Quality control of dietary data collection in the CARDIA study

Change in cardiovascular health among adults with current or past major depressive disorder enrolled in intensive smoking cessation treatment

BACKGROUND

Elevated depressive symptoms and cigarette smoking are independently associated with poorer cardiovascular health (CVH), but it is unknown whether their treatment can synergistically improve CVH. We sought to characterize CVH of adults with comorbid depression and smoking and examine changes in CVH associated with changes in smoking and depression.

METHODS

Participants (N = 300, 55 % women) were adult smokers (≥ 1 cigarette/day) with lifetime major depressive disorder enrolled in a 12-week intervention trial targeting depression and smoking. Multiple linear regression examined prospective associations between changes in depression (Beck Depression Inventory-II), smoking (past 24-hour cigarettes or smoking abstinence), and modified CVH score (per American Heart Association, excluding smoking: diet, physical activity, body mass index, blood glucose, cholesterol, blood pressure).

RESULTS

Baseline mean CVH score was 5.87/12 points (SD = 2.13). No participants met "ideal" on all CVH components (blood glucose: 48 %, cholesterol: 46 %, physical activity: 38 %, body mass index: 24 %, blood pressure: 22 %, diet: 3 %). CVH scores did not change from baseline to end-of-treatment (M = 0.18 points, SD = 1.36, p = .177), nor did change in depression × smoking predict change in CVH (p = .978). However, greater reductions in depression were significantly associated with greater improvements in CVH (β = -0.04, SE = 0.01, p = .015).

LIMITATIONS

This study was limited by a short follow-up period, missing blood glucose and cholesterol data, and treatment-seeking smokers.

CONCLUSIONS

Adults with comorbid depression and smoking had poor CVH. Although integrated treatment for depression and smoking improved both conditions, only reductions in depression were associated with improvements in CVH. These findings have implications for integrating psychosocial treatment into CVH promotion efforts.

REGISTRATION

NCT02378714 (clinicaltrials.gov).

Dietary vitamin E and tocopherol isoforms and incident chronic kidney disease: A 30-y follow-up study from young adulthood to midlife

BACKGROUND

The relationship of dietary vitamin E intake with incident chronic kidney disease (CKD) was not clear as yet. We aimed to examine the associations of dietary total vitamin E and tocopherol isoforms intakes with incident CKD in a 30-year follow-up study from young adulthood to midlife.

METHODS

A total of 4038 American adults aged 18-30 years and without reduced estimated glomerular filtration rate (eGFR) were enrolled from Coronary Artery Risk Development in Young Adults study. Diet was evaluated by a validated dietary-history questionnaire at baseline, and after 7 and 20 years later. The study outcome was incident CKD, defined as an eGFR<60 mL/min/1.73 m² or a urinary albumin to creatinine ratio ≥30 mg/g.

RESULTS

During a 30-year follow-up, 642 (15.9%) participants developed incident CKD. Overall, there was a L-shaped relationship between dietary total vitamin E intake and incident CKD (P for non-linearity<0.001). When total vitamin E intake was assessed as quartiles, compared with those in the first quartile (<4.35 mg α-TE/1000 kcal), the adjusted HRs (95%CI) of incident CKD for participants in the fourth quartile (≥9.61 mg α-TE/1000 kcal) was 0.55 (0.40, 0.75). Moreover, higher intakes of beta-tocopherol and gamma-tocopherol were significantly associated with a lower incident CKD. Higher intake of delta-tocopherol was significantly related to a higher incident CKD. And there was no obvious association of alpha-tocopherol intake with incident CKD.

CONCLUSIONS

There were inverse associations of total vitamin E, beta-tocopherol and gamma-tocopherol intakes, a positive association of delta-tocopherol intake, and no obvious association of alpha-tocopherol intake, with incident CKD among American adults.

The impact of data quality assurance and control solutions on the completeness, accuracy, and consistency of data in a national spinal cord injury registry of Iran (NSCIR-IR)

STUDY DESIGN

Descriptive study.

OBJECTIVE

This study aimed to develop and evaluate a systematic arrangement for improvement and monitoring of data quality of the National Spinal Cord (and Column) Injury Registry of Iran (NSCIR-IR)-a multicenter hospital-based registry.

SETTING

SCI community in Iran.

METHODS

Quality assurance and quality control were the primary objectives in improving overall quality of data that were considered in designing a paper-based and computerized case report. To prevent incorrect data entry, we implemented several validation algorithms, including 70 semantic rules, 18 syntactic rules, seven temporal rules, and 13 rules for acceptable value range. Qualified and trained staff members were also employed to review and identify any defect, inaccuracy, or inconsistency in the data to improve data quality. A set of functions were implemented in the software to cross-validate, and feedback on data was provided by reviewers and registrars.

RESULTS

Socio-demographic data items were 100% complete, except for national ID and education level, which were 97% and 92.3% complete, respectively. Completeness of admission data and emergency medical services data were 100% except for arrival and transfer time (99.4%) and oxygen saturation (48.9%). Evaluation of data received from two centers located in Tehran proved to be 100% accurate following validation by quality reviewers. All data was also found to be 100% consistent.

