A genetic risk factor for major depression and suicidal ideation is mitigated by physical activity

Effects of the glucocorticoid receptor gene (NR3C1) and subjective birth experience on the risk of postpartum depression and maternal bonding

Postpartum depression (PPD) is a serious health care issue that affects a substantial share of women giving birth. PPD is considered a severe stress response that is likely associated with impaired HPA-axis activity. However, genetic findings regarding HPA-axis effects on PPD are scarce and inconsistent. Inconsistencies may be due to the neglect of environmental (stressful) events such as perinatal trauma or averse subjective birth experiences associated with PPD. Therefore, the present study aims to investigate whether the NR3C1 gene and subjective birth experience interact on PPD and postpartum bonding to the child. N = 277 mothers provided gene samples and self-report data on PPD and postpartum bonding. We genotyped 11 polymorphisms on the NR3C1 gene (including the prominent BCL1) and conducted haplotype analyses. A negative subjective birth experience was associated with both PPD and maternal postpartum bonding. Our results further show a significant main effect of NR3C1 haplotype (F_{1, 275} = 6.42, p = .012, η² =.023) and a haplotype x birth experience interaction (F_{1, 274} = 4.57, p = .033, η² =.016) on PPD. We did not find any NR3C1 haplotype effects on bonding. Our results support the assumption that the glucocorticoid receptor coding NR3C1 gene is involved in the development of PPD. These gene effects become particularly important in presence of a negative environmental event such as the subjective birth experience. This finding allows more targeted preventions in terms of being particularly sensitive to potentially harming environmental influences that may present even stronger risk factors for genetically vulnerable women.

Differential Diagnosis of Major Depressive Disorder and Bipolar Disorder: Genetic and Hormonal Assessment and the Influence of Early-Life Stress

Few studies have assessed biomarkers for the differentiation of major depressive disorder (MDD) and bipolar disorder (BD). However, some elements of depression such as hormones and receptors of the renin-angiotensin-adrenal system (RAAS), the hypothalamus-pituitary-adrenal (HPA) axis, and history of early-life stress (ELS) could be considered for differential diagnosis. Therefore, this study aimed to assess aldosterone and cortisol levels, MR and GR gene polymorphisms, and ELS as potential biomarkers for differentiating MDD and BD. This study presents a case-control design. Groups comprised samples for genetic, cortisol, and aldosterone analysis: healthy control (HC; n = 113/97/103), MDD (n = 78/69/67) and BD (n = 82/68/65) subjects. Furthermore, all subjects were assessed for diagnostic screening, the severity of depression, and history of ELS by applying MINI-PLUS, GRID-HDRS, and CTQ, respectively. In addition, genotype and allelic frequencies of GR (N363S, R22/23K and BclI) and MR (MI180V and -2G/C) polymorphisms were evaluated via PCR. Our findings demonstrate that basal aldosterone levels may be a biomarker for differentiating BD and MDD. Furthermore, ELS affects the HPA axis in BD, cortisol may be considered a biomarker for distinguishing BD and MDD, but only in the absence of ELS, and, finally, history of ELS and MR-2G/C variant alleles are factors that contribute to the severity of depressive symptoms in MDD and BD.

Public health nurses' perceptions on promotive and risk factors for children's mental health: A qualitative interview study

AIM

To describe promotive and risk factors for children's mental health at the individual, interpersonal, organizational, community and public policy levels of the socioecological environment.

DESIGN

A descriptive qualitative interview study.

METHODS

Data were collected in Finland during autumn 2019 via semi-structured interviews. Participants (n = 23) comprised public health nurses who worked in child health clinics and school healthcare. Data were analyzed using inductive content analysis.

RESULTS

Several promotive and risk factors were identified to have affected children's mental health. Intra-family factors were the most important in the opinion of public health nurses, and they were most concerned about family related risk factors. In addition, the descriptions of nurses revealed that children are in a socially unequal position in terms of their place of residence. It was also uncovered that there were fewer social and healthcare and leisure services in small municipalities, the distances to services were longer, which was perceived to complicate the use of services, and the fear of stigma was greater.

CONCLUSION

According to public health nurses, factors at the individual, interpersonal, organizational, community and public policy levels of the socioecological environment affect children's mental health and overall well-being. Consequently, the promotion of children's mental health should be emphasized at every level of the society, considering the whole family.

IMPACT

This study indicated the importance of considering factors that affect children's mental health at all levels of the socioecological environment. The results can be reflected in the relation of the socioecological model of health promotion and used in planning the work of nurses in primary healthcare and other relevant nursing settings to emphasize promotive and preventive work.

Trauma Exposure and Functional Movement Characteristics of Male Tactical Athletes

CONTEXT

Tactical athletes commonly experience high levels of physical stress, which may increase their risk of musculoskeletal injury. It is critical to understand psychological predictors of functional movement (FM), which may help prevent musculoskeletal injury in this population.

OBJECTIVE

To determine the associations of combat and trauma exposure with FM characteristics of male tactical athletes. Secondary objectives were to explore confounding influences of age and physical injury history as well as the mediating role of bodily pain.

DESIGN

Cross-sectional study.

SETTING

Research laboratory.

PATIENTS OR OTHER PARTICIPANTS

Eighty-two healthy, male, active-duty US Navy Explosive Ordnance Disposal personnel (age = 34.0 ± 6.7 years).

MAIN OUTCOME MEASURE(S)

Participants completed measures of combat exposure, trauma exposure, physical injury history, and bodily pain. We assessed FM characteristics (ie, Functional Movement Screen [FMS], Y-Balance Test), from which we derived a composite functional status (CFS) measure. Hypotheses were tested using correlational and multiple regression (causal-steps) models.

