaire (N = 1918 twin pairs). We investigated whether adult SES, as measured by both the Index of Relative Socioeconomic Disadvantage (IRSD) and the Australian Socioeconomic Index 2006 (AUSEI06), was associated with BMI after controlling for factors shared by twins within a pair. The primary analysis was a linear mixed-effects model that estimated effects both within and between pairs. Between pairs, a 10-unit increase in AUSEI06 was associated with a 0.29 kg/m2 decrease in BMI (95% CI [-.42, -.17], p < .001), and a 1-decile increase in IRSD was associated with a 0.26 kg/m2 decrease in BMI (95% CI [-.35, -.17], p < .001). No association was observed within pairs. In conclusion, higher adult SES was associated with lower BMI between pairs, but no association was observed within pairs. Thus, the link between adult SES and BMI may be due to confounding factors common to twins within a pair.

The Association Between Chronic Disease and Psychological Distress: An Australian Twin Study.

There is a commonly observed association between chronic disease and psychological distress, but many potential factors could confound this association. This study investigated the association using a powerful twin study design that can control for unmeasured confounders that are shared between twins, including genetic and environmental factors. We used twin-paired cross-sectional data from the Adult Health and Lifestyle Questionnaire collected by Twins Research Australia from 2014 to 2017. Linear regression models fitted using maximum likelihood estimations (MLE) were used to test the association between self-reported chronic disease status and psychological distress, measured by the Kessler Psychological Distress Scale (K6). When comparing between twin pairs, having any chronic disease was associated with a 1.29 increase in K6 (95% CI: 0.91, 1.66; p < .001). When comparing twins within a pair, having any chronic disease was associated with a 0.36 increase in K6 (95% CI: 0.002, 0.71; p = .049). This within-pair estimate is of most interest as comparing twins within a pair naturally controls for shared factors such as genes, age and shared lived experiences. Whereas the between-pair estimate does not. The weaker effect found within pairs tells us that genetic and environmental factors shared between twins confounds the relationship between chronic disease and psychological distress. This suggests that associations found in unrelated samples may show exaggerated estimates.

The Association between Socioeconomic Status and Psychological Distress: A Within and Between Twin Study.

Low socioeconomic status (SES) has been established as a risk factor for poor mental health; however, the relationship between SES and mental health problems can be confounded by genetic and environmental factors in standard regression analyses and observational studies of unrelated individuals. In this study, we used a within-pair twin design to control for unmeasured genetic and environmental confounders in investigating the association between SES and psychological distress. We also employed within-between pair regression analysis to assess whether the association was consistent with causality. SES was measured using the Index of Relative Socio-economic Disadvantage (IRSD), income and the Australian Socioeconomic Index 2006 (AUSEI06); psychological distress was measured using the Kessler 6 Psychological Distress Scale (K6). Data were obtained from Twins Research Australia's Health and Lifestyle Questionnaire (2014-2017), providing a maximum sample size of 1395 pairs. Twins with higher AUSEI06 scores had significantly lower K6 scores than their co-twins after controlling for shared genetic and environmental traits (ßW [within-pair regression coefficient] = -0.012 units, p = .006). Twins with higher income had significantly lower K6 scores than their co-twins after controlling for familial confounders (ßW = -0.182 units, p = .002). There was no evidence of an association between the IRSD and K6 scores within pairs (ßW, p = .6). Using a twin design to eliminate the effect of potential confounders, these findings further support the association between low SES and poor mental health, reinforcing the need to address social determinants of poor mental health, in addition to interventions targeted to individuals.

Twins Research Australia: A New Paradigm for Driving Twin Research.

Twins Research Australia (TRA) is a community of twins and researchers working on health research to benefit everyone, including twins. TRA leads multidisciplinary research through the application of twin and family study designs, with the aim of sustaining long-term twin research that, both now and in the future, gives back to the community. This article summarizes TRA's recent achievements and future directions, including new methodologies addressing causation, linkage to health, economic and educational administrative datasets and to geospatial data to provide insight into health and disease. We also explain how TRA's knowledge translation and exchange activities are key to communicating the impact of twin studies to twins and the wider community. Building researcher capability, providing registry resources and partnering with all key stakeholders, particularly the participants, are important for how TRA is advancing twin research to improve health outcomes for society. TRA provides researchers with open access to its vibrant volunteer membership of twins, higher order multiples (multiples) and families who are willing to consider participation in research. Established four decades ago, this resource facilitates and supports research across multiple stages and a breadth of health domains.