CONCLUSIONS

This approach to quality assurance and consistency validation proved to be effective. Our solutions resulted in a significant decrease in the number of missing data.

The importance of effective registries in pulmonary diseases and how to optimize their output

Randomized controlled trials (RCTs) are essential for the approval of new therapies; however, because of their design, they provide little insight concerning disease epidemiology/etiology and current clinical practice. Particularly, in lung disease, rigid inclusion/exclusion criteria can limit the generalizability of pivotal trial data. Noninterventional studies (NIS), conducted through the well-established mechanism of patient registries, are undervalued as a means to close data gaps left by RCTs by providing essential data that can guide patient care at different levels from clinical decision-making to health-care policy. While NIS contribute valuable data in all disease areas, their importance in rare diseases cannot be underestimated. In respiratory disease, registries have been essential in understanding the natural history and different phenotypes of rare conditions, such as alpha 1 antitrypsin deficiency, cystic fibrosis, and idiopathic pulmonary fibrosis. Importantly, additional therapeutic outcome data were generated. While measures for enhancing data quality in RCTs have evolved significantly, the approach and effectiveness of registries is variable. Within this article, we review the contribution of registries to pulmonary disease and make recommendations for their effective management. Additionally, we assess limitations of registry data as well as challenges to registry operation, including the impact of the European Union General Data Protection Regulation.

Evaluation of the dietary intake data coding process in a clinical setting: Implications for research practice

BACKGROUND

High quality dietary intake data is required to support evidence of diet-disease relationships exposed in clinical research. Source data verification may be a useful quality assurance method in this setting. The present pilot study aimed to apply source data verification to evaluate the quality of the data coding process for dietary intake in a clinical trial and to explore potential barriers to data quality in this setting.

METHODS

Using a sample of 20 cases from a clinical trial, source data verification was conducted between three sets of data derived documents: transcripts of audio-recorded diet history interviews, matched paper-based diet history forms and outputs from nutrition analysis software. The number of cases and rates of discrepancies between documents were calculated. A total of five in-depth interviews with dietitians collecting and coding dietary data were thematically analysed.

RESULTS

Some 2024 discrepancies were identified. The highest discrepancy rate was 57.49%, and occurred between diet history interviews and nutrition analysis software outputs. Sources of the discrepancies included both quantities and frequencies of food intake. The highest discrepancy rate was for the food group "vegetable products and dishes". In-depth interviews implicated recall bias of trial participants as a cause of discrepancies, but dietitians also acknowledged a possible subconscious influence of having to code reported foods into nutrition analysis software programs.

CONCLUSION

The accuracy of dietary intake data appeared to depend on the level of detailed food data required. More support for participants on reporting consumption, and incorporating supportive tools to guide estimates of food quantities may facilitate a more consistent coding process and improve data quality. This pilot study offers a novel method and an overview of dietary intake data coding measurement errors. These findings may warrant further investigation in a larger sample.

Quality Control Measures over 30 Years in a Multicenter Clinical Study: Results from the Diabetes Control and Complications Trial / Epidemiology of Diabetes Interventions and Complications (DCCT/EDIC) Study

Implementation of multicenter and/or longitudinal studies requires an effective quality assurance program to identify trends, data inconsistencies and process variability of results over time. The Diabetes Control and Complications Trial (DCCT) and the follow-up Epidemiology of Diabetes Interventions and Complications (EDIC) study represent over 30 years of data collection among a cohort of participants across 27 clinical centers. The quality assurance plan is overseen by the Data Coordinating Center and is implemented across the clinical centers and central reading units. Each central unit incorporates specific DCCT/EDIC quality monitoring activities into their routine quality assurance plan. The results are reviewed by a data quality assurance committee whose function is to identify variances in quality that may impact study results from the central units as well as within and across clinical centers, and to recommend implementation of corrective procedures when necessary. Over the 30-year period, changes to the methods, equipment, or clinical procedures have been required to keep procedures current and ensure continued collection of scientifically valid and clinically relevant results. Pilot testing to compare historic processes with contemporary alternatives is performed and comparability is validated prior to incorporation of new procedures into the study. Details of the quality assurance plan across and within the clinical and central reading units are described, and quality outcomes for core measures analyzed by the central reading units (e.g. biochemical samples, fundus photographs, ECGs) are presented.

Weight gain among men and women who have a child enter their home

Parenthood is associated with decreased physical activity and dietary changes. Previously, mothers have been the focus of studies examining the influence of children on parents' body mass index (BMI), largely ignoring whether parenting affects fathers. This study assessed weight gain in mothers and fathers (by birth or other), using longitudinal repeated-measures models to assess BMI changes over time; parents were compared with nonparents. Data were from the Coronary Artery Risk Development in Young Adults cohort study and included 2,881 black and white adults, ages 18 to 30 years, without children at baseline (1985-1986), and from four urban locations. At each time point (years 2, 5, and 7), changes in BMI from baseline were analyzed, comparing those who had their children in their household at that time point (parents) and those without children (nonparents). The "child effect" is the mean difference in BMI change in parents compared with nonparents. In fathers, overall, the child effect was not significant (black males: 0.30; P=0.09; white males: 0.03; P=0.77). Among black men, however, interactions between age and parental status were significant (P=0.02). Black men who were aged 18 to 24 years at baseline and became fathers during the next 7 years demonstrated a significant child effect, gaining an average of 0.68 more in BMI than nonfathers (P=0.003). Mothers of both races demonstrated the child effect; for blacks it was 0.65 (P=0.003) and for whites it was 1.12 (P≤0.001). These data reveal that becoming a parent can affect the BMI of some adults and suggest that obesity-prevention interventions for children and adult-focused healthy-lifestyle interventions could have additional impact through a family focus targeting both parent and child outcomes.

