In Ischemic Heart Disease, Reduced Sensitivity to Pressure at the Sternum Accompanies Lower Mortality after Five Years: Evidence from a Randomized Controlled Trial.

Background: Autonomic nervous system dysfunction (ANSD) is associated with negative prognosis of ischemic heart disease (IHD). Elevated periosteal pressure sensitivity (PPS) at the sternum relates to ANSD and sympathetic hyperactivity. Two previous observational case-control studies of the effect of reduction of PPS suggested lower all-cause mortality from IHD and stroke. We now used a specific daily, adjunct, non-pharmacological program of reduction of elevated PPS to test the hypothetical association between the intervention and reduced all-cause mortality in patients with stable IHD in a randomized controlled trial (RCT). Methods: We completed active (n = 106) and passive interventions (n = 107) and compared the five-year mortalities. We also compared the five-year individual all-cause mortality of each participant to approximately 35.000 members of the general population of Denmark. Pooling the mortality data from the active group of the RCT with the two preliminary studies, we registered the mortality following active intervention of 1.168 person-years, compared to 40 million person-years of the pooled general population. Results: We recorded fewer deaths of the active RCT intervention group than of the corresponding control group from the general population (p = 0.01), as well as of the passive RCT intervention group (p = 0.035). The meta-analysis of the three studies together demonstrated reduced 4.2-year all-cause mortality of 60% (p = 0.007). Conclusions: The test of the hypothetical effect of an intervention aimed at the attenuation of ANSD accompanied by a lowered PPS revealed reduced all-cause mortality in patients with stable IHD.

Measuring child and adolescent well-being in Denmark: Validation and norming of the Danish KIDSCREEN-10 child/adolescent version in a national representative sample of school pupils in grades five through eight.

KIDSCREEN-10 is a generic instrument for measuring global health-related quality of life among 8-18-year-old children and adolescents. This study examines the criterion-related construct validity and psychometric properties of the Danish language version of the KIDSCREEN-10 using Rasch models. A further aim was to construct Danish norms based on the resulting person parameter estimates from the Rasch models. Data consists of a nationally representative cross-sectional survey of 8171 children in the 5th to 8th grade of primary school in Denmark. No adequate fit to the Rasch model or a graphical loglinear Rasch model could be established for the KIDSCREEN-10 in the full sample of children (n = 8171). Results based on analyses with increasing samples sizes showed that even with the smallest sample item 3 (Kid3) of the KIDSCREEN-10 did not fit the Rasch model. After elimination of Kid3, substantial local dependence and differential item functioning relative to gender and grade level was still present. Already with a sample size of 630 fit to the Rasch model or a graphical loglinear Rasch model adjusting for local dependence and differential item functioning was not established. Therefore, generation of Danish norms was not realizable, as this requires valid sum scores and estimates of the person parameters for an adequate number of cases. Thus, the Danish language version of the child/adolescent self-report KIDSCREEN-10 questionnaire cannot be recommended for use in population-level studies. Neither can use in small sample be recommended as adjustment for differential item functioning and local dependence is ambiguous.

The Early Functional Abilities-revised may bridge the gap between the disorder of consciousness and the functional independence scales: evidence from Rasch analysis.

