Urinary 1-hydroxypyrene as a comprehensive carcinogenic biomarker of exposure to polycyclic aromatic hydrocarbons: a cross-sectional study of coke oven workers in China

Purpose

Polycyclic aromatic hydrocarbons (PAHs) are multiple compounds that include many carcinogens. We conducted a cross-sectional study in steel plant workers in Anshan, China, to identify biomarkers that reflect the carcinogenicity of PAHs.

Methods

Subjects were 57 workers and 20 controls. Level of personal exposure to PAHs was measured using GC–MS. In accordance with the assessment methods defined by the United States Environmental Protection Agency (US EPA), 15 PAHs were selected for the analysis. For the measurement of urinary metabolites, urine samples were treated with β-glucuronidase and analyzed using HPLC with a fluorescence detector.

Results

The mean range of personal exposure to 15 PAHs (total PAHs) was 178.85, 47.08–1,329.45 (geometric mean, 5th and 95th percentile) μg/m³. Ten known urinary metabolites (1-hydroxynaphthalene, 2-hydroxynaphthalene, 2-hydroxyfluorene, 1-hydroxyphenanthrene, 3-hydroxyphenanthrene, 9-hydroxyphenanthrene, 1-hydroxypyrene, 3-hydroxybenz[a]anthracene, 6-hydroxychrysene, and 3-hydroxybenzo[a]pyrene) and four unknown peaks were detected. The highest correlation was between total PAHs and urinary 2-hydroxynaphthalene (Spearman r = 0.716, P < 0.01). Among the detected urinary metabolites, 2-hydroxyfluorene, 1-hydroxyphenanthrene, 3-hydroxyphenanthrene, and 1-hydroxypyrene were found to correlate significantly with the “Σ carcinogenic potency of PAHs” (sum of seven carcinogenic PAHs calculated from the levels of personal PAHs and relative potency factors), and with the greatest correlation found for 1-hydroxypyrene (Spearman r = 0.630, P < 0.01).

Conclusions

The analysis of personal exposure to 15 PAHs and 10 urinary metabolites, and calculation of Σ carcinogenic potency, indicated that urinary 1-hydroxypyrene was the most comprehensive carcinogenic biomarker of exposure to PAHs.     

Effects of Physiochemical Properties of Test Media on Nanoparticle Toxicity to Daphnia magna Straus

The physicochemical property of standard test media significantly influenced the aggregation and dissolution of Ag, CuO and ZnO nanoparticles (NPs) and the toxicity of the NPs to Daphnia magna. For all the NPs, the highest amount of metal ions was released from the ISO medium, whereas acute toxicity to D. magna was highest in the moderately hard water medium (EC₅₀ = 4.94, 980, and 1,950 μg L^?1 for Ag, CuO, and ZnO, respectively). By comparing EC₅₀ values based on the total and dissolved concentrations of NPs with those of metal salt solutions, we found that both particulate and dissolved fractions were likely responsible for the toxicity of Ag NPs, whereas the dissolved fraction mostly contributed to the toxicity of CuO and ZnO NPs.     

Psychometric properties of quality of life and health-related quality of life assessments in people with multiple sclerosis

Purpose

There is substantial interest in testing interventions for improving quality of life (QOL) and health-related quality of life (HRQOL) in people with multiple sclerosis (MS). Yet, there is limited research on the psychometric properties of QOL [e.g., Satisfaction with Life Scale (SWLS), Leeds MS Quality of Life Scale (LMSQOL)] and HRQOL [e.g., Short Form 12 Health Survey (SF-12) and Multiple Sclerosis Impact Scale-29 (MSIS-29)] measures in this population. Such research is important for designing and interpreting interventions. We examined the test–retest reliability, measurement error, and interpretability of QOL (i.e., SWLS and LMSQOL) and HRQOL (i.e., SF-12 and MSIS-29) measures over 6 months in people with MS.