The impact of fine-tuning of optical recognition system on database reliability

Although optical reading systems are important tools to transfer data from a paper form to electronic databases, the impact of system fine-tuning on the final error rate is not usually considered. At the end of a multi-step process involving paper form design training of operators, and fine-tuning procedure, the final rate of error can be reduced from 0.65% to 0.05%. Fine-tuning should be introduced as a standard procedure while using optical reading systems.

Changes in diet behavior when adults become parents

BACKGROUND

Cross-sectional studies suggest that parents eat more saturated fat than nonparents. Few studies exist on other dietary factors or using longitudinal data.

OBJECTIVE

To compare change in daily dietary intake of selected foods and nutrients across 7 years between adults who have children enter the home and those who do not.

DESIGN

Analysis of data from the Coronary Artery Risk Development in Young Adults cohort study. Dietary intake was assessed by the diet history questionnaire used in that study. The main dependent variables were change from baseline (1985-1986) to Year 7 (1992-1993) for intake of percent saturated fat, energy, daily servings of fruits and vegetables and sugar-sweetened beverages, and frequency of fast-food intake. The primary independent variable was whether or not participants had children in their home by Year 7.

PARTICIPANTS

Two thousand five hundred sixty-three black and white adults who did not have children at baseline from four urban centers.

STATISTICAL ANALYSES PERFORMED

Linear regression adjusting for baseline demographics, energy intake, physical activity, and smoking status.

RESULTS

Parents were more likely to be women, full-time workers, married, and older. Diet did not differ at baseline. Seven-year change in diet for parents and nonparents did not differ for fruit and vegetable, sugar-sweetened beverages, or fast food. Percent saturated fat decreased among both groups but parents showed a smaller decrease in percent saturated fat (1.59 vs 2.10; P<0.001). Compared with nonparents, parents increased energy intake by 79 kcal/day (P=0.058), but this difference did not reach statistical significance.

CONCLUSIONS

Parenthood does not have unfavorable effects on parents' diets, but neither does it lead to significant improvements. In fact, parents lag behind their childless counterparts in decreasing intake of saturated fat and overall diets remain poor. Nutrition education programs and food and nutrition practitioners should develop strategies to support and motivate healthy eating habits in parents.

Serum urate and its relationship with alcoholic beverage intake in men and women: findings from the Coronary Artery Risk Development in Young Adults (CARDIA) cohort

OBJECTIVE

To investigate if beer, liquor (spirits), wine and total alcohol intakes have different associations with serum urate (SU) concentrations at different ages in a cohort of young men and women.

METHODS

Data from 3123 participants at baseline and follow-up at 20 years were used, with balanced proportions of Caucasians and African Americans. The relationships of SU with categories of beer, liquor, wine and total alcohol intake referent to no intake were examined in sex-specific, cross-sectional analyses.

RESULTS

Mean age (SD) at the beginning of follow-up was 25.1 (3.6) years. Compared with non-drinkers, significant associations between higher SU concentrations and greater beer intake were observed among men and women, with more pronounced and consistent associations for women. An association between greater liquor intake and higher SU concentrations was only seen for men at the year 20 evaluation. Wine intake was not associated with SU in either sex and total alcohol was associated with higher SU concentrations in both men and women. The magnitude of the associations between alcoholic beverages intake and SU was modest (≤0.03 mg/dl/alcoholic beverage serving).

CONCLUSION

An association between higher SU concentrations and greater beer intake was consistent and pronounced among women, but also present in men. Despite the small magnitude of the increases in SU associated with alcohol intake, clinical implications in conditions such as cardiovascular disease and gout in young adults who are moderate and heavy drinkers cannot be ruled out.

Higher dietary intake of long-chain omega-3 polyunsaturated fatty acids is inversely associated with depressive symptoms in women

OBJECTIVE

Experimental and observational data suggest that a higher dietary intake of long-chain omega-3 polyunsaturated acids may lead to a decreased risk of depressive disorders. We assessed multivariable-adjusted associations of fish consumption and dietary intakes of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) with depressive symptoms in a population-based sample of 3317 African-American and Caucasian men and women from the Coronary Artery Risk Development in Young Adults study.

METHODS

Diet was assessed in year 7 (1992-1993) and depressive symptoms were measured in years 10 (1995-1996), 15 (2000-2001), and 20 (2005-2006) by the 20-item Center for Epidemiological Studies Depression Scale. Depressive symptoms were defined as a Center for Epidemiological Studies Depression Scale score > or =16 or self-reported use of antidepressant medication.

