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To date, Web-based 24-hour recalls have not been validated using objective biomarkers. From 2006 to 2009, the validity of 6 Web-based DietDay 24-hour recalls was tested among 115 black and 118 white healthy adults from Los Angeles, California, by using the doubly labeled water method, and the results were compared with the results of the Diet History Questionnaire, a food frequency questionnaire developed by the National Cancer Institute. The authors performed repeated measurements in a subset of 53 subjects approximately 6 months later to estimate the stability of the doubly labeled water measurement. The attenuation factors for the DietDay recall were 0.30 for blacks and 0.26 for whites. For the Diet History Questionnaire, the attenuation factors were 0.15 and 0.17 for blacks and whites, respectively. Adjusted correlations between true energy intake and the recalls were 0.50 and 0.47 for blacks and whites, respectively, for the DietDay recall. For the Diet History Questionnaire, they were 0.34 and 0.36 for blacks and whites, respectively. The rate of underreporting of more than 30% of calories was lower with the recalls than with the questionnaire (25% and 41% vs. 34% and 52% for blacks and whites, respectively). These findings suggest that Web-based DietDay dietary recalls offer an inexpensive and widely accessible dietary assessment alternative, the validity of which is equally strong among black and white adults. The validity of the Web-administered recall was superior to that of the paper food frequency questionnaire. [ABSTRACT FROM PUBLISHER]

The purpose of this study was to examine relative validity of a food frequency questionnaire (FFQ) to measure food acculturation in young Mexican-origin children. In 2006, Spanish-speaking staff interviewed mothers in a community-based sample of households from Ventura, California (US) (n = 95) and Guanajuato, Mexico (MX) (n = 200). Data included two 24-h dietary recalls (24-DR); a 30-item FFQ; and anthropometry of the children. To measure construct, convergent, and discriminant validity, data analyses included factor analysis, Spearman correlations, t-test, respectively. Factor analysis revealed two constructs: 1) a US food pattern including hamburgers, pizza, hot dogs, fried chicken, juice, cereal, pastries, lower fat milk, quesadillas, and American cheese and 2) a MX food pattern including tortillas, fried beans, rice/noodles, whole milk, and pan dulce (sweet bread). Out of 22 food items that could be compared across the FFQ and mean 24-DRs, 17 were significantly, though weakly, correlated (highest r = 0.62, for whole milk). The mean US food pattern score was significantly higher, and the MX food pattern score, lower in US children than in MX children (p < 0.0001). After adjusting for child's age and gender; mother's education; and household size, the US food pattern score was positively related to body mass index (BMI) z-scores (beta coefficient: +0.29, p = - 0.004), whereas the MX food pattern score was negatively related to BMI z-scores (beta coefficient: -0.28, p = 0.002). This tool may be useful to evaluate nutrition education interventions to prevent childhood obesity on both sides of the border., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Objectives: We assessed whether an anti-tobacco television advertisement called "Stages," which depicted a woman giving a brief emotional narrative of her experiences with tobacco use, would be recalled more often and have a greater effect on smoking cessation than 3 other advertisements with different intended themes., Methods: Our data were derived from a sample of 2596 California adult smokers. We used multivariable log-binomial and modified Poisson regression models to calculate respondents' probability of quitting as a result of advertisement recall., Results: More respondents recalled the "Stages" ad (58.5%) than the 3 other ads (23.1%, 23.4%, and 25.6%; P<.001). Respondents who recalled "Stages" at baseline had a higher probability than those who did not recall the ad of making a quit attempt between baseline and follow-up (adjusted risk ratio [RR]=1.18; 95% confidence interval [CI]=1.03, 1.34) and a higher probability of being in a period of smoking abstinence for at least a month at follow-up (adjusted RR=1.55; 95% CI=1.02, 2.37)., Conclusions: Anti-tobacco television advertisements that depict visceral and personal messages may be recalled by a larger percentage of smokers and may have a greater impact on smoking cessation than other types of advertisements.

Purpose: Because of the automated nature of knowledge, experts tend to omit information when describing a task. A potential solution is cognitive task analysis (CTA). The authors investigated the percentage of knowledge experts omitted when teaching a cricothyrotomy to determine the percentage of additional knowledge gained during a CTA interview., Method: Three experts were videotaped teaching a cricothyrotomy in 2010 at the University of Southern California. After transcription, they participated in CTA interviews for the same procedure. Three additional surgeons were recruited to perform a CTA for the procedure, and a "gold standard" task list was created. Transcriptions from the teaching sessions were compared with the task list to identify omitted steps (both "what" and "how" to do). Transcripts from the CTA interviews were compared against the task list to determine the percentage of knowledge articulated by each expert during the initial "free recall" (unprompted) phase of the CTA interview versus the amount of knowledge gained by using CTA elicitation techniques (prompted)., Results: Experts omitted an average of 71% (10/14) of clinical knowledge steps, 51% (14/27) of action steps, and 73% (3.6/5) of decision steps. For action steps, experts described "how to do it" only 13% (3.6/27) of the time. The average number of steps that were described increased from 44% (20/46) when unprompted to 66% (31/46) when prompted., Conclusions: This study supports previous research that experts unintentionally omit knowledge when describing a procedure. CTA is a useful method to extract automated knowledge and augment expert knowledge recall during teaching.

Background: Currently, no simplified approach to estimating food costs exists for a large, nationally representative sample., Objective: The objective was to compare 2 approaches for estimating individual daily diet costs in a population of low-income women in California., Design: Cost estimates based on time-intensive method 1 (three 24-h recalls and associated food prices on receipts) were compared with estimates made by using less intensive method 2 [a food-frequency questionnaire (FFQ) and store prices]. Low-income participants (n = 121) of USDA nutrition programs were recruited. Mean daily diet costs, both unadjusted and adjusted for energy, were compared by using Pearson correlation coefficients and the Bland-Altman 95% limits of agreement between methods., Results: Energy and nutrient intakes derived by the 2 methods were comparable; where differences occurred, the FFQ (method 2) provided higher nutrient values than did the 24-h recall (method 1). The crude daily diet cost was $6.32 by the 24-h recall method and $5.93 by the FFQ method (P = 0.221). The energy-adjusted diet cost was $6.65 by the 24-h recall method and $5.98 by the FFQ method (P < 0.001)., Conclusions: Although the agreement between methods was weaker than expected, both approaches may be useful. Additional research is needed to further refine a large national survey approach (method 2) to estimate daily dietary costs with the use of this minimal time-intensive method for the participant and moderate time-intensive method for the researcher.