Methods

Individuals with MS (n = 274) completed the SWLS, LMSQOL, SF-12 and MSIS-29 on two occasions, 6 months apart. We estimated test–retest reliability [intraclass correlation coefficient (ICC)], measurement error [standard error of measurement (SEM) and coefficient of variation] and interpretability [smallest detectable change (SDC)].

Results

Intraclass correlation coefficient values ranged between moderate and good (ICC range = 0.669–0.883); the MSIS-29 physical component had the best reliability, and the SF-12 mental component had the worst reliability. Measurement error, based on percent SEM, varied among measures; the physical and mental components of the SF-12 (%SEM = 4.6 and 5.3, respectively) had the best measurement error, and the MSIS-29 mental component (%SEM = 13.2) and the SWLS (%SEM = 12.7) had the worst measurement error. Interpretability, based on percent SDC, varied among measures; interpretability was best for the physical and mental components of the SF-12 (%SDC = 12.7 and 14.7, respectively) and worst for the MSIS-29 mental component (%SDC = 36.7) and the SWLS (%SDC = 35).

Conclusion

We provide novel data for helping researchers and clinicians select and interpret QOL and HRQOL measures and scores for interventions among people with MS. Such information will better inform our understanding of intervention effectiveness.     

Patient’s response to a simple question on recovery after hemodialysis session strongly associated with scores of comprehensive tools for quality of life and depression symptoms

Purpose

Many maintenance hemodialysis patients do not feel well after the hemodialysis session and need a time to recover. The main objective of the study was to investigate whether a simple question about the need of some time to recover from hemodialysis was associated with scores of comprehensive tools of depression symptoms and health-related quality of life (HRQOL).

Methods

Cross-sectional evaluation of 800 Brazilian patients enrolled in the Prospective Study of the Prognosis of Chronic Hemodialysis Patients (PROHEMO). The KDQOL-SF was used for HRQOL and the 20-item CES-D and BDI for depression symptoms. Linear and logistic models were used for multivariable adjustments.

Results

Patients who reported some time to recover (30 %) had significantly (P < 0.001) higher depression symptoms scores (mean difference = 4.75 for CES-D and 4.48 for BDI). HRQOL scores were, in general, lower for patients who referred a time to recover, with mean differences larger than 4.0 (P < 0.05) both for physical and mental components. Strong associations of needing a time to recover and lower scores of several kidney disease-targeted HRQOL components were also observed. Differences in depression symptoms and HRQOL were largely reduced after adjustments for symptoms (muscle pain/cramps, faintness, fatigue, nausea/vomiting).

Conclusions

The results support the validity of a simple question on post-hemodialysis recovery as a proxy for scores of complex instruments for depression symptoms and HRQOL. The results suggest that the poorer HRQOL and higher depression probability in patients who need a time to recover from hemodialysis could be partially explained by the presence of hemodialysis-related symptoms.     

Distribution of polycyclic aromatic hydrocarbons concentrations simultaneously obtained in gas,rainwater and particles

This study reported the distribution of polycyclic aromatic hydrocarbons (PAHs) concentrations simultaneously obtained in gas/rain/particle in rain event from 2010 to 2012 in Osaka, Japan. A sampling method for rain and the materials of a rain collector were also surveyed. Benzene and a glass bottle were used to prevent the decrease of PAHs in rainwater. The average concentration of Σ9PAHs in rainwater ranged between 17.49 and 646.52 ng dm^?3. The mean ratio of these Σ9PAHs in gas versus particles was 77.9 and 68.3 % during rain and no rain, respectively. During rain, the PAHs in particles were scavenged by rain and were incorporated via washout by collision with each other. Therefore, the ratio of PAHs in rainwater was similar to that in particles. The low molecular weight LMW-PAHs from gas were recognized as being dissolved in rain but did not affect the ratio of PAHs in rain. Four rings PAH were dominant in gas/rain/particles. The seasonal variation of Σ9PAHs in rainwater was reported and discussed, and the PAHs levels during the winter and spring were higher compared with that of summer and autumn. Furthermore, the sampling method of PAHs in snow is also developed.     