RESULTS

In unadjusted models, trauma exposure was inversely associated with the FMS (P = .005) and CFS (P = .009) scores. In adjusted models, these relationships were robust to the confounding influences of age and physical injury history. Trauma exposure and bodily pain were substantive, independent predictors of FMS and CFS in causal-steps models (all P values < .05), implying additive rather than mediated effects (R²_adj = 0.18-0.20). Combat exposure did not predict FM characteristics.

CONCLUSIONS

To our knowledge, this is the first evidence of the influence of trauma exposure on the FM characteristics of male tactical athletes, independent of age, physical injury, and bodily pain. This program of research may help to advance the prevention and treatment of musculoskeletal injuries in the tactical environment.

Blast exposure interacts with genetic variant 5HTTLPR to predict posttraumatic stress symptoms in military explosives personnel

The first of its kind, this study determined whether blast exposure interacts with genetic variant 5HTTLPR to predict posttraumatic stress (PTS) symptoms in 78 military explosives operators. In all models, blast-exposed 5HTTLPR S carriers registered definitively higher PTS symptoms in comparison to non-exposed S carriers, as well as exposed and non-exposed LL carriers (all p < 0.01). All findings were robust to confounding influences of age and traumatic brain injury diagnosis. Not only is blast exposure prevalent in EOD personnel, but it also interacts with genetic predisposition to predict trauma symptoms in this unique, at-risk military population.

Genetic, Physiologic, and Behavioral Predictors of Cardiorespiratory Fitness in Specialized Military Men

Introduction

Cardiorespiratory fitness (CRF) is a crucial performance requirement of specialized military occupations. Age and physical activity are established predictors of CRF, but it is not clear how these predictors combine with each other and/or with genetic predisposition. The goal of this study was to derive inclusive explanatory models of CRF in US Navy Explosive Ordnance Disposal (EOD) operators, synthesizing conventional (e.g., age, body composition, and physical activity) and novel influences (e.g., genetic variance).

Materials and Methods

In this cross-sectional study, 40 male, active duty EOD operators completed a graded exercise test to assess maximal oxygen consumption and ventilatory threshold (VT) using the Bruce protocol. Aerobic performance was further quantified via time of test termination and time at which VT was achieved. Body composition was determined via dual x-ray absorptiometry, and physical activity was assessed by self-report. Genetic variants underlying human stress systems (5HTTLPR, BclI, −2 C/G, and COMT) were assayed. Descriptive analyses were conducted to summarize subject characteristics. Hypotheses were tested with linear regression models. Specifically, separate univariate regression models first determined associations between each of the independent and dependent variables. This protocol was approved by the Naval Health Research Center Institutional Review Board (NHRC.2015.0013).

Results

In univariate regression models, age, body composition, physical activity, and 5HTTLPR consistently predicted CRF and/or aerobic performance (R2 range 0.07–0.55). Multivariate regression models routinely outperformed the univariate models, explaining 36–62% of variance.

Conclusion

This study signifies a shift toward inclusive explanatory models of CRF and aerobic performance, accounting for combined roles of genetic, physiologic, and behavioral influences. Although we were able to quantify combined effects, we were unable to evaluate interaction effects (e.g., gene–gene, gene–behavior) due to limited statistical power. Other limitations are that this specialized military population may not readily generalize to broader populations, and the current sample was all male. Considering these limitations, we aim to replicate this study in various populations, both male and female. Despite its limitations, this study reflects a shift toward more comprehensive predictive models of CRF, explaining the unique and shared contributions of genetic predisposition, physiology, and behavior. These findings have implications for assessment, selection, and training of specialized military members, and may also impact mission success and survivability. Future studies are needed to better characterize additive, interactive, and mediated effects.

Physical activity and suicidal ideation: A systematic review and meta-analysis

BACKGROUND

A potential approach to suicide prevention that has not been closely examined, but which holds promise in terms of widespread dissemination without major side-effects, is physical activity (PA). This systematic review and meta-analysis set out to: (a) explore associations between PA and suicidal ideation (SI) levels, and (b) investigate the effect of PA interventions on SI.

METHODS

Major electronic databases were searched from inception up to 05/2017 to identify quantitative studies reporting an association between PA and SI. A quantitative correlates synthesis and random effects meta-analysis were conducted.

RESULTS

Fourteen of 21 studies in adults (67%) (n = 130,737), 7/14 (50%) in adolescents (n = 539,170) and 2/3 (67%) in older adults (n = 50,745) found a significant negative association between PA- and SI-levels. Pooled adjusted meta-analysis of 14 effect sizes over eight studies and 80,856 people found that those who were "active" versus those who were "inactive" were less likely to have SI (OR = 0.87, 95%CI = 0.76-0.98). Additionally, meeting PA guidelines conferred a significant protective effect against SI (OR = 0.91, 95%CI = 0.51-0.99, P = 0.03; N studies = 3, n people = 122,395), while not meeting guidelines was associated with increased SI (OR = 1.16, 95%CI = 1.09-1.24, P < 0.001; N = 4, n = 78,860). Data from the intervention studies (N = 3, n = 121) was mixed and limited.

LIMITATIONS

Our findings are based mainly on cross-sectional studies, while the majority of studies did not include a rigorous physical activity assessment.

CONCLUSIONS

The current study suggests that higher PA levels are associated with lower SI. However, the associations observed need to be confirmed in prospective observational studies and controlled trials.