Heritability of Initiation and Duration of Breastfeeding Behavior

2013 ◽  
Vol 16 (2) ◽  
pp. 575-580 ◽  
Author(s):  
Lucia Colodro-Conde ◽  
Juan F. Sánchez-Romera ◽  
Juan R. Ordoñana
Keyword(s):  
Environmental Factors ◽  
Genetic Factors ◽  
Model Fitting ◽  
Monozygotic Twins ◽  
Best Fitting ◽  
Short And Long Term ◽  
Genetic And Environmental Factors ◽  
Duration Of Breastfeeding ◽  
Natural Way

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.

scholarly journals A Genetic Analysis of Coffee Consumption in a Sample of Dutch Twins

2009 ◽  
Vol 12 (2) ◽  
pp. 127-131 ◽  
Author(s):  
Jaqueline M. Vink ◽  
Annemieke S. Staphorsius ◽  
Dorret I. Boomsma
Keyword(s):  
Environmental Factors ◽  
Genetic Factors ◽  
Model Fitting ◽  
Coffee Consumption ◽  
Genetic Influences ◽  
Psychoactive Substance ◽  
Twin Registry ◽  
Genetic And Environmental Factors ◽  
Dutch Twins ◽  
Twin Resemblance

AbstractCaffeine is by far the most commonly used psychoactive substance. Caffeine is consumed regularly as an ingredient of coffee. Coffee consumption and coffee preference was explored in a sample of 4,495 twins (including 1,231 pairs) registered with the Netherlands Twin Registry. Twin resemblance was assessed by tetrachoric correlations and the influence of both genetic and environmental factors was explored with model fitting analysis in MX. Results showed moderate genetic influences (39%) on coffee consumption. The remaining variance was explained by shared environmental factors (21%) and unique environmental factors (40%). The variance in coffee preference (defined as the proportion of coffee consumption relative to the consumption of coffee and tea in total) was explained by genetic factors (62%) and unique environmental factors (38%).

A Male Monozygotic Twinship Discordant for Homosexuality

1971 ◽  
Vol 118 (547) ◽  
pp. 675-682 ◽  
Author(s):  
K. Davison ◽  
H. Brierley ◽  
C. Smith
Keyword(s):  
Environmental Factors ◽  
Genetic Factors ◽  
Prison Population ◽  
Monozygotic Twins ◽  
Monozygotic Twin ◽  
The Third ◽  
Relative Contribution ◽  
Quantitative Rating ◽  
Genetic And Environmental Factors ◽  
Sexual Identification

The relative contribution of genetic and environmental factors to the development of homosexual behaviour is a controversial subject. The original suggestion that homosexuality is a purely inherited trait has been attributed to Krafft-Ebing (Kallmann, 1952). Perhaps the strongest support for this view was Kallmann's series of 40 male monozygotic twin pairs showing 100 per cent concordance for the overt practice and quantitative rating of homosexual behaviour (Kallmann, 1952). This report has been criticized, and Kallmann later conceded that the 100 per cent concordance was possibly a statistical artefact (Kallmann, 1960). Habel (1950), who obtained the index twins from a prison population, found concordant homosexuality in 3 out of 5 monozygotic pairs (60 per cent), but none of 5 dizygotic pairs. In a more recent study, Heston and Shields (1968) found concordant homosexuality in 2 out of 5 monozygotic pairs (40 per cent) and 1 out of 7 dizygotic pairs (14 per cent). Heston and Shields (1968) also report a family with a sibship of 14 which included 3 pairs of male monozygotic twins, in two of which both twins were homosexual and in the third both heterosexual; no environmental factors which differentiated the homosexual from the heterosexual sibs could be detected. These workers also refute the suggestion that the tendency for monozygotic twins to be more alike with regard to homosexuality than dizygotic twins is related not to genetic factors but to problems of sexual identification which predispose to homosexuality (Money, 1962) by pointing out that there is no evidence that monozygotic twins per se are especially prone to become homosexual.

