Validation and reliability of the Turkish version of Contact Lens Dry Eye Questionnaire-8 (CLDEQ-8)

PurposeContact lens dry eye questionnaire-8 (CLDEQ-8) quantifies the disturbing symptoms with the aim of assessing the satisfaction and overall opinion of contact lens wearers. The aim of this study was to develop Turkish version and to evaluate the validity and reliability of the questionnaire.MethodsCLDEQ-8 was translated into Turkish language, using the back translation methods. In a sample of 10 individuals, validation of translation was checked as pre-test evaluation. Turkish version of CLDEQ-8 questionnaire was conducted in 100 soft contact lens wearers. Validity was investigated using Rasch analysis and reliability by Cronbach’s alpha (α) and person separation index (PSI).ResultsThe participants were healthy other than refractive errors. Their mean age was 25.19 ± 7.03 years and male to female ratio was 14/86. All of them were silicone-hydrogel soft contact lens wearers. Their contact lens history was 3.13 ± 3.77 years and mean refraction error was -2.69 ± 1.64 diopters.The whole 8 items were consistent with the Rasch model (p > 0.05) and unidimensional (paired t test, p = 0.1). Both Cronbach’s alpha and PSI values were higher than 0.7 (α = 0.873, PSI = 0.867). There were not functional differences in questionnaire items regarding overall age groups (Andersen LR test, p = 0.518).ConclusionTurkish version of the CLDEQ-8 conforms to the Rasch model and provides the one dimensional assumption. The questionnaire has internal consistency, is valid and reliable in Turkish contact lens wearers.     

A psychometric evaluation of the Smoking Consequences Questionnaire-Adult in smokers with psychiatric conditions.

Rates of smoking among individuals with psychiatric conditions are much greater than those seen in the general population, yet little is known about the psychometric properties of commonly used instruments that assess smoking-related variables among smokers with psychiatric conditions. The present study examined the factor structure and psychometric characteristics of the Smoking Consequences Questionnaire-Adult (SCQ-A; Copeland, Brandon, & Quinn, 1995, Psychological Assessment, 7, 484-494) among smokers with psychiatric conditions. A confirmatory factor analysis of the instrument indicated that the factor structure derived by the instrument's authors provided an adequate fit to the data. In addition, many of the 10 subscales of the SCQ-A demonstrated adequate internal consistency as assessed by Cronbach's alpha as well as adequate test-retest reliability over the course of 1 week. Based on the data derived from this sample, the SCQ-A has adequate psychometric properties for applications involving smokers with psychiatric conditions.     

Assessment of four validated questionnaires for screening of dry eye disease in an African cohort

PurposeTo evaluate the 5-item dry eye questionnaire (DEQ-5) for measurement precision and unidimensionality, and assess the ability of Ocular Surface Disease Index (OSDI), McMonnies Dry Eye Questionnaire (MQ), Ocular Comfort Index questionnaires (OCI), and DEQ to predict clinical measures of DED in an African population.MethodParticipants (n = 113; mean age 24.7 ± 5.4 years) completed all four questionnaires administered in a randomized order. Internal consistency and test-retest reliability of the instruments were assessed. A masked examiner performed clinical dry eye tests in both eyes of participants and the results used to classify into either “dry” or “non-dry” groups. The diagnostic criteria for dry eye disease were tear break up time (TBUT) < 10 s plus at least one of Schirmer <15 mm in 5 min., > 5 corneal staining spot, or > 9 conjunctival staining spots. Rasch analysis was performed to assess the DEQ for unidimensionality and measurement precision, and receiver operating characteristic curve (AUC) analysis was used to assess the ability of the four questionnaires to predict clinical measures of DED.ResultsThe responses from the DEQ-5 met the Rasch analysis criterion of unidimensionality with infit and outfit values of between 0.74–1.43 mean-square and 0.69–1.49 mean-square, respectively, and measurement precision of 2.33. Internal consistency and test-retest reliability of each test was high, with Cronbach alpha >0.70 for the questionnaire and their respective subscales but internal consistency reliability of the MQ was poor (Cronbach’s alpha = 0 .29?0 0.52). Each test segregated the “dry” and “non-dry” groups with moderate (all AUC 0.70?0.80) and similar accuracy (P > .05).ConclusionThe DEQ -5 demonstrated adequate measurement precision and unidimensionality. Each of the four questionnaires showed psychometric validity for clinical use in the African population, and modest and similar accuracy when screening for dry eye signs but the performance of the McMonnies questionnaire was limited in terms of internal consistency reliability.     

