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.

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.

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.

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.

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.

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.

P10.18.A Replication of previous GWAS identifies TERT and near EGFR SNVs as risk factors in EPIC glioma patients: a nested case-control study

Background

Gliomas, the most common malignant primary brain tumors in adults, typically have a poor prognosis irrespective of medical care. Previous large genome-wide association studies (GWAS) have identified 27 single-nucleotide variants (SNVs) that are significantly associated with glioma. However, most of the GWAS are conducted by case-control study designs, it is therefore prone to bias when rapidly lethal cases don’t have chance to be included in the study. This study aims to replicate the previous GWAS findings using prospective study design.

Material and Methods

We conducted a nested case-control study within the European Prospective Investigation into Cancer (EPIC) cohort from 7 European countries. GSA-MD Infinium global screening array was used for genotyping. Some subjects were genotyped by other platforms previously. In total, 468 glioma patients and 481 controls were included. The genotypes of 27 SNVs were extracted and for ungenotyped SNVs, datasets were imputed using SHAPEIT v4.1.3 and IMPUTE5 v1.1.5 based on the Haplotype Reference Consortium (Release 1.1) reference panel. Conditional logistic regression model was used to investigate the additive effect of SNVs on the risk of glioma.

Results

21 SNVs showed a consistent direction of effect with previous studies, whereas 6 SNVs did not (ORs between 0.72-0.99 and not significant). After adjusting for multiple testing, two SNVs, rs10069690 (TERT), and rs75061358 (near EGFR) were significantly associated with glioma risk. We observed that prominent OR (2.23, 95%CI=1.49-3.33) of rs75061358 in our study compared to the result from previous GWAS, which implied rs75061358 might be not only a risk factor but also affect survival. Different risk direction was observed for rs77633900 in ETFA gene (OR=0.72, 95%CI=0.51-1.01).

Conclusion

Our findings further confirmed the genetic role on the etiology of glioma in the European population. The potential biases from the previous GWAS are required to be elucidated.

Educational qualification differences and early labor market exit among men: the contribution of labor market marginalization measured across the working life

BACKGROUND

The present study aims to investigate the association between educational qualification and early labor market exit among men and to examine the contribution of labor market marginalization measured across the working life on this association.

METHOD

A register-linked cohort study was conducted including men who completed military service in 1969/70 (born between 1949 and 1951) and were alive at age 55 and not disability pension beneficiaries (n = 40 761). Information on the highest level of educational qualification and the outcome of early exit (disability pension, sickness absence, unemployment, and early old-age pension) was obtained from Swedish nationwide registers between the ages of 55 and 64 years. Labor market marginalization was defined as periods of long-term unemployment and sickness absence over the working life and up to follow-up. Cox regression analyses were used to obtain hazard ratios (HR) with 95% confidence intervals (CI).

RESULTS

Low-educated men were more likely to leave the labor force early due to disability pension or sickness absence (HR: 2.48), unemployment (HR: 2.09), and early old-age pension with- (HR:1.25) and without -income (HR: 1.58). Labor market marginalization across the working life explained a large part of the association for the more involuntary early exit routes (disability pensions, sickness absence, unemployment) and explained very little with regards to the more voluntary early exit routes (early old-age pension with and without income).

CONCLUSION

Exposure to labor market marginalization across the working life was important in explaining educational differences in early labor market exit due to disability pension or sickness absence and unemployment. This study underscores the importance of identifying and implementing preventive measures in the workplace (e.g. adaptions) to prevent new spells of sickness absence and unemployment, especially among low educated individuals.

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.

An extended version of Necessary Condition Analysis (NCA) allows more specific conclusions: an example involving well-being and resilience

BACKGROUND

After conducting necessary condition analysis (NCA), researchers have concluded that a certain, not too low, level of well-being is necessary but not sufficient for a high level of resilience. However, as acknowledged by the developers of the test, NCA only evaluates if the association between two variables is characterized by some unspecified type of non-randomness and not conditions of necessity.