Using Rasch analysis to examine the distress thermometer’s cut-off scores among a mixed group of patients with cancer

Purpose

The distress thermometer (DT) is commonly used in cancer care to improve detection of distress. The DT’s recommended cut-off score of 4 or 5 has typically been established using the Hospital Anxiety and Depression Scale (HADS) by receiver operating characteristic curve analysis. The present analysis complements these studies by critically examining the use of the HADS to identify the DT’s cut-off score and corroborating the DT’s cut-off scores using item response theory (Rasch analysis).

Methods

The DT and HADS were completed by 340 patients with cancer. Rasch dimensionality analysis was performed on the HADS-Total, and test characteristic curves were examined to equate the DT and the HADS subscales. Identified DT cut-off scores were then examined for their sensitivity and specificity.

Results

Rasch analysis did not support the unidimensionality of HADS-Total. The test characteristic curves indicated that a cut-off score of ≥8 on the HADS-Anxiety and HADS-Depression subscales was equivalent to a score of 6 and 7 on the DT, respectively. However, a DT cut-off score of 5 resulted in the best balance between sensitivity and specificity across the HADS-Anxiety and HADS-Depression subscales.

Conclusions

Despite being a popular practice, the present findings did not support combining the HADS-Anxiety and HADS-Depression subscales to identify the DT’s cut-off score. Furthermore, these results inform the use of the DT as a preliminary screening tool and suggest that when a single screen is used, a DT cut-off score of 6 or 7 might be more appropriate than the typical cut-off score of 4.     

Similarities and Differences in the Epidemiology of Pyloric Stenosis and SIDS

Similar temporal declines in infantile hypertrophic pyloric stenosis (IHPS) and sudden infant death syndrome (SIDS) and other common features have led to hypotheses about a shared etiology. We carried out a population-based study to highlight similarities and differences between IHPS and SIDS. We used vital statistics and hospitalization data on all live births in Washington State, USA (1987–2009). Changes in IHPS and SIDS rates over time were quantified using rate ratios with 95 % confidence intervals (CI). The duration between birth and diagnosis of IHPS or SIDS was examined as a function of gestational age at birth. Logistic regression analysis was used to identify risk factors and quantify adjusted temporal trends (2000–2008). Although both IHPS and SIDS rates declined significantly between 1987 and 2008, the patterns and magnitude of the declines (40 and 74 %, respectively) were different. IHPS and SIDS shared risk factors such as maternal smoking and single parent status but other factors showed qualitatively or and quantitatively different associations. Primiparity was a risk factor for IHPS [odds ratio (OR) 1.24, 95 % CI 1.09–1.41], and a protective factor for SIDS (OR 0.44, 95 % CI 0.36–0.55), while male sex had a stronger association with IHPS (OR 4.51, 95 % CI 3.85–5.28 vs 1.36, 95 % CI 1.13–1.64). Both IHPS and SIDS showed significant inverse associations between gestational age at birth and chronologic age at diagnosis/death. IHPS and SIDS share some epidemiologic features and risk factors but other risk factors have qualitatively or quantitatively different effects and recent temporal trends in the two diseases are dissimilar.     

Polycyclic Aromatic Hydrocarbons Degrading Microflora in a Tropical Oil-Production Well

The surrounding environment near Dagang oil-production well suffers polycyclic aromatic hydrocarbons (PAHs) pollution. In the present study, indigenous microorganisms capable of degrading PAHs were isolated and the efficiency of PAHs removal was investigated. Seven PAH-degrading strains were isolated with the ability to grow on naphthalene, phenanthrene, pyrene and fluorene. They belonged to the genus Pseudomonas, Bacillus and Rhodococcus. The strain having the highest degrading capacity for each PAH was selected by the screening test. The removal efficiency of PAHs was found to be in the order of naphthalene > fluorene > phenanthrene > pyrene. The kinetics of PAHs degradation was then followed by liquid chromatography determination and the results showed it conforms to a first-order reaction kinetic model. This study would be highly important for investigating the ability of microorganisms to utilize PAHs as growth substrates.     