Italian translation and validation of the Contact Lens Dry Eye Questionnaire-8 (CLDEQ-8)

PurposeTo translate and validate an Italian version of the CLDEQ-8 (CLDEQ-8_IT).MethodsThe study was carried out in two phases. In the first phase, a cross-cultural adaptation of CLDEQ-8 to Italian was performed by forward and backward translation in sequence. In the second phase, a multi-centre study was conducted for the validation of the questionnaire. Validity CLDEQ-8_IT was evaluated against three gestalt questions: overall opinion of soft contact lenses (CLs), global self-assessments of eye sensitivity and eye dryness. Reliability was evaluated by test–retest assessment in a subgroup of subjects. Finally, the psychometric properties of CLDEQ-8_IT were explored by Rasch analysis.ResultsTwo hundred and forty soft CL wearers, fluent Italian speakers (73 males and 167 females), between 18 and 70 years of age were enrolled. A significant correlation was found between CLDEQ-8_IT and each of the three Gestalt questions. The cutoff score of 12 points demonstrated the best balance between sensitivity and specificity in differentiating wearers grading their CLs as “Excellent/Very good” from those reporting their overall opinion as “Good/Fair/Poor”. The Intraclass Correlation Coefficient between test and retest was 0.88 (95% CI: 0.81–0.92). Finally, infit and outfit statistics using Rasch analysis for the 8 items were in a good range, however Principal Components Analysis revealed a certain degree of multi-dimensionality of the instrument. Also, item 8 analysis could be computed after merging the last two response categories.ConclusionThe CLDEQ-8_IT showed very good validity and reliability in measuring symptoms of CL wearers, comparable to the original English language version. A cut-off of 12 was confirmed as yielding the best balance between sensitivity and specificity in detecting CL wearers who could benefit from clinical management of their CL-related symptoms. Collapsing of the response options 5 and 6 in the last item of questionnaire could optimise its functioning.     

The Chinese version of the Pediatric Refractive Error Profile2 (PREP2): Translation,validation and reliability

ObjectiveThis study aimed to develop and evaluate an adapted Chinese version of the Pediatric Refractive Error Profile2 (PREP2) and to evaluate its acceptability, reliability, and validity in a population of Chinese children with refractive error.MethodsThe Chinese version of the PREP2 was translated using a standardized procedure and then administered to consecutive outpatients with refractive error. Reliability was assessed by the Cronbach’s alpha coefficient for internal consistency and test–retest reliability. Validity of the questionnaire was assessed by item discriminant validity, construct validity, known-groups validity, and concurrent validity.ResultsA total of 104 subjects were recruited for the study and all completed the Chinese version of the PREP2 questionnaire with no problems. A random sample of 50 patients completed the questionnaire twice within one week. The Cronbach’s alpha coefficients ranged from 0.71 to 0.89 across scales, and the intraclass correlation coefficient ranged from 0.86 to 0.92, indicating excellent internal consistency and test–retest reliability. The item-scale correlation coefficients between the items and the corresponding scales ranged from 0.39 to 0.88. The translated questionnaire had good discriminatory power between contact lens wearers and spectacle wearers. Significant correlations were found between the scales and traditional clinical parameters, such as spherical equivalent and uncorrected visual acuity, showing good construct and concurrent validity.ConclusionThe Chinese version of the PREP2 exhibited good internal consistency, test–retest reliability, item-scale correlation, discriminatory power, construct validity, and concurrent validity. Therefore, it may be adopted as an acceptable, reliable, and valid instrument for the measurement of vision-related quality of life in Chinese children with refractive error.     