METHOD

Earlier reported data on the association between well-being and resilience among Filipino adults (N = 533) in COVID-19 quarantine were re-analyzed with an extended version of NCA.

RESULTS

Analyses indicated a significant necessity effect of resilience on overall well-being, which is not logically compatible with well-being being necessary but not sufficient for resilience. Analyses with an extended version of NCA suggested that the association between overall well-being and resilience was characterized by equal degrees of necessity and sufficiency.

CONCLUSIONS

The original version of NCA is only capable of evaluating if the association between two variables is characterized by some unspecified type of non-randomness. The extended version of NCA allows researchers to draw more specific conclusions.

Personality trait by intelligence interaction effects on grades tend to be synergistic

BACKGROUND

Earlier research has identified both synergistic and compensatory personality traits by intelligence interaction effects on academic performance.

METHODS

The present study employed data on intelligence, personality traits, and academic performance in the 1997 National Longitudinal Survey of Youth (NLSY97, N = 8984).

RESULTS

Some intelligence by personality trait interaction effects, mainly involving indicators of dependability, on high school grades were identified. The interaction effects tended to be synergistic, meaning that the association between the trait and grades tended to strengthen with increased intelligence. A positive association between intelligence and the reliability in the measurement of a dependability composite score accounted for a substantial portion of the synergistic dependability by intelligence interaction effect on academic performance.

CONCLUSIONS

Personality trait by intelligence interaction effects on academic performance tend to be synergistic and may, at least to some degree, be due to a positive association between intelligence and reliability in the measurement of personality traits.

Dangers of residual confounding: a cautionary tale featuring cognitive ability, socioeconomic background, and education

BACKGROUND

Cognitive ability and socioeconomic background (SEB) have been previously identified as determinants of achieved level of education. According to a "discrimination hypothesis", higher cognitive ability is required from those with lower SEB in order to achieve the same level of education as those with higher SEB. Support for this hypothesis has been claimed from the observation of a positive association between SEB and achieved level of education when adjusting for cognitive ability. We propose a competing hypothesis that the observed association is due to residual confounding.

METHODS

To adjudicate between the discrimination and the residual confounding hypotheses, data from the 1997 National Longitudinal Survey of Youth (NLSY97, N = 8984) was utilized, including a check of the logic where we switched predictor and outcome variables.

RESULTS

The expected positive association between SEB and achieved level of education when adjusting for cognitive ability (predicted by both hypotheses) was found, but a positive association between cognitive ability and SEB when adjusting for level of education (predicted only by the residual confounding hypothesis) was also observed.

CONCLUSIONS

These results highlight the potential use of reversing predictors and outcomes to test the logic of hypothesis testing, and support a residual confounding hypothesis over a discrimination hypothesis in explaining associations between SEB, cognitive ability, and educational outcome.

Technological readiness and implementation of genomic-driven precision medicine for complex diseases

The fields of human genetics and genomics have generated considerable knowledge about the mechanistic basis of many diseases. Genomic approaches to diagnosis, prognostication, prevention and treatment - genomic-driven precision medicine (GDPM) - may help optimize medical practice. Here, we provide a comprehensive review of GDPM of complex diseases across major medical specialties. We focus on technological readiness: how rapidly a test can be implemented into health care. Although these areas of medicine are diverse, key similarities exist across almost all areas. Many medical areas have, within their standards of care, at least one GDPM test for a genetic variant of strong effect that aids the identification/diagnosis of a more homogeneous subset within a larger disease group or identifies a subset with different therapeutic requirements. However, for almost all complex diseases, the majority of patients do not carry established single-gene mutations with large effects. Thus, research is underway that seeks to determine the polygenic basis of many complex diseases. Nevertheless, most complex diseases are caused by the interplay of genetic, behavioural and environmental risk factors, which will likely necessitate models for prediction and diagnosis that incorporate genetic and non-genetic data.

