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PubMed2006

Bed-sharing, breastfeeding and maternal moods in Barbados.

Bed-sharing among Barbadian mothers and infants was studied in relationship to maternal and infant characteristics. This prospective study followed 226 healthy, well-nourished mother-infant dyads at birth, 7 weeks, 3 months, and 6 months postpartum. At each age, approximately half of the infants shared the same beds as their mothers. Bed-sharing was associated with demographic characteristics, especially fewer home conveniences, and also maternal characteristics, including less information seeking by the mother and younger maternal age at first pregnancy. Bed-sharing was also associated with lower infant birth weights. Maternal moods were significantly correlated with bed-sharing, such that mothers who reported having more despair and anxiety were also more likely to sleep with their infants. Bed-sharing was also significantly associated with increased breastfeeding at all infant ages, but this relationship was no longer significant once the effects of maternal moods were controlled. This study emphasizes the importance of assessing maternal moods in studies evaluating the risk and benefits of bed-sharing.

Adult↗
PubMed2005

Shared decision-making in primary care: tailoring the Charles et al. model to fit the context of general practice.

OBJECTIVE: To explore the application of the original Charles et al. model of shared treatment decision-making [Charles C, Gafni A, Whelan T. Shared decision-making in the medical encounter: what does it mean? (or it takes at least two to tango). Soc Sci Med 1997;44:681-92; Charles C, Gafni A, Whelan T. Decision-making in the physician-patient encounter: revisiting the shared treatment decision-making model. Soc Sci Med 1999;49:651-61] in the context of general practice, and to determine whether the model needs tailoring for use in this clinical context. METHODS: Conceptual paper, presenting the defining characteristics of general practice compared to the original clinical context for which the model was developed (i.e. life threatening disease with different treatment options), and exploring how the model can be tailored for use in the context of general practice. RESULTS: We identify two areas where the original model requires tailoring: sharing the decision-making around agreeing on an agenda for each consultation; and adapting the information transfer component of the model to acknowledge that doctors may not be the only, or even the main, source of technical information for patients. Finally, we explore the importance of shared decision-making in the context of chronic disease. CONCLUSION: The Charles et al. model can be tailored for use in general practice. PRACTICE IMPLICATIONS: Tailoring the model for use in general practice has implications for research, in terms of identifying the additional physician competencies needed for implementation. Policy makers who wish to promote shared decision-making need to ensure that incentives which prioritize access and health outcomes do not militate against shared decision-making in general practice.

Acute Disease↗
PubMedDate not supplied

Parents sharing information with their children about genetic conditions.

INTRODUCTION: Nurses are in an ideal situation to help families share information with their children about genetic conditions. While many factors contribute to this decision making, little is known about how parents decide when and how to convey this information to their children. The purpose of this qualitative analysis was to examine parents' beliefs and strategies related to sharing information about a genetic condition with their affected and unaffected children. METHOD: One hundred thirty-nine parents participated in this study. Narrative analysis and fundamental qualitative description were employed to identify approaches and strategies that parents used to share information with their children. RESULTS: Parents' information sharing approaches and strategies were grounded in the goal of promoting the child's adaptation to the genetic condition. Parents shared information based on their assessment of the child's developmental readiness and interest and described information sharing as an unfolding process that continued throughout childhood. DISCUSSION: The approaches and strategies contribute to understanding the processes associated with information sharing between parents and their children and between health care professionals and parents.

Adaptation, Psychological↗
PubMed1997

Ways forward for shared learning between nursing and social work students.

This paper is based on the work of Connor (1995) which examined the potential for shared learning on qualifying programmes of social work and nurse education in Wales. The research was carried out mainly by interviewing 44 providers of social work and nurse education in the 13 colleges delivering qualifying courses throughout Wales. The main findings indicate that: nursing and social work educators have a positive attitude to shared learning, provided that the focus is on sharing appropriate areas of learning and not on joint training; there are considerable areas of commonality between social work and nurse education that could be shared; obstacles to shared learning mainly concern structural and resource issues which would require the appropriate political will to implement shared learning programmes; and there are a wide variety of models that could be used to implement future shared learning. The management of this project with its commitment to collaboration between the two professional groups throughout the process of enquiry is offered as a model for further research projects.

