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Biomedical subjects

D L McGee

Publications and source records attributed to D L McGee.

At least 37 records · Page 2Linked to original sources
PubMed1997

One size fits all: implications for assessing dietary behavior.

Accurate assessment of dietary behavior is central to the design, implementation, and evaluation of intervention programs aimed at behavior change, and use of an Eating Behaviors Questionnaire (EBQ) has been suggested for measuring dimensions of dietary fat behavior. The EBQ has proven useful in characterizing fat-related dietary patterns among middle-class, highly educated, highly motivated white women. To investigate the generalizability of the instrument, we provide findings from a community-based sample of 235 African-Americans in Maywood, Illinois, a middle-class working community outside Chicago. The sample consisted of 159 women and 76 men with an average age of 47.4 +/- 13.8 years for women and 48.1 +/- 12.1 years for men (mean +/- standard deviation; range, 18 to 87 years). The EBQ is based on four broad behavioral domains (ie, avoidance, modification, substitution, and replacement) associated with fat-related eating patterns. These behavioral domains are composed of specific dietary behaviors (factors). Using a scoring system that allowed all participants to be included in all analyses, we identified a set of factors characterizing eating patterns in our sample that differed from those reported previously. When the factors were converted to scales using unit scoring, the average value suggested a tendency toward a higher fat eating pattern. Results indicate that although behavioral domains appear to be constant across populations, fat-related eating patterns are not. These observations have implications for understanding the diversity of fat-related dietary patterns across groups and for planning appropriate behavior change strategies.

Adult↗
PubMed1997

Relative weight and mortality in U.S. blacks and whites: findings from representative national population samples.

PURPOSE: To examine the impact of relative weight on mortality in black and white men and women. METHODS: Two representative national populations samples were used: the NHANES-I Epidemiologic Follow-up Study (NHEFS), and the National Health Interview Survey (NHIS). The principal analysis focused on 13,242 participants in the NHEFS and 114,954 in the NHIS. Minimum mortality was estimated from both categorical analysis and a logistic model. RESULTS: Minimum mortality ranged from a body mass index (BMI) of 25 to 32 kg/m2. The model-estimated BMI of minimum mortality for NHEFS was 27.1 (24.8-29.4, 95% CI), 26.8 (24.7-28.9, 95% CI), 24.8 (23.8-25.9, 95% CI) and 24.3 (23.2-25.4, 95% CI); for black men, black women, white men and white women, respectively, whereas for NHIS the corresponding values were 30.2 (24.8-35.6, 95% CI) 26.4 (24.2-28.7, 95% CI), 27.1 (25.5-28.7, 95% CI), and 25.6 (24.2-27.0, 95% CI). In all groups the shape of the relative risk curve was virtually identical and a broad range of BMI values in the middle of the distribution was associated with low relative mortality risk. Averaging the results from both surveys, the observed BMI of minimum risk was 3.1 kg/m2 higher in black men and 1.5 kg/m2 higher in black women than in their white counterparts; when adjusted for covariates these differences were only of borderline statistical significance, however. CONCLUSIONS: Because of the wide range of BMI values associated with low risk, and the consistency of the point of the up-turn in risk, group specific definitions of optimal values do not appear to be warranted.

Adult↗
PubMed1997

Socioeconomic status and health in blacks and whites: the problem of residual confounding and the resiliency of race.

A large number of epidemiologic studies have focused on racial/ethnic differences, particularly between blacks and whites. Because health endpoints and racial categorizations are associated with socioeconomic status, investigators generally adjust for socioeconomic indicators. The intention is usually to control for confounding, thereby making groups comparable and excluding socioeconomic status as an alternative explanation to hypotheses of innate physiologic differences. A threat to the validity of these analyses is therefore the presence of residual confounding. We identify four potential sources of residual confounding in this analytical design: categorization of socioeconomic status variables, measurement error in socioeconomic indicators, use of aggregated socioeconomic status measures, and incommensurate socioeconomic indicators. Using simulations and examples from the literature, we demonstrate that the effect of residual confounding is to bias interpretation of data toward the conclusion of independent racial/ethnic group effects. Investigators often refer to possible "genetic" differences on the basis of models that control for socioeconomic status. We propose that such conclusions on the basis of this analytical strategy are generally unwarranted. Racial/ethnic differences in disease are a pressing public health concern, but the current approach does not often provide a basis for inference about putative biological factors in the etiology of this disparity.

Black or African American↗
PubMed1996

Short stature and risk of mortality and cardiovascular disease: negative findings from the NHANES I epidemiologic follow-up study.

OBJECTIVES: This study sought to examine the relation between body height and incidence of myocardial infarction, coronary heart disease, overall mortality and mortality from cardiovascular disease. BACKGROUND: An association between short stature and increased risk of fatal and nonfatal cardiovascular disease has been observed in several studies, attracting considerable attention. METHODS: We used data from the First National Health and Nutrition Examination Survey (NHANES I) Epidemiologic Follow-Up Study, a prospective study of a large random sample of the U.S. population, to examine the association between height and risk of four end points. RESULTS: Baseline data were collected from 1971 to 1975 for 13,031 respondents (5,296 men, 7,735 women), and the average follow-up period was 13 years, through 1987. Height was inversely associated with risk of all four of the end points studied in both men and women. However, after adjustment for age and years of education in Cox proportional hazards analyses, the relation no longer existed. Using the same adjustment procedures, persons in the lowest height quintile had no increase in risk compared with those in the highest category. The findings were consistent for men and women, blacks and whites and different age groups. CONCLUSIONS: Data from this study in a national sample do not support the hypothesis of an inverse height-heart disease relation.