Background: Published literature on assessing the functional health literacy (FHL) level of patients in pharmacy practice is lacking., Objectives: To assess FHL in an outpatient pharmacy setting and the associations between FHL and patient recall of medications., Methods: In a cross-sectional study of 79 English-speaking adults recruited from 3 outpatient pharmacies, patients were given the Short Test of Functional Health Literacy in Adults and asked to recall their medication names, dosages, frequencies, and indications. Patients' responses were compared with pharmacy records (medication name, dosage, frequency) and Facts and Comparisons (indication)., Results: Of the 79 patients, 27 had inadequate FHL. Correct medication names were recalled less frequently by patients with inadequate FHL compared with patients with adequate FHL (60% vs 84%, P<.001). Similarly, correct dosages (71% vs 83%, P=.03) and frequencies (62% vs 85%, P<.001) were reported less often by patients with inadequate FHL. There was no significant difference in the frequency of correct indications for medications between the 2 groups., Conclusions: Inadequate FHL is associated with poor recall of correct medication name, dosage, and administering frequency. Future research to evaluate the effect of pharmacists on improving patients' recall of medication name, dosage, and frequency is warranted., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Time-activity data are traditionally collected by telephone interviews or through paper diaries, which are time consuming and costly. As a potential alternative that may greatly save staff time, a web survey to collect time-activity data was developed and tested in this study. We collected 24-h recall web diaries from 151 parents of young children mostly under 55 years of age (who also answered for their children) and 55 older adults (≥ 55 years of age) both on a weekday and a weekend day every 3 months during an 18-month period. The performance and reliability of the web surveys collected were evaluated, including the survey-completion rate, and the percentage of surveys with unreasonable time being reported as spent sleeping and with missing reports of being in transit between locations. We also compared the web-survey data with time-activity information we collected from the same subjects in telephone interviews and found that these data sources were fairly consistent with each other. However, we observed slightly more compliance issues for the web than the telephone survey, but most of these issues could be addressed and minimized by refining some questions or the survey interface. Our study suggests that it is critical to reduce participants' burden and improve survey interface design for optimal compliance and data quality. In conclusion, web surveys are a promising method to consider for time-activity data collection.

Purpose: Physical activity (PA) diaries reduce the recall error inherent in self-reported PA but are burdensome. The purpose of this study was to compare a cell phone-based diary with a paper diary and examine the reliability and validity of the cell phone diary., Methods: In a pilot study, 25 women and 23 men, age 45-65 yr, completed cell phone and paper PA diaries 4 d·wk(-1) for three consecutive weeks and a user satisfaction survey. In the subsequent validation study, 623 middle-age participants (52.5% women) were asked to complete the cell phone diary and wear an accelerometer for two 7-d periods, approximately 6 months apart. They also completed two PA questionnaires. Fitness, body mass index, and percent body fat were obtained as indirect validation criteria., Results: Estimates of PA from the cell phone and paper diaries were similar (mean within person difference = -43.8 MET·min·d(-1) of total PA, SD = 360, P = 0.49, 7.4 min·d(-1) of moderate-vigorous PA, SD = 66, P = 0.53). Users preferred the cell phone diary over the paper diary (59.6% vs 35.4%). In the subsequent study, intraclass correlations for the cell phone diary ranged from 0.55 for light PA to 0.63 for vigorous PA. Although PA estimates from the cell phone diary were generally significantly higher than those from the accelerometer and the questionnaires, correlations for moderate and vigorous PA were moderate (ρ = 0.25-0.59 with the questionnaires and 0.27-0.35 with the accelerometer). The correlations between the cell phone diary and the indirect validation criteria were generally in the expected direction and of moderate magnitude., Conclusions: A cell phone-based PA diary is equivalent to a paper diary, acceptable to users, and a relatively reliable and valid approach to self-reported PA.

In October 2007, wildfires burned nearly 300,000 acres in San Diego County, California. Emergency risk communication messages were broadcast to reduce community exposure to air pollution caused by the fires. The objective of this investigation was to determine residents' exposure to, understanding of, and compliance with these messages. From March to June 2008, the authors surveyed San Diego County residents using a 40-question instrument and random digit dialing. The 1,802 respondents sampled were predominantly 35-64 years old (65.9%), White (65.5%), and educated past high school (79.0%). Most (82.5%) lived more than 1 mile away from the fires, although many were exposed to smoky air for 5-7 days (60.7%) inside and outside their homes. Most persons surveyed reported hearing fire-related health messages (87.9%) and nearly all (97.9%) understood the messages they heard. Respondents complied with most to all of the nontechnical health messages, including staying inside the home (58.7%), avoiding outdoor exercise (88.4%), keeping windows and doors closed (75.8%), and wetting ash before cleanup (75.6%). In contrast, few (<5%) recalled hearing technical messages to place air conditioners on recirculate, use High-Efficiency Particulate Air filters, or use N-95 respirators during ash cleanup, and less than 10% of all respondents followed these specific recommendations. The authors found that nontechnical message recall, understanding, and compliance were high during the wildfires, and reported recall and compliance with technical messages were much lower. Future disaster health communication should further explore barriers to recall and compliance with technical recommendations.

Objective: To assess convergent validity, factorial validity, test-retest reliability and internal consistency of a diet quality food behaviour checklist (FBC) for low-literate, low-income Spanish speakers., Design: Participants (n 90) completed three dietary recalls, the Spanish-language version of the US Department of Agriculture (USDA) Household Food Security Survey Module (HFSSM) and the Spanish-language FBC. Factor structure was examined using principal component analysis. Spearman correlation coefficients between FBC item responses and nutrient intakes from 24 h recalls were used to estimate convergent validity. Correlation coefficients were also calculated between FBC item responses at two time points in another group of participants (n 71) to examine test-retest reliability. Cronbach's α coefficient was determined for items within each sub-scale., Setting: Non-profit community agencies serving low-income clients, migrant farm worker camps and low-income housing sites in four California counties., Subjects: Spanish-speaking women (n 161) who met income eligibility for the SNAP-Ed (Supplemental Nutrition Assistance Program-Education)., Results: Factor analysis resulted in six sub-scales. Responses to nineteen food behaviour items were significantly correlated with hypothesized 24 h recall data (with a maximum correlation of 0·44 for drinking milk and calcium) or the USDA HFSSM (0·42 with the food security item). Coefficients for test-retest reliability ranged from 0·35 to 0·79. Cronbach's α ranged from 0·49 for the diet quality sub-scale to 0·80 for the fruit and vegetable sub-scale., Conclusions: The twenty-two-item FBC and instruction guide will be used to evaluate USDA community nutrition education interventions with low-literate Spanish speakers. This research contributes to the body of knowledge about this at-risk population in California.

