Suchergebnisse

Postcoital psychological symptoms (PPS) is a virtually unexplored phenomenon in the female population even though women frequently complain about irritability and motiveless crying after intercourse and/or orgasm. The aim of this study was to explore the epidemiology and genetic influences of PPS in a UK population sample of women. 1,489 unselected female twins aged 18–85 completed questions on recent and persistent PPS and potential risk factors. Standard methods of quantitative genetic analysis were used to model latent genetic and environmental factors influencing variation in PPS. For identification of potential risk factors, regression analyses were conducted. Phenotypic variation in PPS was explored using a genetic variance component analysis (VCA) approach. We found 3.7% of women reported suffering from recent PPS and 7.7% from persistent PPS. Relationship satisfaction and experience of abuse were found to be independently associated with recent (OR 4.5, 95% CI 4.13–4.87 and OR 1.3, 95% CI 1.02–1.34, respectively) and persistent PPS (OR 2.53, 95% CI 2.17–2.81 and OR 1.16, 95% CI 1.09–1.26, respectively). VCA revealed that phenotypic variance was best explained by an additive genetic (AE) model, ascribing 28% (for recent PPS) and 26% (for persistent PPS) of phenotypic variance to additive genetic effects, with the rest being a result of individual experiences and random measurement error. To our knowledge, this is the first and largest study investigating the epidemiology of PPS. It seems that the most important targets for intervention and prevention occur outside of the family, such as relationship quality and satisfaction, and history of abuse.

Although the co-occurrence among symptoms of insomnia, fatigue, and depression has been frequently reported, the etiology of this co-occurrence remains poorly understood. A total of 3,758 adult female twins in the United Kingdom completed a mail-out survey including six questions concerning frequency and severity of symptoms of insomnia, fatigue, and depression. Correlations among the scores of the three symptoms ranged from 0.35 to 0.44. Among various multivariate models we tested, the common-pathway model explained the data best. In the best-fitting model, the common factor was explained approximately equally by genetic and unique environmental factors (49% and 51%, respectively). In addition to the common variance, there was a significant specific variance in each symptom, where unique environmental factors were much larger than genetic factors. These results imply that although there are shared genetic liabilities for the development of symptoms of depression, fatigue, and insomnia, it is environmental experiences that make etiological distinctions among three symptoms.

AbstractBehavior genetics has convincingly shown the importance of genetic factors in objective tests of memory function. However, self-report memory tests have received little attention. This study used items from the Multifactorial Memory Questionnaire (MMQ) to estimate the heritability of self-reported memory contentment and ability in 909 monozygotic (MZ) and 1034 dizygotic (DZ) twin pairs aged between 20 and 84 years from the St Thomas' Adult UK Twin Register. Heritability estimates ranged between 37% and 64% for contentment (e.g., reporting to worry about one's memory) and approximately 45% for ability (e.g., reporting a tendency to forget keys). Shared family environmental influences (between 32% and 33%) were found for some abilities (e.g., learning to use a new gadget). Given their clinical significance and ease of administration, these tests could prove to be useful in examining memory functioning in large-scale population studies.

AbstractA healthy diet is associated with the improvement or maintenance of health parameters, and several indices have been proposed to assess diet quality comprehensively. Twin studies have found that some specific foods, nutrients and food patterns have a heritable component; however, the heritability of overall dietary intake has not yet been estimated. Here, we compute heritability estimates of the nine most common dietary indices utilized in nutritional epidemiology. We analyzed 2590 female twins from TwinsUK (653 monozygotic [MZ] and 642 dizygotic [DZ] pairs) who completed a 131-item food frequency questionnaire (FFQ). Heritability estimates were computed using structural equation models (SEM) adjusting for body mass index (BMI), smoking status, Index of Multiple Deprivation (IMD), physical activity, menopausal status, energy and alcohol intake. The AE model was the best-fitting model for most of the analyzed dietary scores (seven out of nine), with heritability estimates ranging from 10.1% (95% CI [.02, .18]) for the Dietary Reference Values (DRV) to 42.7% (95% CI [.36, .49]) for the Alternative Healthy Eating Index (A-HEI). The ACE model was the best-fitting model for the Healthy Diet Indicator (HDI) and Healthy Eating Index 2010 (HEI-2010) with heritability estimates of 5.4% (95% CI [−.17, .28]) and 25.4% (95% CI [.05, .46]), respectively. Here, we find that all analyzed dietary indices have a heritable component, suggesting that there is a genetic predisposition regulating what you eat. Future studies should explore genes underlying dietary indices to further understand the genetic disposition toward diet-related health parameters.

