The Lower Extremity Functional Scale could be an alternative to the Western Ontario and McMaster Universities Osteoarthritis Index physical function scale

ObjectivesTo compare the test–retest reliability and validity of the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) physical function (PF) subscale and the Lower Extremity Functional Scale (LEFS) in community-dwelling adults with hip osteoarthritis (OA).Study Design and SettingOne hundred adults with symptomatic hip OA participated in the study. Test–retest reliability was assessed by administering the WOMAC and LEFS at participants' initial visits and after 1 week. Discriminant validity from pain measures was assessed by examining the WOMAC-PF and the LEFS correlations with the PF and bodily pain subscales of the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36). Convergent validity was assessed by comparing correlations between the WOMAC-PF and LEFS with the gait speed test, step test, and timed stair tests. Intraclass correlation coefficients (ICCs), standard error of measurement, and Pearson correlation coefficients were calculated.ResultICC estimates of 0.90 and 0.92 were obtained for the WOMAC-PF and LEFS, respectively. The minimal detectable change scores were 9.1 WOMAC-PF and 9.9 LEFS points. Discriminant validity was evident for the LEFS but not for the WOMAC-PF. The WOMAC-PF and LEFS showed similar levels of convergent validity; however, WOMAC-PF and gait speed showed a relatively low correlation.ConclusionThe LEFS has good measurement properties—namely test–retest reliability and cross-sectional construct validity—and it could be an alternative to WOMAC-PF.     

四格移步试验在平衡功能障碍儿童中的信效度研究

目的 研究四格移步试验在平衡功能障碍的儿童中的信度效度,为儿童平衡功能障碍的临床评估提供试验依据。方法 研究对象为2018年1月-2019年2月在深圳市儿童医院就诊的平衡功能受损129例儿童,所有研究对象在1周内由A、B两名评估员评估3次,A负责第1、3次评估,B负责第2次评估;第1次评估内容为四格移步试验(FSST)、 Berg平衡量表(BBS)、计时起立行走测试(TUG)及10 m步行测试(10MWT),每个试验间休息3~5 min;第2、3次评估仅评估FSST,评估过程中,评估员不互相讨论,各自记录数据;应用Pearson相关性分析法检验FSST、BBS总分、TUG、10MWT评定结果的相关性以反映FSST的信度,分析FSST的评定者间信度及重测信度,应用CDM软件包检测区分度。结果 FSST与BBS、TUG、10MWT结果的相关系数为-0.985(-0.782~-0.605)、0.678(0.572~0.761)、0.721(0.626~0.795)(P＜0.001);FSST的评定者间信度为0.957,重测信度为0.979;不同年龄的患儿区分度(D)为0.801~0.989,不同病因的患儿区分度为(D)0.707~0.824。结论 FSST用于儿童平衡功能评估具较高的平行效度、评定者间一致性信度及重测信度,值得临床推广。     

Timed Up and Go (TUG) Reference Values and Predictive Cutoffs for Fall Risk and Disability in Singaporean Community-Dwelling Adults: Yishun Cross-Sectional Study and Singapore Longitudinal Aging Study