Diminishing returns as a function of the association between within-individual average performance and variance

It has been demonstrated that the worst performance rule (WPR) effect can occur as a result of statistical dependencies in the data. Here, we examine whether this might also be the case for Spearman's law of diminishing returns (SLODR). Two proposed SLODR criteria are the skewness of the estimated latent ability factor and the correlation between this latent ability and within-individual residual variance. Using four publicly available datasets, covering quite different dimensions of behavior, we show that both these criteria are affected by the correlation between within-individual average performance and variance on the test scores. However, the influence of this correlation on the two criteria goes in opposite directions, which suggests that it generally might be difficult to get results that unambiguously support SLODR. These results might have far-reaching implications for the literature, to the extent that various research findings attributed to human cognitive functioning might in fact be due to trivial statistical dependencies in data. This is an important issue to address for future research.

The new accounting for expected adjusted effect test (AEAE test) has higher positive predictive value than a zero-order significance test

OBJECTIVE

The present simulation study aimed to assess positive predictive value (PPV) and negative predictive value (NPV) for our newly introduced Accounting for Expected Adjusted Effect test (AEAE test) and compare it to PPV and NPV for a traditional zero-order significance test.

RESULTS

The AEAE test exhibited greater PPV compared to a traditional zero-order significance test, especially with a strong true adjusted effect, low prior probability, high degree of confounding, large sample size, high reliability in the measurement of predictor X and outcome Y, and low reliability in the measurement of confounder Z. The zero-order significance test, on the other hand, exhibited higher NPV, except for some combinations of high degree of confounding and large sample size, or low reliability in the measurement of Z and high reliability in the measurement of X/Y, in which case the zero-order significance test can be completely uninformative. Taken together, the findings demonstrate desirable statistical properties for the AEAE test compared to a traditional zero-order significance test.

A comparison of models with weight, height, and BMI as predictors of mortality

Introduction

Body mass index (BMI) is a composite variable of weight and height, often used as a predictor of health outcomes, including mortality. The main purpose of combining weight and height in one variable is to obtain a measure of obesity independent of height. It is however unclear how accurate BMI is as a predictor of mortality compared with models including both weight and height or a weight × height interaction as predictors.

Methods

The current study used conscription data on weight, height, and BMI of Swedish men (N = 48,904) in 1969/70 as well as linked data on mortality (3442 deaths) between 1969 and 2008. Cox proportional hazard models including combinations of weight, height, and BMI at conscription as predictors of subsequent all-cause and cause-specific mortality were fitted to data.

Results

An increase by one standard deviation on weight and BMI were associated with an increase in hazard for all-cause mortality by 5.4% and 11.5%, respectively, while an increase by one standard deviation on height was associated with a decrease in hazard for all-cause mortality by 9.4%. The best-fitting model indicated lowest predicted all-cause mortality for those who weighed 60.5 kg at conscription, regardless of height. Further analyses of cause-specific mortality suggest that this weight seems to be a compromise between lower optimal weights to avoid cancer and CVD mortality and a higher optimal weight to not die by suicide.

Conclusions

According to the present findings, there are several ways to make better use of measured weight and height than to calculate BMI when predicting mortality.

Accounting for Expected Adjusted Effect

The point that adjustment for confounders do not always guarantee protection against spurious findings and type 1-errors has been made before. The present simulation study indicates that for traditional regression methods, this risk is accentuated by a large sample size, low reliability in the measurement of the confounder, and high reliability in the measurement of the predictor and the outcome. However, this risk might be attenuated by calculating the expected adjusted effect, or the required reliability in the measurement of the possible confounder, with equations presented in the present paper.