Curriculum↗
PubMed2000

The sharing of injecting paraphernalia by intravenous drug users (IDUs) within a Worcestershire cohort, with specific reference to water and filters.

Britain continues to have a drug misuse health strategy that is HIV led. Because of this, little attention has been paid to other blood-borne viruses such as hepatitis. Moreover, while the provision of needle exchange schemes has been particularly successful in containing the spread of HIV, they have had less impact on the prevalence of hepatitis within IDU cohorts. Thus, it is necessary to understand more about the potential pathways through which the hepatitis viruses can be transmitted. One way of achieving this is to assess the propensity of IDUs to share other items of injecting paraphernalia such as water and filters. In addition, it is useful to gauge the level of opinion with respect to health hazards associated with sharing such items, amongst injecting drug users. This study reports on a small pilot project initiated to assess the degree of sharing of filters and water among 40 needle exchange service users in Worcestershire. Results based on questionnaires show that sharing of water and filters is very high within the sample group. Indeed, only 10% of clients reported never sharing either water or filters. The study also demonstrates that although injectors are aware of the health risks associated with sharing (including hepatitis transmission), they continue to participate in high risk sharing activities. Moreover, the majority of IDUs questioned have a mis-conception with respect to the most hygienic sources of water for injecting. For example, only 10% consider sterile water to be the most hygienic source for injecting, with >70% considering tap water in one form or another to be safe. The study is important because it highlights the value of providing sterile water and filters to IDUs to meet their basic and fundamental needs. It is hoped that the findings from this small project will have a wider transferability to other IDU cohorts throughout the UK and beyond.

Journal Article↗
PubMed1998

Comparative mtDNA phylogeography of neotropical freshwater fishes: testing shared history to infer the evolutionary landscape of lower Central America.

Historical biogeography seeks to explain contemporary distributions of taxa in the context of intrinsic biological and extrinsic geological and climatic factors. To decipher the relative importance of biological characteristics vs. environmental conditions, it is necessary to ask whether groups of taxa with similar distributions share the same history of diversification. Because all of the taxa will have shared the same climatic and geological history, evidence of shared history across multiple species provides an estimate of the role of extrinsic factors in shaping contemporary biogeographic patterns. Similarly, differences in the records of evolutionary history across species will probably be signatures of biological differences. In this study, we focus on inferring the evolutionary history for geographical populations and closely related species representing three genera of primary freshwater fishes that are widely distributed in lower Central America (LCA) and northwestern Colombia. Analysis of mitochondrial gene trees provides the opportunity for robust tests of shared history across taxa. Moreover, because mtDNA permits inference of the temporal scale of diversification we can test hypotheses regarding the chronological development of the Isthmian corridor linking North and South America. We have focused attention on two issues. First, we show that many of the distinct populations of LCA fishes diverged in a relatively brief period of time thus limiting the phylogenetic signal available for tests of shared history. Second, our results provide reduced evidence of shared history when all drainages are included in the analysis because of inferred dispersion events that obscure the evolutionary history among drainage basins. When we restrict the analysis to areas that harbour endemic mitochondrial lineages, there is evidence of shared history across taxa. We hypothesize that there were two to three distinct waves of invasion into LCA from putative source populations in northwestern Colombia. The first probably happened in the late Miocene, prior to the final emergence of the Isthmus in the mid-Pliocene; the second was probably coincident with the rise of the Isthmus in the mid-Pliocene, and the third event occurred more recently, perhaps in the Pleistocene. In each case the geographical scale of the dispersion of lineages was progressively more limited, a pattern we attribute to the continuing development of the landscape due to orogeny and the consequent increase in the insularization of drainage basins. Thus, the fisheye view of LCA suggests a complex biogeographic history of overlaid cycles of colonization, diversification, sorting and extinction of lineages.