This study tested the hypothesis that latent list and text recall invoke somewhat different processes. A bivariate outcome path model of latent list and text recall evaluated the effects of age, latent speed, working memory, and vocabulary as their predictors. Independent of age, working memory reliably predicted both recall variables, whereas speed reliably predicted list recall only. The relationship between vocabulary and recall was mediated by age, working memory, and speed. The generalizability of this model, based on data from the 1994 testing of the Long Beach Longitudinal Study, was evaluated across samples by testing its invariance on baseline data from an additional panel and for eventual attrition at baseline and at a subsequent testing of retested participants and dropouts. Results showed that the model was invariant over all groups, supporting a replicable distinction between list and text recall.

We tested the hypothesis that ruminating about a previous aggressive prime interacts with a subsequent minor frustration to augment aggression. Sixty participants watched a video showing a murder during a bank robbery (the aggressive prime). Those in the rumination condition were asked to write about the video for 20 min. In the no rumination condition, participants were given 20 min to complete an irrelevant task. Participants were then either frustrated or not frustrated. Our results supported the main hypothesis. Relative to the control condition, neither rumination nor frustration alone impacted aggression. Rumination, in combination with a minor frustration, however, increased the recommended prison sentence towards the targets. We discuss the implications of our findings., (2007 Wiley-Liss, Inc.)

Objectives: To investigate the effect of metabolic syndrome on cognitive function in an elderly Latino population and to determine whether inflammation modifies this association., Design: A longitudinal cohort study., Setting: Sacramento area and the surrounding California counties from 1998 to 1999., Participants: One thousand six hundred twenty-four Latinos aged 60 and older who participated in the Sacramento Area Latino Study of Aging., Measurements: Baseline metabolic syndrome was calculated using the Third Adult Treatment Panel of the National Cholesterol Education Program. Cognitive function was measured using the Modified Mini-Mental State Examination (3MS) and the Delayed Word-List Recall (DelRec), a verbal memory test. The effect of metabolic syndrome on cognitive change scores was examined using random effects models; in addition, the effect of the individual components of the syndrome on cognitive change was examined., Results: Of the 1,624 participants, 718 (44%) had metabolic syndrome at baseline. Those with metabolic syndrome had worse 3-year change scores on 3MS (P=.04) and DelRec (P=.03). Multivariate adjustment attenuated the results for DelRec but not for 3MS. This association was especially pronounced in participants with a high serum level of inflammation, resulting in an average 3MS score 0.64 points lower per year (P=.03) for those with metabolic syndrome. Individual components of metabolic syndrome were not associated with cognitive decline except for elevated glucose on the DelRec (P=.02) and high blood pressure on 3MS (P=.05)., Conclusion: Metabolic syndrome and inflammation may both contribute to cognitive decline in older people of diverse backgrounds. The results also suggest that, in elderly Latinos, the composite measure of metabolic syndrome is a greater risk for cognitive decline than its individual components.

Objective: To investigate the psychometric properties of the physical activity (PA) measure of the Women's Health Initiative (WHI)., Methods: Women diagnosed with breast cancer and enrolled in the Women's Healthy Eating and Living Study (average age 55 years) wore an accelerometer for 1 week and completed the 7-day Physical Activity Recall (PAR) and brief WHI measure., Results: Both self-reports correlated 0.73 with the accelerometer and had 100% sensitivity for meeting the current PA guideline, but specificity was significantly higher for the PAR., Conclusions: The WHI measure had comparable validity, sensitivity, and measurement bias compared to the widely accepted PAR.

Objective: The objective of this study was to compare patient recall of menopausal hormone therapy, obtained by personal interview, with that recorded in physicians' records., Design: Data were from a case-control study of women aged 55 to 64 years at diagnosis of breast cancer in Los Angeles County, CA, between 1987 and 1989. Medical record information on 1,115 women reporting hormone therapy use (652 case patients and 463 control participants) was sought from 2,734 physicians and obtained from 1,350. Physician records for an additional 126 case patients and 90 control participants not reporting hormone therapy but reporting oral contraceptive use or benign breast disease were also obtained., Results: Agreement between interview and physician records was 85% (kappa=0.59) for ever/never use of estrogen and 84% (kappa=0.59) for progestogen. The correlations for months of use were 0.43 and 0.34, respectively. For both drugs participants tended to report longer use, primarily because they reported earlier starting ages. Older and unmarried women recalled more unconfirmed estrogen use, whereas naturally menopausal women were more likely to report no estrogen use when the medical record was positive. We found no evidence of preferential recall bias by case patients., Conclusions: Interviews provide a moderately reliable measure for ever use of postmenopausal estrogen and progestogen. Recalled details are less reliable and may be affected by age, type of menopause, and recall interval.

Self-reported perinatal exposures to chemicals or pollutant sources in case-control studies of birth defects may be inaccurate due to misreporting among mothers. In a case-control study of neural tube defects delivered in California in 1987-1988, mothers of case and control infants were asked whether they lived within 0.25 mile (400 m) of agricultural crops. Responses were compared against a gold standard derived from historical agricultural land-use survey maps. The odds ratio for self-reported proximity to any crops (1.62, 95% confidence interval: 1.08, 2.43) appeared to be positively biased compared with the estimate for map-based proximity (1.17, 95% confidence interval: 0.79, 1.71). This pattern was also observed for proximity to specific crops such as nonpermanent and orchard crops. For vineyards, however, we observed an increased risk associated with map-based proximity (odds ratio=2.45, 95% confidence interval: 1.08, 5.58) but not with self-reported proximity (1.09, 95% confidence interval: 0.51, 2.34). The sensitivity of self-reported proximity to any crops was greater for case (65.7%) than control mothers (50.0%) while specificity was about the same for case and control mothers (87.5 vs. 89.3%), suggesting that control mothers under-reported proximity to crops. Differential reporting was also observed between geographic regions, urban and rural residents, and across levels of maternal employment and education. These results suggest differential reporting between case and control mothers as well as an influence from maternal demographic characteristics on reporting accuracy.

