Reliability and validity of self-reported male balding patterns for use in epidemiologic studies

PURPOSE: To evaluate the validity and reliability of self-reported male balding patterns in an epidemiologic study. METHODS: Participants were 100 men 50-76 years old who were randomly selected from a cohort study of over 77,000 men and women. To assess hair patterning, men selected from among 3 sets of pictures that best described their hair patterning at age 30, at age 45, and at their current age. The categories were little or no hair loss, frontal baldness, and vertex baldness. The self-reporting was done a second time 3 months later. An interviewer independently assessed each man's current hair patterning using the same classification scheme. RESULTS: Test-retest reliability (kappa) of self-reported hair patterning was 0.74, 0.71, and 0.81 for age 30, age 45, and current age, respectively. The kappa for the comparison of the subject's report of current hair patterning to the interviewer's assessment was 0.47. CONCLUSION: Hair patterning represents a noninvasive biomarker that may be an indicator of increased disease risk. While trained observers may represent the gold standard, our study indicates that men are fairly accurate in self-reporting their balding patterns and are quite reliable in reporting their hair patterning at earlier ages.     

Validity of self reported work history

Many epidemiological studies of the relation between work and disease use information on work history obtained by interview from the study subjects. A validation study was undertaken to evaluate the accuracy of this information collected from 100 workers in a shipbuilding industry. The information furnished by the workers was compared with that present in the company's registers. The work history (job titles and starting dates) was relatively accurate and the validity varied with the number of events to declare and with their duration; it also depended on the type of information and the precision required.     

Validity of self reported work history.

Many epidemiological studies of the relation between work and disease use information on work history obtained by interview from the study subjects. A validation study was undertaken to evaluate the accuracy of this information collected from 100 workers in a shipbuilding industry. The information furnished by the workers was compared with that present in the company's registers. The work history (job titles and starting dates) was relatively accurate and the validity varied with the number of events to declare and with their duration; it also depended on the type of information and the precision required.     

Validity of self reported diagnoses of cancer in a major Spanish prospective cohort study

INTRODUCTION: This study aims to assess the validity of self reported diagnoses of cancer by persons recruited for the Spanish EPIC (European prospective investigation into cancer and nutrition) cohort study and to identify variables associated with correctly reporting a diagnosis of cancer. METHODS: 41 440 members of EPIC were asked at the time of recruitment whether they had been diagnosed with cancer and the year of diagnosis and site. The process of validating self reported diagnoses of cancer included comparison of the cohort database with the data from the population based cancer registries. Cancer diagnostic validity tests were calculated. The association between a correct report and certain sociodemographic, tumour related, or health related variables were analysed by logistic regression. RESULTS: The overall sensitivity of self reported diagnoses of cancer is low (57.5%; 95% CI: 51.9 to 63.0), the highest values being shown by persons with a higher level of education or with a family history of cancer and the lowest values by smokers. Breast and thyroid cancers are those with the highest diagnostic validity and uterus, bladder, and colon-rectum those with the lowest. In both sexes the variables showing a significant association with a correct report of cancer are: higher education level, number of previous pathologies, invasive tumour, and, in women, a history of gynaecological surgery. CONCLUSIONS: The overall sensitivity of self reported diagnoses of cancer is comparatively low and it is not recommended in epidemiological studies for identifying tumours. However, self reported diagnoses might be highly valid for certain tumour sites, malignant behaviour, and average to high levels of education.     

Validity of self reported occupational exposures to hand transmitted and whole body vibration

OBJECTIVES—To assess the accuracy with which workers report their exposure to occupational sources of hand transmitted (HTV) and whole body vibration (WBV).
METHODS—179 Workers from various jobs involving exposure to HTV or WBV completed a self administered questionnaire about sources of occupational exposure to vibration in the past week. They were then observed at work over 1 hour, after which they completed a second questionnaire concerning their exposures during this observation period. The feasibility of reported sources of exposure during the past week was examined by questioning managers and by inspection of tools and machines in the workplace. The accuracy of reported sources and durations of exposure in the 1 hour period were assessed relative to what had been observed.
RESULTS—The feasibility of exposure in the previous week was confirmed for 97% of subjects who reported exposure to HTV, and for 93% of subjects who reported exposure to WBV. The individual sources of exposure reported were generally plausible, but occupational use of cars was substantially overreported, possibly because of confusion with their use in travel to and from work. The accuracy of exposures reported during the observation period was generally high, but some sources of HTV were confused—for example, nailing and stapling guns reported as riveting hammers, and hammer drills not distinguished from other sorts of drill. Workers overestimated their duration of exposure to HTV by a median factor of 2.5 (interquartile range (IQR) 1.6-5.9), but estimated durations of exposure were more accurate when the exposure was relatively continuous rather than for intermittent short periods. Reported durations of exposure to WBV were generally accurate (median ratio of reported to observed time 1.1, IQR 1.0-1.2).
CONCLUSIONS—Sources of recent occupational exposure to vibration seem to be reported with reasonable accuracy, but durations of exposure to HTV are systematically overestimated, particularly when the exposure is intermittent and for short periods. This raises the possibility that dose-response relations may have been biased in some of the studies on which exposure standards might be based, and that the levels in currently proposed standards may be too high. Future studies should pay attention to this source of error during data collection.