ATP Synthetase Complexes↗
PubMed2001

The process of developing a research questionnaire to measure attitudes to shared learning.

This article discusses the process by which a questionnaire was developed specifically to measure attitude to shared learning. Over a three-year period the attitude questionnaire was developed and tested using pre-registration students who were engaged in a shared learning programme. These pre-registration students were from three professional groups, namely occupational therapy (OT), diagnostic radiography (DR), and therapeutic radiography (TR). While the study hypothesis was that shared learning would improve attitudes over the three-year period, the focus of this article is to discuss the process by which the research instrument was developed. The rationale for focusing on the process is a simple one. After a diligent literature search it was clear that there were no attitude questionnaires specific to attitude measurement in relation to shared learning. Thus without an already validated attitude to a shared learning questionnaire, it became imperative to create systematically a credible attitude measure of shared learning. The process centred on understanding how monadic scales are constructed and used to measure attitudes and perceptions of participants. Amongst a number of processes to be followed was the need also to check the reliability of the developed questionnaire. This was done using the Cronbach alpha coefficient. A Cronbach alpha coefficient of 0.7 was set as a minimum reliability requirement, which was duly satisfied. The outcome of this process was that it very useful to learn how to produce a suitable instrument to measure attitude to shared learning and to add in a small way to the range of attitude questionnaires available.

Journal Article↗
PubMed1990

Parallel evolution of antibody variable regions by somatic processes: consecutive shared somatic alterations in VH genes expressed by independently generated hybridomas apparently acquired by point mutation and selection rather than by gene conversion.

We identified, in independently generated hybridoma antibodies, blocks of shared somatic alterations comprising four consecutive amino acid replacements in the CDR2s of their heavy chain variable regions. We found that the nucleotide sequences encoding the shared replacements differed slightly. In addition, we performed genomic cloning and sequencing analyses that indicate that no genomic sequence could encode the block of shared replacements in any one of the antibodies and thus directly serve as a donor by a recombinational process. Finally, in a survey of other somatically mutated versions of the same heavy chain variable gene, we found several examples containing one, two, or three of the shared CDR2 mutations in various combinations. We conclude that the shared somatic alterations were acquired by several independent events. This result, and the fact that the antibodies containing the four shared mutations were elicited in response to the same antigen and are encoded by the same VH and VK gene segments, suggests that an intense selection pressure has fixed the shared replacements by favoring the clonal expansion of B cells producing antibodies that contain them. The basis of this selection pressure is addressed elsewhere (Parhami-Seren, B., L. J. Wysocki, M. N. Margolies, and J. Sharon, manuscript submitted for publication).

Amino Acid Sequence↗
PubMed2004

Are depressed patients more likely to share health care decisions with others?

OBJECTIVES: To determine whether psychological variables, particularly depression, influence patients' willingness to share medical decisions with family members or friends. DESIGN: Cross-sectional interviews. SETTING: Oncology and general geriatrics outpatient clinics of an urban VA medical center. PARTICIPANTS: Ninety-five patients with a Charlson comorbidity index score greater than 5. MEASUREMENTS: Subjects described the way that they make health care decisions with friends or family as a dichotomous variable ("shared" versus "not shared") and as a 5-point ordinal variable (the degree to which they share decisions). Patients also completed the 15-item version of the Geriatric Depression Scale (GDS), the Global Distress Index of the Memorial Symptom Assessment Scale, and selected tests of cognitive function and health literacy. RESULTS: Patients with a GDS score higher than 5 were more likely to share decision-making (16/26 versus 26/69; odds ratio 2.58; p = 0.040), as were patients who were married (23/35 versus 19/60; odds ratio 3.63; p = 0.001). In multivariable regression models, a short form GDS score higher than 5 was independently associated with a willingness to share decision with others. CONCLUSION: These results suggest that depression may have a clinically significant influence on patients' willingness to share health care decisions with others. Health care providers should be alert to this possibility, particularly when the decision at hand is significant.