Diminishing returns as a function of disturbance

According to Spearman's law of diminishing returns (SLODR), IQ test scores are more g saturated among those with low, compared to those with high, ability. The present simulation shows that such difference in saturation can be observed if test scores are affected by a disturbing factor, for example, low motivation, illness, or linguistic confusion, that varies in magnitude between individuals. More contemporary criteria of SLODR can also be satisfied if test scores are affected by disturbance, especially if the disturbance variable is negatively skewed. This indicates a possible threat against the validity of findings supporting SLODR and points at the importance for researchers to try to eliminate the influence of such disturbing factors from their studies.

Threshold-like associations as a function of disturbance

According to the intelligence-creativity threshold hypothesis, there should be a positive association between intelligence and creative potential up to a certain point, the threshold, after which a further increase in intelligence should have no association with creativity. In the present simulation study, the measured intelligence and creativity of virtual subjects were affected by their true abilities as well as a disturbance factor that varied in magnitude between subjects. The results indicate that the hypothesized threshold-like association could be due to some disturbing factor, for example, low motivation, illness, or linguistic confusion, that varies between individuals and that affects both measured intelligence and measured creativity, especially if the actual association between intelligence and creativity is weak. This, together with previous negative findings, calls the validity of the intelligence-creativity threshold hypothesis into question.

Predicting the Effect of a Predictor When Controlling for Baseline

The present simulation study indicates that a method where the regression effect of a predictor (X) on an outcome at follow-up (Y1) is calculated while adjusting for the outcome at baseline (Y0) can give spurious findings, especially when there is a strong correlation between X and Y0 and when the test-retest correlation between Y0 and Y1 is relatively weak. Researchers wishing to avoid spurious findings and Type 1 errors should be aware of this phenomenon and are recommended to verify found effects by an unadjusted effect of X on the Y1-Y0 difference.

Predicting the Significance of Necessity

With Necessary Condition Analysis (NCA), a necessity effect is estimated by calculating the amount of empty space in the upper-left corner in a plot with a predictor X and an outcome Y, and recently a method for testing the statistical significance of the necessity effect through permutation has been proposed. In the present simulation study, this method was found to give significant results already with a very weak true population necessity effect, i.e., exhibit high power, unless the sample size is very small. However, in some situations the significance of the necessity effect tends to increase with increased degree of sufficiency, which is paradoxical for a method whose objective is to find necessary but not sufficient conditions.

Using Logistic Regression to Predict Onset and Recovery With Tau Equivalency

Many studies analyze the effect of a predictor X on the onset or recovery of an outcome Y, for example some kind of disorder. The findings from this simulation study indicate that such effects can be found even if there are no changes in individuals’ true scores on the outcome, i.e., with tau equivalency, given some degree of positive test-retest correlation of the outcome and a correlation between the predictor and the outcome at baseline. Researchers predicting onset/recovery should be aware of this fact and in order not to draw hasty conclusions to control for what can be expected from these correlations alone.

Necessity as a Function of Skewness

With necessary condition analysis (NCA), a necessity effect is estimated by calculating the amount of empty space in the upper left corner in a plot with a predictor X and an outcome Y. In the present simulation study, calculated necessity effects were found to have a negative association with the skewness of the predictor and a positive association with the skewness of the outcome. Also the standard error of the necessity effect was found to be influenced by the skewness of the predictor and the skewness of the outcome, as well as by sample size, and a way to calculate a confidence interval for the necessity effect is presented. At least some of the findings obtained with NCA are well within the range of what can be expected from the skewness of the predictor and the outcome alone.

The evolving relationship between premorbid intelligence and serious depression across the lifespan - A longitudinal study of 43,540 Swedish men

BACKGROUND

An association between higher intelligence and lower probability of serious depression has previously been established. Yet, to our knowledge, no large prospective study has examined the relationship across the lifespan.

METHODS

A cohort of 49,321 Swedish men was followed from conscription in 1969-70 (age 18-20) through to 2008. Odds ratios (OR) for first time hospitalisation for depression (FTHD) were calculated in relation to intelligence for distinct time periods across the lifespan, while controlling for established risk factors for depression.