Quality of life along the diabetes continuum: a cross-sectional view of health-related quality of life and general health status in middle-aged and older Finns

Purpose

To examine the general health status and health-related quality of life (HRQOL) along the diabetes continuum of middle-aged and older Finns, and to determine the glucose metabolism stage by which the HRQOL has decreased noticeably.

Methods

The cross-sectional sample consisted of 920 persons aged 51–75 from the general population in a single municipality in a rural area of Eastern Finland. Data were adjusted for age, sex, smoking history, current alcohol consumption, employment and marital status. The HRQOL and health status were evaluated using two preference-based HRQOL instruments, 15D and SF-6D, and one health profile instrument, 36-Item Short Form Health Survey (SF-36).

Results

Individuals with impaired glucose tolerance (IGT) and type 2 diabetes had noticeably low mean SF-6D, 15D and general health status. The decrease in overall HRQOL was mainly due to a decline in the physical dimensions of HRQOL. The adjusted odds ratios (95 % CI) for having noticeably low HRQOL on SF-6D, 15D and general health dimension of SF-36 associated with IGT were 1.95 (1.18–3.25), 1.35 (0.84–2.18) and 2.00 (1.21–3.29), respectively.

Conclusions

The progression along the diabetes continuum was significantly associated with a decrease in HRQOL and health status. Furthermore, the data indicate that when a person is detected to have IGT, the HRQOL and general health status have already diminished noticeably. The prevailing evidence suggests that detection and intervention before a patient develops IGT is essential in order to minimize the loss of quality of life and quality-adjusted life years.     

Acute and Chronic Response of Daphnia magna Exposed to TiO2 Nanoparticles in Agitation System

Aquatic toxicity of titanium dioxide nanoparticles (TiO₂ NPs) to Daphnia magna was characterized using a completely stirred bioassay system intended to keep particles in suspension thereby maintaining a consistent exposure. The 48-h LC₅₀ was 4.5 mg/L TiO₂ NPs, whereas LC₅₀ values for 7 and 14-days exposures were 2.7 and 1.9 mg/L, respectively. An exposure of 1.5 mg/L over a 21-days exposure resulted in significant reductions in fecundity. While reproduction was initially reduced in the 0.5 and 1.0 mg/L exposures, it recovered and was similar to the control by 21 days. For reproduction inhibition, NOEC was 1.0 mg/L. Exposure to 2.5 mg/L TiO₂ NPs resulted in 40 % of the organisms failing to become gravid; all surviving organisms exposed to 5.0 mg/L failed to become gravid. The increased sensitivity was due to the refinement in the bioassay system that kept NP in suspension resulting in consistent exposure concentrations.     

Health-related quality of life and body mass index among US adolescents

Purpose

To examine the magnitude of differences in health-related quality of life (HRQOL) by body mass index (BMI) in a population-based sample of United States adolescents overall and by sex, and to provide national prevalence estimates of reported HRQOL outcomes for not only obese and overweight but also underweight adolescents.

Methods

From the 2001 through 2010 cross-sectional National Health and Nutrition Examination Surveys, we estimated the percentages of four HRQOL outcomes—self-rated health, physically unhealthy days, mentally unhealthy days, and activity limitation days—in four BMI categories—obese, overweight, normal weight, and underweight—of approximately 6,000 US adolescents aged 12–17 years. We also estimated the percentages for boys and girls separately.

Results

Substantial gaps in self-rated health exist between normal-weight adolescents and those who are obese and overweight, but not underweight. Eighteen percent (95 % CI 15–22) of obese adolescents reported fair or poor health compared to only 5 % (95 % CI 4–7) of normal-weight adolescents. Thirty-seven percent (95 % CI 33–42) of obese adolescents reported excellent or very good health, compared to 65 % (94 % CI 63–67) of normal-weight adolescents. However, all BMI groups reported similar percentages of physically unhealthy days, mentally unhealthy days, and activity limitation days. The associations between HRQOL and BMI groups did not vary by sex. Boys generally reported significantly better self-rated health and mental health than girls. Specifically, obese boys reported better self-rated health, mental health, and fewer activity limitation days than obese girls.