Adult↗
PubMed1998

Sharing and archiving data is fundamental to scientific progress.

The persuasive argument for sharing and archiving data is that scientists must build on the shoulders of other scientists, that science is cumulative and replicative, and that science must be open. Sharing and archiving data are just a small part of all that is implied by that principle, but it is inextricably part of our obligation as social and behavioral scientists to conduct our work in the open. Only then can others see and understand what we did, and only then will someone have a chance to confirm that we were right, or to prove that we were wrong. Moreover, data archiving and sharing create opportunities for addressing questions not envisioned by the initial investigators. Indeed, by supplementing or pooling archived data, new and original data sets can be created that permit analyses well beyond the purpose or scope of the initial data collection. Of course, the creativity and labor of initial investigators should be protected, and the privacy of research participants must be safeguarded. These protections and safeguards, however, are not antithetical to data archiving and sharing. They simply raise questions about when and how data archiving and sharing should take place. In our view, the benefits of properly archived and shared data for outweigh the potential for harm. As indicated above, this is a perspective shared by several funding agencies of behavioral and social research, including the NIA.

Data Collection↗
PubMed2003

Does egg-sharing compromise the chance of donors or recipients achieving a live birth?

BACKGROUND: To evaluate the effect of egg-sharing and the outcome of assisted reproductive treatment (ART) in standard IVF/ICSI patients, egg-sharing donors and egg-sharing recipients. METHODS: Descriptive cohort study to evaluate 276 egg-sharing cycles involving 192 egg-sharers, 274 recipient cycles receiving eggs from egg-sharers and 1098 non-egg-sharing standard IVF/ICSI cycles from January 1998 to December 2002. Patients were divided into three groups: group A, egg-sharers; group B, non-egg-sharers, age <36 years, FSH <10 IU/l, BMI <30 kg/m(2); and group C, egg-sharing recipients, all ages. Duration and amount of gonadotrophin required to achieve follicular maturity, number of eggs collected and donated, fertilization rate, pregnancy rates and live birth rates were compared between donor, recipient and standard IVF/ICSI patients. The chi(2 )test was used to test for statistical significance (P < 0.05). RESULTS: There was no significant difference in pregnancy rate and live birth rate of egg-sharers, group A (42.0%, 33.0%), non-egg-sharers, group B (40.0%, 30.9%) and recipients, group C (41.4%, 28.6%). The number of oocytes collected, number of mature follicles and amount of gonadotrophin used was not significantly different between the two groups (A and B). The average number of embryos transferred and the mean number of eggs allocated between egg-sharers and recipients was not statistically different. CONCLUSION: Egg-sharing does not compromise the chance of achieving a pregnancy or live birth for the egg-sharer or the recipient as compared to standard IVF/ICSI patients. The egg-sharers were not at a higher potential risk of ovarian stimulation syndrome and there was no imbalance of egg allocation.

Adult↗
PubMed1998

Eating from a shared plate affects food consumption in vitamin A-deficient Nepali children.