RESULTS

There was a linear association between higher intelligence in youth and lower odds for FTHD during the entire follow-up period, 1973-2008. The association got progressively weaker across the lifespan. During 1973-80, one step down on the stanine scale was associated with an unadjusted increase in OR of 1.34 [95% confidence interval (CI) 1.26-1.42], adjusted OR 1.23 [1.15-1.32]; while, during 2001-2008, the ORs were less than half of the magnitude of the first period, unadjusted 1.14 [1.07-1.21], and adjusted 1.09 [1.01-1.17].

LIMITATIONS

The study includes men only, and the number of available places for in-patient care decreased during the follow-up period.

CONCLUSION

For the first time, we have shown that the association between lower intelligence and depression decreases over time. The attenuation of the association in the adjusted models suggests a slower accumulation of depressogenic stressors among people with a higher IQ-score. Further exploration of intelligence's role in the etiology of depression across the lifespan is required in order to facilitate adequate diagnoses and ameliorating interventions.

Associations between genetics, medical status, physical exercise and psychological well-being in adults with cystic fibrosis

Background

Cystic fibrosis (CF) is the most common autosomal recessive, life-shortening disease among people of European origin. Type of genetic mutation and regular physical exercise has an impact on clinical outcome. This cross-sectional study explores the associations between genetics, medical status, physical exercise and psychological well-being in adult patients with CF.

Methods

Adult patients with CF (N=68; mean age: 32.2; range 18–67 years; 46% women) completed the Cystic Fibrosis Questionnaire-Revised and Hospital Anxiety Depression Scale. Measures about lung function/forced expiratory volume in 1 s per cent predicted, body mass index, physical working capacity, immunoglobulin G, CF Transmembrane Conductance Regulator (CFTR) mutations, and physical exercise were obtained. structural equation modelling was used to fit models to data.

Results

A cftr gene mutation×age interaction effect indicates a psychological disadvantage increasing with age of having more severe CFTR mutations; >65% of the effect is mediated by medical status. Physical exercise has a positive effect on psychological well-being, but >75% of the effect is mediated by medical status.

Conclusions

Psychological well-being decreases with age in patients with more severe cftr mutations, to a large extent due to a parallel deterioration of medical status. Physical exercise has a positive effect on psychological well-being if resulting in better health only. To manage the complexity of these patients' needs, the CF-care should emphasise a holistic approach and offer individualised exercise/treatment programmes and psychological competence.

Trapezius Muscle Activity of Cash Register Work Compared to Department Work in the Supermarket

The MyoElectric (ME) activity from the trapezius muscle in 24 female supermarket employees doing cash register work were evaluated and compared to department work in the supermarket. The result shows that the cash register work typically is of a more static nature than the other tasks tested. Contrary to what was anticipated there were no major difference in the subject's ability to find muscle rest when doing work at the various departments at the supermarket compared to working at the cash register, however large individual differences were observed. The results indicates, that by introducing job rotation, where the cash register work is mixed with other work in the supermarket, the cashiers may be able to break the long-standing static activation of the neck and shoulder region and possibly prevent neck and shoulder pain to develop.

Is poor self-rated health associated with low-grade inflammation in 43,110 late adolescent men of the general population? A cross-sectional study

OBJECTIVE

Self-rated health is a powerful predictor of long-term health and mortality, hence the importance of a better understanding of its biological determinants. Previous studies have shown that low-grade inflammation is associated with poor self-rated health in clinical and healthy populations, but the evidence is sparse in men and completely lacking for men in late adolescence. The aim of this study was to investigate the association between low-grade inflammation and self-rated health among conscripts. It was hypothesised that high levels of inflammatory factors would be associated with poor self-rated health.