ObjectivesThe “timed up and go” (TUG) test is a simple and widely used test of overall functional mobility. There is a paucity of TUG normative data among Asian individuals who differ in habitual gait speed and fall risk from Western population. The objectives of this study were to determine TUG reference values and optimum cutoffs predicting prevalent and incident disability for community-dwelling adults.DesignOne cross-sectional (Study 1–Yishun Study) and one longitudinal (Study 2–Singapore Longitudinal Aging Study) study in Singapore.Setting and ParticipantsStudy 1 comprised 538 nondisabled, community-dwelling adults aged between 21 and 90 years. Study 2 comprised 1356 community-dwelling older adults aged ≥55 years followed for 3 years.MethodsStudy 1 collected TUG reference values and assessed physiological fall risk (PFR) using the Physiological Profile Assessment (PPA). Study 2 assessed association of TUG with disability with the Barthel Index and the Lawton scale at baseline and follow-up.ResultsFrom Study 1, mean TUG time for individuals aged 60 to 74 years was 9.80 seconds, shorter than values reported for Westerners of 12.30 seconds. It was significantly associated with high PFR [odds ratio (OR) 1.14, 95% confidence interval (CI) 1.03–1.27], 74.0% agreement, Cohen's kappa = 0.314 (95% CI 0.238–0.390); area under the curve = 0.85 (95% CI 0.80–0.90). A TUG cutoff of 10.2 seconds discriminated high PFR from low PFR with 84.4% sensitivity and 72.6% specificity. In Study 2, the threshold for observing significantly increased risk of disability was ≥9.45 seconds for prevalent disability (OR 2.98, 95% CI 1.41–6.78), functional decline (OR 2.68, 95% CI 1.33–5.80), and incidental disability (OR 2.25, 95% CI 1.08–4.97).Conclusions and ImplicationsTUG reference values and cutoff predicting disability for community-dwelling older adults in Singapore are consistent with Asian data and lower than for Western individuals. TUG could be used to guide development and evaluation of risk screening of adverse health outcomes across the life span in Singapore.     

Development of Food Literacy Assessment Tool Targeting Adults With Low Income

ObjectiveDevelop and test validity and reliability of the Food Literacy Assessment Tool (FLitT) in adults with low income.DesignFace validity was tested using cognitive interviews, content validity using expert review, and internal consistency reliability and test-retest reliability based on 2 administrations of the survey.SettingUrban choice food pantry in Cincinnati, OH.ParticipantsThere were 10 and 98 adults with low income for the cognitive interview and survey, respectivelyVariables MeasuredKnowledge, self-efficacy, and behavior required to plan and manage, select, prepare, and eat in relation to food.AnalysisCronbach α and Kuder-Richardson Formula 20 for internal consistency reliability and intraclass correlation coefficient (ICC) for test-retest reliability.ResultsCognitive interviews and expert feedback suggested modifications to improve the clarity of FLitT and offer more response options. Testing shows acceptable internal consistency in self-efficacy (Cronbach α = 0.92) and behavior (Cronbach α = 0.90) but not in knowledge (Kuder-Richardson Formula 20 = 0.51). The FLitT shows acceptable test-retest reliability for knowledge (ICC = 0.84), self-efficacy (ICC = 0.70), and behavior (ICC = 0.93).Conclusions and ImplicationsThe FLitT was developed and tested for face and content validity and internal and test-retest reliability in adults with low income. Additional research is needed to conduct a second round of face validity and test construct validity using factor analysis with a larger size.     

The Perceive,Recall, Plan and Perform (PRPP) system for persons with Parkinson’s disease: a psychometric study

Background: The Perceive, Recall, Plan &; Perform (PRPP) system of task analysis might be feasible to evaluate occupational performance and information processing strategies for persons with Parkinson’s disease (PD).

Aim: To evaluate: (1) the random error between raters (inter-rater study), (2) the random error within raters (intra-rater study), and (3) the internal consistency of the PRPP.

Materials and methods: (1) video-recorded performance of meaningful activities of 13 Dutch persons with PD, scored independently by 38 Dutch PRPP trained occupational therapists were included in the analysis. The random error between raters was analyzed with two-way random Intraclass Correlation Coefficients (ICC). (2) Four videos were scored twice by 30 raters (6 week time interval). The random error within raters was analyzed using one-way random ICC’s. (3) Internal consistency study: data of 190 persons with PD were analyzed using Cronbach’s alpha (α).

Results: Inter-rater reliability ranged from slight to moderate (ICC=?0.06–0.43). The mean intra-rater reliability ranged from moderate to almost perfect (ICC=?0.60–0.83). Internal consistency is good (α?=?0.60–0.86).

Conclusion: The limited inter-rater reliability but adequate intra-rater reliability and internal consistency show the feasibility of the PRPP when used for persons with PD. Implications for reliable clinical use are discussed.     