Comparison of the performance of the dry eye questionnaire (DEQ-5) to the ocular surface disease index in a non-clinical population

ObjectiveTo compare the performance of the dry eye questionnaire (DEQ-5) with the Ocular Surface Disease Index (OSDI) and further validate the DEQ-5 questionnaire.MethodsA population-based cross-sectional study conducted in Ghana. OSDI and DEQ-5 questionnaires were administered to participants. Cronbach’s alpha was used to evaluate the reliability of the OSDI and DEQ-5 questionnaires. Analysis of variance was used to evaluate the discriminant validity of DEQ-5. Concurrent validity was evaluated using the Spearman correlation analysis. A receiver operating characteristic (ROC) curve was generated to describe the sensitivity and specificity of the DEQ-5 questionnaire for diagnosis of dry eye symptoms. Cohen Kappa was used to evaluate agreement between the two questionnaires.ResultsThe reliability of the overall OSDI and DEQ-5 scores were 0.919 and 0.819 respectively. The mean (SD) DEQ-5 scores for asymptomatic, mild, moderate and severe dry eye symptoms as defined by the OSDI grading were 3.05 (2.73), 5.13 (3.69), 7.65 (3.30) and 9.77 (4.16) respectively. There was a statistically significant correlation between total OSDI and total DEQ-5 scores (r_s = 0.649, p < 0.0001). The area under the curve (AUC) of the ROC curve for DEQ-5 was 0.835 (95 % CI: 0.796 – 0.875). A DEQ-5 threshold of 5.5 yielded maximum sensitivity (0.712) and specificity (0.827). The Cohen kappa using a the DEQ-5 total score threshold of 5.5 was K = 0.539 (p < 0.0001).ConclusionIn conclusion, performance of the DEQ-5 questionnaire in discriminating symptoms of dry eye is comparable to the OSDI questionnaire. The DEQ-5 questionnaire is a valid measure of dry eye symptoms and can be used as a dry eye symptoms assessment tool in both clinical and epidemiological studies.     

Validation of a Turkish version of the food choice questionnaire

The purpose of this study was to test the validity and reliability of the food choice questionnaire (FCQ) for Turkish consumers. A total of 963 voluntary consumers participated in this study. Confirmatory factor analysis (CFA) with a diagonally weighted least squares estimation method was used to assess the construct validity. Results showed that factor loadings were similar to the original FCQ. CFA results indicated an acceptable fit. Test-retest reliability was tested with intraclass correlation coefficient (ICC) and the ICC values ranged from 0.89 to 0.95. Results show that the Turkish version of FCQ was validated and it appears to be a reliable research instrument.     

A self-administered questionnaire to measure cigarette withdrawal symptoms: the Cigarette Withdrawal Scale.

Because few tobacco withdrawal scales have been submitted to appropriate validity analyses, we sought to develop and assess the validity of a new, self-administered scale measuring cigarette withdrawal symptoms. We generated the instrument content by conducting a qualitative survey of 404 smokers and ex-smokers. Then we tested 61 items on the Internet in 3,050 smokers and ex-smokers. Subsamples provided comprehensive retest data after 17 days (n = 1218) and smoking status after 41 days (n = 673). The study resulted in a 21-item, six-dimension scale labeled the Cigarette Withdrawal Scale (CWS-21). The six subscales cover the main components of nicotine or tobacco withdrawal in the Diagnostic and Statistical Manual of Mental Disorders and International Statistical Classification of Diseases and Related Health Problems and in qualitative data: Depression-anxiety, craving, irritability-impatience, appetite-weight gain, insomnia, and difficulty concentrating. The six scores had a satisfactory test-retest reliability (r = .60-.71) and a high internal consistency (Cronbach's alpha = .83-.96). The factor structure of the scale was robust in a bootstrap resampling procedure. In ex-smokers, all scores except appetite-weight gain and insomnia predicted relapse at 41-day follow-up. In recent ex-smokers who had quit smoking less than 14 days before baseline, all scores except appetite-weight gain decreased between baseline and the 17-day retest. In baseline ex-smokers who relapsed to smoking at the 17-day retest, appetite-weight gain decreased and craving increased between baseline and retest. CWS-21 is a reliable, valid, multidimensional measure of cigarette withdrawal symptoms that is sensitive to change over time and predicts relapse to smoking.     

