Phenotypic, Genetic and Environmental Architecture of the Components of Sleep Quality

The genetic and environmental underpinnings of sleep quality have been widely investigated. However, less is known about the etiology of the different sleep quality components and their associations. Subjective sleep quality has been studied most commonly using the Pittsburgh Sleep Quality Index (PSQI). Therefore, this work aimed to study the structure of sleep quality dimensions in a population-based twin sample by examining the etiology of the associations among the PSQI components themselves and between them. The sample comprised 2129 participants from the Murcia Twin Registry. In order to study the phenotypic, genetic and environmental structure of the PSQI we used three alternative multivariate twin models including all seven sub-scales of the PSQI (subjective sleep quality, latency, duration, efficiency, disturbances, use of sleeping medication and daytime dysfunction): a multivariate model (with seven separate correlated factors), a common pathway model and an independent pathway model. The multivariate correlated factors model showed the best fit to the data. All twin models indicated significant genetic overlap among most of the PSQI components, except daytime dysfunction and use of sleep medication. Bivariate heritability explained between 25 and 50% of the covariance for most associations between dimensions. Furthermore, the common pathway model showed that around one third of the variance (0.32; CI 95% 0.18.0.43) of a latent factor common to all questionnaire dimensions is explained by genetic factors. Genetic influences on a latent factor common to all questionnaire dimensions produced the same heritability estimates as the PSQI global score. However, sleep quality dimensions showed considerable specificity regarding its genetic-environmental structure.Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature. GRANT SUPPORT: Funding: Ministerio de Ciencia, Innovación y Universidades - Spain (RTI2018-095185-B-I00) co-funded by European Regional Development Fund (FEDER)

Heritability of sleep quality in a middle-aged twin sample from Spain

©2018. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/ This document is the Accepted version of a Published Work that appeared in final form in Sleep. To access the final edited and published work see https://doi.org/10.1093/sleep/zsy110Study objectives: Sleep quality is associated with health throughout the life span, which is particularly salient in middle-age and older adulthood. Sleep quality appears to be influenced by both genetic and environmental factors. However, there is still limited information about genetic influences on sleep quality in middle-aged adults, and particularly in those from certain geographical locations. We estimated the magnitude of genetic and environmental influences on sleep quality in a representative sample of middle-aged Spanish twins. Methods: The sample comprised 2150 individuals born between 1939 and 1966, who participate in the Murcia Twin Registry. In order to estimate the heritability of sleep quality variables we performed univariate analyses for the global score on the Pittsburgh sleep quality index and for each of its components. Results: We found moderate but significant heritability (34%) for sleep quality. The genetic variance of the components of the Pittsburgh index ranged from 30% to 45%, except for sleep efficiency for which no genetic influence could be detected. In summary, there was a moderate genetic influence on most dimensions of sleep quality in a sample of adult male and female twins. Shared environment influences were not found. Conclusions: This study adds new information regarding the underlying determinants of sleep quality by providing heritability estimates in a middle-aged population-based representative sample from a geographical location that has not been included in studies of this type previously. This could provide a reference point for future research regarding sleep research in middle-age

Effects of Social Attitude Change on Smoking Heritability

Societal attitudes and norms to female smoking changed in Spain in the mid-twentieth century from a restrictive to a tolerant, and an even pro-smoking, posture, while social attitudes remained stable for males. We explored whether this difference in gender-related social norms influenced the heritability of two tobacco use measures: lifetime smoking and number of years smoking. We used a population-based sample of 2285 twins (mean age = 55.78; SD = 7.45; 58% females) whose adolescence began between the mid-1950s and the early 1980s. After modeling the effect of sex and year of birth on the variance components, we observed that the impact of the genetic and shared environmental factors varied differently by birth cohort between males and females. For females, shared environment explained a higher proportion of variance than the genetic factors in older cohorts. However, this situation was inverted in the younger female cohorts. In contrast, no birth cohort effect was observed for males, where the impact of the genetic and environmental factors remained constant throughout the study period. These results suggest that heritability is larger in a permissive social environment, whereas shared-environmental factors are more relevant in a society that is less tolerant to smoking

Nausea and Vomiting During Pregnancy is Highly Heritable.

Nausea and vomiting during pregnancy (NVP) affects about 70 % of all expectant mothers and commonly impacts their physical health and psychosocial functioning. The aim of this study was to estimate the heritability of the presence, duration and severity of NVP. The sample consisted of 1723 women (M age = 41.78, SD = 11.67) including twins in both complete and incomplete pairs and their sisters from two cohorts participating in the NVP Genetics Consortium. The sample comprised 159 monozygotic and 140 dizygotic complete twin pairs, and 69 twin-sister pairs. We applied an extended twin design using OpenMx and Mx for secondary analysis. Individual differences in NVP were best explained by additive genetic and unique environmental effects. Heritability estimates were 73 % (95 % CIs = 57-84 %) for presence, 51 % (95 % CIs = 36-63 %) for duration and 53 % (95 % CIs = 38-65 %) for severity of NVP. The genetic correlation between duration and severity was almost perfect. Our results show that genes play an important role in different aspects of NVP and justify the importance of searching for genetic variants.</p