Objective: To examine the influence of meal decision-making and preparation on Hispanic women's dietary practices., Design: One-on-one structured interviews were conducted, assessing meal decision-making and preparation practices, barriers, and behavioral strategies to eating low-fat and high-fiber diets, fat and fiber intake, demographic, and other psychosocial factors., Subjects/setting: The study population included 357 Hispanic women living in the southern or central regions of San Diego County. Participants were recruited via random-digit dialing to a tailored nutrition communication intervention., Main Outcome Measure: Household decision-making style (alone vs with family) by household activity (decides meals, prepares meals, and decides snacks)., Statistical Analyses Performed: Multiple logistic regressions were used to evaluate associations between the predictors and dependent variable. All models included adjustments for potential confounders, such as marital status, education, employment, age, and acculturation., Results: A positive statistical association between Hispanic women's acculturation level and shared decision-making style was found. Also, Hispanic women in shared decision-making households faced greater psychosocial barriers to healthful eating and reported less healthful eating compared with Hispanic women in traditional households. Women in shared decision-making households were more likely to eat at fast-food restaurants, less likely to engage in behavioral strategies promoting fiber consumption, eat more saturated fat, and encounter more barriers to reduce dietary fat as compared with Hispanic women in traditional households. Acculturation did not attenuate differences in psychosocial and dietary practices between shared decision-making and traditional households., Conclusions: Study findings suggest intervention efforts should focus on different aspects of healthful eating among Hispanic women in shared-decision, compared with traditional, households.

Are expert witnesses needed in child sexual abuse cases to educate jurors about children's memory, suggestibility, and reactions to abuse, or do jurors already know what such experts could tell them? To cast light on this question, we surveyed jurors and jury-eligible college students and compared their beliefs with what is known via scientific research regarding children's memory and ability to testify, reactions to interrogation, and reactions to sexual abuse. We also asked participants to infer results of four widely cited studies of children's suggestibility. Participants' beliefs were consistent with findings from research on some issues (e.g., that children can be led to claim that false events occurred) but diverged from the scientific consensus on other issues (e.g., whether children can remember painful events in infancy). Similarly, participants sometimes overestimated and sometimes underestimated the level of suggestibility observed in empirical studies. Individual differences in accuracy were related to participants' gender, education and ethnicity, and there was considerable disagreement among participants on many questions. Implications of findings for the admissibility of expert testimony in child abuse cases are discussed.

This study examined which kinds of self-defining memories show spontaneous references to larger meanings, and listener responses to two kinds of meaning-lessons and insights. Narratives of three self-defining memories and episodes of telling the memories to others were collected from each of 168 late adolescents (M age=19). Narratives were coded for event type (relationship, mortality, achievement, and leisure) and for references to tension and to meaning (lesson or insight). Narratives of memorable episodes of having told the memories to others were coded for listener response (positive or negative). References to meaning emerged in one-fourth of the memory narratives, and meaning was more common for self-defining memory narratives that contained references to tension. Memories that reportedly had not been told to others in the past showed the same proportion of meaning as did memories that had been told to others (23%), with insights more prevalent than lessons. For memories that had been told to others, insights were more likely to be accepted by listeners than lessons. Implications were discussed for understanding the development of meaning in self-defining memories and the collaborative construction of identity.

Background: Television viewing is associated with childhood obesity. Eating during viewing and eating highly advertised foods are 2 of the hypothesized mechanisms through which television is thought to affect children's weight., Objectives: Our objectives were to describe the amounts and types of foods that children consume while watching television, compare those types with the types consumed at other times of the day, and examine the associations between children's body mass index (BMI) and the amounts and types of foods consumed during television viewing., Design: Data were collected from 2 samples. The first sample consisted of ethnically diverse third-grade children, and the second consisted predominantly of Latino fifth-grade children. Three nonconsecutive 24-h dietary recalls were collected from each child. For each eating episode reported, children were asked whether they had been watching television. Height and weight were measured by using standard methods and were used to calculate BMI., Results: On weekdays and weekend days, 17-18% and approximately 26% of total daily energy, respectively, were consumed during television viewing in the 2 samples. Although the fat content of the foods consumed during television viewing did not differ significantly from that of the foods consumed with the television off, less soda, fast food, fruit, and vegetables were consumed with the television on. The amount of food consumed during television viewing was not associated with children's BMI, but in the third-grade sample, the fat content of foods consumed during television viewing was associated with BMI., Conclusions: A significant proportion of children's daily energy intake is consumed during television viewing, and the consumption of high-fat foods on weekends may be associated with BMI in younger children.

Purpose: It is unclear how well questionnaire or so-called reference methods of dietary assessment correlate with true dietary intake. We develop a method to estimate such correlations., Methods: An error model is described that uses data from a food frequency questionnaire (Q), a reference method (R), and a biological marker (M). The model does not assume the classical error model for either R or M, or that the correlation between errors in the questionnaire and reference data is zero. Credible intervals can be placed about correlations between R, Q, M and true dietary data (T), also about the correlations between errors in reference and questionnaire data., Results: Application of this model to a validation data set mainly found correlations in the range 0.4 to 0.8, and that correlations (R,T) generally exceeded correlations (Q,T), providing evidence that R is more valid than Q. Estimated correlations between errors in R and Q were often far from zero suggesting that regression calibration to imperfect reference data is problematic unless these error correlations can be estimated., Conclusion: A biological marker in addition to dietary data, allows calculation of correlations between estimated and true dietary intakes under reasonable assumptions about errors. However, sensitivity analyses are necessary on one variable.

As part of the Lipid Research Clinics (LRC) Program Prevalence Study of coronary heart disease risk factors, nutrient intakes of two US populations over 59 years of age were determined by 24-hour recalls in the 1970s. Characteristics of the populations were (1) California: suburban, upper-middle class, 95% high school graduates, 10% blue collar occupations; (2) Oklahoma: rural lower-middle class, 75% high school graduates, and 40% blue-collar occupations. Macronutrients consumed by both populations were similar, except for alcohol. For both men and women, energy intake was approximately 25 kcal/kg/day (body weight) sources of energy were approximately 40% from carbohydrate, 16% from protein, 37% from fat, and 4% from alcohol. The Oklahoma population, however, consumed significantly less alcohol than did Californians. Percentages of calories from fatty acids were approximately 14% from saturated and 6% from polyunsaturated, which yielded a polyunsaturated: saturated ratio of 0.48. The intake of cholesterol for women was 190 mg/1000 kcal and for men, 210 mg/1000 kcal. Between the ages of 60 and 69, the Oklahoma men consumed more energy than did the California men. Both sexes demonstrated lower energy intakes with advancing age and with increasing body mass index. The higher energy intake of the Oklahoma cohort aged 60-69 was attributed to the greater physical demands of their occupations, but this difference disappeared after age 70. The California and Oklahoma women had similar caloric intakes beyond age 60. In summary, the LRC findings suggest that geographically diverse American populations consumed in the late 1970s remarkably similar intakes of macronutients and cholesterol, with the only major exception being energy from alcoholic beverages.

