A formal model accounting for measurement reliability shows attenuated effect of higher education on intelligence in longitudinal data.

The effect of higher education on intelligence has been examined using longitudinal data. Typically, these studies reveal a positive effect, approximately 1 IQ point per year of higher education, particularly when pre-education intelligence is considered as a covariate in the analyses. However, such covariate adjustment is known to yield positively biased results if the covariate has measurement errors and is correlated with the predictor. Simultaneously, a negative bias may emerge if the intelligence measure after higher education has non-classical measurement errors as in data from the 1970 British Cohort Study that were used in a previous study of the effect of higher education. In response, we have devised an estimation method that used iterated simulations to account for both classical measurement errors in the covariate and non-classical errors in the dependent variable. Upon applying this method in a reanalysis of the data from the 1970 British Cohort Study, we find that the estimated effect of higher education diminishes to 0.4 IQ points per year. Additionally, our findings suggest that the impact of higher education is somewhat more pronounced in the initial 2 years of higher education, aligning with the notion of diminishing marginal cognitive benefits.

Prospective effects of mindfulness on anxiety and depressive symptoms may be spurious: Simulated reanalysis of a meta-analytic cross-lagged panel analysis.

A recent meta-analysis claimed decreasing prospective effects of acting with awareness and non-reacting, two facets of dispositional mindfulness, on subsequent anxiety and depressive symptoms. However, the meta-analytic cross-lagged effects were estimated while adjusting for a prior measurement of the outcome variable and it is known that such adjusted cross-lagged effects may be spurious due to correlations with residuals and regression to the mean. We fitted competing models on simulations of the same meta-analytic data and found that prospective effects of the mindfulness facets on anxiety and depressive symptoms probably were spurious. It is important for researchers to be aware of limitations of adjusted cross-lagged effects, meta-analytically estimated or not, in order not to overinterpret findings.

Impact of lumacaftor/ivacaftor on the bacterial and fungal respiratory pathogens in cystic fibrosis: a prospective multicenter cohort study in Sweden.

BACKGROUND: A significant decline in pulmonary exacerbation rates has been reported in CF patients homozygous for F508del treated with lumacaftor/ivacaftor. However, it is still unclear whether this reduction reflects a diminished microbiological burden. OBJECTIVES: The aim of this study was to determine the impact of lumacaftor/ivacaftor on the bacterial and fungal burden. DESIGN: The study is a prospective multicenter cohort study including 132 CF patients homozygous for F508del treated with lumacaftor/ivacaftor. METHODS: Clinical parameters as well as bacterial and fungal outcomes 1 year after initiation of lumacaftor/ivacaftor were compared to data from 2 years prior to initiation of the treatment. Changes in the slope of the outcomes before and after the onset of treatment were assessed. RESULTS: Lung function measured as ppFEV1 (p < 0.001), body mass index (BMI) in adults (p < 0.001), and BMI z-score in children (p = 0.007) were improved after initiation of lumacaftor/ivacaftor. In addition, the slope of the prevalence of Streptococcus pneumoniae (p = 0.007) and Stenotrophomonas maltophilia (p < 0.001) shifted from positive to negative, that is, became less prevalent, 1 year after treatment, while the slope for Candida albicans (p = 0.009), Penicillium spp (p = 0.026), and Scedosporium apiospermum (p < 0.001) shifted from negative to positive. CONCLUSION: The current study showed a significant improvement in clinical parameters and a reduction of some of CF respiratory microorganisms 1 year after starting with lumacaftor/ivacaftor. However, no significant changes were observed for Pseudomonas aeruginosa, Staphylococcus aureus, or Aspergillus fumigatus, key pathogens in the CF context.

Using the theory of planned behavior to predict parents' disclosure of donor conception to their children: a longitudinal study.