Correlated genetic and non-shared environmental influences account for the co-morbidity between female sexual dysfunctions

2008 ◽  
Vol 39 (1) ◽  
pp. 115-127 ◽  
Author(s):  
K. Witting ◽  
P. Santtila ◽  
F. Rijsdijk ◽  
M. Varjonen ◽  
P. Jern ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Sexual Function ◽  
Genetic Factors ◽  
Environmental Influences ◽  
Model Fitting ◽  
Sexual Dysfunctions ◽  
Co Morbidity ◽  
Genetic And Environmental Factors ◽  
Correlated Factors ◽  
Best Fit

BackgroundPrevious studies have shown moderate heritability for female orgasm. So far, however, no study has addressed the pattern of genetic and environmental influences on diverse sexual dysfunctions in women, nor how genetic and environmental factors contribute to the associations between them.MethodThe sample was drawn from the Genetics of Sex and Aggression (GSA) sample and consisted of 6446 female twins (aged 18–43 years) and 1994 female siblings (aged 18–49 years). The participants responded to the Female Sexual Function Index (FSFI), either by post or online.ResultsModel fitting analyses indicated that individual differences on all six subdomains of the FSFI (desire, arousal, lubrication, orgasm, satisfaction, and pain) were primarily due to non-shared (individual-specific) environmental influences. Genetic influences were modest but significant, whereas shared environmental influences were not significant. A correlated factors model including additive and non-additive genetic and non-shared environmental effects proved to have the best fit and suggested that both correlated additive and non-additive genetic factors and unique environmental factors underlie the co-occurrence of the sexual function problems.ConclusionsThe findings suggest that female sexual dysfunctions are separate entities with some shared aetiology. They also indicate that there is a genetic susceptibility for sexual dysfunctions. The unique experiences of each individual are, however, the main factors determining if, and which, dysfunction develops.

scholarly journals Behavioral medicine challenges in the shadow of a global pandemic

2020 ◽  
Author(s):  
Alyssa T Brooks ◽  
Hannah K Allen ◽  
Louise Thornton ◽  
Tracy Trevorrow
Keyword(s):  
Environmental Factors ◽  
Health Behavior ◽  
Health Behaviors ◽  
Natural Experiment ◽  
Direct Effects ◽  
Global Pandemic ◽  
Wide Range ◽  
Future Data ◽  
Short And Long Term

Abstract Health behavior researchers should refocus and retool as it becomes increasingly clear that the challenges of the COVID-19 pandemic surpass the direct effects of COVID-19 and include unique, drastic, and ubiquitous consequences for health behavior. The circumstances of the pandemic have created a natural experiment, allowing researchers focusing on a wide range of health behaviors and populations with the opportunity to use previously collected and future data to study: (a) changes in health behavior prepandemic and postpandemic, (b) health behavior prevalence and needs amidst the pandemic, and (c) the effects of the pandemic on short- and long-term health behavior. Our field is particularly challenged as we attempt to consider biopsychosocial, political, and environmental factors that affect health and health behavior. These realities, while daunting, should call us to action to refocus and retool our research, prevention, and intervention efforts

scholarly journals interactions between genetic and environmental factors determine direction of population lateralization

2005 ◽  
Vol 28 (4) ◽  
pp. 598-598 ◽  
Author(s):  
chao deng
Keyword(s):  
Environmental Factors ◽  
Genetic Factors ◽  
Head Rotation ◽  
Head Turning ◽  
Genetic And Environmental Factors ◽  
Genetically Determined

direction of the embyro's head rotation is determined by asymmetrical expression of several genes (such as shh, nodal, lefty, and fgf8) in hensen's node. this genetically determined head-turning bias provides a base for light-aligned population lateralization in chicks, in which the direction of the lateralization is determined by genetic factors and the degree of the lateralization is determined by environmental factors.