Associations of TNF-Α −308 G>A and TNF-Β 252 A>G with Physical Function and BNP—Rugao Longevity and Ageing Study

To explore the associations of TNF-α −308 G>A (rs1800629) and TNF-β 252 A>G (rs909253) with physical function and plasma B-type natriuretic peptide (BNP). Data of 1747 community-dwelling elders from the ageing arm of the Rugao Longevity and Ageing Study was used. Physical function was measured by handgrip strength, Timed Up and Go (TUG) test and 5-meter walking test (5MWT). AA genotype of the TNF-α −308 G>A was associated with higher mean time of TUG test and 5MWT (multivariable adjusted β=5.75 and 5.70, respectively, p<0.05), compared with GG genotype. For the TNF-β 252 A>G polymorphism, GG genotype was associated with higher mean time of TUG test and 5MWT (multivariable adjusted β=1.55 and 0.83, respectively, p<0.05) and lower handgrip strength (multivariable adjusted β=−0.69, p<0.05), compared with AA genotype. Further, GG was associated with greater odds of low handgrip strength (OR=1.47, 95% CI=1.06–2.04), low speed of TUG test (OR=1.87, 95% CI=1.20–2.01) and elevated BNP (OR=1.30, 95% CI=1.08–1.84). GG also interacted with elevated BNP to be associated with greater odds of low handgrip strength and 5MWT. TNF-β 252 A>G was associated with physical function measurements, plasma BNP level, and odds of elevated BNP in an elderly population. TNF-β 252 A>G also interacted with elevated BNP to be associated with greater odds of physical function measurements.     

Feasibility and reliability of the mini nutritional assessment (MNA) in older adults with intellectual disabilities

Objective

Feasibility and reliability of the Mini Nutritional Assessment (MNA) in older adults with intellectual disabilities (ID).

Design

Instrument development.

Setting

Three care providers for people with ID.

Participants

48 persons aged 50 years and over with borderline to profound ID and their professional caregivers.

Measurements

The MNA was performed by means of interviews with participants (N = 12) and caregivers (N = 48) and physical assessments of participants (N = 47). Aspects of feasibility: completion of interview, difficulty of answering interview items, duration of interview and completion of physical assessment. Aspects of reliability: inter-observer reliability between caregivers and between participants and caregivers, test-retest reliability and internal consistency. For inter-observer and test-retest reliability, intraclass correlation coefficients (ICC) were calculated, and for internal consistency Chronbach??s alpha.

Results

All participants and caregivers completed the interview part. For 7 out of 12 personally interviewed participants and none of the caregivers, at least 3 out of 15 questions were difficult to answer. Mean duration of the interview was 7 minutes in participants and 4 minutes in caregivers. Physical assessment was successfully performed in 40 participants (85.1%). In the remaining 7 participants (14.9%) missing values were retrieved from the medical records. ICCs (95% confidence interval) for test-retest and inter-observer reliability between caregivers were good, 0.85 (0.72?C0.92) and 0.86 (0.74?C0.92) respectively, but ICC for inter-observer reliability between caregivers and persons with ID was low, 0.03 (?0.51 ?0.59). Internal consistency was 0.61.

Conclusion

The MNA is feasible and reliable for older people with ID. Interview data can be reliably obtained through caregivers, but not through people with ID.     

Resistance Training Improves Muscle Strength and Function,Regardless of Protein Supplementation,in the Mid- to Long-Term Period after Gastric Bypass