STUDY QUESTION: Can the application of the theory of planned behavior (TPB) help predict heterosexual parents' disclosure of donor conception to their children? SUMMARY ANSWER: Parents with a stronger will to act in accordance with social norms favoring disclosure were more likely to start the disclosure process within the next 5-9 years. WHAT IS KNOWN ALREADY: In contrast to single mothers by choice and same-sex couples, heterosexual couples need to make an active decision to disclose their use of donor conception to their child. While disclosure at an early age is encouraged by international guidelines, many heterosexual-couple parents struggle with this. A previous study has found an association between parental scores of TPB factors and disclosure intention, but so far, no study has applied the TPB to predict parents' disclosure behavior. STUDY DESIGN, SIZE, DURATION: The present study is based on the fourth and fifth waves of data collection (T4 and T5) in a nation-wide longitudinal study. Participating parents had conceived through identity-release oocyte donation (n = 68, response rate 65%) and sperm donation (n = 62, response rate 56%) as part of a heterosexual couple. PARTICIPANTS/MATERIALS, SETTING, METHODS: The present study is part of the prospective longitudinal Swedish Study on Gamete Donation (SSGD). Consecutive recruitment of couples starting oocyte or sperm donation treatment was conducted at all seven fertility clinics providing gamete donation in Sweden during a 3-year period (2005-2008). Participants were requested to complete postal surveys at five time points. The present study includes heterosexual-couple parents following oocyte or sperm donation who participated at the two latest time points when their children were 7-8 years old (T4), and 13-17 years old (T5). At T4, participants completed the study-specific TPB Disclosure Questionnaire (TPB-DQ) measuring attitudes and intentions to disclose the donor conception to the child, and disclosure behavior was assessed at both T4 and T5. Data from those participants who had not yet disclosed at T4 were analyzed using survival analysis with Cox regressions. MAIN RESULTS AND THE ROLE OF CHANCE: Forty participants had not disclosed the donor conception to their children at T4 and, out of these, 13 had still not disclosed at T5. We found a significant association between scores of the TPB factor Subjective norms at T4 and their subsequent disclosure behavior at T5 (HR = 2.019; 95% CI: 1.36-3.01). None of the other factors were significantly associated with disclosure behavior. LIMITATIONS, REASONS FOR CAUTION: The present study concerns heterosexual-couple parents with children conceived following treatment with gametes from open-identity donors, which limits the generalizability of our findings to other groups and contexts. Other limitations include the risk of systematic attrition due to the longitudinal study design and decreased statistical power due to few participants. WIDER IMPLICATIONS OF THE FINDINGS: Our findings highlight the importance of perceived subjective norms for parents' disclosure behavior and indicate that the co-parent's opinion about disclosure is of particular relevance in this regard. Counselors should focus on supporting prospective parents to initiate and maintain a healthy and open dialogue about concerns around building a family with donor conception. STUDY FUNDING/COMPETING INTEREST(S): The study was funded by the Swedish Research Council. The authors have no competing interests to declare. TRIAL REGISTRATION NUMBER: N/A.

Breastfeeding, cognitive ability, and residual confounding: A comment on studies by Pereyra-Elìas et al.

Recent studies found positive effects of breastfeeding on the child's cognitive ability and educational outcomes even when adjusting for maternal cognitive ability in addition to a large number of other potential confounders. The authors claimed an important role of breastfeeding for the child's cognitive scores. However, it is well known that error in the measurement of confounders can leave room for residual confounding. In the present reanalyses, we found incongruent effects indicating simultaneous increasing and decreasing effects of breastfeeding on the child's cognitive ability and educational outcomes. We conclude that findings in the reanalyses may have been due to residual confounding due to error in the measurement of maternal cognitive ability. Consequently, it appears premature to assume a genuine increasing effect of breastfeeding on the child's cognitive ability and educational outcomes and claims in this regard may be challenged.

Spurious prospective effects between general and domain-specific self-esteem: A reanalysis of a meta-analysis of longitudinal studies.

A recent meta-analysis, of 38 studies with data from 43 independent samples (total N = 24,668), claimed evidence for positive reciprocal prospective effects, and hence for both top-down and bottom-up processes, between general and domain-specific self-esteem. However, the meta-analytic cross-lagged effects were estimated while adjusting for a prior measurement of the outcome variable and it is known that such adjusted cross-lagged effects may be spurious due to correlations with residuals and regression to the mean. In the present reanalyses, we found all of the prospective effects to be spurious. Consequently, claims about increasing prospective effects and top-down and bottom-up processes between general and domain-specific self-esteem can be questioned. It is important for researchers to be aware of the limitations of cross-lagged panel analyses, and of analyses of correlational data in general, in order not to overinterpret findings.