BACKGROUND: There is a tremendous clinical and research need to bridge the gap between disorder of consciousness and functional independence scales with a single unidimensional measure in people with acquired brain injury. AIM: To calibrate an essentially unidimensional subset of items from the Italian Early Functional Abilities (EFA), demonstrating internal construct validity and sufficient reliability for individual patient measurement. DESIGN: Multicenter observational cross-sectional study. SETTING: Inpatients from 11 different Italian Rehabilitation centers. POPULATION: Three hundred sixty-two adult patients with a disorder of consciousness due to an acquired brain injury. METHODS: The Italian version of EFA was administered to the sample and then submitted to Mokken analysis, Confirmatory Factor Analysis, Rasch analysis, Confirmatory Bifactor Analysis, and external construct validity. RESULTS: According to Mokken Analysis (all item scalability coefficients Hj positive; all item-pair scalability coefficients Hij >0.3; scale coefficient H=0.762), and Confirmatory Factor Analysis (RMSEA=0.081; SRMR=0.048; CFI=0.995; TLI=0.995), the Italian EFA showed a sufficient preliminary unidimensionality. Within Rasch Analysis, a final 12-item solution for the EFA (EFA-R) was calibrated. EFA-R is "essentially unidimensional" according to the following requirements: 1) analysis of residual correlations which supported item essential local independence; 2) a robust correlation between item subtests (rho=0.950); 3) only 2.1% of cases with significant difference between person parameter estimates by different subscales; 4) an explained common variance equal to 0.916 obtained from a final Confirmatory Bifactor Analysis. It also satisfied invariance requirement (unconditional χ220=9.81; P=0.457, conditional class-interval based χ235=33.1; P=0.557), and monotonicity. The reliability (Person Separation Index=0.887) was adequate for person measurements. A practical raw-score-to-measure conversion table based on the EFA-R calibration was devised. Finally, EFA-R strongly correlated with Coma Recovery Scale-Revised (rho=0.922) and motor FIM™ (rho=0.808). CONCLUSIONS: EFA-R is an essentially unidimensional subset of 12 items with adequate internal construct validity and sufficient reliability for individual patient measurement under the Rasch Model Theory framework. CLINICAL REHABILITATION IMPACT: EFA-R has the potential to measure people's functional abilities whose consciousness is improving despite ongoing severe motor-functional impairments during the early stages of rehabilitation. It provides "a measurement bridge" between the disorder of consciousness and the functional independence scales in patients with severe acquired brain injury.

Reduction of Pressure Pain Sensitivity as Novel Non-pharmacological Therapeutic Approach to Type 2 Diabetes: A Randomized Trial.

BACKGROUND: Autonomic nervous system dysfunction (ANSD) is known to affect glucose metabolism in the mammalian body. Tradition holds that glucose homeostasis is regulated by the peripheral nervous system, and contemporary therapeutic intervention reflects this convention. OBJECTIVES: The present study tested the role of cerebral regulation of ANSD as consequence of novel understanding of glucose metabolism and treatment target in type 2 diabetes (T2D), suggested by the claim that the pressure pain sensitivity (PPS) of the chest bone periosteum may be a measure of cerebral ANSD. DESIGN: In a randomized controlled trial of 144 patients with T2D, we tested the claim that 6 months of this treatment would reduce PPS and improve peripheral glucose metabolism. RESULTS: In the active treatment group, mean glycated hemoglobin A1c (HbA1c) declined from 53.8 to 50.5 mmol/mol (intragroup p = 0.001), compared with the change from 53.8 to 53.4 mmol/mol in the control group, with the same level of diabetes treatment but not receiving the active treatment (between group p = 0.036). Mean PPS declined from 76.6 to 56.1 units (p < 0.001) in the active treatment group and from 77.5 to 72.8 units (p = 0.02; between group p < 0.001) in the control group. Changes of PPS and HbA1c were correlated (r = 0.37; p < 0.001). CONCLUSION: We conclude that the proposed approach to treatment of T2D is a potential supplement to conventional therapy. CLINICAL TRIAL REGISTRATION: www.clinicaltrials.gov (NCT03576430).

What is a PROM and why do we need it?

The purpose of this article was to introduce the reader to the nature of patient-reported outcome measures (PROMs) and pitfalls in their use. PROMs collect subjective information directly from the patient regarding specific or general conditions and add to clinical and functional outcomes, and turn unmeasurable subjective qualities into quantitative measures. PROMs are questionnaires consisting of items: questions or statements with predefined response options. The items in an adequate PROM have been developed by involvement of patients with the condition in focus, and the PROM has been validated for these patients using suitable statistical methods. An adequate well-targeted PROM is more responsive than an inadequate PROM. Unfortunately, many studies use inadequate PROMs as outcomes. The methods used to generate PROMs should be described as thoroughly as those used to develop any other types of measurement instruments, and the choice of PROM should always be explained and thereby justified. If the PROM used is not adequate, the consequences for the interpretation of the results should be discussed. In many cases, an adequate PROM does not exist. If the best available PROM is chosen, there are methods to validate the adequacy of the chosen PROM, which make an interpretation of the study results possible.

Psychometric validation of PROM instruments.