The authors examined the relationship of authoritarian, authoritative, and permissive parenting styles and the number of years in the United States with self-perception (academic competence, morality, and self-reliance) as recalled by Korean American college students (N = 144). Authoritative parenting behaviors were most common in Korean American families, followed by authoritarian behaviors, with permissive behaviors a distant 3rd. Authoritative parenting styles and the number of years lived in the United States were predictive of higher academic competence. Authoritarian and permissive parenting styles were predictive of lower self-reliance, whereas number of years lived in the United States was related to higher self-reliance. Those findings provide partial support for generalizing D. Baumrind's (1971) model of parenting styles to Korean American families, and the findings demonstrate the importance of considering acculturation issues in parenting studies.

Background and Objectives: Type 2 diabetes, which is highly prevalent in older Mexican Americans, may influence cognitive functioning. We examined the association of diabetes with decline in global cognitive function and memory function over a 2-year period., Methods: Study subjects were derived from an existing cohort of Latinos aged 60 and over in the SALSA project (n=1,789). Statistical analysis was conducted using logistic regression and a generalized estimating equation (GEE)., Results: Logistic regression analysis indicated that baseline diabetes was a significant predictor of major cognitive impairment in Modified Mini Mental State Exam (3MSE) (OR=1.68, 95% CI=1.21, 2.34) and word-list test (OR=1.31, 95% CI=0.99, 1.75). GEE analysis showed that there was no significant difference between diabetic and nondiabetic subjects in change of cognitive scores over 2 years (3MSE, mean=-0.58, 95% CI=-1.48, 0.32; word-list test, mean=-0.10, 95% CI=-0.32, 0.11)., Conclusions: More diabetic complications were associated with major cognitive decline among diabetic subjects. Research on long-term impact of treatment for type 2 diabetes is warranted.

In the 1940s and 1950s many people in the United States appear to have thought they dreamed in black and white. For example, Middleton (1942) found that 70.7% of 277 college sophomores reported "rarely" or "never" seeing colors in their dreams. The present study replicated Middleton's questionnaire and found that a sample of 124 students in 2001 reported a significantly greater rate of colored dreaming than the earlier sample, with only 17.7% saying that they "rarely" or "never" see colors in their dreams. Assuming that dreams themselves have not changed over this time period, it appears that one or the other (or both) groups of respondents must be profoundly mistaken about a basic feature of their dream experiences.

Background: Screening mammogram and Pap smear rates are lower for women in underserved racial and ethnic groups, yet may be overestimated due to reliance on patients' self-reports. The purpose of this study was to determine accuracy of self-reports of mammograms and Pap smears in a multiethnic, multilingual population of African American, Latina, Chinese, Filipina, and White women residing in low-income census tracts of Alameda County, California., Methods: Following a baseline telephone survey of 1,464 women regarding receipt of mammograms and Pap smears, we examined computerized and written medical records to validate the dates and locations of tests reported by women., Results: Of 1,464 subjects, 94.9% reported having had a Pap smear, and 87% reported having had a mammogram. For Pap smears, in a subsample of 448 cases, we validated only 69.4% of the women's self-reports, and for mammography, in a subsample of 846 women, we validated only 75.4% of the self-reports. Validation rates differed significantly by ethnicity and site of care for both Pap smears and mammograms., Conclusions: Population estimates of breast and cervical cancer screening rates based upon patient self-reports need to be adjusted downward, by as much as one-quarter to one-third, for low-income, ethnic women.

This study examined the utility and accuracy of collateral reports of smoking status among 256 abstinent alcoholic smokers (140 males, 116 females) treated for smoking cessation. Data were gathered prospectively from two randomized clinical trials of behavioral smoking cessation treatment conducted in San Diego, CA. The mean age of the participants was 42.0 years (S.D.= 10.0) and 93% were Caucasian. Self-reported smoking status was obtained at posttreatment (1 week after the target quit date) and at 1 year. Collateral reports obtained by telephone and expired air carbon monoxide (CO) levels of < 10 ppm were used to confirm self-reported smoking status. Collateral reports were available for 89.1% of subjects at posttreatment and 90.6% of subjects at 1 year. The smoking abstinence rates were similar when using collateral reports or CO confirmation of smoking status at both time points. Collateral reports refuted self-reported abstinence as often or more than CO levels, and showed relatively high concordance with CO levels. In conclusion, collateral reports have utility and are reasonably accurate for confirming self-reported smoking status in clinical trials of smoking cessation for abstinent alcoholic smokers.

Background: Policy and clinical decisions regarding children's nutrition are often based on dietary intake estimates from self-reports. The accuracy of these estimates depends on memory of both the type of food eaten and the amount consumed. Although children's self-reports of food intake are widely used, there is little research on their ability to estimate food portions., Objective: To assess the validity of children's estimates of the food portions they consume by means of 2 types of measurement aids: standard 2-dimensional food portion visuals and manipulative props., Design: Randomized controlled trial., Participants: Fifty-four African American girls aged 8 to 12 years., Main Outcome Measures: Girls were served a standard meal and actual intake was assessed by weighing food portions before and after the meal. On completion of the meal, dietitians collected food recalls and portion size estimates from the girls by means of both manipulative props and 2-dimensional food portion visuals, administered in a randomized order., Results: Absolute value percentage differences between actual and estimated grams of food consumed averaged 58.0% (SD, 102.7%) for manipulative props and 32.8% (SD, 72.8%) for 2-dimensional food portion visuals. Spearman correlations between actual and estimated intakes with both portion size measurement aids were high (range, r = 0.56 to 0.79; all P<.001), with the exception of bread intake (r = 0.16, P =.43). Correlations with actual intakes did not differ significantly between the 2 methods., Conclusions: Children's self-reported portion size estimates are appropriate for ranking children's relative intakes, but they result in sizable errors in quantitative estimates of food and energy intakes. Caution should be used in interpreting quantitative dietary intake estimates derived from children's self-reports.