DESIGN

Data from 49,321 men (18-21 years) conscripted for military service in 1969 and 1970 were used. Inflammation had been measured through erythrocyte sedimentation rate (ESR). Self-rated health had been assessed on a five-point scale, and was dichotomised into Good ('Very good'/'Good'/'Fair') versus Poor ('Poor'/'Very poor'). Data from 43,110 conscripts with normal levels of ESR, and who reported self-rated health remained after exclusion of those with ESR <1 and >11 mm/h. Associations were calculated using logistic regression analyses. Adjustments were made for body mass index, socioeconomic position, inflammatory disease, emotion regulation, smoking, risky use of alcohol and physical activity.

RESULTS

High levels of ESR were associated with higher odds for poor self-rated health (OR: 1.077 for each unit mm/h increase in ESR, 95% CI 1.049 to 1.105).

CONCLUSIONS

The present study shows for the first time a significant association between a marker of inflammation and self-rated health in late adolescent men, adding to evidence of an association between low-grade inflammation and subjective health perception also in men, as previously demonstrated in women. Further support for inflammation as part of a general psychobiological process that underpins subjective health perception is hereby provided.

Fathers' intelligence measured at age 18-20 years is associated with offspring smoking: linking the Swedish 1969 conscription cohort to the Swedish Survey of Living Conditions

Background

An association between lower IQ of parents, measured early in life, and smoking among their offspring has been reported. The extent to which other background factors account for this association is unknown.

Methods

Data on IQ, smoking, mental health, social class, parental divorce and social problems in a cohort of men born during 1949–1951 and conscripted for military service in 1969 were linked to smoking data on 682 offspring interviewed in the Swedish Surveys of Living Conditions 1984–2009.

Results

In an age-adjusted model, a one-step decrease on a stanine scale was associated with an OR of 1.19 (95% CI 1.04 to 1.35) for offspring smoking. Adjusting for father's socioeconomic background and smoking, mental illness and social problems in youth only marginally lowered the OR's.

Conclusions

Lower IQ among fathers measured at ages 18–20 years was associated with smoking in their offspring. The association was not explained by father's social class in childhood or a higher prevalence of mental illness, social problems or smoking measured among the fathers in their late adolescence.

Anxiety and depression in adults with cystic fibrosis: a comparison between patients and the general population in Sweden and three other European countries

BACKGROUND

Cystic fibrosis (CF) is the most common autosomal recessive life-shortening disease among Caucasians. Studies exploring the prevalence of anxiety and depression in adult CF patients are few, show inconsistent findings and rarely include comparisons with general populations. Prevalence and degree of anxiety and depression were investigated in adult CF patients in Sweden, Belgium, Germany and the UK, and compared to corresponding general population data.

METHODS

Adult non-transplanted CF patients from the three largest CF-centres (out of four) in Sweden (N = 129; Age range 18-70 years; 50 % women) completed the Hospital Anxiety and Depression Scale (HADS). Studies using HADS in adult CF populations in the UK, Germany, and Belgium were included, as well as HADS normative data from the corresponding general populations.

RESULTS

No elevated risk for anxiety and depression was found among the CF patients. However, a Country x Group interaction effect emerged; CF patients experienced a higher degree of anxiety than the general population in Sweden, but not in the other countries, though this finding did not remain significant in a logistic regression analysis. In Sweden the effect was limited to women. A Country x Group interaction effect was also found for Depression; CF patients experienced lower degree of depression than the general population in Sweden, Germany and the UK, but not in Belgium/Netherlands.

CONCLUSIONS

Contrary to earlier outcomes, the present results do not indicate any general elevated risk for anxiety and depression among CF patients. Anxiety was slightly higher in the Swedish CF population, compared to the general population; this finding was not seen in the other countries. Depression among CF patients was lower than or similar to that in the general populations in the studied countries.