Transfer of near infrared spectrometric models for silage crude protein detection between different instruments

This study was undertaken to distinguish different collected spectra from near infrared reflectance spectroscopy (NIRS) for silages using different configurations and types of NIRS, and how well the different techniques for transferring NIRS calibrations perform for silage crude protein detection. In the study, 2 Fourier transform instruments and 1 scanning grating instrument were involved. Five correction and transfer methods were tested and evaluated: slope/bias, local centering, orthogonal signal correction, direct standardization, and piecewise direct standardization. We concluded that the spectra obtained with 3 instruments were different and not solely due to the differences in offset. All of the methods for calibration transferring between 2 Fourier transform instruments and 1 Fourier transform instrument versus 1 scanning grating instrument could improve the predictions, but not all of the results could be accepted. The slope/bias, orthogonal signal correction, and local centering techniques were successful for calibration transferring of 2 Fourier transform instruments, considering their good performance. The best result was given for orthogonal signal correction ahead of the other 4 techniques for transferring calibrations between instruments of Fourier transform and scanning grating, and it was evaluated as moderately useful.     

Waterpipe smoking: construction and validation of the Lebanon Waterpipe Dependence Scale (LWDS-11).

Waterpipe smoking is becoming fashionable in Lebanon, but no studies have studied nicotine dependence related to waterpipe smoking. A score was constructed from 21 items and subsequently submitted to two factor analyses, which led to the extraction of four factors. Reliability and test-retest reproducibility were measured. Convergent construct validity and discriminant validity also were assessed for different smokers' samples. The Lebanon Waterpipe Dependence Scale-11 (LWDS-11) was composed of four subscales, the first representing nicotine dependence, the second negative reinforcement, the third psychological craving, and the fourth positive reinforcement. Internal consistency and test-retest reproducibility were adequate, and the subscales correlated adequately with measurements of nicotine metabolites, exhaled carbon monoxide levels, and the frequency of waterpipe smoking. The LWDS-11 discriminated between mild, moderate, and heavy waterpipe smokers, based on a threshold score of 10. Results were biologically and psychologically sound. This is the first scale to characterize waterpipe dependence. With further improvement and confirmation, it could become a useful clinical and epidemiological tool.     

基于小型西瓜的两种便携式近红外分析仪对比研究

目的 比较两种近红外便携仪器对西瓜品质的无损检测应用, 从而为广大消费者提供一些使用参考依据。方法 以87个小型西瓜京秀样品为样品集, 对市面上现有的K、A两种的常用便携式近红外分析仪从其数据采集方式、数据处理方法、仪器硬件具体性能参数等方面进行了对比分析。结果 仪器K的模型精确度最高、稳定性最好, 仪器A的适用范围广、通用性强且便宜。结论 对于非研究机构的用户而言, A仪器明显优于K仪器。     

Culinary acculturation assessment inventory (CAAI): Construction and validation in first generation immigrant consumers in Turkey