Objective: To evaluate cognitive functioning throughout the menstrual cycle in women who suffer from premenstrual dysphoric disorder (PDD) and controls. RESEARCH HYPOTHESIS: Measures of cognitive function will discriminate between women with prospectively documented PDD and women without PDD during the late-luteal phase of the menstrual cycle., Participants: The participants consisted of 37 women who met operationalized, prospectively documented criteria of premenstrual dysphoric disorder and 32 women without PDD who served as controls., Design: A series of neurocognitive tasks were used to assess selective, sustained attention, reaction time, and cognitive flexibility in women with PDD and controls. Tests were administered on two occasions: once during the follicular phase of the menstrual cycle, and once during the late-luteal phase., Results: Repeated measures and discriminant analyses failed to demonstrate significant group differences between women with PDD and controls in neurocognitive functioning., Conclusions: The findings indicated that cognitive functioning in the late-luteal phase was not compromised in either group, in spite of subjective reports from the PDD group. The findings suggest that complaints of cognitive dysfunction may be mediated by altered perceptions and sociocultural expectations rather than by identifiable cognitive deficits.

Objectives: The purpose of this paper is to present longitudinal data on nutrient intakes of youth with emphases on differences by sex and race/ethnicity. Nutrients selected for examination are those implicated in chronic disease., Design: 24-hour dietary recalls were collected from a cohort of third, fifth and eighth graders (n = 1874)., Setting and Subjects: The sample is drawn from the Child and Adolescent Trial for Cardiovascular Health and includes students from California, Louisiana, Minnesota and Texas., Results: Across the total sample, nutrient intakes met recommended levels except that total fat, saturated fat and sodium consistently exceeded recommendations and calcium and iron intake of girls consistently fell short of recommended levels. Nutrient consumption between third and eighth grade differed by sex and race/ethnicity for a number of nutrients. In particular, females' intake of energy from total fat, calcium, iron, folic acid, vitamin A and vitamin D decreased over time relative to males' intakes, controlling for overall energy intake. Compared with the other ethnic/racial groups, African-American students increased their intake of energy from total fat and saturated fat over time., Conclusions: Our results suggest that the diets of youth change over time, and negative trends are more common in females than in males and in African-American and Hispanics compared with Caucasian students. Nutrition education and intervention are needed throughout childhood and adolescence with an emphasis on choosing healthful foods. In addition, greater attention to differential opportunities and reinforcements for females and males, and Caucasian, Hispanic and African-American students is warranted.

In 2 experiments, we examined the interplay of 2 types of memory errors: forgetting and false memory--errors of omission and commission, respectively. We examined the effects of 2 manipulations known to inhibit retrieval of studied words--directed forgetting and part-list cuing--on the false recall of an unstudied "critical" word following study of its 15 strongest associates. Participants cued to forget the 1st of 2 studied lists before studying the 2nd recalled fewer List 1 words but intruded the missing critical word more often than did participants cued to remember both lists. By contrast, providing some studied words as cues during recall reduced both recall of the remaining studied words and intrusions of the critical word. The results suggest that forgetting can increase or decrease false memories, depending on whether such forgetting reflects impaired access to an entire episode or retrieval competition among elements of an episode.

Objective: Describe whether users of vitamin-mineral supplements differed from nonusers in micronutrient intakes or in nutrition awareness., Design: Cross-sectional, observational study., Subjects: One thousand five hundred thirty-two students now in grade 8, who participated in the Third Child and Adolescent Trial for Cardiovascular Health tracking study and who also provided a single 24-hour dietary recall., Statistical Analyses Performed: Mixed-model analysis of covariance was used to ascertain if supplement users had higher vitamin and mineral intakes from food sources, and to examine if supplement users had better nutrition awareness than nonusers., Results: The 24-hour recall showed that 17.6% of the students reported using vitamin-mineral supplements. Users reported a mean of 1.4 supplements, of which 47% were multivitamin or multimineral preparations, 37% were single nutrients, and 16% were combinations. White persons and residents of Minnesota and California were more likely to be supplement users. Users had higher micronutrient intakes from food sources for 16 of the 20 nutrients studied after adjusting for gender, race/ethnicity, site, treatment condition, and within-school variability. Users had higher scores on a health behavior survey for food choice and slightly but not significantly higher nutrition knowledge scores., Conclusions: Vitamin-mineral supplement use is prevalent among eighth-grade students. Users have higher nutrient intakes from foods, higher total intakes for several micronutrients, higher nutrition awareness, and differ in their demographic characteristics from nonusers.

Purpose: To assess intake of several vitamins in preparation for a large cohort study investigating the effect of diet on risk of colon and prostate cancer., Methods: The dietary intake of several vitamins were assessed using eight different 24-hour recalls and a 200-item food frequency questionnaire (FFQ) from each subject. Participants also attended a clinic where blood was drawn and body composition, weight, height, and blood pressure were measured. A total of 97 black and 96 nonhispanic white subjects participated. The levels of alpha-tocopherol, carotene, folate, and vitamin C in the blood were correlated with the dietary intakes as measured by both 24-hour recalls and FFQ., Results: Correlations between blood levels and energy-adjusted dietary intake assessed by 24-hour recalls (with supplements) were as follows: carotene (adjusted for serum cholesterol): 0.47 and 0.55 in black and white subjects, respectively; alpha-tocopherol (adjusted for serum cholesterol): 0.61 (blacks) and 0.50 (whites); vitamin C: 0.22 (blacks) and 0.17 (whites); folate: 0.54 (blacks) and 0.55 (whites). Correlations between blood levels and FFQ indices were smaller in magnitude: 0.34 and 0.28 for carotene in black and white subjects, respectively, 0.37 and 0.56 for alpha-tocopherol (adjusted for serum cholesterol), 0.20 and 0.03 for vitamin C and 0.24 and 0.32 for folate., Conclusions: The correlations observed were generally of modest to moderate size and were similar to or larger than those reported by others. This is despite variations in absorption, metabolism, and excretion of the vitamins and suggests that both the 24-hour recalls and the FFQ contain valid information.