Resilience to Stress and Adversity: A Narrative Review of the Role of Positive Affect.

The modern conception of mental health encompasses not only mental illness but also mental wellbeing, including positive emotional states and other forms of positive experience. Accordingly, research on resilience - that is, recovery or adaptation following adversity - has recently expanded to consider the roles of positive affect in the resilience process. To review this research, we performed a keyword search of all peer-reviewed journals within the American Psychological Association's PsycInfo database, retrieving all studies of positive affect in the context of resilience. These studies measured positive affect either as the outcome of the resilience process or as a resilience resource in its own right. With positive affect as the outcome, the literature suggests that various resilience resources can promote positive affect following a stressor, especially positive personality traits (eg, hope, optimism, self-compassion) and supportive interpersonal connections. With positive affect as a resilience resource, the literature suggests that higher levels of positive affect may protect individuals from the impact of stress on a number of outcomes, such as depression and trauma symptoms. In all, the reviewed research showcases a wide range of stressors, resources, and outcomes, and there are numerous openings for future discoveries in this promising area of inquiry.

Measuring mental wellbeing in clinical and non-clinical adolescents using the COMPAS-W Wellbeing Scale.

Introduction: Adolescence is a key period of vulnerability for poor mental health as the brain is still developing and may be more sensitive to the negative impacts of stress and adversity. Unfortunately, few measures comprehensively assess wellbeing in adolescents. Methods: The 26-item COMPAS-W Wellbeing Scale for adults was validated in a sample of 1,078 adolescents aged 13-17 years old (51.67% male, 79.13% non-clinical vs 20.87% psychiatric or developmental clinical cases). The six COMPAS-W sub-scales and total scale were examined in this sample using second-order confirmatory factor analysis, and psychometric testing. Results: The 23-item COMPAS-W demonstrated the best fit for this sample according to goodness-of-fit indices (χ 2 (220, 1078) = 1439.395, p < 0.001, CFI = 0.893, TLI = 0.877, RMSEA = 0.070, SRMR = 0.095). Internal reliability for the confirmed 23-item COMPAS-W model was run for the total scale (α = 0.912) and sub-scales (Composure, α = 0.735; Own-worth, α = 0.601; Mastery, α = 0.757; Positivity, α = 0.721; Achievement, α = 0.827; and Satisfaction, α = 0.867). Test-retest reliability over 6 weeks was also good for the total scale at r = 0.845 and the sub-scales: Composure (r = 0.754), Own-worth (r = 0.743), Mastery (r = 0.715), Positivity (r = 0.750), Achievement (r = 0.750), and Satisfaction (r = 0.812). Compared with non-clinical participants' wellbeing (M = 90.375, SE = 0.400), those with clinical diagnoses reported lower wellbeing, both for those with developmental diagnoses (M = 85.088, SE = 1.188), or psychiatric diagnoses (M = 78.189, SE = 1.758), or combined developmental and psychiatric diagnoses (M = 77.079, SE = 2.116). Yet, when wellbeing category scores were considered by diagnosis group, both non-clinical and clinical groups demonstrated incidence across all three categories of languishing, moderate and flourishing wellbeing, in support of the dual-continua model of mental health. On average, younger adolescents' (13-14 years) wellbeing did not differ from older adolescents' (15-17 years) wellbeing; however, for sex, males scored 1.731 points significantly higher in wellbeing compared with females (p = 0.028); and American participants scored 3.042 points significantly higher in wellbeing compared with Australian participants (p < 0.001). Discussion: In conclusion, the 23-item COMPAS-W is a reliable measure of wellbeing for adolescents, both for those with and without developmental and psychiatric diagnoses.