Muscle Dissatisfaction and Muscle-Enhancing Substance Use: A Population-Based Twin Study in Young Adult Men

2006 ◽  
Vol 9 (3) ◽  
pp. 431-437 ◽  
Author(s):  
Anu Raevuori ◽  
Anna Keski-Rahkonen ◽  
Richard J. Rose ◽  
Aila Rissanen ◽  
Jaakko Kaprio
Keyword(s):  
Substance Use ◽  
Environmental Factors ◽  
Twin Study ◽  
Genetic Factors ◽  
Population Based ◽  
Tetrachoric Correlation ◽  
Polychoric Correlation ◽  
Adult Men ◽  
Genetic And Environmental Factors ◽  
Best Fit

AbstractIn the population-based FinnTwin16 study, proportions of genetic and environmental factors contributing to muscle dissatisfaction and muscle-enhancing substance use were assessed in 319 pairs of twin brothers: 141 monozygotic (MZ) and 178 dizygotic (DZ) pairs. In addition there were 86 twin individuals from pairs in which only one co-twin responded. Of all respondents, 30% experienced high muscle dissatisfaction. The corresponding proportion of muscle-enhancing substance use was 10%. The subjects were similar in age (23.8 years, 95% confidence interval [CI] 23.76–23.84), body mass index (23.7, 95% CI 23.5–23.9), and waist circumference (84.5 cm, 95% CI 83.7–85.2), independent of their muscle dissatisfaction or muscle-enhancing substance use status and independent of their zygosity. The MZ polychoric correlation for muscle dissatisfaction was .39 (95% CI .17–.58) and .27 for DZ pairs (95% CI .07–.46). The MZ tetrachoric correlation for muscle-enhancing substance use was .65 (95% CI .28–.87) and .56 for DZ pairs (95% CI .26–.78). The AE model, where additive genetic factors (A) accounted for 42% (95% CI .23–.59) and unique environmental factors (E) 58% (95% CI .41–.77) of the liability, provided the best fit for muscle dissatisfaction. The CE model, where common environmental factors (C) accounted for 60% (95% CI .37–.77) and unique environmental factors (E) 40% (95% CI .23–.63) of the liability, provided the best fit for muscle-enhancing substance use. Both genetic and unique (nonfamilial) environmental factors are involved in muscle dissatisfaction in the population. Nongenetic factors (both familial and non-familial) appear to best explain the use of muscle-enhancing substances.

scholarly journals Environmental and Genetic Contributions to Indicators of Oral Malodor in Twins

2011 ◽  
Vol 14 (6) ◽  
pp. 568-572 ◽  
Author(s):  
Walter A. Bretz ◽  
Aaron Biesbrock ◽  
Patricia M. Corby ◽  
Andrea L. Corby ◽  
Walter G. Bretz ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Genetic Factors ◽  
Sulfur Compounds ◽  
Exhaled Breath ◽  
Tongue Coating ◽  
Oral Malodor ◽  
Volatile Sulfur Compounds ◽  
Item Questionnaire ◽  
Genetic And Environmental Factors ◽  
Genetic Contributions

This study aimed to: (1) determine concordance rates of self-reported and subjectively determined indicators of oral malodor in twins; (2) determine the relative contributions of genetic and environmental factors to levels of volatile sulfur compounds (VSCs) in intraoral and exhaled breath. Fifty-one twin pairs participated in the study. Measurements of VSCs were obtained by a halimeter. The presence of tongue coatings was determined and twins filled out a 32-item questionnaire on oral malodor indicators independently of one another. Estimates of heritability (h2) for halimeter measurements were computed by SOLAR. The concordance rates for the presence of tongue coating among identical and fraternal twins were 67% and 11%, respectively. In the 10 most informative items, 70% exhibited higher concordance rates for identical than for fraternal twins. Of particular interest were the differences in concordance rates for dry mouth, sinus infection and unusual sweating. The h2 for intra-oral breath was 0.28 ± 0.17 (NS), whereas the h2 for exhaled breath was 0.50 ± 0.20 (p = .0207). The concordance rates of tongue coatings and malodor indicators were higher in identical twins than in fraternal twins. Intraoral breath VSC values were primarily attributable to environmental factors, whereas exhaled breath VSC values were partially explained by genetic factors.