Distorted meta-analytic findings on peer influence: A reanalysis.

In a recent meta-analysis, Giletta et al. (2021) [1] found a positive effect of peers' behavior at time 1 on target youths' behavior at time 2 while adjusting for target youths' behavior at time 1 and claimed to have quantified peer influence. However, it is established that controlled cross-lagged effects could be due to correlations with measurement errors and reversion in the direction of the mean rather than due to true decreasing or increasing effects. Here, in a reanalysis of the same meta-analytic data as used by Giletta et al., we found that peer influence, as operationalized by Giletta et al., may have been distorted (i.e. spurious). We do not claim that peer influence does not exist, but it may be hard, maybe not even possible, to prove by analyses of observational data that it does exist. Difficulties to prove causal effects by analyses of observational data is common for all areas of research and not specific for research on peer influence.

Is internet-based parent training for everyone? Predictors and moderators of outcomes in group vs. internet-based parent training for children with disruptive behavior problems.

Parent training is an effective treatment for disruptive behavior problems in children. However, as there is limited access to traditional face-to-face treatment, other delivery formats have been evaluated. This study aims to evaluate possible predictors and moderators of outcome, completion and engagement in parent training when delivered in group or through the internet. A recent randomized controlled non-inferiority trial (N = 161) demonstrated equal effectiveness of the parent training program Comet when delivered in group (gComet) and through the internet (iComet). Demographic, clinical and theory-driven variables were studied to find predictors and moderators of treatment effect, completion and engagement. Linear mixed effects models were used to determine predictors and moderators of change in disruptive behavior from baseline to the 3- and 12-month follow-up. Most variables did not have significant predictive or moderating effects. However, there were some variables that predicted or moderated outcomes that may have implications for practice (e.g., comorbid emotional problems, preferred treatment format, and ADHD). This trial can contribute to guiding clinical work with children with disruptive behavior and results indicate that parent training in both treatment formats can be offered regardless of a range of demographic and clinical factors. Taking patients' treatment preferences into account can increase treatment completion.

Human scent as a first-line defense against disease.

Individuals may have a different body odor, when they are sick compared to healthy. In the non-human animal literature, olfactory cues have been shown to predict avoidance of sick individuals. We tested whether the mere experimental activation of the innate immune system in healthy human individuals can make an individuals' body odor be perceived as more aversive (intense, unpleasant, and disgusting). Following an endotoxin injection (lipopolysaccharide; 0.6 ng/kg) that creates a transient systemic inflammation, individuals smelled more unpleasant compared to a placebo group (saline injection). Behavioral and chemical analyses of the body odor samples suggest that the volatile components of samples from "sick" individuals changed qualitatively rather than quantitatively. Our findings support the hypothesis that odor cues of inflammation in axillary sweat are detectable just a few hours after experimental activation of the innate immune system. As such, they may trigger behavioral avoidance, hence constituting a first line of defense against pathogens of infected conspecifics.

Unmasking artifactual links: A reanalysis reveals No direct causal relationship between self-esteem and quality of social relations.

A meta-analysis conducted by Harris and Orth (2020) found positive prospective cross-lagged effects between quality of social relations and self-esteem in included longitudinal studies. Harris and Orth concluded that the link between self-esteem and quality of social relations is reciprocal and characterized by a positive feedback loop. However, meta-analytic effects were estimated while controlling for a prior measurement of the outcome and such effects are known to be susceptible to artifactual (i.e. spurious) effects due to correlations with measurement errors and reversion to mediocrity. We reanalyzed the same data and found paradoxical effects indicating, simultaneously, both increasing and decreasing effects between self-esteem and social relations. These findings suggest that prospective effects between self-esteem and quality of social relations are artifactual rather than due to a true reciprocal effect. Thus, these findings have important theoretical implications and challenge both the risk regulation model, which posits that self-esteem has a causal effect on quality of social relations, and the sociometer theory, which claims that quality of relations is the cause and self-esteem the effect. The present results prompt further investigation into the underlying mechanisms driving these artifactual associations. Additionally, the study highlights the importance of considering methodological limitations in future meta-analyses to improve the accuracy of causal inferences.