The aim was to provide an overview of the different statistical methods for validation of patient-reported outcome measures, ranging from simple statistical methods available in all software packages to advanced statistical models that require specialized software. A non-technical summary of classical test theory (CTT) and modern test theory (MTT) is provided. Specifically, confirmatory factor analysis, item response theory, and Rasch analysis is outlined. One CTT and three MTT methods were used to validate the two subscales (Symptoms and Quality of Life) from the Knee Injury and Osteoarthritis Outcome Score (KOOS). For each methodology, two analyses were considered: (i) a unidimensional analysis ignoring the pre-specified dimensionality, and (ii) a two-dimensional analysis using the pre-specified dimensionality. While CTT did not adequately address central issues regarding the validity of the KOOS subscales, the three MTT methods yielded very similar results. In conclusion, MTT methods offer analysis of all relevant properties related to the validity of patient-reported outcome measures, while this is not the case for CTT. Claims about sufficient validity based on CTT methods are inadequate and should not be trusted.

Cross-diagnostic scale-banking using rasch analysis: Developing a common reference metric for generic and health condition-specific scales in people with rheumatoid arthritis and stroke.

OBJECTIVES: To develop a common reference metric of functioning, incorporating generic and health condition-specific disability instruments, and to test whether this reference metric is invariant across 2 health conditions. DESIGN: Psychometric study using secondary data analysis. Firstly, the International Classification of Functioning, Disability and Health (ICF) Linking Rules were used to examine the concept equivalence between the World Health Organization Disability Assessment Schedule (WHODAS 2.0), Health Assessment Questionnaire (HAQ) and Functional Independence Measure (FIMTM). Secondly, a scale-bank was developed using a reference metric approach to test-equating, based on the Rasch measurement model. PARTICIPANTS: Secondary analysis was performed on data from 487 people; 61.4% with rheumatoid arthritis and 38.6% with stroke. RESULTS: Three sub-domains of the WHODAS 2.0 and all items of the HAQ and FIMTM motor mapped on to the ICF chapters d4 Mobility, d5 Self-care and d6 Domestic life. Test-equating of these scales resulted in good model fit, indicating that a scale bank and associated reference metric across these 3 instruments could be created. CONCLUSION: This study provides a transformation table to enable direct comparisons among instruments measuring physical functioning commonly used in rheumatoid arthritis (HAQ) and stroke (FIMTM motor scale), as well as in people with disability in general (WHODAS 2.0).

The DISABKIDS generic and diabetes-specific modules are valid but not directly comparable between Denmark, Sweden, and Norway.

BACKGROUND/OBJECTIVES: Government guidance promote benchmarking comparing quality of care including both clinical values and patient reported outcome measures in young persons with type 1 diabetes. The aim was to test if the Nordic DISABKIDS health-related quality of life (HrQoL) modules were construct valid and measurement comparable within the three Nordic countries. METHODS: Data from three DISABKIDS validation studies in Sweden, Denmark, and Norway were compared using Rasch and the graphical log-linear Rasch modeling. Monte Carlo methods were used to estimate reliability coefficient and target was defined as the point with the lowest SE of the mean. Self-report data were available from 99 Danish (8-18 years), 103 Norwegian (7-19 years), and 131 Swedish (8-18 years) young people. RESULTS: For the DISABKIDS higher scores on most subscales were noted in the Norwegian population. The Swedish sample had a significantly higher score on the "Diabetes treatment" subscale and scores closer to optimal target than the other countries. For each country, construct validity and sensitivity were acceptable when accounting for differential item function (DIF) and local dependency (LD). Less LD and DIF were found if only Denmark and Norway were included. The combined model was reliable; however, some differences were noted in the scale translations relating to the stem and response alternatives, which could explain the discrepancies. CONCLUSION: The Nordic versions of the DISABKIDS questionnaires measures valid and reliable HrQoL both within and between countries when adjusted for DIF and LD. Adjusting the Likert scales to the same respond categories may improve comparability.

Assessment of cognitive ability at conscription for the Danish army: Is a single total score sufficient?