Eighteen-Month Follow-Up of Internet-Based Parent Management Training for Children with Conduct Problems and the Relation of Homework Compliance to Outcome

The primary aim of the present study was to evaluate if previously reported treatment gains of a parent management training (PMT) program, administered via Internet, were retained from post to the 18-month follow-up. Another aim was to evaluate homework compliance as a predictor of short and long-term outcomes. Participants were parents of 58 children (3-11 years) with conduct problems who received a 10-week self-directed PMT program, with limited therapist support. Parents of 32 children (55.2 %) responded at all measurement point (baseline, post-test and follow-up) and analyses showed that child conduct problems continued to decrease during the 18-month period after the intervention whereas parenting skills deteriorated somewhat from post treatment. Pre- to post-treatment change in child conduct problems was predicted by parental engagement in homework assignments intended to reduce negative child behaviors. The findings provide support for the use of Internet-based PMT and stress the importance of parental compliance to homework training.

Does high intelligence improve prognosis? The association of intelligence with recurrence and mortality among Swedish men with coronary heart disease

BACKGROUND

Lower intelligence early in life is associated with increased risks for coronary heart disease (CHD) and mortality. Intelligence level might affect compliance to treatment but its prognostic importance in patients with CHD is unknown.

METHODS

A cohort of 1923 Swedish men with a measure of intelligence from mandatory military conscription in 1969-1970 at age 18-20, who were diagnosed with CHD 1991-2007, were followed to the end of 2008.

PRIMARY OUTCOME

recurrent CHD event. Secondary outcome: case fatality from the first event, cardiovascular and all-cause mortality. National registers provided information on CHD events, comorbidity, mortality and socioeconomic factors.

RESULTS

The fully adjusted HRs for recurrent CHD for medium and low intelligence, compared with high intelligence, were 0.98, (95% CIs 0.83 to 1.16) and 1.09 (0.89 to 1.34), respectively. The risks were increased for cardiovascular and all-cause mortality with lower intelligence, but were attenuated in the fully adjusted models (fully adjusted HRs for cardiovascular mortality 1.92 (0.94 to 3.94) and 1.98 (0.89 to 4.37), respectively; for all-cause mortality 1.63 (1.00 to 2.65) and 1.62 (0.94 to 2.78), respectively). There was no increased risk for case-fatality at the first event (fully adjusted ORs 1.06 (0.73 to 1.55) and 0.97 (0.62 to 1.50), respectively).

CONCLUSIONS

Although we found lower intelligence to be associated with increased mortality in middle-aged men with CHD, there was no evidence for its possible effect on recurrence in CHD.

Prediagnostic transcriptomic markers of Chronic lymphocytic leukemia reveal perturbations 10 years before diagnosis

BACKGROUND

B-cell lymphomas are a diverse group of hematological neoplasms with differential etiology and clinical trajectories. Increased insights in the etiology and the discovery of prediagnostic markers have the potential to improve the clinical course of these neoplasms.

METHODS

We investigated in a prospective study global gene expression in peripheral blood mononuclear cells of 263 incident B-cell lymphoma cases, diagnosed between 1 and 17 years after blood sample collection, and 439 controls, nested within two European cohorts.

RESULTS

Our analyses identified only transcriptomic markers for specific lymphoma subtypes; few markers of multiple myeloma (N = 3), and 745 differentially expressed genes in relation to future risk of chronic lymphocytic leukemia (CLL). The strongest of these associations were consistently found in both cohorts and were related to (B-) cell signaling networks and immune system regulation pathways. CLL markers exhibited very high predictive abilities of disease onset even in cases diagnosed more than 10 years after blood collection.

CONCLUSIONS

This is the first investigation on blood cell global gene expression and future risk of B-cell lymphomas. We mainly identified genes in relation to future risk of CLL that are involved in biological pathways, which appear to be mechanistically involved in CLL pathogenesis. Many but not all of the top hits we identified have been reported previously in studies based on tumor tissues, therefore suggesting that a mixture of preclinical and early disease markers can be detected several years before CLL clinical diagnosis.