Prospective associations between social support and posttraumatic stress disorder may be spurious: A re-meta-analysis of longitudinal studies and a simulation.

A recent meta-analysis concluded to have found proof for both a social causation model, according to which social support protects against posttraumatic stress disorder (PTSD), and a social selection model, which claims that PTSD erodes social support. However, the prospective cross-lagged effects were estimated while adjusting for a prior measurement of the outcome and this method is vulnerable for spurious findings due to correlations with residuals and regression toward the mean. The present re-analyses of the meta-analytic effects indicated that depending on used model one can choose to claim that social support has either a decreasing, an increasing, or no prospective effect on subsequent change in PTSD symptom severity, and vice versa. Therefore, claims over and above a negative cross-sectional correlation between social support and PTSD, including the social causation and social selection models, can be questioned. The findings were validated by analyses of simulated data, which indicated that prospective effects were not necessary for the observed meta-analytic associations.

A randomized controlled trial of Safer Kids - A program for parents reported for child abuse: Short-term effects on further reports of child abuse and related risk factors.

BACKGROUND: Millions of children are victims of child abuse world-wide. Consequences include long-term health impacts and large societal costs. Parent training is promising to prevent abuse, but challenges with motivation and attrition must be overcome to reach parents in need. OBJECTIVE: To assess the effectiveness and acceptability of Safer Kids, a cognitive behavioral therapy-based parenting program delivered immediately after a report of child abuse. Safer Kids is used within the Child Welfare Services (CWS) in Sweden but has never been evaluated in an RCT. PARTICIPANTS AND SETTING: In total, 112 families with children 2-12 years referred to the Swedish CWS for physical or emotional child abuse participated. METHODS: Families were randomized to Safer Kids or intervention as usual (IAU). Data from parents, children and CWS were analyzed with multilevel and survival analyses. Primary outcomes were parent-rated child abuse potential and re-reports of abuse. Secondary outcomes were child abuse risk factors and treatment satisfaction. RESULTS: Data 4 and 7 months from baseline were available for 96 % of the families. All except one family (98 %) who started Safer Kids completed the program. Both groups improved from baseline to follow-ups on most effectiveness outcomes. The changes were not statistically different between groups. Parents and social workers were more satisfied with Safer Kids than IAU. CONCLUSIONS: Short manualized parenting programs can be a way to reach parents reported for child abuse with support. Safer Kids is a viable option to the CWS's standard interventions, as it was equally effective and slightly better accepted than IAU.

Dangers of including outcome at baseline as a covariate in latent change score models: Results from simulations and empirical re-analyses.

Latent change score modeling is a type of structural equation modeling used for estimating change over time. Often change is regressed on the initial value of the outcome variable. However, similarly to other regression analyses, this procedure may be susceptible to regression to the mean. The present study employed simulations as well as re-analyses of previously published data, claimed to indicate reciprocal promoting effects of vocabulary and matrix reasoning on each other's longitudinal development. Both in simulations and empirical re-analyses, when adjusting for initial value on the outcome, latent change score modeling tended to indicate an effect of a predictor on the change in an outcome even when no change had taken place. Furthermore, analyses tended to indicate a paradoxical effect on change both forward and backward in time. We conclude that results from latent change score modeling are susceptible to regression to the mean when adjusting for the initial value on the outcome. Researchers are recommended not to regress change on the initial value included in the calculation of the change score when employing latent change score modeling but, instead, to define this parameter as a covariance.

Necessary condition analysis has either low specificity or low sensitivity: Results from simulations and empirical analyses of grit, depression, and anxiety.