AbstractOne thousand and seventy three pairs of adult monozygotic (MZ) twins and 895 pairs of same sex adult dizygotic (DZ) twins from the United Kingdom (UK) completed the Humor Styles Questionnaire: a 32-item measure which assesses two positive and two negative styles of humor. MZ correlations were approximately twice as large as DZ correlations for all four humor styles, and univariate behavioral genetic model fitting indicated that individual differences in all of them can be accounted for entirely by genetic and nonshared environmental factors, with heritabilities ranging from .34 to .49. These results, while perhaps not surprising, are somewhat at odds with a previous study that we conducted in North America (Vernon et al., in press) in which genetic factors contributed significantly to individual differences in the two positive humor styles, but contributed far less to the two negative styles, variance in which was instead largely due to shared and nonshared environmental factors. We suggest that differences between North American and UK citizens in their appreciation of different kinds of humor may be responsible for the different results obtained in these two studies.

AbstractThe second to fourth finger length ratio (2d:4d) has been the subject of much recent work and is thought to be related to diverse gender and hormone-related traits including sports ability, disease susceptibility, attractiveness and sexuality. It is established in utero and remains constant in adulthood. Familial clustering has been thought to contribute to the development of 2d:4d from early studies but no twin studies exploring heritability have been reported to date. In this study, a sample of 456 female twin pairs (148 monozygotic [MZ], 308 dizygotic [DZ]) aged 18 to 79 years was used to estimate the heritability of 2d:4d for the right and left hands. Finger lengths were derived from hand xrays. Variance components analysis was used to estimate and contrast genetic and environmental effects on this phenotype. The mean 2d:4d was 0.92 (SD = 0.001) for both hands. The MZ intraclass correlation was higher than in DZ (.66 vs. .35 for right 2d:4d, and .71 vs. .37 for left 2d:4d). The best fit model included additive polygenic and unique environmental effects ('AE' model), with no significant common environmental effects detected. Heritability was estimated to be approximately 66% for 2d:4d (95% confidence interval 0.5–0.78). These results suggest a substantial genetic contribution to the determination of this hormonally related skeletal ratio in women, which could be more influential than the effects of common prenatal environmental factors. However the current study design does not preclude the possibility of confounding between heritability estimates and unobserved prenatal effects.

AbstractIn humans, in contrast to animals, the genetic influences on infidelity are unclear. We report here a large study of over 1600 unselected United Kingdom female twin pairs who confidentially reported previous episodes of infidelity and total lifetime number of sexual partners, as well as attitudes towards infidelity. Our findings demonstrate that infidelity and number of sexual partners are both under moderate genetic influence (41% and 38% heritable, respectively) and the genetic correlation between these two traits is strong (47%). Conversely, attitudes towards infidelity are driven by shared and unique environmental, but not genetic, influences. A genome-wide linkage scan identified three suggestive but nonsignificant linkage areas associated with infidelity and number of sexual partners on chromosomes 3, 7 and 20 with a maximum LOD score of 2.46. We were unsuccessful in associating infidelity or number of sexual partners with a locus implicated in other mammals' sexual behavior, the vasopressin receptor gene. Nonetheless, our findings on the heritabil-ity of sexual infidelity and number of sexual partners provide support for certain evolutionary theories of human sexual behavior, as well as justifying further genetic and molecular research in this domain.

AbstractThe present study investigated the location of trait emotional intelligence (trait EI or trait emotional self-efficacy) within the context of the HEXACO model — a more comprehensive personality framework than the conventional Big Five structure. A total of 666 MZ and 526 DZ adult twin pairs from the United Kingdom completed the short form of the Trait Emotional Intelligence Questionnaire (TEIQue-SF) and the short form of the HEXACO Personality Inventory (HEXACO-60). Many significant phenotypic correlations between the TEIQue-SF and the HEXACO-60 were obtained, which were strongest for HEXACO Extraversion, and weakest for HEXACO Honesty–Humility. As was expected, Emotionality was the only HEXACO dimension to correlate negatively with TEIQue-SF scores. Bivariate behavioral genetic analyses revealed that all phenotypic correlations were attributable to common genetic and common nonshared environmental factors. The study confirms the validity of trait EI as a constellation of emotional self-perceptions located at the lower levels of personality.