Conclusions

Substantially, significant differences in some domains of HRQOL are found between above normal-weight and normal-weight US adolescents. This relationship between BMI and HRQOL is robust and observed among both boys and girls.     

Effects of Ce(III) and CeO2 Nanoparticles on Soil-Denitrification Kinetics

Cerium (Ce)-based compounds, such as CeO₂ nanoparticles (NPs), have received much attention in the last several years due to their popular applications in industrial and commercial uses. Understanding the impact of CeO₂ NPs on nutrient cycles, a subchronic toxicity study of CeO₂ NPs on soil-denitrification process was performed as a function of particle size (33 and 78 nm), total Ce concentration (50–500 mg L^?1), and speciation [Ce(IV) vs. Ce(III)]. The antimicrobial effect on the soil-denitrification process was evaluated in both steady-state and zero-order kinetic models to assess particle- and chemical-species specific toxicity. It was found that soluble Ce(III) was far more toxic than Ce(IV)O₂ NPs when an equal total concentration of Ce was evaluated. Particle size-dependent toxicity, species-dependent toxicity, and concentration-dependent toxicity were all observed in this study for both the steady-state and the kinetic evaluations. Changes in physicochemical properties of Ce(IV)O₂ NPs might be important in assessing the environmental fate and toxicity of NPs in aquatic and terrestrial environments.     

Breast Cancer Incidence Rates Among Orthodox Jewish Women

BRCA 1/BRCA2 founder mutations have been documented among Ashkenazi Jews. Little is known about cancer rates and cancer-related health behaviors among an insular subset of this population, Orthodox Jews. The goal of this study was estimate the risk of breast and ovarian among the Orthodox Jewish population. We used geo-coding with surveillance, epidemiology, and end results (SEER) data to identify this subgroup and estimate breast and ovarian cancer rates. Relative to neighborhoods with lower estimated Jewish populations, higher breast cancer rates were found in neighborhoods with higher estimated Orthodox Jewish population, there were no comparable differences in ovarian cancer rates. Implications include more research on health behaviors that may contribute to breast cancer in this insular community.     

Danish population-based reference data for the EORTC QLQ-C30: associations with gender,age and morbidity

Purpose

General population reference data are useful in the interpretation of health-related quality of life (HRQoL) results, but for the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire C30 (EORTC QLQ-C30), such data have been published for only seven countries. In 1992, Danish general population data were collected from women only for EORTC QLQ-C30 version 1. Since no Danish reference data exists for men and women for the QLQ-C30 version 3.0, the aims of this study were to generate such data and to investigate the associations between EORTC QLQ-C30 outcomes and age, gender and morbidity, as well as trends over time.

Methods

An age- and gender-stratified random sample of 3,080 Danes was drawn from the Danish Civil Registration System. The EORTC QLQ-C30 was administered electronically and by mail along with a short questionnaire concerning socio-demographics/morbidity.

Results

Responses were obtained from 1,832 individuals (60.1 % of 3,009 eligible individuals). Response rates varied across age groups, ranging from 41.9 % (20–29 years) to 76.1 % (70–79 years). The majority of subscales were strongly associated with age and morbidity. Between genders only small, but clinically meaningful and statistically significant differences were found in five out of fifteen scales. When comparing Danish women 20 years ago and today, a tendency toward slightly improved function/reduced symptoms was observed, but the differences were small and statistically significant in only three subscales.

Conclusion

This study is the first to present Danish general population reference values for the EORTC QLQ-C30 version 3.0. Age and morbidity are important potential confounders that must be taken into account in HRQoL studies.     