Objectives: Initially the stated goal of Necessary Condition Analysis (NCA) was to help identify conditions that are necessary but not sufficient for some outcome. However, later the developers of the test asserted that the test is for identifying if the association between two variables is characterized by some indeterminate type of non-randomness. The objective of the present study was to assess the ability of NCA to achieve its originally as well as its more newly stated objective. Furthermore, the performance of NCA was compared with the performance of ordinary linear regression analysis. Methods: Data simulating various deviations from randomness as well as empirical data on grit, depression, and anxiety in the 1997 National Longitudinal Survey of Youth (NLSY97) were analyzed with NCA and with linear regression. Results: For its initially stated objective, NCA displayed low specificity. For its more newly stated objective, NCA exhibited low sensitivity. Ordinary linear regression analysis was better than NCA at identifying non-random associations, especially negative associations. Conclusions: There does not appear to exist any convincing reasons to use the significance test in NCA instead of ordinary linear regression analysis. There appears to be confusion about how results from NCA should be interpreted, maybe even among the developers of the test.

Parent Training via Internet or in Group for Disruptive Behaviors: A Randomized Clinical Noninferiority Trial.

OBJECTIVE: To evaluate if an internet-delivered parent training program is noninferior to its group-delivered counterpart in reducing child disruptive behavior problems (DBP). METHOD: This noninferiority randomized clinical trial enrolled families seeking treatment in primary care in Stockholm, Sweden, for DBP in a child 3-11 years of age. Participants were randomized to internet-delivered (iComet) or group-delivered (gComet) parent training. The primary outcome was parent-rated DBP. Assessments were made at baseline and 3, 6, and 12 months. Secondary outcomes included child and parent behaviors and well-being and treatment satisfaction. The noninferiority analysis was determined by a one-sided 95% CI of the mean difference between gComet and iComet using multilevel modeling. RESULTS: This trial included 161 children (mean age 8.0); 102 (63%) were boys. In both intention-to-treat and per-protocol analyses, iComet was noninferior to gComet. There were small differences in between-group effect sizes (d = -0.02 to 0.13) on the primary outcome with the upper limit of the one-sided 95% CI below the noninferiority margin at 3-, 6-, and 12-month follow-up. Parents were more satisfied with gComet (d = 0.49, 95% CI [0.26, 0.71]). At 3-month follow-up, there were also significant differences in treatment effect on attention-deficit/hyperactivity disorder symptoms (d = 0.34, 95% CI [0.07, 0.61]) and parenting behavior (d = 0.41, 95% CI [0.17, 0.65]) favoring gComet. At 12-month follow-up, there were no differences in any outcomes. CONCLUSION: Internet-delivered parent training was noninferior to group-delivered parent training in reducing child DBP. The results were maintained at 12-month follow-up. This study supports internet-delivered parent training being used as an alternative to group-delivered parent training in clinical settings. CLINICAL TRIAL REGISTRATION INFORMATION: Randomized Controlled Trial of Comet via the Internet or in Group Format; https://www. CLINICALTRIALS: gov/; NCT03465384.

Associations Between Cognition and Serotonin 1B Receptor Availability in Healthy Volunteers: A [11C]AZ10419369 Positron Emission Tomography Study.

BACKGROUND: The serotonin system has been implicated in several psychiatric disorders. All major psychiatric disorders are associated with cognitive impairment, but treatment improving cognitive deficits is lacking, partly due to limited understanding of the neurobiology of cognitive functioning. Several markers for the serotonin system have been associated with cognitive functions. Our research group previously has reported a positive correlation between serotonin (5-HT1B) receptor availability in the dorsal brainstem and visuospatial memory in a pilot study of healthy individuals. Here, we aim to replicate our previous finding in a larger group of healthy volunteers as well as to investigate putative associations between 5-HT1B receptor availability and other cognitive domains. METHODS: Forty-three healthy individuals were examined with positron emission tomography using the 5-HT1B receptor radioligand [11C]AZ10419369 and a visuospatial memory test to replicate our previous finding as well as tests of verbal fluency, cognitive flexibility, reaction time, and planning ability to explore other domains potentially associated with the serotonin system. RESULTS: Replication analysis revealed no statistically significant association between 5-HT1B receptor availability in the dorsal brainstem and visuospatial memory performance. Exploratory analyses showed age-adjusted correlations between 5-HT1B receptor availability in whole brain gray matter and specific brain regions, and number of commission errors, reaction time, and planning ability. CONCLUSIONS: Higher 5-HT1B receptor availability was associated with more false-positive responses and faster reaction time but lower performance in planning and problem-solving. These results corroborate previous research supporting an important role of the serotonin system in impulsive behavior and planning ability.