Keywords: vibration; exposure; assessment; validity     

Validity of self reported utilisation of primary health care services in an urban population in Spain

STUDY OBJECTIVE: To assess the validity and factors related with the validity of self reported numbers of visits to a primary health care centre, in comparison with the recorded number. DESIGN: Cross sectional study. SETTING: The urban area served by the Zaidín-Sur Primary Health Care Centre (Granada, Spain). PARTICIPANTS: Two population samples (236 high users and 420 normal users) who were seen at the centre from 1985 to 1991 were interviewed in 1993. MAIN RESULTS: A net tendency to overreport the actual number of visits was observed. Absolute concordance between self reported and recorded utilisation decreased as time interval lengthened, although this mainly reflected the increase in maximum variability both with time interval length and with the number of recorded visits. Corrected Spearman rho coefficients obtained between the number of self reported and recorded visits ranged from 0.602 for the two weeks before the interview to 0.678 for the year before. Regression slopes of self reported utilisation upon recorded utilisation did not change between periods. In multiple regression analyses the actual number of visits was the main factor associated with both underreporting and overreporting. Older age was also significantly associated with underreporting. Poor health status and high satisfaction with health care were significantly associated with overreporting. CONCLUSIONS: There was a substantial degree of inaccuracy in self reported utilisation, with a net tendency to overreport the number of visits. In relative terms, however, accuracy of self reports did not seem to decrease appreciably as the recall time lengthened. To compare the accuracy of different measures, it is important to take into account the maximum variability of each one. Otherwise, contradictory results may be obtained.     

Dietary patterns using Traditional Chinese Medicine principles in epidemiological studies

Dietary intake and nutritional factors have been shown to be associated with many chronic diseases, such as heart disease, obesity, diabetes, and cancer. There are many approaches to studying dietary intake in relationship to disease; each approach has its strengths and weaknesses. Examples of different methods of studying dietary patterns will be reviewed. In most cultures, consumed and preferred foods are based on cultural and societal influence. Thus, it is important to consider dietary patterns within the context of culture in addition to the standard nutrients or food groupings approach. Traditional Chinese Medicine (TCM) offers another dimension to food analysis. Our approach classifies dietary intake based on Traditional Chinese Medicine principles of yin and yang, hot and cold, and acidic and alkaline forming food concepts in a case-control study of dietary factors and breast cancer. Our results complement previously reported findings of an increased risk of breast cancer associated with dietary fats in Taiwanese women. Our discussion will focus on the implication of using this dietary pattern research and the challenge of combining this research with culturally sensitive messages to improve health. Our ultimate goal is to design an intervention strategy for disease prevention and health promotion that is culturally appropriate for specific populations.     

Validity of biological tests in epidemiological toxicology

Summary The authors emphasize the need to introduce the concept of validity (sensitivity and specificity) of biological test methods in epidemiological toxicology (occupational and public health). Up till now too often relevant information is lost, because the frequency distribution of individual data is not taken into account. The method of calculating parameters of validity is demonstrated. These parameters add relevant information for determining the feasibility of test methods; they provide valuable information not presented by classical statistical treatment of data. Several examples have been worked out to elucidate the approach.Professor in public health, particularly in regard to occupational medicine and environmental health, Faculty of Medicine, University of Amsterdam.Research worker Coronel Laboratory.     

Occurrence of self reported hand eczema in Swedish bakers

OBJECTIVES: To estimate the risk of bakers developing hand eczema. The importance of atopy was studied as well as change of job due to hand eczema. METHODS: A retrospective cohort study was performed among bakers trained in Swedish trade schools in 1961-89 (n = 2923). School referents followed other programmes (n = 1258); population controls were randomly selected from the general population (n = 1258). A questionnaire on self reported hand eczema, year of onset of hand eczema, change of work due to hand eczema, childhood eczema, family atopy, and work history was posted to all participants. RESULTS: The incidence of hand eczema among male controls was 4.4-5.4 cases/1,000 person-years compared with 16.7 for bakery work. The corresponding figures for women were 11.3-14.1 compared with 34.4. The relative risk for male bakers was 3.5 (95% confidence interval (95% CI) 2.8 to 4.5) and for female bakers 2.8 (2.2 to 3.6). Skin atopy increased the incidence about threefold and a synergistic effect of atopy and exposure was indicated. Also, bakers had changed job significantly more often than controls. CONCLUSIONS: Swedish bakers, mainly working during the 1970s and 1980s, have about a threefold increased risk of hand eczema. There seems to be a synergistic effect of atopy and occupational exposure.

