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Posttraumatic stress disorder (PTSD) and eating disorders (ED) frequently co-occur, but the mechanisms underlying this association remain unclear. EDs are characterized by features of maladaptive eating behaviors including disinhibited eating and cognitive dietary restraint. Identifying the genetic overlap between PTSD symptoms and maladaptive eating behaviors may elucidate biological mechanisms and potential treatment targets. A community sample of 400 same-sex twins (102 monozygotic and 98 dizygotic pairs) completed the PTSD Checklist-Civilian (PCL-C) for PTSD symptoms and the Three-Factor Eating Questionnaire-Reduced (TFEQ-R18) for eating behaviors (uncontrolled eating, emotional eating, and cognitive dietary restraint). We used biometric modeling to examine the genetic and environmental relationships between PCL-C and TFEQ-R18 total and subscales scores. Heritability was estimated at 48% for PTSD symptoms and 45% for eating behavior overall. Bivariate models revealed a significant genetic correlation between PTSD symptoms and eating behavior overall (rg =.34; CI:.07,.58) and Uncontrolled Eating (rg =.53; CI:.24,.84), and a significant environmental correlation between PTSD symptoms and Emotional Eating (re =.30; CI:.12,.45). These findings suggest the influence of common etiology. Future research and clinical efforts should focus on developing integrated treatments. [ABSTRACT FROM AUTHOR]

In 1984, Hrubec and Robinette published what was arguably the first review of the role of twins in medical research. The authors acknowledged a growing distinction between two categories of twin studies: those aimed at assessing genetic contributions to disease and those aimed at assessing environmental contributions while controlling for genetic variation. They concluded with a brief section on recently founded twin registries that had begun to provide unprecedented access to twins for medical research. Here we offer an overview of the twin research that, in our estimation, best represents the field has progress since 1984. We start by summarizing what we know about twinning. We then focus on the value of twin study designs to differentiate between genetic and environmental influences on health and on emerging applications of twins in multiple areas of medical research. We finish by describing how twin registries and networks are accelerating twin research worldwide. [ABSTRACT FROM AUTHOR]

Objectives: Chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) is characterized by pain and voiding symptoms in the absence of an obvious infection or other cause. CP/CPPS frequently occurs with non-urological chronic overlapping pain conditions (COPCs) of unknown etiology. We conducted a co-twin control study in men discordant for chronic prostatitis (CP), an overarching diagnosis of which approximately 90% is CP/CPPS. The primary aim was to investigate the contribution of familial factors, including shared genetic and common environmental factors, to the comorbidity of CP and COPCs.Methods: Data from 6824 male twins in the Vietnam Era Twin Registry were examined to evaluate the association between self-reported lifetime physician diagnosis of CP with COPCs including fibromyalgia, chronic fatigue syndrome, irritable bowel syndrome, temporomandibular disorder, tension headaches, and migraine headaches. Random effects logistic regression models were used and within-pair analyses evaluated confounding effects of familial factors on the associations.Results: There were significant associations between CP and all 6 examined COPCs. After adjusting for shared familial influences in within twin pair analyses, the associations for all COPCs diminished but remained significant. Familial confounding was strongest for the association of CP with fibromyalgia and temporomandibular disorder and smallest for irritable bowel syndrome.Conclusions: CP and COPCs are highly comorbid. These associations can be partially explained by familial factors. The mechanisms underlying these relationships are likely diverse and multifactorial. Future longitudinal research can help to further elucidate specific genetic and environmental mechanisms and determine potentially causal relationships between CP and its comorbidities. [ABSTRACT FROM AUTHOR]