Objectives: To evaluate the validity of food behavior items, using a biological measure (serum carotenoids) as the criterion for validity of fruit and vegetable intake, and the results from multiple 24-hour recalls to test convergent validity with nutrient intake., Design: Participants responded to 39 food-behavior questions and later completed three 1-day dietary recalls. Serum carotenoid levels were determined for a 59% randomly selected subsample., Subjects/setting: A convenience sample of 100 English-speaking, low-income women participating in a Food Stamp Nutrition Education Program in 8 California counties. Statistical analyses Spearman correlation coefficients were calculated between responses to the food behavior items and (a) serum carotenoid levels and (b) mean nutrient intakes from the 24-hour recalls. Cronbach's coefficient alpha was determined for items within broad food behavior topics., Results: Responses to 10 food behavior items were significantly correlated with serum carotenoid levels (correlations greater than 0.45 were found for choosing low-fat foods and a self-evaluation of overall dietary quality). An additional 12 items showed hypothesized associations with the 24-hour recall data (with a maximum correlation 0.50 for number of eggs per week and dietary cholesterol). Cronbach's coefficient alpha ranged from 0.28 (for 5 fat and cholesterol items) to 0.79 (for 9 fruit and vegetable items)., Applications/conclusions: Nutrition professionals can use these methods to validate items for food behavior checklists for specific populations. The items described here may be useful when designing instruments to administer to low-income women in a community setting.

Experimental research on eyewitness identification follows a standard principle of experimental design. Perpetrator-present and perpetrator-absent lineups are constructed with the same foils, so that the two conditions are identical except for the presence or absence ofthe trueperpetrator ofthe crime. However, this aspect of the design simulates conditions that do not correspond to those of real criminal investigations. Specifically, these conditions can create perp-absent lineups in which the foils are selected based on their similarity to an unknown person--the real perpetrator. Analysis of the similarity relations predicts that when foils for perp-absent lineups are selected based on their match to the perpetrator the false identification rate will be lower than if the foils are selected based on their match to the innocent suspect. This prediction was confirmed in an experiment that compared these two perp-absent lineup conditions. These results suggest that false identification rates in previous experiments would have been higher if the foils had been selected based on their match to the innocent suspect, rather than the absent perpetrator.

This article outlines the purposes, design, and findings of the Long Beach Longitudinal Study, a multipanel study of adults aged 28 through the upper reaches of the life span. The goal of the study is to identify normal short- and long-term longitudinal changes in memory and cognition across adulthood, and to develop models to explain cognitive changes. Descriptive findings of 3- and 16-year longitudinal change patterns are identified, as well as results suggesting the role of cognitive processing resources and intellectual ability in memory change. Change patterns of the oldest-old, who differ from less elderly adults, are discussed.

Meat consumption predicts risk of several chronic diseases. The authors validate the accuracy of meat consumption reported by food frequency questionnaires and the mean of eight 24-hour recalls, using urinary methylhistidine excretion, in 55 Black and 71 White Adventist subjects in Los Angeles and San Diego, California, in 1994-1997. 1-Methylhistidine excretion predicts vegetarian status in Black (p = 0.02) and in White (p = 0.005) subjects. Spearman's correlation coefficients between 1-methylhistidine and estimated meat consumption were usually between 0.4 and 0.6 for both food frequency questionnaires and 24-hour recall data. This is despite the chance collection of dietary recalls and urines from omnivores on meatless days.

The goal of this investigation was to determine whether women who did not report preferred numbers for their last menstrual period (LMP) may be a group of women who are particularly careful in keeping track of their menstrual cycles and therefore have more accurate LMP dating--based on a comparison with ultrasound examinations. We also sought to estimate the frequency with which preferred numbers are reported in different sources of data and for different subgroups of women. First, we examined the 1987 California birth certificates in which LMP was collected at the time of birth (n = 504853). We also examined the records of 43880 women participating in the California Alpha-fetoprotein (AFP) Screening Program between 1986 and 1987, for whom gestational ages based on both early ultrasound examination and LMP were collected before 20 weeks of gestation. In the 1987 California birth certificates, seven numbers--1, 5, 10, 15, 20, 25 and 28--were recorded more frequently than expected. An estimated 12.9% of these records had preferred numbers. The most frequently recorded number was 15, occurring 2.5 times more often than expected (P < 0.01). In the data of the AFP Screening Program, the same seven numbers were preferred, and approximately 7.9% of records were affected by number preference. Comparisons with measurements of gestational age based on ultrasound demonstrated that LMP-based gestational ages in which non-preferred numbers are reported for the LMP are slightly more accurate than those in which preferred numbers are reported (P < 0.01). In most cases, number preference appears to introduce small errors into measurements of gestational age, probably as a result of rounding. Thus, the effect of number preference may be primarily of interest to research studies in which small errors in the measurement of gestational age will have a significant impact on findings.

California's Hispanic infants have lower immunization levels than non-Latino white infants, 53.7% versus 65.2%, respectively. Spanish-language radio is an effective mass media venue for imparting information to Latino populations. It has been demonstrated that lack of parental knowledge of infant immunization timing is associated with delayed immunization coverage. In an effort to improve Latino parent knowledge of immunization timing, two Spanish-language radio commercials were developed to be used in conjunction with community-based educational efforts. In order to gage the potential educational impact of the two commercials, they were pretested with a group of low-income Spanish-speaking Latino parents who represented members of the target population for whom the commercials were created. Both commercials were rated favorably by parents, and elicited immunization-specific responses. Although correct recall of the simplified, basic immunization schedule was low, the level of immunization response consistency and overall approval of both commercials appear to support their use as part of Latino infant immunization educational outreach in California.

Previous studies have demonstrated the existence of an "unequal facilitation" effect in spatial memory. In those experiments, the provision of appropriate environmental support for recall was shown to enhance the recall performance of older adults more than that of young adults. In some cases, this process resulted in parity of performance between the two age groups. The present study evaluated the relative contribution of environmental support to the unequal facilitation effect at encoding and retrieval in a spatial memory task. Results, indicate that, although the provision of environmental support at both encoding and retrieval is necessary for optimal recall across the adult life span, the primary influence of such support for recall in the elderly derives from its presence at encoding.