This case-control study evaluates the relationship between shared-plate eating behavior in young Nepali children (aged 1-6 y) and risk of vitamin A deficiency. Day-long observations of dietary practices were conducted on 7 d over a 15-mo period in 162 households: 81 households with a child with a known history of mild xerophthalmia (cases) were matched with 81 having a non-xerophthalmic child of similar age (controls). Shared-plate eating occurred in 25% of all feeding episodes and at least once in 65% of all days observed. Overall, children engaging in shared-plate eating were significantly more likely to consume grains, vegetables, carotenoid-rich vegetables, pulses, fruits, meats and fish, and dairy products and had significantly larger portion sizes for grains, vegetables, fruits, pulses and dairy products, compared with children who ate alone. In general, feeding behaviors between case and control children tended to be similar. However, shared-plate feeding episodes among case children were significantly less likely to include meats or fish [odds ratio (OR) = 0.5, confidence interval (CI) = 0.3-0.8], dairy products (OR = 0.6, CI = 0.4-0.9) or pulses (OR = 0.7, CI = 0.5-1.0). Individual-plate feeding episodes among case children were more likely to include vegetables (OR = 1.3, CI = 1.0-1.6) than those of control children. Case children were more likely to share a plate with a male adult (OR = 1.7, CI = 1.0-2.8), but less likely to eat from a plate shared with females of any age compared with controls (female adult: OR = 0.6, CI = 0.4-0.9; female child: OR = 0.6, CI = 0.4-1.0). Shared-plate eating may benefit a young child's dietary intake, but the identity of the food sharer may modify this influence.

Adult↗
PubMed2001

Dynamic cervical plates: biomechanical evaluation of load sharing and stiffness.

STUDY DESIGN: An in vitro biomechanical study using a simulated cervical corpectomy model to compare the load-sharing properties and stiffnesses of two static and two dynamic cervical plates. OBJECTIVES: To evaluate the load-sharing properties of the instrumentation with a full-length graft and with 10% graft subsidence and to measure the stiffness of the instrumentation systems about the axes of flexion-extension, lateral bending, and axial torsion under these same conditions. SUMMARY OF BACKGROUND DATA: No published reports comparing conventional and dynamic cervical plates exist. METHODS: Six specimens of each of the four plate types were mounted on ultra-high molecular weight polyethylene-simulated vertebral bodies. A custom four-axis spine simulator applied pure flexion-extension, lateral bending, and axial torsion moments under a constant 50 N axial compressive load. Load sharing was calculated through a range of applied axial loads up to 120 N. The stiffness of each construct was calculated in response to +/-2.5 Nm moments about each axis of rotation with a full-length graft, a 10% shortened graft, and no graft. ANOVA and Fisher's post hoc test were used to determine statistical significance (alpha < or = 0.05). RESULTS: The two locked cervical plates (CSLP and Orion) and the ABC dynamic plate were similar in flexion-extension, lateral bending, and torsional stiffness. The DOC dynamic plate was consistently less stiff. The Orion plate load shared significantly less than the other three plates with a full graft. Both the ABC and the DOC plates were able to load share with a shortened graft, whereas the conventional plates were not. CONCLUSIONS: All plates tested effectively load share with a full-length graft, whereas the two dynamic cervical plates tested load share more effectively than the locked plates with simulated graft subsidence. The effect of dynamization on stiffness is dependent on plate design.

Bone Plates↗
PubMed1997

The high grade match kidney sharing algorithm of the South-Eastern Organ Procurement Foundation (SEOPF): altering recipient demographics through improved matching.

BACKGROUND: Studies of kidneys shared through the South-Eastern Organ Procurement Foundation (SEOPF) have shown that regional organ procurement (ROP) trays can predict negative crossmatch in highly sensitized patients when the HLA match is of a high grade. In an attempt to offer more well-matched kidneys to highly sensitized patients, SEOPF organized the High Grade Match (HGM) Program. METHODS: This United Network for Organ Sharing (UNOS)-approved allocation variance requires mandatory sharing of all kidneys by participating centers after UNOS mandatory sharing requirements have been met. The HGM levels of sharing are: (1) 0 A,B mismatch (MM); panel-reactive antibody (PRA) > or = 40%; negative ROP crossmatch; (2) 0 B,DR MM with > or = 40% PRA; negative ROP crossmatch; (3) 0 B,DR MM with PRA < 40%. Non-HGM cadaveric transplants at the same participating centers--locally or distally procured--serve as the control group. RESULTS: During the first 18 months of this program, the 23 participating centers shared 124 kidneys of the 1592 that were available. Well-matched kidneys (two mismatches or less) accounted for 91.1% in the HGM group, but only 19% of the controls (P<0.0001). Highly sensitized patients (PRA > or = 40%) represented 13.8% of the HGM group, but only 3.3% of the non-HGM group (P<.0001). With HGM kidneys, there was a shift in recipient demographics. Patients with blood group O, female patients, older patients, and retransplanted patients all accounted for significantly larger percentages of the HGM group compared with the non-HGM control group. The racial composition of the recipients of high-grade matches was, however, no different than that of the control recipients at the same centers. CONCLUSION: The HGM Program resulted in longer ischemia times, but graft survival was not affected. The 1-year actuarial graft survival rate (Kaplan-Meier) for HGM kidneys was not different from the control cadaveric graft survival rate. By sharing kidneys based on improved HLA matches with consideration for high PRA, the HGM Program offered more transplant opportunities to women, blood group O recipients, retransplants, and older patients.