Predictors of health-related quality of life changes after lifestyle intervention in persons at risk of type 2 diabetes mellitus

Purpose

To assess health-related quality of life (HRQOL) of subjects at risk of type 2 diabetes undergoing lifestyle intervention, and predictors for improved HRQOL.

Methods

The Finnish Diabetes Risk Score was used by general practitioners to identify individuals at risk. Low-intensity interventions with an 18-month follow-up were employed. HRQOL was assessed using the SF-36 at baseline and compared with results from a general Norwegian population survey and further at 6 and 18 months. Simple and multiple linear regression analyses were applied to identify predictors of changes in HRQOL of clinical importance.

Results

Two hundred and thirteen participants (50 % women; mean age: 46 years, mean body mass index: 37) were included: 182 returned for 18-month follow-up, of whom 172 completed the HRQOL questionnaire. HRQOL was reduced with clinical significance compared with general Norwegians. The mean changes in HRQOL from the baseline to the follow-up were not of clinical importance. However, one out of three individuals achieved a moderate or large clinical improvement in HRQOL. The best determinant for improved HRQOL was obtained for a composite, clinically significant lifestyle change, i.e. both a weight reduction of at least 5 % and an improvement in exercise capacity of at least 10 %, which was associated with an improvement in five out of the eight SF-36 domains.

Conclusion

Subjects at risk of type 2 diabetes report a clinically important reduction in HRQOL compared with general Norwegians. The best predictor of improved HRQOL was a small weight loss combined with a small improvement in aerobic capacity.     

Assessing the validity of single-item life satisfaction measures: results from three large samples

Purpose

The present paper assessed the validity of single-item life satisfaction measures by comparing single-item measures to the Satisfaction with Life Scale (SWLS)—a more psychometrically established measure.

Methods

Two large samples from Washington (N = 13,064) and Oregon (N = 2,277) recruited by the Behavioral Risk Factor Surveillance System and a representative German sample (N = 1,312) recruited by the Germany Socio-Economic Panel were included in the present analyses. Single-item life satisfaction measures and the SWLS were correlated with theoretically relevant variables, such as demographics, subjective health, domain satisfaction, and affect. The correlations between the two life satisfaction measures and these variables were examined to assess the construct validity of single-item life satisfaction measures.

Results

Consistent across three samples, single-item life satisfaction measures demonstrated substantial degree of criterion validity with the SWLS (zero-order r = 0.62–0.64; disattenuated r = 0.78–0.80). Patterns of statistical significance for correlations with theoretically relevant variables were the same across single-item measures and the SWLS. Single-item measures did not produce systematically different correlations compared to the SWLS (average difference = 0.001–0.005). The average absolute difference in the magnitudes of the correlations produced by single-item measures and the SWLS was very small (average absolute difference = 0.015–0.042).

Conclusions

Single-item life satisfaction measures performed very similarly compared to the multiple-item SWLS. Social scientists would get virtually identical answer to substantive questions regardless of which measure they use.     

Conceptualizing global health-related quality of life in bladder cancer

Purpose

Patients’ values for health outcomes are central to treatment decisions in bladder cancer (BCa). An instrument incorporating the expressed preferences of BCa patients, as measured by utility, can inform clinical guidelines, resource allocation and policy decisions. Developing this instrument requires a formal conceptual framework summarizing the important domains comprising global health-related quality of life (HRQOL) in BCa.

Methods

We performed a systematic literature search on the HRQOL effects of BCa and its treatments to generate initial items in Medline, Embase, CINAHL and PsychInfo up to January 2013. Thematic synthesis was used to group related items into overarching themes (domains) and create a provisional conceptual framework. In focus groups, 12 BCa experts and 47 BCa patients with diverse clinical histories generated further items to inform the final conceptual framework.