Børge Priens Prøve (BPP) was developed for the Danish Army by psychologist Børge Prien in the 1950s, as a test of general cognitive ability for use at conscription for the Danish armed forces. The final BPP (1957) had four subtests; a Raven-like matrix subtest, and three subtests measuring verbal, numerical, and visuospatial ability. The BPP is a speeded test counting the number of correct responses within 45 minutes. Thus, we consider the BPP as a measure of "cognitive efficiency" rather than a pure measure of cognitive ability. The BPP is still in use.Using techniques available in 1960, Rasch concluded that the matrices and numerical tests appeared to satisfy the requirements of the Rasch (Probabilistic models for some intelligence and attainment tests, Danish Institute for Educational Research, Copenhagen; 1960) model, while the verbal and visuospatial tests did not. Since then, there have been, to our knowledge, no published studies of the psychometric scaling properties of the BPP, partly because the practice of the Danish draft board has been to record only the total score. We examine these properties by analysis of data from two cohorts (n = 9,491), using the Leunbach (A probabilistic measurement model for assessing whether two tests measure the same personal factor. The Danish Institute of Educational, Copenhagen, Denmark; 1976) model to assess whether the sum of the four subtests provides a statistically sufficient measure of a common latent trait. Since we found only weak evidence against fit to the Leunbach model, we claim that this warrants the use of a summarized total BPP score. We examined whether BPP subscales suffered from differential test functioning (DTF) relative to samples. Weak, and for practical purposes too weak, DTF was suggested for one subscale.

Test equating sleep scales: applying the Leunbach's model.

BACKGROUND: In most cases, the total scores from different instruments assessing the same construct are not directly comparable, but must be equated. In this study we aimed to illustrate a novel test equating methodology applied to sleep functions, a domain in which few score comparability studies exist. METHODS: Eight scales from two cross-sectional self-report studies were considered, and one scale was common to both studies. The International Classification of Functioning, Disability and Health (ICF) was used to establish content comparability. Direct (common persons) and indirect (common item) equating was assessed by means of Leunbach's model, which equates the scores of two scales depending on the same person parameter, taking into account several tests of fit and the Standard Error of Equating (SEE). RESULTS: All items were linked to the body functions category b134 of the ICF, which corresponds to 'Sleep functions'. The scales were classified into three sleep aspects: four scales were assessing mainly sleep disturbance, one quality of sleep, and three impact of sleep on daily life. Of 16 direct equated pairs, 15 could be equated according to Leunbach's model, and of 12 indirect equated pairs, 8 could be equated. Raw score conversion tables between each of these 23 equated pairs are provided. The SEE was higher for indirect than for direct equating. Pairs measuring the same sleep aspect did not show better fit indices than pairs from different aspects. The instruments mapped to a higher order concept of sleep functions. CONCLUSION: Leunbach's equating model has been successfully applied to a functioning domain little explored in test equating. This novel methodology, together with the ICF, enables comparison of clinical outcomes and research results, and facilitates communication among clinicians.

Assessment of family functioning in families with a child diagnosed with type 1 diabetes: Validation and clinical relevance of the general functioning subscale of the McMaster family assessment device.

BACKGROUND: Type 1 diabetes (T1D) can have a negative effect on family functioning, which is associated with deterioration in metabolic control. Therefore, a valid tool for assessing family functioning is clinically relevant. We assessed the quality and validity of the Danish general functioning (GF) subscale of the family assessment device (FAD). Additionally, we investigated GF scores among adolescents with T1D and their parents and the relationship between family functioning and background variables, including metabolic control. METHODS: All Danish families with a child diagnosed with T1D (N = 1997) were invited to participate in a web-based survey. In total, 616 adolescents (aged 12-17 years) and 1035 parents (of children aged 2-17 years) responded. The quality and validity of measurements made using the GF subscale were assessed using the Rasch model and graphical log-linear Rasch models (GLLRMs). Differences among GF responses were also assessed using GLLRMs. The relationships between GF scores and background variables were examined by multivariate analyses. RESULTS: A dichotomized version of the GF subscale provided essentially valid measures of family functioning. Furthermore, the GF subscale measured family functioning most accurately in families with worse family functioning than in our population. To accurately characterize family functioning, it is important to take both parent's and adolescent's perceptions into account. Family functioning was associated with glycated hemoglobin (HbA1c) levels, and discrepancies in family functioning were associated with higher HbA1c levels. CONCLUSIONS: A dichotomized GF subscale is useful for assessment of family functioning. Parent's and adolescent's scores should be kept separate. Family functioning is associated with HbA1c levels.