ABO Blood-Group System↗
PubMed2000

The importance of H2 haplotype sharing in the induction of specific unresponsiveness by pretransplant blood transfusions.

BACKGROUND: The beneficial effect on graft survival achieved by pretransplant blood transfusions is well established. Previous studies have shown that the degree of major histocompatibility complex (MHC) (mis)-match between the transfusion donor and the recipient plays a determining role. However, other factors are also involved. In this study, we explored the hypothesis that, in addition to sharing of MHC antigens between the transfusion donor and the recipient, the MHC type of the organ donor is also of importance. METHODS: To mimic the human situation, F1 mice, rather than inbred strains, were pretreated with haplotype-shared allogeneic whole blood transfusions and transplanted with hearts of organ donors with different matched or mismatched H2 haplotypes. RESULTS: When a heart was transplanted 1 week after donor-specific transfusion (DST; blood transfusion donor=organ donor), an excellent prolongation of graft survival was obtained (median survival time: 77 days vs. 9 days in untreated mice). However, this was only the case when a haplotype was shared with the recipient; a DST given with no match between organ donor (=BT donor) and recipient did not induce any prolongation. Furthermore, in order to obtain the optimal beneficial effect of a haplotype-shared blood transfusion, the other haplotype of the transfusion donor had to be mismatched with the recipient. The immunogenetic studies showed that haplotype-shared blood transfusions in combinations where the H2 type of the organ donor differed from that of the transfusion donor are less efficient in inducing prolongation of graft survival. CONCLUSIONS: These results demonstrate that haplotype-shared blood transfusions can induce a significantly prolonged survival of cardiac allografts in F1 mice. The immunogenetic studies suggest that presentation of alloantigen-derived peptides in the context of self MHC (the indirect pathway of allorecognition) is essential for the beneficial effect of haplotype-shared blood transfusions.

Animals↗
PubMed2003

The effect of publicly reporting hospital performance on market share and risk-adjusted mortality at high-mortality hospitals.

BACKGROUND: It is unclear whether publicly reporting hospitals' risk-adjusted mortality affects market share and mortality at outlier hospitals. OBJECTIVES: To examine hospitals' market share and risk-adjusted mortality from 1991 to 1997 at hospitals participating in Cleveland Health Quality Choice (CHQC). RESEARCH DESIGN: Time series. SUBJECTS: Changes in market share were examined for all patients hospitalized with acute myocardial infarction, heart failure, gastrointestinal hemorrhage, obstructive pulmonary disease, pneumonia, or stroke at all 30 nonfederal hospitals in Northeast Ohio. Patients insured by Medicare were used to examine changes in mortality. MEASURES: Trends in market share (proportion of patients with the target conditions discharged from a given hospital) and risk-adjusted 30-day mortality. RESULTS: CHQC identified several hospitals with consistently higher than expected mortality. The five hospitals with the highest mortality tended to lose market share (mean change -0.6%, 95% CI -1.9-0.6), but this was not significant. The only outlier hospital with a large decline in market share had declining volume for 2 years before being declared an outlier. Risk-adjusted mortality declined only slightly at hospitals classified by us as "below average" (-0.8%; 95% CI, 2.9-1.8%) or "worst" (-0.4%; 95% CI -2.3-1.7). However, risk-adjusted mortality at one hospital changed from consistently above expected to consistently below expected shortly after first being declared an outlier. CONCLUSION: Despite CHQC's strengths, identifying hospitals with higher than expected mortality did not adversely affect their market share or, with one exception, lead to improved outcomes. This failure may have resulted from consumer disinterest or difficulty interpreting CHQC reports, unwillingness of businesses to create incentives targeted to hospitals' performance, and hospitals' inability to develop effective quality improvement programs.