Results

We retrieved 1,275 citations and reviewed 170 full-text publications. One hundred and sixty-nine items were extracted into 12 domains. Study investigators used the findings from the focus groups to confirm the domains and condense the list to 83 clinically important items. Functional limitations in work, travel, social interaction and sleep lowered HRQOL in many domains. The final conceptual framework included BCa-specific (urinary, sexual, bowel, body image) and generic domains (pain, vigor, social, psychological, sleep, functional, family relationship, medical care relationship).

Conclusions

A conceptual framework including 12 domains can serve as the foundation for the development of an instruments measuring global HRQOL in BCa and in particular, one that can measure patient preferences and generate utilities.     

The Measurement Properties of Mentoring Relationship Quality Scales for Mentoring Programs

The measurement properties of two new scales designed to measure global and engagement mentoring relationship quality (Global Mentoring Relationship Quality Scale and Quality of Mentoring Relationship Engagement Scale) were examined among 272 mentors, 491 children, and 554 parents participating in Big Brothers Big Sisters community mentoring programs across Canada. Results demonstrated their unidimensionality, moderate convergent validity, good external validity, and weak-to-moderate reporter concordance. Longitudinal analyses demonstrated good predictive validity of mentor and parent mentoring relationship quality scales with respect to predicting mentoring relationship status.     

Factorial structural analysis of the Spanish version of WHOQOL-BREF: an exploratory structural equation model study

Purpose

The purpose of this study was to analyze the factor structure of the abbreviated Spanish version of the World Health Organization Quality of Life (WHOQOL-BREF; WHOQOL Group in Psychol Med 28(3): 551–558, 1998b) questionnaire in a sample of individuals from several Spanish-speaking countries.

Method

The data were based on a sample of 1,972 undergraduates from nine Spanish-speaking countries. Within the framework of a somewhat wider research protocol, they were administered the WHOQOL-BREF.

Results

The data were initially analyzed using a confirmatory factor analysis, which yielded a poor fit to the four-factor theoretical model. Based on these results, the best solution was estimated assuming structural invariance across countries. The data showed a four-factor structure that differed slightly from the model proposed. This four-factor model was subsequently analyzed using exploratory structural equation modeling (ESEM; Asparouhov and Muthén in Struct Equ Model 16(3): 397–438, 2009) to obtain the invariant structure across countries and an estimation of the relation between the four latent factors. The results obtained allowed us to establish that the factor structure of WHOQOL-BREF maintains the four-factor solution hypothesized for a Spanish-speaking population, although the solution has a different and more complex configuration than the original one with a clear tendency toward non-orthogonality of the latent factors.

Conclusions

As has been suggested by some studies on the application of ESEM, it is reasonable to think that the ESEM approximation is a useful approach for conducting the factor analysis of instruments measuring complex psychological phenomena.     

Vitamin D and health-related quality of life in a community sample of older Canadians

Purpose

To assess how vitamin D status is associated with health-related quality of life (HRQOL) among older residents of Canada.

Design

We analysed baseline data of 1,493 Canadians aged 50 years and over in Alberta on HRQOL (EQ-5D-5L) and serum 25-hydroxyvitamin D (25(OH)D) as a measure of vitamin D status. We applied multivariable regression methods to examine the association between vitamin D status and each of the five dimensions and the summary index of the EQ-5D-5L.

Results

Participants with higher serum 25(OH)D levels were significantly less likely to report problems with mobility, usual activities, and depression and anxiety. Specifically, age- and gender-adjusted odds ratios for reporting problems with mobility, usual activities, and depression and anxiety were 0.58 (95 % confidence interval 0.44–0.78), 0.67 (0.50–0.89), and 0.67 (0.51–0.88) per 100 nmol/L increase in 25(OH)D, respectively. No significant associations were observed for problems with self-care and with pain and discomfort. HRQOL scores combining the responses of each of the five dimensions increased significantly with increasing serum 25(OH)D levels.

Conclusions

This is the first study to reveal the importance of vitamin D for the five dimensions of HRQOL in a community-based sample. The observed associations of vitamin D and HRQOL call for intervention studies to strengthen the evidence of the potential benefits of vitamin D supplementation for HRQOL among older adults.