scholarly journals The structure of genetic and environmental risk factors for phobias in women

2011 ◽  
Vol 41 (9) ◽  
pp. 1987-1995 ◽  
Author(s):  
N. Czajkowski ◽  
K. S. Kendler ◽  
K. Tambs ◽  
E. Røysamb ◽  
T. Reichborn-Kjennerud
Keyword(s):  
Environmental Factors ◽  
Social Phobia ◽  
Population Based ◽  
The Other ◽  
Twin Model ◽  
Co Morbidity ◽  
Twin Models ◽  
Best Fitting ◽  
Dsm Iv ◽  
Genetic And Environmental Factors

BackgroundTo explore the genetic and environmental factors underlying the co-occurrence of lifetime diagnoses of DSM-IV phobia.MethodFemale twins (n=1430) from the population-based Norwegian Institute of Public Health Twin Panel were assessed at personal interview for DSM-IV lifetime specific phobia, social phobia and agoraphobia. Comorbidity between the phobias were assessed by odds ratios (ORs) and polychoric correlations and multivariate twin models were fitted in Mx.ResultsPhenotypic correlations of lifetime phobia diagnoses ranged from 0.55 (agoraphobia and social phobia, OR 10.95) to 0.06 (animal phobia and social phobia, OR 1.21). In the best fitting twin model, which did not include shared environmental factors, heritability estimates for the phobias ranged from 0.43 to 0.63. Comorbidity between the phobias was accounted for by two common liability factors. The first loaded principally on animal phobia and did not influence the complex phobias (agoraphobia and social phobia). The second liability factor strongly influenced the complex phobias, but also loaded weak to moderate on all the other phobias. Blood phobia was mainly influenced by a specific genetic factor, which accounted for 51% of the total and 81% of the genetic variance.ConclusionsPhobias are highly co-morbid and heritable. Our results suggest that the co-morbidity between phobias is best explained by two distinct liability factors rather than a single factor, as has been assumed in most previous multivariate twin analyses. One of these factors was specific to the simple phobias, while the other was more general. Blood phobia was mainly influenced by disorder specific genetic factors.

Longitudinal Genetic Analysis of Plasma Lipids

2006 ◽  
Vol 9 (4) ◽  
pp. 550-557 ◽  
Author(s):  
Rita P. Middelberg ◽  
Nicholas G. Martin ◽  
John B. Whitfield
Keyword(s):  
Environmental Factors ◽  
Measurement Errors ◽  
Genetic Factors ◽  
Plasma Lipids ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Study Participant ◽  
Biological Variation ◽  
Long Term Effects

AbstractThe consensus from published studies is that plasma lipids are each influenced by genetic factors, and that this contributes to genetic variation in risk of cardiovascular disease. Heritability estimates for lipids and lipoproteins are in the range .48 to .87, when measured once per study participant. However, this ignores the confounding effects of biological variation measurement error and ageing, and a truer assessment of genetic effects on cardiovascular risk may be obtained from analysis of longitudinal twin or family data. We have analyzed information on plasma high-density lipoprotein (HDL) and low-density lipoprotein (LDL) cholesterol, and triglycerides, from 415 adult twins who provided blood on two to five occasions over 10 to 17 years. Multivariate modeling of genetic and environmental contributions to variation within and across occasions was used to assess the extent to which genetic and environmental factors have long-term effects on plasma lipids. Results indicated that more than one genetic factor influenced HDL and LDL components of cholesterol, and triglycerides over time in all studies. Nonshared environmental factors did not have significant long-term effects except for HDL. We conclude that when heritability of lipid risk factors is estimated on only one occasion, the existence of biological variation and measurement errors leads to underestimation of the importance of genetic factors as a cause of variation in long-term risk within the population. In addition our data suggest that different genes may affect the risk profile at different ages.

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