RESULTS

In the entire cohort, the highest quintiles of intakes of EPA (> or =0.03% energy), DHA (> or =0.05% energy), and EPA + DHA (> or =0.08% energy) were associated with a lower risk of depressive symptoms at year 10 (P for trends = 0.16, 0.10, and 0.03, respectively). The observed inverse associations were more pronounced in women. For the total number of occasions with depressive symptoms, the multivariable adjusted odds ratios (95% confidence interval) in women were 0.75 (0.55-1.01) for fish intake, 0.66 (0.50-0.89) for EPA, 0.66 (0.49-0.89) for DHA, and 0.71 (0.52-0.95) for EPA + DHA when comparing the highest with the lowest quintiles. Analyses of continuous Center for Epidemiological Studies Depression Scale scores revealed inverse associations with fourth-root-transformed omega-3 variables in women.

CONCLUSION

Our findings suggest that dietary intakes of fish and long-chain omega-3 fatty acids may be inversely associated with chronic depressive symptoms in women.

Attainment of precision in implementation of 24 h dietary recalls: INTERMAP UK

Collection of complete and accurate dietary intake data is necessary to investigate the association of nutrient intakes with disease outcomes. A standardised multiple-pass 24 h dietary recall method was used in the International Collaborative Study of Macro- and Micronutrients and Blood Pressure (INTERMAP) to obtain maximally objective data. Dietary interviewers were intensively trained and recalls taped, with consent, for randomly selected evaluations by the local site nutritionist (SN) and/or country nutritionists (CN) using a twelve-criterion checklist marked on a four-point scale (1, retrain, to 4, excellent). In the Belfast centre, seven dietary interviewers collected 932 24 h recalls from 40-59-year-old men and women. Total scores from the 134 evaluated recalls ranged from thirty-four to the maximum forty-eight points. All twelve aspects of the interviews were completed satisfactorily on average whether scored by the SN (n 53, range: probing 3.25 to privacy of interview 3.98) or CN (n 19, range: probing 3.26 to pace of interview and general manner of interviewer 3.95); the CN gave significantly lower scores than the SN for recalls evaluated by both nutritionists (n 31, Wilcoxon signed rank test, P=0.001). Five evaluations of three recalls identified areas requiring retraining or work to improve performance. Reporting accuracy was estimated using BMR; energy intake estimates less than 1.2 x BMR identifying under-reporting. Mean ratios in all age, sex and body-mass groups were above this cut-off point; overall, 26.1 % were below. Experiences from the INTERMAP Belfast centre indicate that difficulties in collection of dietary information can be anticipated and contained by the systematic use of methods to prevent, detect and correct errors.

IGF-1, IGFBP-3, and Nutritional Factors in Young Black and White Men: The CARDIA Male Hormone Study

Nutritional factors might play a role in regulating serum levels of insulin-like growth factors (IGFs), which are associated with some cancers. We examined the associations of nutritional factors with IGF-1 and IGF binding protein-3 (IGFBP-3). Serum IGF-1 and IGFBP-3 levels and dietary intake were measured in 459 black and 682 white male subjects of the Coronary Artery Risk Development in Young Adults study at the Year 7 (1992-1993) exam. Analysis of covariance and multivariable linear regression were used to assess associations of IGFs with dietary factors by race. IGF-1 was positively associated with magnesium in both black and white men (P = 0.008 and 0.05, respectively). Calcium was positively significantly related to IGF-1 in black men (P = 0.04) and marginally so in white men (P = 0.09). In black men, IGFBP-3 was positively associated with magnesium (P = 0.02), and one serving of milk per day was associated with an 8.23-ng/ml higher IGF-1 concentration (P = 0.05). Tests for interaction, however, revealed no differences between blacks and whites in the associations of nutrients with IGF-1 or IGFBP-3. In conclusion, the associations of dietary factors with serum IGF-1 and IGFBP-3 observed in our study corroborate those from other studies and generally do not differ between black and white men.

A comparison of error detection rates between the reading aloud method and the double data entry method

Data entry and its verification are important steps in the process of data management in clinical studies. In Japan, a kind of visual comparison called the reading aloud (RA) method is often used as an alternative to or in addition to the double data entry (DDE) method. In a typical RA method, one operator reads previously keyed data aloud while looking at a printed sheet or computer screen, and another operator compares the voice with the corresponding data recorded on case report forms (CRFs) to confirm whether the data are the same. We compared the efficiency of the RA method with that of the DDE method in the data management system of the Japanese Registry of Renal Transplantation. Efficiency was evaluated in terms of error detection rate and expended time. Five hundred sixty CRFs were randomly allocated to two operators for single data entry. Two types of DDE and RA methods were performed. Single data entry errors were detected in 358 of 104,720 fields (per-field error rate=0.34%). Error detection rates were 88.3% for the DDE method performed by a different operator, 69.0% for the DDE method performed by the same operator, 59.5% for the RA method performed by a different operator, and 39.9% for the RA method performed by the same operator. The differences in these rates were significant (p<0.001) between the two verification methods as well as between the types of operator (same or different). The total expended times were 74.8 hours for the DDE method and 57.9 hours for the RA method. These results suggest that in detecting errors of single data entry, the RA method is inferior to the DDE method, while its time cost is lower.