Inadequate protein intake and low levels of physical activity are common long-term sequelae after bariatric surgery and can negatively affect muscle strength (MS) and physical function (PF). The study investigated the effects of resistance training with or without protein supplementation on MS and PF. The study, which involved a 12-week controlled trial (n = 61) of individuals 2–7 years post-Roux-en-Y gastric bypass (RYGB), comprised four groups: whey protein supplementation (PRO; n = 18), maltodextrin placebo (control [CON]; n = 17), resistance training combined with placebo (RTP; n = 11), and resistance training combined with whey protein supplementation (RTP+PRO; n = 15). An isokinetic dynamometer was used to measure MS (peak torque at 60°/s and 180°/s). PF was measured with the 30-s sit-to-stand (30-STS), 6-min walk (6-MWT), and timed up-and-go (TUG) tests. There were improvements in the absolute and relative-to-bodyweight peak torque at 60°/s and 180°/s, TUG, 6-MWT and 30-STS in the RTP and RTP+PRO groups, but not in the CON and PRO groups. Changes in MS were significantly correlated with changes in PF between the pre- and post-intervention periods. A supervised resistance training program, regardless of protein supplementation, improved MS and PF in the mid-to-long-term period after RYGB and can lead to clinical benefits and improved quality of life.     

Feasibility, Reliability, and Validity of Three Health-State Valuation Methods Using Multiple-Outcome Vignettes on Moderate-Risk Pregnancy at Term

ObjectivesPreference-based health-state valuation methods such as discrete choice experiment (DCE) are claimed to be superior than attitude-based valuation methods like visual analogue scale (VAS) and time trade-off (TTO). We compared VAS, TTO, and DCE in terms of feasibility, reliability, and validity using vignettes depicting moderate-risk pregnancy at term.MethodsPeople from the community (n = 97) participated in both a panel session and an individual home assignment. Each participant valuated 46 vignettes with VAS, TTO, and DCE. Each vignette consisted of five attributes: maternal health antepartum, time between diagnosis and delivery, process of delivery, maternal outcome, and neonatal outcome. The questionnaire included Feasibility, which we evaluated by questionnaire. Test–retest reliability and interobserver consistency were assessed by intraclass correlation (ICC), and variance consistency by generalization theory. Convergent validity was determined with ICC and Cohen's kappa; construct validity was determined with linear regression, multinomial logit modeling, and Kendall's Tau-b correlation (τ).ResultsThe DCE was reported as most feasible (DCE: 87% vs. VAS: 69% vs. TTO: 42%). Test–retest reliability was high overall and equal (VAS: ICC = 0.77; TTO: ICC = 0.79; DCE: κ = 0.78). The VAS had the highest interobserver reliability (ICC = 0.73). Convergent validity between VAS and DCE was high (κ = 0.79) and there was sufficient construct validity between VAS and DCE (τ = 0.68). The TTO yielded less optimal results. Generally, neonatal and maternal outcomes weighed most, whereas process outcomes weighed least in moderate-risk pregnancy at term.ConclusionsIn our context of multidimensional health states with complex trade-offs, DCE was superior to TTO and performed equal to VAS, with DCE displaying slightly higher user feasibility.     

Immunogenicity and safety of an intradermal fractional third dose of ChAdOx1 nCoV-19/AZD1222 vaccine compared with those of a standard intramuscular third dose in volunteers who previously received two doses of CoronaVac: A randomized controlled trial

IntroductionThe CoronaVac vaccine is widely used in Thailand to combat the coronavirus disease 2019 (COVID-19) pandemic. The limited immunogenicity of this vaccine is a concern, especially because of expanding delta variant outbreaks. A third boost may enhance antiviral immune responses.MethodsThis non-inferiority randomized controlled trial evaluated the immunogenicity and safety of an intradermal (ID) fractional third dose of AZD1222 vaccine compared with those of a standard intramuscular (IM) third dose. Participants were enrolled from August 9, 2021 to August 13, 2021 at Chulabhorn Hospital, Bangkok, Thailand. The eligibility criteria were age 18 years or older and prior two-dose Coronavac vaccination completed at least 2 months previously. Participants were randomly assigned to one of three groups by block randomization: (i) standard dose by IM administration (IM), (ii) 20% of the standard dose ID (ID1), or (iii) 40% of the standard dose ID (ID2). The primary endpoint was the geometric mean ratio of anti-receptor binding domain antibody in the ID1/ID2 vs. the IM groups 14 days post-vaccination.ResultsA total of 125 participants were randomized (IM, n = 41; ID1, n = 41; and ID2, n = 43). One participant was lost to follow-up by day 14 post-vaccination in the ID1 group. The geometric mean ratio (95% confidence interval) of anti-receptor binding domain antibody was 0.94 (0.80–1.09) in the ID1 group and 1.28 (0.95–1.74) in the ID2 group. Immunogenicity in both ID groups met the non-inferiority criteria. Local adverse events were more common in the ID groups than in the IM group but were mostly mild to moderate in severity.ConclusionAn ID fractional third dose of AZD1222 was non-inferior to a standard IM third dose among individuals previously vaccinated with CoronaVac. Adverse events associated with the ID fractional third dose included mild to moderate local site reactions. This vaccination strategy may help conserve vaccine supply.     