Construct validity of a service-setting based measure to identify mental health problems in infancy.

Accumulating research document the needs of intervention towards mental health problems in early childhood. The general child health surveillance offers opportunities for early detection of mental health vulnerability, conditioned the availability of feasible and validated measures. The Copenhagen Infant Mental Health Questionnaire, CIMHQ, was developed to be feasible for community health nurses and comprehensive regarding the range of mental health problems seen in infancy. Previous testing of the CIMHQ has documented feasibility and face validity. The aim was to investigate the construct validity of the general population measure by using the Rasch measurement models, and to explore the differential functioning of the CIMHQ relative to a number of characteristics of the infants, local independence of items, and possible latent classes of infants. CIMHQ was tested in 2,973 infants from the general population, aged 9-10 months. The infants were assessed by community health nurses at home visits, in the period from March 2011 to December 2013. Rasch measurement models were used to investigate the construct validity of the CIMHQ. Analyses showed an overall construct valid scale of mental health problems, consisting of seven valid subscales of specific problems concerning eating, sleep, emotional reactions, attention, motor activity, communication, and language, respectively. The CIMHQ fitted a graphical loglinear Rasch model without differential item function. Analyses of local homogeneity identified two latent classes of infants. A simple model with almost no local dependency between items is proposed for infants with few problems, whereas a more complicated model characterizes infants with more problems. The measure CIMHQ differentiates between infants from the general population with few and more mental health problems, and between subgroups of problems that potentially can be targets of preventive intervention.

A step towards a new delimitation of functional somatic syndromes: A latent class analysis of symptoms in a population-based cohort study.

OBJECTIVES: The current delimitation of functional somatic syndromes (FSS) is inconsistent. We aimed to investigate somatic symptom profiles in the general adult population to contribute to a new, data-driven delimitation of FSS. METHODS: Information on 31 self-reported somatic symptoms used in the delimitation of various FSS and bodily distress syndrome (BDS) was obtained from the DanFunD study-a population-based cohort study on 9656 adults (participation 33.6%) from Greater Copenhagen, Denmark. Latent class analysis was used to identify symptom profiles. The profiles were described by their relation with sex, age, chronic disease, self-perceived health, symptom impact, self-reported FSS, and BDS case-status. RESULTS: Eight symptom profiles were identified. The largest profile had no symptoms (49% of the population). Three profiles were characterized by a few, specific symptoms: muscle and joint pain (17%), gastrointestinal symptoms (6%), and general symptoms (13%). Three profiles had multiple symptoms in specific combinations: musculoskeletal and general symptoms (7%); fatigue, musculoskeletal and gastrointestinal symptoms (3%); and cardiopulmonary, gastrointestinal and general symptoms (3%). Lastly, one profile (2%) had high probability of all symptoms. The last four profiles (15%) were strongly associated with BDS case-status, poor self-perceived health and high impact of symptoms. Analyses excluding persons with multi-symptomatic chronic disease showed similar results. CONCLUSIONS: We identified eight symptom profiles characterized by specific combinations of symptoms. Four of these had multiple symptoms from several bodily systems showing large overlap with BDS, possibly indicating subtypes of FSS. The profiles contribute to a new delimitation of FSS by illustrating the importance of specific symptom combinations.

Validation of the Early Functional Abilities scale: An assessment of four dimensions in early recovery after traumatic brain injury.

OBJECTIVE: The Early Functional Abilities scale assesses the restoration of brain function after brain injury, based on 4 dimensions. The primary objective of this study was to evaluate the validity, objectivity, reliability and measurement precision of the Early Functional Abilities scale by Rasch model item analysis. A secondary objective was to examine the relationship between the Early Functional Abilities scale and the Functional Independence Measurement™, in order to establish the criterion validity of the Early Functional Abilities scale and to compare the sensitivity of measurements using the 2 instruments. METHODS: The Rasch analysis was based on the assessment of 408 adult patients at admission to sub-acute rehabilitation in Copenhagen, Denmark after traumatic brain injury. RESULTS: The Early Functional Abilities scale provides valid and objective measurement of vegetative (autonomic), facio-oral, sensorimotor and communicative/cognitive functions. Removal of one item from the sensorimotor scale confirmed unidimensionality for each of the 4 subscales, but not for the entire scale. The Early Functional Abilities subscales are sensitive to differences between patients in ranges in which the Functional Independence Measurement™ has a floor effect. CONCLUSION: The Early Functional Abilities scale assesses the early recovery of important aspects of brain function after traumatic brain injury, but is not unidimensional. We recommend removal of the "standing" item and calculation of summary subscales for the separate dimensions.