The effect of immigration upon immigrants’ choice of food should be captured not only with dietary intake, but also through assessing culturally-based culinary exposures. This approach would advance dietary acculturation research towards culinary acculturation. For this purpose, Culinary Acculturation Assessment Inventory (CAAI) is developed, using visual items. Validity and reliability of CAAI relating to the Turkish Cuisine were determined in a group of first-generation immigrants. Recommended scale development methods were employed. The initial version, including 40 items across two domains of dietary intake and culinary exposures was administered to 256 participants (162 immigrants from 53 countries, 94 Turkish participants). Exploratory factor analyses were performed to identify dietary and culinary practice patterns. Final version of CAAI included 37 items, comprising five factors in dietary domain as basic, meat-heavy, starch-heavy, and accessory foods patterns (Cronbach’s alpha: 0.834), and one factor in cuisine-related practices domain (Cronbach’s alpha: 0.732). Construct validity was investigated by Multiple Analysis of Covariance (MANCOVA) comparing CAAI factor scores between the immigrant and Turkish participants. Among immigrants, comparisons were made according to acculturation proxies, while accounting for potential covariates. Factor scores that differed significantly between the immigrants and Turkish people (basic and cuisine-related practices patterns) also differed significantly among immigrants with high vs. low fluency in Turkish. In conclusion, CAAI is a reliable and valid measure of culinary acculturation of immigrant population. This novel instrument and its short version can be adapted and used in other countries to capture the culinary acculturation of their immigrants.     

Reliability and validity of a Short Form of the Tobacco Craving Questionnaire.

The Tobacco Craving Questionnaire (TCQ) is a valid and reliable 47-item self-report instrument that assesses tobacco craving in four dimensions: emotionality, expectancy, compulsivity, and purposefulness. For use in research and clinical settings, we constructed a 12-item version of the TCQ by selecting three items from each of the four factors that exhibited optimal within-factor reliability (Cronbach's alpha coefficient) and inter-item correlation. Smokers (N = 196) completed the TCQ-Short Form (TCQ-SF) after overnight tobacco deprivation and on a separate day during ad libitum smoking. Confirmatory factor analyses indicated acceptable model fit for a 4-factor model, with congruence coefficients suggesting high to very high similarity in factor patterns and magnitude of factor loadings between the TCQ and TCQ-SF in both conditions. Scores on each factor were significantly greater after tobacco deprivation than ad libitum smoking, were associated with measures of tobacco withdrawal, and varied with degree of nicotine dependence. Cronbach's alpha coefficients and average inter-item correlations were similar in both conditions and were consistent with reliability values obtained in the initial validation of the TCQ. Test-retest correlation coefficients were also similar to those found in a previous study. These findings suggest that the TCQ-SF is as valid and reliable as the 47-item TCQ in measuring tobacco craving.     

Evaluation of invasive instruments for assessment of veal colour at time of classification

In a random selection of 480 veal carcasses, invasive measurements were made on the longissimus lumborum (LL) and biceps femoris (BF) with the Colormet, Hennessy Grading Probe (HGP4; LL only) and Invasive Meat Colour Meter. Surface colour of the rectus abdominis (RA) was determined instrumentally with the Minolta Chromameter and Surface Meat Colour Meter and visually by two persons, using a colour standard. All measurements were made at 30-40 min post mortem. Of the measurements made on the RA, the Surface Meat Colour Meter was best related to both visual judgements (r = -0·79; -0·73). The correlation coefficient between both visual judgements was 0·77. Clear differences were found between the invasive instruments in their ability to determine veal colour. The correlation coefficients between the invasive measurements and both visual judgements varied for the Colormet L (?)-value from -0·18 to -0·35, for the HGP4 from -0·40 to -0·49, and for the Invasive Meat Colour Meter from -0·69 to -0·74. Both for LL and BF the best relationships were found between the Invasive Meat Colour Meter and the Surface Meat Colour Meter (RA).     