Comparative Effectiveness of Functional Tests in Fall Prediction After Hip Fracture

ObjectivesTo assess the validity of 4 functional tests in predicting falls within the first year after hip fracture.DesignProspective study of functional tests shortly after hip surgery and incident falls during 12 months' follow-up.Setting and ParticipantsThe sample comprised 173 adults with acute hip fracture, aged 65 years and older (79% women, 77% community dwelling, mean age 84.2 years), who participated in a clinical trial of vitamin D or home exercise.MethodsWe assessed 4 functional tests [Timed Up and Go test (TUG), grip strength, and knee flexor and extensor strength in the nonoperated leg] by trained study physiotherapists at baseline (1-12 days after hip fracture surgery). During 12 months' follow-up, we ascertained all fall events by monthly personal phone calls, a telephone hotline, and a patient diary. Then we compared TUG and strength test performance at baseline between future single fallers, recurrent fallers, and nonfallers over the 12-month follow-up. All analyses adjusted for age, body mass index, gender, 25-hydroxyvitamin D status at baseline, days of follow-up, and treatment allocation (the original trial tested vitamin D treatment and/or a home exercise program).ResultsNinety-two of 173 (53%) participants fell and experienced 212 falls. Participants who became recurrent fallers (n = 54) had significantly longer TUG times at baseline than those who did not fall (n = 81) in the following 12 months (mean TUG for recurrent fallers = 71.6 seconds, SD = 8.2 seconds, vs mean TUG for nonfallers = 51.4 seconds, SD = 6.9 seconds; P = .02). There were no significant differences in TUG times between single fallers and nonfallers. For all 3 strength tests, there were no significant differences between single fallers, recurrent fallers, and nonfallers.Conclusions and ImplicationsIn this population of frail older adults recruited shortly after hip fracture surgery, only the TUG test discriminated between future recurrent fallers and nonfallers over a 12-month follow-up. Because of the high incidence and serious consequences of falls in older adults after a hip fracture, it is very important to identify practical and clinically related tests to predict repeated falls in the first year after a hip fracture, which is of great public health importance.     

POWERSforID: Personalized online weight and exercise response system for individuals with intellectual disability: A randomized controlled trial

BackgroundObesity is associated with early mortality and chronic disease among adults with intellectual disability (ID), yet there is a paucity of effective weight management interventions for this population.Objective/hypothesisThis pilot study examined a tailored intervention on weight loss, waist circumference, A1c, and lipid profile among adults with ID.MethodsObese adults (BMI ≥ 30 kg/m²) with mild to moderate ID were randomized to an intervention (n = 17) or comparison group (n = 18) for a 24-week trial. All participants completed health-related questionnaires and clinic visits. Participants in the intervention group received access to an online weight management platform that assisted them in monitoring their diet and physical activity along with weekly coaching calls (weeks 1–12) that were tapered off to calls every other week (weeks 12–24). The comparison group completed questionnaires and clinic visits, but did not receive access to the online platform or calls. Differences in weight, waist circumference, percent body fat, A1c, lipid profile were assessed at baseline and at week 24.ResultsThe intervention group reduced body weight by an average of 2.7% (−2.6 kg; p = 0.02) and waist circumference by 3.4% (−3.89 cm; p = 0.02) versus the comparison. There were no statistically significant group by time interactions observed among other variables.ConclusionAdults with ID who received the intervention were able to maintain or slightly reduce their body weight and waist circumference after the 24-week intervention. Despite not achieving the targeted sample size, the pilot study findings serve as a basis for developing accessible weight management interventions for people with ID.     