Dietary intake of n-3, n-6 fatty acids and fish: Relationship with hostility in young adults—the CARDIA study

BACKGROUND

Hostility has been shown to predict both the development and manifestation of coronary disease. Examining the inter-relation of dietary intake of fish and of polyunsaturated (n-3 and n-6) essential fatty acids with hostility may provide additional insights into the cardioprotective effect of dietary fish and polyunsaturated fatty acids.

OBJECTIVE

To examine the association of dietary n-3, n-6 fatty acids and fish with level of hostility in a sample of 3581 urban white and black young adults.

DESIGN

Cross-sectional observational study as part of an ongoing cohort study. A dietary assessment in 1992-1993 and measurement of hostility and other covariates in 1990-1991 were used in the analysis.

RESULTS

The multivariate odds ratios of scoring in the upper quartile of hostility (adjusting for age, sex, race, field center, educational attainment, marital status, body mass index, smoking, alcohol consumption and physical activity) associated with one standard deviation increase in docosahexaenoic acid (DHA, 22:6) intake was 0.90 (95% CI=0.82-0.98; P=0.02). Consumption of any fish rich in n-3 fatty acids, compared to no consumption, was also independently associated with lower odds of high hostility (OR=0.82; 95% CI=0.69-0.97; P=0.02).

CONCLUSIONS

These results suggest that high dietary intake of DHA and consumption of fish rich in n-3 fatty acids may be related to lower likelihood of high hostility in young adulthood. The association between dietary n-3 fatty acids and hostile personality merits further research.

Association of education with dietary intake among young adults in the bi-ethnic Coronary Artery Risk Development in Young Adults (CARDIA) cohort

OBJECTIVE

To examine associations of changes in dietary intake with education in young black and white men and women.

DESIGN

The Coronary Artery Risk Development in Young Adults (CARDIA) study, a multi-centre population-based prospective study. Dietary intake data at baseline and year 7 were obtained from an extensive nutritionist-administered diet history questionnaire with 700 items developed for CARDIA.

SETTING

Participants were recruited in 1985-1986 from four sites: Birmingham, Alabama; Chicago, Illinois; Minneapolis, Minnesota; and Oakland, California.

SUBJECTS

Participants were from a general community sample of 703 black men (BM), 1006 black women (BW), 963 white men (WM) and 1054 white women (WW) who were aged 18-30 years at baseline. Analyses here include data for baseline (1985-1986) and year 7 (1992-1993).

RESULTS

Most changes in dietary intake were observed among those with high education (>or=12 years) at both examinations. There was a significant decrease in intake of energy from saturated fat and cholesterol and a significant increase in energy from starch for each race-gender group (P<0.001). Regardless of education, taste was considered an important influence on food choice.

CONCLUSION

The inverse relationship of education with changes in saturated fat and cholesterol intakes suggests that national public health campaigns may have a greater impact among those with more education.

Racial differences in early-onset renal disease among young adults: the coronary artery risk development in young adults (CARDIA) study

Although 11 million people in the United States have chronic renal insufficiency, little is known about ethnic/racial disparities for early-onset renal impairment. This study sought to determine whether there is an independent association between race/ethnicity and early-onset renal impairment and to identify other risk factors that might account for observed disparities. All Coronary Artery Risk Development in Young Adults subjects in which serum creatinine was measured at the year 15 examination were identified (n = 3554), excluding those who were pregnant at year 15. Potential risk factors at study entry (ages 18 to 30 yr, 1985 to 1986) included age, weight, gender, race/ethnicity, glucose, uric acid, and systolic BP. Renal impairment was defined as creatinine > or =1.5 mg/dl for men and > or = 1.2 mg/dl for women at year 15 (ages 33 to 45 yr). Fifty-two (2.7%) women and 39 (2.4%) men had renal impairment at the year 15 examination. In bivariate analyses, the odds of renal impairment among black women was estimated to be 2.4-fold that of white women, and among black men, the odds of renal impairment were 9.0-fold that of white men. In multivariate analysis, the odds of an elevated creatinine among black women compared with white women reduced to a nonsignificant 1.5-fold, whereas among men, the odds of an elevated creatinine among blacks was 11.4-fold that of whites. Although adjustment for baseline glucose levels accounted for much of the association between ethnicity and elevated creatinine among women, adjustment for weight, systolic BP, uric acid, glucose, and socioeconomic status did not account for the association between ethnicity and renal impairment among men. The data suggest that there are ethnic differences in the development of early-onset renal dysfunction. Among women, these differences are modest and largely accounted for by differences in glucose levels early in adult life. Differences in race/ethnicity related risk of early-onset renal impairment are particularly large among men and are not accounted for by the metabolic or socioeconomic factors evaluated.

Defining and improving data quality in medical registries: a literature review, case study, and generic framework

Over the past years the number of medical registries has increased sharply. Their value strongly depends on the quality of the data contained in the registry. To optimize data quality, special procedures have to be followed. A literature review and a case study of data quality formed the basis for the development of a framework of procedures for data quality assurance in medical registries. Procedures in the framework have been divided into procedures for the co-ordinating center of the registry (central) and procedures for the centers where the data are collected (local). These central and local procedures are further subdivided into (a) the prevention of insufficient data quality, (b) the detection of imperfect data and their causes, and (c) actions to be taken / corrections. The framework can be used to set up a new registry or to identify procedures in existing registries that need adjustment to improve data quality.