Questioning the vulnerability model: Prospective associations between low self-esteem and subsequent depression ratings may be spurious.

BACKGROUND: According to the vulnerability model, low self-esteem makes people more depressed. Support for the vulnerability model comes almost exclusively from analyses using cross-lagged panel models, showing a negative effect of initial self-esteem on subsequent depression ratings when adjusting for initial depression. However, it is well known that such adjusted effects are susceptible to regression toward the mean. METHODS: Data from four waves of measurements in five different samples (total N = 2703) were analyzed with two different cross-lagged panel models, two different random intercept cross-lagged panel models, and two different latent change score models, predicting change forwards as well as backwards in time. RESULTS: High initial self-esteem predicted both decreased and increased depression ratings between measurements and an increase in self-esteem between measurements predicted a concurrent decrease in depression ratings. LIMITATIONS: Only data from two western countries, Switzerland and USA, were analyzed. Whether the main finding, that a prospective effect of self-esteem on subsequent depression ratings might be spurious, applies to other countries and cultures remains an open question. CONCLUSIONS: Due to the incongruent results, any causal effect of self-esteem on depression ratings, and thus the vulnerability model as such, cannot be corroborated by the data and models analyzed here. Instead, we propose, tentatively, that prospective associations between self-esteem and depression ratings may be spurious due to a combination of reasons, including regression toward the mean. The indication that depression might not be affected by measures to improve individuals' self-esteem is of clinical relevance.

Antibiotic hypersensitivity in cystic fibrosis - Low frequency of anaphylaxis over 16 000 courses.

AIMS: Drug hypersensitivity reactions (DHR) to antibiotics are common and a substantial issue in managing patients with cystic fibrosis (CF). This study aimed to assess the prevalence and clinical features as well as risk factors of DHR to antibiotics in CF. METHOD: A 20-year retrospective study was conducted among 226 CF patients (100 children and 126 adults) attending our centre. The Swedish Registry for Cystic Fibrosis and electronic medical records enabled us to ascertain the number and routes of antibiotic courses. All suspected DHR were evaluated. RESULTS: The patients had a total of 16 910 antibiotic courses, of which 6832 (40%) were intravenously administered. Of 226 enrolled CF patients, 70 (31%) developed overall 131 DHR to antibiotics. The prevalence of DHR increased with advancing age (P < .001). Beta-lactams elicited 71% of all DHR and piperacillin was the most common single culprit (30% of intravenous and 24% of all DHR). Reactions were mild to moderate and mostly limited to skin; no severe cutaneous adverse reactions were observed. Additionally, anaphylaxis was rare, constituting 2.3% (3/131) of all DHR. Patients with DHR were exposed to significantly more courses of antibiotics than those without DHR (median 124 vs. 46, retrospectively, P < .001). CONCLUSIONS: DHR to antibiotics, particularly to beta-lactams, are increased in CF patients, and associated with a higher number of cumulative exposures because of recurrent infections. However, severe cutaneous or systemic DHR, such as anaphylaxis, appear to be rare.

Regression to the mean in latent change score models: an example involving breastfeeding and intelligence.

BACKGROUND: Latent change score models are often used to study change over time in observational data. However, latent change score models may be susceptible to regression to the mean. Earlier observational studies have identified a positive association between breastfeeding and child intelligence, even when adjusting for maternal intelligence. METHOD: In the present study, we investigate regression to the mean in the case of breastfeeding and intelligence of children. We used latent change score modeling to analyze intergenerational change in intelligence, both from mothers to children and backward from children to mothers, in the 1979 National Longitudinal Survey of Youth (NLSY79) dataset (N = 6283). RESULTS: When analyzing change from mothers to children, breastfeeding was found to have a positive association with intergenerational change in intelligence, whereas when analyzing backward change from children to mothers, a negative association was found. CONCLUSIONS: These discrepant findings highlight a hidden flexibility in the analytical space and call into question the reliability of earlier studies of breastfeeding and intelligence using observational data.