 

     

International variation in socioeconomic inequalities in self reported health.

STUDY OBJECTIVE--To assess the extent to which the size of socioeconomic inequalities in self reported health varies among industrialised countries. DESIGN--Cross sectional data on the association between educational level and several health indicators were obtained from national health interview surveys. This association was quantified by means of an inequality index based on logistic regression analysis. SETTING--The national, non-institutionalised populations of the United Kingdom, Sweden, Denmark, Germany, The Netherlands, Italy, the United States, and Canada were studied. The age group was 15-64 years, and the study period was 1983-90. PARTICIPANTS--Representative population samples with the number of respondents ranging from approximately 6000 (Denmark) to 90,000 (the United States) were studied. MAIN RESULTS--For men, the smallest health inequalities were observed for the United Kingdom and Sweden, and the largest inequalities for Italy and the United States. Other countries held an intermediate position. The same international pattern was observed for women, except that relatively small inequalities were also observed for Dutch women. CONCLUSIONS--The results agree to a large extent with those of previous comparative studies. The international pattern observed here may be partly related to "subjective" aspects of self reported health, such as the propensity to complain and illness behaviour. The results challenge the view that disease and disability are distributed less equally in the UK than in countries like Sweden.     

Validity of reported energy intake in obese and nonobese adolescents

Daily metabolizable energy intake (ME) and total daily energy expenditure (TEE) were measured in 28 nonobese and 27 obese adolescents over a 2-wk period. Reported ME was significantly (p less than 0.001) lower than measured TEE in both the nonobese and the obese groups (2193 +/- 618 vs 2755 +/- 600 kcal/d and 1935 +/- 722 vs 3390 +/- 612 kcal/d, respectively). Reported ME as a percentage of TEE was significantly lower in the obese than the nonobese group (58.7 +/- 23.6% vs 80.6 +/- 18.7%, respectively). When reported ME was adjusted to account for changes in body energy stores, reported ME still remained significantly lower than TEE in both groups. ME was highly reproducible over the 2-wk period. Intraclass correlation coefficients among days for subjects with complete 14-d diaries were 0.87 and 0.89 for nonobese and obese groups, respectively. In both groups, interindividual variability in ME was significantly greater than intraindividual variability. Our data suggest that reported ME in nonobese and obese adolescents is not representative of TEE or energy requirements.     

Measurement of self reported active exposure to cigarette smoke

STUDY OBJECTIVE—The number of cigarettes smoked per day is an imprecise indicator of exposure to cigarette smoke, and biochemical assessment of exposure is not always feasible. The aim of this study was to develop more accurate measures of self reported active exposure to cigarette smoke.
DESIGN—Mail survey in 386 smokers, retest at one month in 94 participants (24%), analysis of saliva cotinine in 98 participants (25%), collection of empty cigarette packs in 214 participants (55%), collection of cigarette butts in 107 participants (28%). Ten questions and items intended to assess active exposure to cigarette smoke were tested and compared with saliva cotinine, the Fagerström test for nicotine dependence, and self rated dependence.
SETTING—A population sample in Geneva, Switzerland, in 1999.
PARTICIPANTS—323 daily smokers and 63 occasional smokers.
MAIN RESULTS—Measures that were associated with saliva cotinine included the number of cigarettes smoked per day (r²=0.36), smoking intensity (r²=0.40), the type of cigarettes smoked (regular versus light) (r²=0.04), smoking when ill (r²=0.15) and a single item rating of the total quantity of smoke inhaled (r²=0.27). A multivariate model combining the first four items explained the largest proportion of the variance in cotinine (r²=0.63), substantially more than was explained by the number of cigarettes per day alone, by 75% in all smokers and by 110% in daily smokers.
CONCLUSIONS—The study identified measures of exposure to smoke that reflect saliva cotinine better than the number of cigarettes per day. These measures can be used in studies of the dose related risk of smoking and in smoking reduction studies.