Measurement of dietary intake in the UNC Alumni Heart Study. University of North Carolina

BACKGROUND

Research needs to identify diet and disease associations to provide direction about effecting change in individuals with dietary behaviors that increase risk of chronic disease. Inclusion of dietary assessment in the University of North Carolina Alumni Heart Study (UNCAHS) provides the opportunity to prospectively investigate dietary intake and chronic disease associations with measures of personality and behavioral risk factors.

METHODS

Development of the UNCAHS food frequency questionnaire and nutrient intake of 4,443 middle-aged men and women is provided stratified by total fat and vitamin A intake within demographic and health behavior categories.

RESULTS

Alumni consume diets close to that recommended by current dietary guidelines. Both men and women have low calcium intake. Thirty-nine percent of the alumni consume diets with 30% of kilocalories from fat or less and 88% meet the RDA for vitamin A. Never smokers had lower fat diets and greater intakes of vitamin A than former or current smokers. Over 54% of alumni currently took vitamin/mineral supplements.

CONCLUSIONS

UNCAHS participants will be tracked as they approach older ages with apparently less risk for diet-related chronic diseases than many Americans. The psychosocial correlates of these eating behaviors will be evaluated as disease endpoints occur.

Seven-year tracking of dietary factors in young adults: the CARDIA study

OBJECTIVES

This report determines the extent to which young adults in the highest and lowest intake quintiles of 13 nutrients remain in the same or adjacent quintiles (i.e., "tracked") relative to each other, over 7 years.

METHODS

Data from baseline and year 7 of the CARDIA study were divided into race/gender-specific quintiles for each nutrient and cross-tabulated.

RESULTS

For most nutrients, over 60% of those in the lowest absolute intake quintile at year 0 remained in the lowest or second-lowest quintile at year 7. A similar pattern was seen with highest absolute intake quintiles at years 0 and 7. Tracking was attenuated when nutrient density, rather than absolute intake, was examined.

CONCLUSIONS

Ingrained dietary habits may cause high- or low-intake groups to retain relative ranking, even in the face of secular, age-, or lifestyle-related trends in dietary intake.

Relationship between changes in dietary sucrose and high density lipoprotein cholesterol: the CARDIA study. Coronary Artery Risk Development in Young Adults

PURPOSE

Cross-sectional data from several observational studies have suggested that dietary sucrose may be inversely associated with high density lipoprotein cholesterol (HDL-C). This study examined associations between energy from dietary sucrose and HDL-C at baseline, year 7 and longitudinally (year 7 minus baseline) in a cohort of young black and white men and women from the Coronary Artery Risk Development in Young Adults (CARDIA) study.

METHODS

The sample included 4734 black men, black women, white men and white women, ages 18-30 years, in 1985-86 (baseline); 3513 at year 7; and 3335 for longitudinal analyses. Multivariate analyses was used with adjustment for age, BMI, cigarettes smoked per day, physical activity score, and alcohol intake.

RESULTS

Multivariate analyses indicated that energy intake from sucrose was inversely associated with HDL-C for each race-gender group at baseline, year 7, and longitudinally from baseline to year 7. This association was significant at baseline for black men, and white men and women (p < 0.01); at year 7 for white men and black women (p < 0.01), and longitudinally for white men, white women, and black women (p < 0.05).

CONCLUSIONS

The consistent inverse associations between energy from dietary sucrose and HDL-C observed in both cross-sectional and longitudinal analyses, and in different race and gender groups in CARDIA suggest that lowering dietary sucrose intake may be beneficial for those who may have low HDL-C.

Association of dietary fish and n-3 fatty acid intake with hemostatic factors in the coronary artery risk development in young adults (CARDIA) study

Hemostatic factors play an important role in the complications of ischemic heart and vessel disease. Dietary fats such as n-3 fatty acids have been shown to possibly influence hemostatic factors. However, most studies reporting an inverse association between cardiovascular disease and fish and n-3 fatty acid consumption used supplemental doses of fish oil or intakes exceeding the typical amount consumed by the US population. This report examined the associations of usual intakes of fish, linolenic acid, eicosapentaenoic acid, and docosahexaenoic acid with fibrinogen, factor VII, factor VIII, and von Willebrand factor in the Coronary Artery Risk Development in Young Adults (CARDIA) Study. The analyses reported here included 1672 black and white men and women aged 24 to 42 years in 1992 to 1993. After adjustment for age, body mass index, diabetes, number of cigarettes smoked per day, race, and energy and alcohol consumption, no significant associations were observed between those who consumed no fish versus those who consumed the highest level of dietary fish with respect to fibrinogen, factor VIII, or von Willebrand factor for any race-sex group. Comparisons of tertile 1 versus tertile 3 for dietary linolenic acid, eicosapentaenoic acid, and docosahexaenoic acid were also not significantly associated with fibrinogen, factor VII, factor VIII, or von Willebrand factor for any race-sex group. These data suggest that customary intakes of fish and n-3 fatty acids in populations that generally do not consume large amounts of these food items are not associated with these hemostatic factors.

Double data entry: what value, what price?

