The Taipei Adolescent Twin/Sibling Family Study II: Depression, Insulin Resistance, and Hormonal Factors

Abstract

I n this ongoing longitudinal study of adolescent twins/sibling pairs and their parents in Taipei, we aimed to investigate the genetic and environmental influences on adolescent behavioral development, metabolic risk factors, and the associations between the two. Special focus is on anxious depression, metabolic profile, and hormonal factors such as cortisol and leptin. The first wave of assessment was completed during the period of 2002 to 2005 and included 192 twin pairs, 6 triplets, 56 sibling pairs and their first-degree relatives (484 parents and 142 siblings). We are currently in the process of a second wave assessment as follow-up. Dimensional psychological assessments using self-report questionnaires, as well as categorical assessments based on semistructured clinical interviews, were performed. All subjects received a 2-hour oral glucose tolerance test at the examination site. The metabolic phenotypes including body mass index, blood pressure, levels of glucose, insulin, and lipid profile as well as related hormonal levels were measured. Zygosity was determined using DNA, except for a few twins whose DNA was not available. Such a combination of detailed psychological assessments and metabolic function tests is expected to help shed light on the interrelation of psychological well-being and metabolic functioning.A growing body of literature suggests that metabolic risk factors and anxious depression are closely interrelated. Differences in metabolic function indexes such as body mass index (BMI), levels of glucose, triglyceride, cholesterol, as well as blood pressure were observed in individuals with anxiety, depression, or both, in comparison to controls (Golden et al., 2004;McCaffery et al., 2003;Raikkonen et al., 2002). Intriguingly, these metabolic risk factors also tend to be clustered in adolescents (Cook et al., 2003;Weiss et al., 2004). Similarly, patients with major depression exhibited insulin resistance during an oral glucose tolerance test compared to controls (Winokur et al., 1988). A recent review concluded the existence of an association between depression and type 2 diabetes (Musselman et al., 2003). Furthermore, it has been shown that several hormones such as cortisol, an index of hypothalamic-pituitary-adrenal (HPA) axis activity and leptin, an adiposity hormone involved in food intake and weight regulation, have been involved in the regulation of mood and metabolic function (Atmaca et al., 2005;Bjorntorp, 2001;Kraus et al., 2001;Liuzzi et al., 1999;Livshits et al., 2005). Despite the consistent overlap between these two traits, few studies have adopted an integrative strategy that includes both psychological and physiological assessments to elucidate the etiology of anxiety/depression and metabolic functions.Recognizing the need for integrating psychological and physiological information, we initiated a longitudinal, multivariate study of adolescent twins/sibling pairs aged 12 to 18 years, and their siblings and parents as well, in an attempt to investigate how psychological factors co...

The Beijing Twin Study (BeTwiSt): A Longitudinal Study of Child and Adolescent Development

“…Over the past few decades, a number of welldesigned twin studies have been conducted on child and adolescent psychopathology (see Table 1), mainly in the United States and Europe (Bartels et al, 2007;Eaves et al, 1997;Hewitt et al, 1997;Iacono et al, 2006;Kaprio, 2006;Lemery-Chalfant et al, 2006;Lichtenstein et al, 2007;Neiderhiser et al, 2007;Trouton et al, 2002;van den Bree et al, 2007), with a few studies in Asia and Australia (Ando et al, 2006;Bennett et al, 2006;Huang et al, 2009;Hur Kuo et al, 2006). These studies have contributed significantly to the field by disentangling the intertwined roles of genetic and environmental factors in complex human traits, as well as by providing new information about the complex interplay between genes and the environment.…”