An evaluation of the psychometric properties of the Smoking Self-Efficacy Questionnaire (SEQ-12) among Chinese cardiac patients who smoke

Smoking cessation can reduce both morbidity and mortality among patients who have heart disease. China has the largest number of smokers in the world, and most smokers have low motivation to quit. Regular smoking cessation services are almost nonexistent in China, and little is known about the psychometric properties of instruments in assessing smoking self-efficacy in Chinese, whose cultures differ greatly from those of Westerners. The present study tested the psychometric properties of the Chinese version of the Smoking Self-Efficacy Questionnaire (SEQ-12) among 1,841 Chinese smokers who had heart disease, including (a) factorial structure using confirmatory factor analysis, (b) reliability with Cronbach's alpha, (c) concurrent validity, and (d) predictive validity of successful quitting. Confirmatory factor analysis of the SEQ-12 revealed a modified two-factor model that provided a good fit to the data; item 6 ("urge to smoke") was an indicator for the external stimuli subscale rather than for the internal stimuli subscale. Internal consistency coefficients (.77 for external stimuli and .88 for internal stimuli) were acceptable. Baseline self-efficacy scores were significantly associated positively with stage of readiness to quit, and negatively with cigarettes smoked per day and Fagerstrom Test for Nicotine Dependence (FTND) score. Multivariate logistic regression analysis showed that successful quitting at 1 month and at 3 months were predicted by higher external stimuli score, fewer cigarettes smoked per day, lower FTND scores, and being in the intervention group. We concluded that the Chinese version of the SEQ-12 is a valid and reliable instrument for Chinese cardiac patients who smoke. The SEQ-12 can be used to assess smokers' self-efficacy so that appropriate smoking cessation interventions can be provided.     

微生物数码显微培养计数系统在固体粉末样品检测中的应用

本文研究了微生物数码显微培养计数系统在微生物培养过程中的菌落判定和计数能力。以大肠杆菌、金黄色葡萄球菌、白假丝酵母菌和巴西曲霉四种微生物为测试菌株探讨了传统目测计数方法和仪器计数方法的一致性,并分析了当样品有杂质时对仪器读数的影响。结果显示仪器读数和目视读数具有显著的正相关性(R2=0.85～0.99,p0.05),该仪器在微生物生长过程中能够实现实时监测,当菌落总数超标时能及时起到预警作用,且仪器能显示出培养皿上各点的三维图像,仪器读数结合人工判断,能较好地区分菌落和杂质,接种回收率在105%～155%之间。在实际固体粉末测试样品中应用,结果显示仪器读数和目视读数接近,一致性比例为94%,且仪器读数更为敏感。因此,微生物数码显微培养计数系统可以很好的应用于食品、药品和化妆品中菌落总数的快速准确定量检测。     

Core dimensions of food-related lifestyle: A new instrument for measuring food involvement,innovativeness and responsibility

Segmentation is crucial for targeting product development initiatives and marketing communication nationally as well as internationally. In this paper we use the Food Related Lifestyle instrument that has been applied in the food arena for many years as a ‘stepping stone’ to develop a contemporary, targeted and smaller version of the Food Related Lifestyle instrument, still following the original theoretical framework. In particular we focus on three dimensions that have proven to be of core value in segmentation: food involvement; food innovativeness; and, food responsibility. Based on data collection in six countries (DK, AU, HU, UK, USA and NZ) across two rounds from 2017 to 2019 (total N = 3396), we propose a new core instrument consisting of 15 items that have been tested for cross-cultural validity. Next, we used these three dimensions for segmentation across the six countries by applying multi-level latent class analysis. A solution leading to five different segments could be identified; the foodies, the moderates, the adventurous, the uninvolved and the conservatives. The segments were profiled by means of Schwartz’s ten value domains and measures of self-reported food-related behaviour to check for nomonological validity. We conclude that the 15 items were cross-culturally valid, could be used for segmentation across six countries, and that segment profiling by means of Schwartz values and behavioural items were in line with the theoretical background.     