We challenge the notion that double data entry is either sufficient or necessary to ensure good-quality data in clinical trials. Although we do not completely reject that notion, we quantify some of the effects that poor quality data have on final study results in terms of estimation, significance testing, and power. By introducing digit errors into simulated blood pressure measurements we demonstrate that simple range checks allow us to detect (and therefore correct) the main errors that impact the final study results and conclusions. The errors that cannot easily be detected by such range checks, although possibly numerous, are shown to be of little importance in drawing the correct conclusions from the statistical analysis of data. Exploratory data analysis cannot identify all errors that a second data entry would detect, but on the other hand, not all errors that are found by exploratory data analysis are detectable by double data entry. Double data entry is concerned solely with ensuring, to a high degree of certainty, that what is recorded on the case record form is transcribed into the database. Exploratory data analysis looks beyond the case record form to challenge the plausibility of the written data. In this sense, the second entering of data has some benefit, but the use of exploratory data analysis methods, either as data entry is ongoing or at the end of data entry and as the first stage in an analysis strategy, should always be mandatory.

Seven-year trends in body weight and associations with lifestyle and behavioral characteristics in black and white young adults: the CARDIA study

OBJECTIVES

This study estimated the amount of weight change in a biracial cohort of young adults and the separate components attributable to time-related and aging-related changes, as well as identified possible determinants of weight change.

METHODS

In this population-based prospective study of 18- to 30-year-old African-American and White men and women, body weight and prevalence of overweight were measured from 1985/86 to 1992/93.

RESULTS

Average weight increased over the 7 years, increases ranging from 5.2 kg (SE = 0.2, n = 811) in White women to 8.5 kg (SE = 0.3, n = 882) in African-American women. Significant time-related increases in weight, ranging from 2.0 kg (SE = 1.0) in White women to 4.8 kg (SE = 1.0, n = 711) in African-American men, accounted for 40% to 60% of the average total weight gain. Aging-related increases were also significant, ranging from 2.6 kg (SE = 0.8, n = 944) in White men to 5.0 kg (SE = 1.1) in African-American women. The prevalence of overweight increased progressively in each group. Decreased physical fitness was most strongly associated with weight gain in both sexes.

CONCLUSIONS

The observed dramatic time-related weight gains, most likely due to secular (period-related) trends, are a serious public health concern.

Seven-year trends in plasma low-density-lipoprotein-cholesterol in young adults: the CARDIA Study

To identify determinants of recent secular trends in lipids and characterize their influence on age-related increases in LDL-cholesterol, we examined a cohort of black and white men and women aged 18-30 in 1985-1986. Secular trends were determined by comparing participants aged 25-30 at baseline with those aged 25-30 at year 7 (2788 and 1395 participants, respectively). LDL-cholesterol was lower among those 25-30 at year 7 (5.9 to 10.2 mg/dL, depending on race-sex group; P < 0.001); weight was higher (8.3 to 12.5 lb; P < 0.001); Keys score was lower (-4.2 to -7.3 units; P < 0.001); and use of oral contraceptives was greater (white women only, P < 0.01). Among 4086 participants followed for 7 years, LDL-cholesterol changed little or decreased, despite substantial weight increases in all groups (11.6 to 19.0 lb; P < 0.001). Keys scores decreased by 6.1 to 8.0 units, and use of oral contraceptives decreased (P < 0.001). Declining secular trends in LDL-cholesterol occurred despite upward trends in weight; the decline was associated with lower dietary fat and cholesterol and offset expected age-related increases in LDL-cholesterol.

Dietary antioxidants and plasma lipids: the CARDIA Study

OBJECTIVE

To determine if dietary antioxidants play a role in preventing coronary heart disease (CHD) by having an impact on lipid levels.

METHODS

Data from the Coronary Artery Risk Development in Young Adults (CARDIA) Study were used to assess the associations of reported intake of vitamins A, C, E and beta carotene, and their use in supplements, with lipid levels in a black and white, healthy adult (18 to 30 years of age at the baseline examination) population.

RESULTS

After adjusting for age, education level, physical activity, body size, alcohol consumption and caloric intake, vitamin A, beta carotene, and vitamin C (white women) intake were directly associated with HDL-cholesterol levels among women who smoked cigarettes, with the strongest associations being observed for white women. Black men who took supplements of vitamins A and C and did not smoke cigarettes had significantly higher HDL-cholesterol levels compared to those in the lowest levels of dietary intake. Although vitamin E was associated with higher levels of HDL-cholesterol, the association was only of borderline significance among white men who smoked cigarettes (p = 0.06). We did not observe any consistent associations between antioxidants and other plasma lipids, including total cholesterol, LDL-cholesterol, or triglycerides.

CONCLUSIONS

We conclude that dietary antioxidants are associated with HDL-cholesterol levels in some subsets of the population, although these associations may be operating in conjunction with other lifestyle behaviors.