Consumer Behavior↗
PubMed2002

Assessing the effects of age, sex and shared environment on the genetic aetiology of depression in childhood and adolescence.

BACKGROUND: Depressive symptoms and disorder are experienced by a significant proportion of young people and have long-lasting deleterious effects. The aims of the current investigation were to examine the aetiology of depressive symptoms using a twin design. In particular to examine the effects of sex, age, maternal depression and anxiety symptoms and to examine the aetiology of high depression scores. METHODS: Questionnaires were sent to the families of a population-based sample of twins aged between 8 and 17 years. Parents and children over the age of 11 were asked to complete the Mood and Feelings Questionnaire and Hospital Anxiety and Depression Scale (mothers only). Responses were obtained from 1463 families and data were analysed using genetic model fitting and DeFries and Fulker regression analysis. RESULTS: Depressive symptoms, particularly when self-rated, were significantly genetically influenced. There was evidence of significant heterogeneity according to age, with shared environmental factors more important and genetic factors less important for children aged 8 to 10 than for adolescents aged 11 to 17 years. Some but not all of the shared environmental influences on parent-rated depressive symptoms were accounted for by maternal symptoms of depression and anxiety. There was a significant effect of gender for self-rated depressive symptoms. For boys, genetic factors were of greater importance and common environmental influences of less importance than for girls. Shared environmental effects had a substantial influence on high self-rated depression scores. Adolescents who scored highly on self-rated depression questionnaires experienced significantly more shared life events and their mothers had significantly higher internalising symptoms than adolescents who scoredwithin the normal range. CONCLUSIONS: The results of this study add to the evidence that the aetiology of depressive symptoms differs by age, with genetic factors becoming more important from childhood to adolescence. Some but not all of the shared environmental effect observed for mother-rated depression scores is due to maternal depression and anxiety symptoms. For self-rated depressive symptoms, the importance of genetic and environmental factors may also differ by sex, with genetic influences more important for boys. The aetiology of high depression symptom scores, when self-rated, appears to differ from scores within the normal range in that shared environmental factors appear to be more important. Further research is needed to identify these shared environmental factors using longitudinal models that test genetic and environmental mediation.

Adolescent↗
PubMed1987

The human sex ratio: increase in first-born males to parents with shared HLA-DR antigens.

Maternal-fetal HLA-DR antigen sharing has been reported to affect the sex ratio of first-born. We therefore studied offspring sex ratios and birth orders in 66 families in which parents shared one or more HLA-DR antigens as compared to 61 families with no parental HLA-DR sharing. A significant excess of males was found among first-born children who were HLA-DR compatible with their mothers compared to first-born HLA-DR incompatible children of couples sharing HLA-DR antigens and couples not sharing HLA-DR antigens. Increased numbers of males may persist among children of higher birth orders in families where parents share both HLA-DR antigens, but not among couples sharing only one HLA-DR antigen. We hypothesize that the presence of the H-Y antigen in the male fetus may provide the necessary stimulus for a successful pregnancy in HLA-DR compatible pregnancies and may explain the excess of male births in the general population.

Birth Order↗