     

Exposure-response relations for self reported asthma and rhinitis in bakers

OBJECTIVES—To explore relations between two estimates of exposure to inhalable flour dust, and the incidence rates (IRs) of asthma and rhinitis in bakers.
METHODS—This was a retrospective cohort study among 2923 bakers. A posted questionnaire registered the disease and work history. For every year, each baker was assigned an estimate of the exposure concentration to inhalable flour dust derived from reported job-tasks and dust measurements. Exposure at onset of disease was expressed as current dust exposure concentration, and as cumulative dose of exposure to dust. A multiple Poisson regression analysis assessed the impacts of the exposure estimates on the IRs of asthma and rhinitis.
RESULTS—IRs of asthma and rhinitis increased by dust concentration at onset of disease. The IR of asthma for the bakers with highest exposure (dough makers) was 7.3/1000 person-years in men and 6.5 in women and for rhinitis 43.4 and 38.5, respectively. There was a significant association between the dust concentration at onset of disease and the risk for asthma or rhinitis, but not of the cumulative exposure.
CONCLUSION—The risk of asthma seemed to be increased at inhalable dust concentrations 3 mg/m³ (dough making or bread forming), whereas the risk of rhinitis was increased at all concentrations 1 mg/m³, indicating an increased risk in all bakery job-tasks. The risks seemed to be less dependent on the cumulative exposure dust than the inhalable dust concentrations.


Keywords: bakers; exposure-response relations; flour dust     

Validity of self–reported hysterectomy and tubal sterilisation

Abstract: Both hysterectomy and tubal sterilisation offer significant protection from ovarian cancer, and the risk of cardiovascular disease in women is lowered after hysterectomy. Since little is known about the accuracy of women's self–reports of these procedures, we assessed their reliability and validity using data obtained in a case–control study of ovarian cancer. There was 100 per cent repeatability for both positive and negative histories of hysterectomy and tubal sterilisation among a small sample of women on reinterview. Verification of surgery was sought against surgeons' or medical records, or if these were unavailable, from randomly selected current general practitioners for 51 cases and 155 controls reporting a hysterectomy and 73 cases and 137 controls reporting a tubal sterilisation. Validation rate for self–reported hysterectomy against medical reports (32 cases, 96 controls) was 96 per cent (95 per cent confidence interval (CI) 91 to 99) and for tubal sterilisation (32 cases, 77 controls) it was 88 per cent (CI 81 to 93), which is likely to be an underestimate. Although findings are based on small numbers of women for whom medical reports could be ascertained, they are consistent with other findings that suggest women have good recall of past histories of hysterectomy and tubal sterilisation; this allows long–term effects of these procedures to be studied with reasonable accuracy from self–reports.     

Prevalence of self reported stroke in a population in northern England.

STUDY OBJECTIVE: The aim of this study was to determine the prevalence of stroke survivors in a health district population aged 55 years and over. DESIGN: This was a point prevalence study using two-stage postal questionnaires sent to an age stratified random sample of the population. SETTING: A district health authority in northern England with a resident population of 723,000. SUBJECTS: Altogether 18,827 residents aged 55 years or over. MAIN RESULTS: Prevalence was found to increase with age and, apart from the very elderly, males had a higher prevalence than females. Overall prevalence was found to be 46.8/1,000 (95% CI 42.5, 51.6). 23% of respondents reported full recovery from stroke. Cognitive impairments (33%), problems with lower limbs (33% for right leg; 27% for left leg) and speech difficulties (27%) were the most common residual impairments. CONCLUSIONS: Current guidelines to purchasers on the provision of services to those who have had a stroke may under-estimate prevalence rates by as much as 50%. This could lead to a shortfall in provision of services designed to support people in the months and years following their stroke.     

流行病学研究中的样本代表性问题(一)

研究的样本代表性一直是流行病学领域内具有争议性的话题之一。本文首先对流行病学样本代表性进行定义,同时对研究人群、源人群、目标人群、内部真实性、外部真实性等相关流行病学基本概念进行阐述。在此基础上,本文深入分析了横断面研究、队列研究、病例对照研究、干预性研究四种主要流行病学研究设计中样本代表性的价值和实际可行性。总而言之,除针对人群疾病或健康现状的横断面研究外,多数涉及病因或干预效果推断的流行病学研究不应过度强调样本代表性。     

Publication bias in epidemiological studies

Communication of research findings is the utmost responsibility of all scientists. Publication bias occurs if scientific studies with negative or null results fail to get published. This can happen due to bias in submitting, reviewing, accepting, publishing or aggregating scientific literature that fails to show positive results on a particular topic. Publication bias can make scientific literature unrepresentative of the actual research studies. This can give the reader a false impression about the beneficial effects of a particular treatment or intervention and can influence clinical decision making. Publication bias is more common than it is actually considered to be, but there are ways to detect and prevent it. This paper comments on the occurrence, types and consequences of publication bias and the strategies employed to detect and control it.