Data quality assurance, monitoring, and reporting

In conclusion, the quality assurance and monitoring program is an integral and continuing part of study operations. A system must be devised and implemented by the coordinating center investigators, with the endorsement of the study leadership and support of the field site and resource center personnel. Proactive mechanisms for promoting high-quality data acquisition and reporting must be implemented. Data quality monitoring must address the entire process by which the data are gathered, transmitted, stored, and analyzed. Data quality should be monitored continually, with summary reports prepared and distributed to the study leadership. Appropriate training and certification enhance data quality, and site visits allow data collection and storage processes to be observed directly. The quality assurance and monitoring system must be documented. It should be flexible enough so that new means of quality assurance or monitoring can be added when necessary during the course of the study. At the completion of the study, quality monitoring results should be summarized in a final report regarding the level of quality achieved by the study investigators and personnel. Finally, for a quality assurance and monitoring program to be successful, the coordinating center investigators and personnel must provide prompt feedback and suggestions for corrective action whenever a data quality problem is discovered. This need can be met only when the coordinating center staff understand data quality goals and are up to date with all phases of data management and reporting. Delays in initiating any stage of data management and quality monitoring may result in uncorrectable data problems. Thus, knowledgeable and efficient coordinating center personnel are essential to achieving good data quality studywide.

Associations of body mass and body fat distribution with parity among African-American and Caucasian women: The CARDIA Study

Associations of parity with body fat and its distribution are poorly understood; therefore, we examined the relationships between parity and obesity in young adult women. Body mass index (BMI), skin-folds, and waist-hip ratio were compared in 1452 African-American and 1268 Caucasian nonpregnant women aged 18 to 30, adjusting for age (where no age-parity interactions were present), education, physical activity (assessed by questionnaire) and fitness (assessed by graded exercise test), dietary fat intake, alcohol and smoking. Adjusted mean BMI was significantly higher in African-American women aged 25-30 years with three or more children (28.5 kg/m2) than in those with two (27.0 kg/m2), one (26.2 kg/m2), or no children (26.3 kg/m2). Similar trends were found in Caucasians (BMI = 23.3, 23.4, 23.7, 25.0 kg/m2 for parity = 0, 1, 2, > or = 3, respectively), but the mean BMI was significantly higher in African Americans in each parity group. The association between BMI and parity was not present among women 18-24 years of age. Skinfolds were directly associated with parity in African Americans only. Waist-hip ratios were generally lower among nulliparous than parous women in both ethnic groups; race differences were present only among nulliparas. In conclusion, parity was associated with BMI in women aged 25 to 30 years but did not explain ethnicity-related differences in body mass.

A comparison of two methods to ascertain dietary intake: the CARDIA Study

Data on dietary intake were collected in the Coronary Artery Risk Development in Young Adults (CARDIA) Study at the baseline examination in 1985-86 and again at the second examination 2 years later. At baseline, a diet history questionnaire developed for the CARDIA study was used; at the second exam the NCI (Block) food frequency questionnaire was used. The purpose of the present report is to compare the estimated nutrient intakes obtained with the two instruments; to compare correlations of nutrient intakes obtained at the two exams with those observed for other lifestyle and physiological variables also measured 2 years apart; and to assess ability to test hypotheses relating 2-year changes in risk factors to between-exam differences in reported nutrient intakes. Mean levels of reported intake were generally greater for both blacks and whites on the CARDIA diet history than on the Block food frequency. Rank order correlations of reported nutrient intakes between the two questionnaires indicated greater consistency between instruments for whites (r's ranging between 0.35 and 0.52) than for blacks (r's ranging between 0.29 and 0.45). Correlations over time for nutrients were smaller than those observed for body size measures and lipid levels but were similar in magnitude to those for blood pressure, physical activity, and life events. At both exams, total caloric intake was positively associated with physical activity (range of r's for CARDIA were 0.07 for white women to 0.23 for black men, the range of r's for Block were 0.06 for women to 0.11 for white men). Using data from the two examinations, 2-year changes in total plasma cholesterol were significantly related to 2 year changes in Keys scores. The results of this comparison are useful in that they show similarities and differences between two instruments developed to gather dietary intake data. The study also illustrates the need to monitor young adults during a time when rapid changes occur in many lifestyle and physiologic factors.

A computerized diet history questionnaire for epidemiologic studies

OBJECTIVE

To describe methods used to computerize the diet history questionnaire developed for the Coronary Artery Risk Factor Development in Young Adult (CARDIA) study and to describe quality-control procedures used in conjunction with dietary assessment.

DESIGN

The computerized diet history is being used in a case-control study. Because of the computerized nature of the questionnaire, we developed quality-control procedures that incorporate listening to an audiotape of the interview while visually reviewing recorded data.

SETTING

Three centers involved in a population-based epidemiologic study of colon cancer.

SUBJECTS

Men and women between the ages of 30 and 79 years.

RESULTS

Quality-control results showed that 100% of the computerized forms would be free of errors if the data were subjected to visual review only. Probing errors, which accounted for 47.3% of all errors, were the most commonly encountered errors. In probing errors the interviewer did not probe in a nondirective manner, or the interviewer failed to verify responses that might be considered questionable.

APPLICATIONS

The CARDIA diet history was computerized for use in epidemiologic studies of the association between diet and disease. Review of the audiotapes of the interviews showed that most errors made in obtaining a dietary assessment were not detectable from visual review of the data. Although the quality-control procedures were developed for a computerized diet history questionnaire, they are applicable to other dietary assessment methods.