Psychometric Properties of the National Institute of Neurological Disorders and Stroke and Canadian Stroke Network Neuropsychological Battery in an Asian Older Adult Sample

ObjectiveDespite the wide usage of the National Institute of Neurological Disorders and Stroke and Canadian Stroke Network (NINDS-CSN) neuropsychological battery for the detection of vascular cognitive impairment, its reliability and validity have not been established. Therefore, the present study established the psychometric properties of the battery in cognitively normal older adults in a clinical setting in Singapore.DesignLongitudinal study.Setting and ParticipantsA total of 105 cognitively normal older adults age 50 years and older were assessed in a memory clinic setting.MethodsThe 60-minute NINDS-CSN and 5-minute protocol were administered to participants at baseline and 3-month follow-up. Raw scores were transformed into standardized z scores. Test-retest reliability, concurrent validity and construct (convergent and discriminant) validity were reported.ResultsModerate-to-excellent test-retest reliability (r = 0.36–0.87), concurrent validity, and construct validity (r = 0.41–0.83) were found in both protocols over 3 months (all Ps < 0.01). Although the 5-minute protocol showed moderate validity (r = 0.41), the 60-minute protocol had excellent concurrent validity against a locally validated neuropsychological battery (r = 0.83).Conclusion and ImplicationsThe NINDS-CSN is reliable and valid in assessing cognitive function. The 60-minute protocol demonstrates great utility beyond its current usage in vascular cognitive impairment populations to the general older adult population. The 5-minute protocol can be used as a brief cognitive screening tool in primary healthcare and the community, due to its brevity and accuracy. Future research should further examine the generalizability of the NINDS-CSN battery in other dementias and cognitive disorders.     

Physical Function Differences Between the Stages From Normal Cognition to Moderate Alzheimer Disease

Objectives

We investigated the differences in the physical function test results across stages from normal cognition (NC) to moderate Alzheimer disease (AD) and how risk factors of physical function decline are correlated with the physical function test results.

Reliability of the Perceive, Recall, Plan and Perform System of Task Analysis: A criterion-referenced assessment

Objective:  To conduct preliminary examination of the rater and test-reliability of the Perceive, Recall, Plan and Perform (PRPP) System of Task Analysis, an ecological measure designed to assess task-embedded information processing capacity during occupational therapy assessment of confused and agitated adults following traumatic brain injury.
Methods:  Occupational therapists observed and scored client performance using the PRPP System of Task Analysis. Correlational analysis and measures of agreement were performed to determine interrater and intrarater reliability. Test procedures were examined for reliability and internal consistency.
Results:  Interrater and test reliability considered three factors: therapists, clients and tasks. A moderate level of interrater reliability was achieved between trained therapists (intraclass correlation coefficient (ICC) = 0.60). Test procedures were highly reliable (ICC = 0.88). Across two measurement occasions, therapists showed a tendency towards harder rating on the second test occasion (      –4.5%; 95% confidence interval for     : –10.67%→ 3.17%).
Conclusion:  The findings of this study support the use of criterion-referenced tests in the area of occupational performance measurement. Occupational therapists achieved moderate interrater reliability when measuring the performance of adults with brain injury on various activities of daily living. Test procedures were found to be highly reliable in measuring the occupational performance of adults demonstrating confusion and agitation typical to the stage of post-traumatic amnesia following head injury.     

Does chair type influence outcome in the timed “up and go” test in older persons?

Objective  

To test the effects of the use of a collapsible, portable chair (chair B), as opposed to a ‘standard’ chair (chair A), on the outcome of the timed “Up and Go” (TUG) test.     