A Danish version of self-efficacy in diabetes self-management: A valid and reliable questionnaire affected by age and sex.

BACKGROUND: Managing the chronic illness type 1 diabetes (T1D) is extremely demanding, especially during adolescence. Self-efficacy is belief in one's own capabilities and this is crucial for diabetes management. Having a valid method for measuring self-efficacy is important. OBJECTIVE: Our aims were to psychometrically validate a Danish version of the self-efficacy in diabetes management (SEDM) questionnaire, and to examine the relationship between background variables and self-efficacy. METHODS: All Danish adolescents with T1D (n = 1075) were invited to participate in our study. In total, 689 agreed to participate and 602 completed the study. Data were collected using a web-based survey. All participants were asked to provide a blood sample for HbA1c measurement. Graphical log-linear Rasch modeling (GLLRM) was used to validate the questionnaire and its reliability was assessed using Monte Carlo simulation. RESULTS: We found the questionnaire to be valid and reliable, but it had a dual structure that suggested a need for 2 separate subscales. One subscale related to practical (SEDM1) and the other to emotional (SEDM2) aspects of diabetes management. Both subscales were targeted toward adolescents with lower self-efficacy and were associated with HbA1c. SEDM1 was influenced by treatment modality and age. In SEDM2 we found an interaction between age and sex. CONCLUSION: The Danish version of the SEDM questionnaire should be divided into two parts, each with a valid and reliable subscale for self-efficacy measurement. The relationship between self-efficacy and age seems to differ between boys and girls.

Somatic symptom profiles in the general population: a latent class analysis in a Danish population-based health survey.

PURPOSE: The aim of this study was to identify and describe somatic symptom profiles in the general adult population in order to enable further epidemiological research within multiple somatic symptoms. METHODS: Information on 19 self-reported common somatic symptoms was achieved from a population-based questionnaire survey of 36,163 randomly selected adults in the Capital Region of Denmark (55.4% women). The participants stated whether they had been considerably bothered by each symptom within 14 days prior to answering the questionnaire. We used latent class analysis to identify the somatic symptom profiles. The profiles were further described by their association with age, sex, chronic disease, and self-perceived health. RESULTS: We identified 10 different somatic symptom profiles defined by number, type, and site of the symptoms. The majority of the population (74.0%) had a profile characterized by no considerable bothering symptoms, while a minor group of 3.9% had profiles defined by a high risk of multiple somatic symptoms. The remaining profiles were more likely to be characterized by a few specific symptoms. The profiles could further be described by their associations with age, sex, chronic disease, and self-perceived health. CONCLUSION: The identified somatic symptom profiles could be distinguished by number, type, and site of the symptoms. The profiles have the potential to be used in further epidemiological studies on risk factors and prognosis of somatic symptoms but should be confirmed in other population-based studies with specific focus on symptom burden.

Item analysis using Rasch models confirms that the Danish versions of the DISABKIDS® chronic-generic and diabetes-specific modules are valid and reliable.