Cultural differences in parental attitudes and child-rearing practices among European countries have been demonstrated in previous studies using a scale for assessment of memories of upbringing (the EMBU). In this pilot study we evaluated the EMBU in two previously unstudied populations: a culturally homogeneous sample from Japan (n = 105) and a culturally mixed sample from Southern California (n = 73). The results suggest that, compared to European parents, Japanese parents are more emotionally distant from their children, while the Southern Californians as a group scored similarly to the Europeans. Further studies are needed in order to establish the EMBU as a transcultural tool for assessment of parental rearing behaviour.

Using data collected in a random-digit dial telephone survey in a northern California county, an examination of the impact of alcohol beverage container warning labels was conducted. In a broadly conceived approach to the possible impact of warning labels, we examined recall and content as well as risk assessment and the use of warning labels as public policy to combat drunk driving. In a repeated measures pre- and post-design, respondents reported significantly higher recall of labels and their content in the post-introduction period. Evidence from a multivariate analysis of post-introduction data indicate that both drinking drivers and impaired drivers (based on self-reports) were more likely to recall the labels and their content, an indication that warning labels are reaching "at risk" individuals. In addition, increases in the perceived risk of driving and drinking are consistent with the notion that warning labels, as one part of a larger social movement, are helping to create an atmosphere in which drinking and driving is less acceptable. However, our findings also indicate that, at least among at risk drinking and impaired drivers, increased use of public policies such as warning labels in an effort to reduce the negative consequences of drinking and driving may generate a public opinion backlash.

Using exit interviews, we determined parental recall of their child's diagnosis, treatment, and follow-up instructions after a visit to the emergency department (ED). Over 2 weeks, 159 parents were interviewed. Exclusion criteria were: parental language other than Spanish or English, admission, trauma, child abuse, or a primary psychiatric diagnosis. Neither language nor parental satisfaction with communication (reported in 93%) was associated with ability to state the diagnosis correctly (P = NS). Seventy-five percent (88 of 117) of parents of children given a single diagnosis stated it correctly; 55% (23 of 42) of parents of children given multiple diagnoses were able to correctly state them all (P = 0.013). If a single medication was prescribed, 30% (20 of 67) of parents knew its name, while only 13% (four of 31) knew all names of multiple medications (P = 0.070). Of those parents given a single medication, 51% (34 of 67) knew how to administer it, while only 10% (three of 31) knew how to administer multiple medications (P < 0.001). Similarly, 58% (46 of 79) of parents given a single appointment knew the date and place of their child's follow-up, while only 16% (three of 19) given multiple appointments knew all dates and locations (P = 0.001). These data suggest that despite high parental satisfaction with communication, many parents cannot fully recall their child's diagnosis, treatment, and follow-up--especially when multiple diagnoses, medications, or appointments are given.

Accuracy of recall of hip fracture, heart attack, and cancer was evaluated by comparing data obtained from postal surveys and medical records of participants in the Leisure World Disease Prevention Study. The study cohort comprised 13,897 residents of Leisure World Laguna Hills who responded to a questionnaire first mailed in 1981. Follow-up questionnaires requesting information on recent disease history were mailed in 1983 and 1985 to all living cohort members and were returned by 9,734 (86%) and 8,884 (82%) persons, respectively. The proportion of false-positive answers was about 40% for acute myocardial infarction, but less than 10% for hip fracture and cancer. Many of those who gave a false-positive answer on the questionnaire had a condition that the lay population might easily confuse with the condition of interest (e.g., heart attack vs. other cardiovascular disease). Among persons with the disease of interest recorded in the medical record, the percentage who failed to report their events on the questionnaires was highest for those who had an acute myocardial infarction, followed by those who had cancer and those who had hip fracture. The highest rates of confirmation of cancer were for cancers of the breast, bladder, prostate, and uterus. For closely related sites (e.g., colon and rectum), the reliability of reports decreased. The amount of information obtained varied according to the wording of the questionnaire and the specificity of the questions asked. Improved accuracy of recall was observed when the occurrence of specific diseases was asked in addition to a general question about recent hospitalizations.

Measures of spatial cognition, neighborhood knowledge, and neighborhood use from the research described by Walsh, Krauss, and Regnier (1981) were examined to determine if laboratory tests of spatial cognition were significant predictors of older adults' use of their neighborhoods. The overall results show that laboratory-based measures of spatial cognition and subjects' knowledge of their neighborhoods are both significant predictors of their use of neighborhood goods and services. The ability to learn and remember the location and orientation of objects, when contextual cues were not provided at test, was more predictive of the participants' neighborhood use than either the participants' number of years in the neighborhood or their mobility. Spatial memory as measured by the Educational Testing Service Building Memory task predicted neighborhood knowledge, which was predictive of neighborhood use.

The purpose of this paper is to discuss the history and development of protocol analysis as a useful approach for survey research in the alcohol field, and to describe the results of a pilot study which used protocol analysis to assess the recall strategies used for four standard alcohol questions commonly used in surveys. Twenty-nine subjects were interviewed and asked to think aloud their responses to four alcohol items: frequency of drinking, average quantity, frequency of drinking over 5 drinks, and frequency of drunkenness. Results indicate that respondents most often used anchoring and adjustment and context strategies to arrive at their answers. Suggestions for facilitating the use of specific strategies during an interview are given.

Previous measures of physical activity for epidemiologic studies were considered inadequate to meet the needs of a community-based health education trial. Therefore, new methods of quantifying the physical activity habits of communities were developed which are practical for large health surveys, provide information on the distribution of activity habits in the population, can detect changes in activity over time, and can be compared with other epidemiologic studies of physical activity. Independent self-reports of vigorous activity (at least 6 metabolic equivalents (METs) ), moderate activity (3-5 METs), and total energy expenditure (kilocalories per day) are described, and the physical activity practices of samples of California cities are presented. Relationships between physical activity measures and age, education, occupation, ethnicity, marital status, and body mass index are analyzed, and the reliabilities of the three activity indices are reported. The new assessment procedure is contrasted with nine other measures of physical activity used in community surveys.

Information was collected from dentists of a subset of participants in a case-control interview study conducted in Los Angeles County, California, in August 1980-August 1981 to evaluate the relationship of dental x-rays to tumors of the parotid gland. Complete dental charts were available from 142 dentists of 84 cases and from 130 dentists of 79 controls. Analysis of data from these interview-chart comparisons indicates that recall appears to be unbiased since the measures of agreement between interview and dental chart data are similar for cases and controls. The authors further conclude that interview data alone may be used for case-control comparisons of dental x-ray exposure and would, because of unbiased misclassification, tend to underestimate the relative risks.