Collaborative evaluation of near infrared reflectance analysis for the determination of protein,moisture and hardness in wheat

Different methods for the calibration of near infrared reflectance (n.i.r.) instruments for determination of protein, moisture and kernel hardness in wheat by using 11 instruments of the same model series, were collaboratively assessed. The use of the same calibration constants (other than the bias or intercept constant which must be set separately for each instrument) resulted in significantly better reproducibility in the determination of protein in ground wheat than the use of constants determined separately for each instrument. In the case of accuracy against the reference Kjeldahl method the results using universal constants were not significantly different compared with those using constants individually determined by each laboratory for its own instrument. The use of different grinders of the same type resulted in between-grinder biases in some cases but not in worse reproducibility or accuracy than using one grinder. Therefore, using a common calibration and grinder brings the different laboratories' n.i.r. protein results closer to each other but not necessarily closer to Kjeldahl results. In any case, the agreement of the protein results from one instrument to another or between n.i.r. and Kjeldahl should be within about ±0.50% if the instruments are correctly adjusted. Wheat moisture was measured using unground samples and the same constants (other than the bias) for each instrument when the reproducibility was 0.20% and average accuracy against oven drying was 0.39%. Individual calibrations were not attempted. Wheat kernel hardness, classified as ‘hard’ or ‘soft’, was assessed by eight laboratories on 20 samples using different models of grinder and different constants. Six laboratories achieved a near perfect classification with only three errors in all, but the other two had seven errors between them.     

Assessment of nicotine dependence symptoms in adolescents: a comparison of five indicators

OBJECTIVE: To examine the psychometric properties, test-retest reliability, and convergent construct validity of five indicators of nicotine dependence (ND) symptoms in adolescents. DESIGN: Analysis of baseline data from a prospective study on the natural history of ND in 1264 adolescents aged 12-13 years. SETTING: Ten Montreal high schools. SUBJECTS: 233 grade 7 students who had smoked cigarettes one or more times in the three months preceding the baseline data collection. MAIN OUTCOME MEASURES: Five indicators of ND symptoms including two that are multi-dimensional (a proxy measure of ICD-10 criteria for tobacco dependence; the Hooked on Nicotine Checklist (HONC)) and three new indicators of "symptom clusters" that emerged from principal component analysis (ND/cravings, withdrawal symptoms, self medication). RESULTS: All five indicators demonstrated acceptable internal and test-retest reliability. The correlation between the HONC and ND/cravings was 0.910. All other correlations between indicators ranged between 0.716-0.824. There was considerable overlap in the independent correlates identified for each indicator. CONCLUSIONS: All five indicators performed well psychometrically. Until the meaning, relative importance, and usefulness of each scale is clarified in longitudinal work, decisions regarding which scale(s) are most informative will depend more on the content of the scales, the need for a multi- or unidimensional indicator, and whether or not the scale is theory based.     

Development and validation of a short food-frequency questionnaire for screening women of childbearing age for vitamin A status in northwestern Iran

A high percentage of women in their childbearing years suffer from subclinical vitamin A deficiency; 10% to 20% of pregnant women worldwide are vitamin A deficient. This study aimed to design and validate a short food-frequency questionnaire to serve as a simple screening tool for vitamin A status in women of childbearing age. The sample consisted of 187 healthy, nonpregnant, nonlactating women 15 to 49 years of age, from urban and rural areas of Marand district in East Azerbaijan. Dietary intake was evaluated by a face-to-face interview using a 24-hour dietary recall for two consecutive days and a 41-item qualitative food frequency questionnaire. Height, weight, and serum retinol were measured. Serum retinol values were less than 20 micrograms/dl for three subjects, while an additional 34 subjects (18%) had values between 21 and 30 micrograms/dl. Principal-component analysis performed on the food-frequency questionnaire identified five components that together defined 34.4% of the variance in estimated vitamin A intake and were used to derive a 20-item short food-frequency questionnaire. Internal consistency of the short instrument was acceptable (Cronbach's alpha = .59). Serum retinol was significantly correlated with total vitamin A intake and with intake of vitamin A from plant sources, as estimated by the short food-frequency questionnaire. Important sources of provitamin A in these women's diets included some not typical of other populations: nuts and green leaves of types used elsewhere in small quantities as herbs, but important in Iran because the amount and frequency of consumption are relatively high. We conclude that the questionnaire is relatively valid and potentially useful in identifying women at risk for vitamin A deficiency in this population.