BACKGROUND: Type 1 Diabetes (T1D) has a negative impact on psychological and overall well-being. Screening for Health-related Quality of Life (HrQoL) and addressing HrQoL issues in the clinic leads to improved well-being and metabolic outcomes. The aim of this study was to translate the generic and diabetes-specific validated multinational DISABKIDS® questionnaires into Danish, and then determine their validity and reliability. METHODS: The questionnaires were translated using a validated translation procedure and completed by 99 children and adolescents from our diabetes-department; all diagnosed with T1D and were aged between 8 and 18 years old. The Rasch and the graphical log linear Rasch model (GLLRM) were used to determine validity. Monte Carlo methods and Cronbach's α were used to confirm reliability. RESULTS: The data did not fit a pure Rasch model but did fit a GLLRM when item six in the independence scale is excluded. The six subscales measure different aspects of HrQoL indicating that all the subscales are necessary. The questionnaire shows local dependency between items and differential item functioning (DIF). Therefore age, gender, and glycated hemoglobin (HbA1c) levels must be taken into account when comparing HrQoL between groups. CONCLUSIONS: The Danish versions of the DISABKIDS® chronic-generic and diabetes-specific modules provide valid and objective measurements with adequate reliability. These Danish versions are useful tools for evaluating HrQoL in Danish patients with T1D. However, guidelines on how to manage DIF and local independence will be required, and item six should be rephrased.

Measurement of alienation among adolescents: construct validity of three scales on powerlessness, meaninglessness and social isolation.

BACKGROUND: Psychological alienation is an important concept in the study of adolescents' health and behavior but no gold standard for measuring alienation among adolescents exists. There is a need for new scales with high validity for use in adolescent health and social research. The purpose of the present study was to develop and validate alienation scales in accordance with Seeman's conceptualization of alienation focusing on three independent variants specifically relevant in adolescent health research: powerlessness, meaninglessness and social isolation. METHODS: Cross-sectional data from 3083 adolescents aged 13 to 15 years from the Danish contribution to the cross-national study Health Behaviour in School-aged Children (HBSC) were used. We identified and developed items, addressed content and face validity through interviews, and examined the criterion-related construct validity of the scales using graphical loglinear Rasch models (GLLRM). RESULTS: The three scales each comprised three to five face valid items. The powerlessness scale reflected the adolescent's expectancy as to whether his/her behavior can determine the outcome or reinforcement he/she seeks. The meaninglessness scale reflected the expectancy as to whether satisfactory predictions regarding the effects of one's behavior are possible. Finally, the social isolation scale reflected whether the adolescent had a low expectancy for inclusion and social acceptance. All scales contained some uniform local dependency and differential item functioning. However, only to a limited degree, which could be accounted for using GLLRM. Thus the scales fitted GLLRMs and can therefore be considered to be essentially construct valid and essentially objective. CONCLUSION: The three alienation scales appear to be content and face valid and fulfill the psychometric properties of a good construct valid reflective scale. This suggests that the scales may be appropriate in future large-scale surveys to examine the relation between alienation and a range of adolescent health outcomes such as health, behavior and wellbeing.

Somatic Symptoms: Prevalence, Co-Occurrence and Associations with Self-Perceived Health and Limitations Due To Physical Health - A Danish Population-Based Study.

A high number of somatic symptoms have been associated with poor health status and increased health care use. Previous studies focused on number of symptoms without considering the specific symptoms. The aim of the study was to investigate 1) the prevalence of 19 somatic symptoms, 2) the associations between the symptoms, and 3) the associations between the somatic symptoms, self-perceived health and limitations due to physical health accounting for the co-occurrence of symptoms. Information on 19 somatic symptoms, self-perceived health and limitations due to physical health was achieved from a population-based questionnaire survey of 36,163 randomly selected adults in the Capital Region of Denmark in 2006/07. Chain graph models were used to transparently identify and describe the associations between symptoms, self-perceived health and limitations due to physical health. In total, 94.9% of the respondents were bothered by one or more of the 19 somatic symptoms. The symptoms were associated in a complex structure. Still, recognisable patterns were identified within organ systems/body parts. When accounting for symptom co-occurrence; dizziness, pain in legs, respiratory distress and tiredness were all strongly directly associated with both of the outcomes (γ>0.30). Chest pain was strongly associated with self-perceived health, and other musculoskeletal symptoms and urinary retention were strongly associated with limitations due to physical health. Other symptoms were either moderate or not statistically associated with the health status outcomes. Opposite, almost all the symptoms were strongly associated with the two outcomes when not accounting for symptom co-occurrence. In conclusion, we found that somatic symptoms were frequent and associated in a complex structure. The associations between symptoms and health status measures differed between the symptoms and depended on the co-occurrence of symptoms. This indicates an importance of considering both the specific symptoms and symptom co-occurrence in further symptom research instead of merely counting symptoms.