Investigation of intelligence quotient and psychomotor development in schoolchildren in areas with different degrees of iodine deficiency

This investigation aims to observe the intelligence and psychomotor development of the schoolchildren in iodine deficiency (ID) areas after the adoption of Universal Salt Iodization (USI), and evaluate the effect of the adoption of USI on their intelligence and psychomotor development. 564 schoolchildren (306 males and 258 females, age range from 8 to 13 yrs) from areas with severe, moderate, and mild ID were investigated. Intelligence quotient (IQ) was measured by Combined Raven's test, second edition. Psychomotor development was examined by Jinyi Psychomotor Test Battery (JPB). We found that the IQ scores of all subjects in the severe and moderate ID areas were 102 +/- 15.6 and 99.5 +/-16.6 respectively, lower than those in the mild ID areas (108 +/- 12.4, p < 0.01). The IQ scores correlated negatively with age (partial r = -0.17; beta = -1.95; p < 0.0001). The total T scores of JPB of all subjects in the severe and moderate ID areas were 316 +/- 42.3 and 330 +/- 47.7 respectively, lower than those in the mild ID areas (342 +/- 48.1, p < 0.05). The total T scores of JPB correlated negatively with age (partial r = -0.15; beta = -4.94; p = 0.0006). We may conclude that after the adoption of USI in the ID areas investigated, USI has probably made a contribution to the partial recovery of intelligence and psychomotor development injured by ID in schoolchildren, and should be strengthened.     

Macrophage function as studied by the clearance of 125I-labeled polyvinylpyrrolidone in iron-deficient and iron-replete mice

This study evaluated the effects of iron deficiency and iron repletion on in vivo macrophage function determined by the clearance of 125I-labeled polyvinylpyrrolidone (PVP). Two experiments were done. There were four groups of C57BL/6 female mice in experiment 1: the iron-deficient (ID), pair-fed (PF), control (C) and the high iron (HI) groups. In experiment 2, there were three ID groups (severe to moderate anemia), three PF, one C and four ID groups that were fed adequate iron for 14 (R-14), 7 (R-7), 3 (R-3) days before or on the day of PVP injection (R-0). The overall rate of PVP clearance from blood was lower in ID than in C or PF groups. This clearance is expressed by a constant, K, calculated from natural log (ln) of the cpm and the time postadministration of PVP that blood was drawn. The theoretical individual macrophages function (alpha PVP), derived from K and the weights of body, spleen and liver, was also lower in ID than in C or PF groups. The impairment was most severe with the most severe iron deficiency. Repletion for 7 to 15 d before PVP administration resulted in a partial correction of the clearance. Moderate undernutrition in the PF group had no effect.     

Differential item and test functioning methodology indicated that item response bias was not a substantial cause of country differences in mental well-being

ObjectivesEstablishing the cross-cultural equivalence of the mental well-being construct, as measured with the Warwick-Edinburg Mental Well-being Scale (WEMWBS), by studying potential construct validity biases in two countries with previously reported score differences.Study Design and SettingWe compared the WEMWBS total scores and item responses in Scotland (N = 779) and Catalonia (N = 1,900) general population samples. To assess whether the questionnaire spuriously favored higher scores in Catalonia, we tested for differential item functioning (DIF) by applying ordinal logistic regression on Item Response Theory scores. DIF was tested with likelihood ratio tests and standard effect measures (McFadden Pseudo R², >0.13; relative parameter change, >5%), and differential test functioning (DTF) was tested by plotting differences between full-test and purified (i.e., without DIF items) score estimates.ResultsCatalonia showed higher levels of mental well-being than Scotland (Cohen d = 0.84). Three of 14 WEMWBS items showed small amounts of DIF. DIF did not accrue to DTF, as shown by intraclass correlation coefficient (ICC, 0.999) and case-by-case differences (maximum, 0.12 SD) between total and purified scores. Population differences remained mainly constant across sociodemographics and health outcomes.ConclusionThe WEMWBS measures a distinct well-being construct that is stable across countries, implying that Scotland and Catalonia populations are effectively different in the distribution of mental well-being. This result adds to previous psychometric information and supports WEMWBS as a valid unbiased measures for individual and cross-cultural comparisons.