Educational attainment of same-sex and opposite-sex dizygotic twins : An individual-level pooled study of 19 twin cohorts

Comparing twins from same- and opposite-sex pairs can provide information on potential sex differences in a variety of outcomes, including socioeconomic-related outcomes such as educational attainment. It has been suggested that this design can be applied to examine the putative role of intrauterine exposure to testosterone for educational attainment, but the evidence is still disputed. Thus, we established an international database of twin data from 11 countries with 88,290 individual dizygotic twins born over 100 years and tested for differences between twins from same- and opposite-sex dizygotic pairs in educational attainment. Effect sizes with 95% confidence intervals (CI) were estimated by linear regression models after adjusting for birth year and twin study cohort. In contrast to the hypothesis, no difference was found in women (β = −0.05 educational years, 95% CI −0.11, 0.02). However, men with a same-sex co-twin were slightly more educated than men having an opposite-sex co-twin (β = 0.14 educational years, 95% CI 0.07, 0.21). No consistent differences in effect sizes were found between individual twin study cohorts representing Europe, the USA, and Australia or over the cohorts born during the 20th century, during which period the sex differences in education reversed favoring women in the latest birth cohorts. Further, no interaction was found with maternal or paternal education. Our results contradict the hypothesis that there would be differences in the intrauterine testosterone levels between same-sex and opposite-sex female twins affecting education. Our findings in men may point to social dynamics within same-sex twin pairs that may benefit men in their educational careers.Peer reviewe

Negative responses of highland pines to anthropogenic activities in inland Spain: a palaeoecological perspective

Palaeoecological evidence indicates that highland pines were dominant in extensive areas of the mountains of Central and Northern Iberia during the first half of the Holocene. However, following several millennia of anthropogenic pressure, their natural ranges are now severely reduced. Although pines have been frequently viewed as first-stage successional species responding positively to human disturbance, some recent palaeobotanical work has proposed fire disturbance and human deforestation as the main drivers of this vegetation turnover. To assess the strength of the evidence for this hypothesis and to identify other possible explanations for this scenario, we review the available information on past vegetation change in the mountains of northern inland Iberia. We have chosen data from several sites that offer good chronological control, including palynological records with microscopic charcoal data and sites with plant macro- and megafossil occurrence. We conclude that although the available long-term data are still fragmentary and that new methods are needed for a better understanding of the ecological history of Iberia, fire events and human activities (probably modulated by climate) have triggered the pine demise at different locations and different temporal scales. In addition, all palaeoxylological, palynological and charcoal results obtained so far are fully compatible with a rapid human-induced ecological change that could have caused a range contraction of highland pines in western Iberia

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Heritability of initiation and duration of breastfeeding behavior

Breastfeeding is considered the best and most natural way of feeding infants during the first months of life. Breastfeeding has multiple short- and long-term benefits for the health of the mother and babies, and from an evolutionist standpoint, it would be a behavior worth preserving throughout time. The aim of the present study was to explore the relative influence of genetic and environmental factors in this behavior. Three hundred and ninety pairs of adult female twins provided information about whether they breastfed their children and for how long. Three variables were analyzed: initiation and duration for the first baby, and mean duration for the complete offspring. Polychoric correlations were consistently higher for monozygotic twins, supporting a role for genetic factors (0.49 vs. 0.22 for initiation; 0.44 vs. 0.22 for duration in the first newborn; and 0.52 vs. 0.31 for duration on average). Model-fitting analyses found that in the best-fitting model, variance was explained by additive genetic and non-shared environmental factors, with estimated heritabilities ranging from 0.39 to 0.52 in the measures studied. The rest of the variance would be due to unique environmental factors. We conclude that genetic factors have a significant impact on the complex behavior of breastfeeding

Equality in educational policy and the heritability of educational attainment

Secular variation in the heritability of educational attainment are proposed to be due to the implementation of more egalitarian educational policies leading to increased equality in educational opportunities in the second part of the 20th century. The action of effect is hypothesized to be a decrease of shared environmental (e.g., family socioeconomic status or parents' education) influences on educational attainment, giving more room for genetic differences between individuals to impact on the variation of the trait. However, this hypothesis has not yet found consistent evidence. Support for this effect relies mainly on comparisons between countries adopting different educational systems or between different time periods within a country reflecting changes in general policy. Using a population-based sample of 1271 pairs of adult twins, we analyzed the effect of the introduction of a specific educational policy in Spain in 1970. The shared-environmental variance decreased, leading to an increase in heritability in the post-reform cohort (44 vs. 67%) for males. Unstandardized estimates of genetic variance were of a similar magnitude (.56 vs. .57) between cohorts, while shared environmental variance decreased from .56 to .04. Heritability remained in the same range for women (40 vs. 34%). Our results support the role of educational policy in affecting the relative weight of genetic and environmental factors on educational attainment, such that increasing equality in educational opportunities increases heritability estimates by reducing variation of non-genetic familial origin