Adult↗
PubMed1996

Obesity and hypertension prevalence in populations of African origin. The Investigators of the International Collaborative Study on Hypertension in Blacks.

Obesity has been shown to be associated with hypertension in Africa, the Caribbean, and the United States, but there has not previously been an opportunity to compare the magnitude of this relation and estimate the contribution of obesity to hypertension risk across these populations. The International Collaborative Study on Hypertension in Blacks (ICSHIB) used age-stratified sampling and a standardized protocol to measure blood pressure and hypertension risk factors. We analyzed data on 9,102 men and women, age 25-74 years, from seven sites. We studied hypertension (140/90 mmHg or medication) in relation to body mass index (BMI) and sex-specific BMI cut-points designating "overweight" and "obesity." The prevalence of these conditions ranged from 6% to 63% for overweight, from 1% to 36% for obesity, and from 12% to 35% for hypertension. Adjusted relative risks were similar in most sites, ranging from 1.3 to 2.3 for both cut-points. We found that 6-29% of hypertension in each population was attributable to overweight and 0-16% to obesity. Comparing rural Africa with the United States, 43% of the difference in hypertension prevalence for women was attributable to overweight, and 22% for men, whereas respective values for obesity were 14% and 11%. These results indicate that the association between adiposity and hypertension is roughly constant across a range of environments, with little evidence for variation in susceptibility to effects of overweight in these groups.

Adult↗
PubMed1996

Reproducibility of the measurement of colonic proliferation using bromodeoxyuridine across laboratories.

Although measures of colonic cell proliferation are being used as potential intermediate markers in chemoprevention studies, measurement standardization is still ongoing. This study was designed to assess the reproducibility of the labeling index quantification, as measured by bromodeoxyuridine, across four laboratories experienced in its use. Each institution submitted 10 slides, with one circled area of each slide to be scored. Each site followed its standard procedures for scoring colonic crypts; no attempts to standardize these procedures were made. There was high concordance among the laboratories on whether scorable crypts were present on a particular slide, but only two pairs of laboratories demonstrated agreement statistically greater than that predicted by chance. The overall difference among the sites on the number of scorable crypts was marginally significant (P = 0.083), and there was a highly significant overall difference in the magnitude of the labeling index (P < 0.0001). Sites 1 and 2 tended to have similar results, as did sites 3 and 4, most likely due to common training. Even with these discrepancies, high correlation (r > 0.75) was observed among the reported labeling index values for each pair of laboratories. Without standardized training, these laboratories may differ in the crypts considered appropriate for counting and in whether cells are counted as labeled or unlabeled. These results suggest that standardized training in scoring across all sites performing labeling index determinations is required to assure reproducibility across sites or studies. These results may also help explain discrepancies in the average values of the labeling index reported in the literature.

Analysis of Variance↗
PubMed1995

Left ventricular hypertrophy has a greater impact on survival in women than in men.

BACKGROUND: Echocardiographically determined left ventricular hypertrophy (LVH) has a well-demonstrated association with cardiovascular morbidity and mortality. However, whether or not there is a sex differential in the impact of LVH on mortality has never been systematically explored. METHODS AND RESULTS: This study enrolled 436 consecutive black patients (163 men and 273 women) free of angiographic coronary artery disease from a hospital registry. LVH (left ventricular [LV] mass/body surface area > or = 117 g/m2 in men and > or = 104 g/m2 in women) was present in 84 men (52%) and 119 women (44%). During a mean of 5 years' follow-up (range, 0 to 9), 49 patients (26 men and 23 women) died. The mortality rate was 5.40 per 100 patient-years in men with LVH and 2.58 in men without LVH (crude relative risk [RR] = 2.09) and 3.21 and 0.66, respectively, in women (RR = 4.87). In Cox regression analysis, adjusting for age, hypertension, and ejection fraction, the RR of total death for LVH versus non-LVH was 2.0 (95% confidence interval [CI], 0.8 to 5.0) in men and 14.3 (95% CI, 1.6 to 11.7) in women. For cardiac death, RR was 1.3 (95% CI, 0.4 to 3.7) and 7.5 (95% CI, 1.6 to 33.8) in men and women, respectively. Analyses using LV mass indexed by height or height with the use of different LVH cut points, comparing patients in the highest sex-specific tertile of mass index to those in the lower two tertiles, and the use of LV mass indexes as continuous variables similarly demonstrated a greater increase in risk of either fatal end point among women than men. CONCLUSIONS: These findings indicate a sex difference in the contribution of LV mass and hypertrophy to mortality in the absence of coronary artery disease.

Adult↗
PubMed1994

Iron status and coronary heart disease: negative findings from the NHANES I epidemiologic follow-up study.

The potential association between iron status and coronary heart disease has received increased attention recently. The authors examine this hypothesis in the First National Health and Nutrition Examination Survey (NHANES I) Epidemiologic Follow-up Study. The study consisted of 4,237 respondents (1,827 men, 2,410 women) aged 40-74 years at baseline. During the average 13-year follow-up, 489 persons (289 men, 200 women) had an acute myocardial infarction, and 1,151 persons (633 men, 518 women) developed coronary heart disease (included myocardial infarction and other forms of chronic ischemic heart disease). In logistic regression analyses, adjusting for baseline age, systolic blood pressure, serum cholesterol, smoking status, and education, serum iron was inversely associated with the risk of myocardial infarction in women (relative risk = 0.82 for an increase of 5.4 mumol/liter (equivalent to about 1 standard deviation), 95% confidence interval (CI) 0.70-0.95), but not in men. Total iron-binding capacity and transferrin saturation were not related to myocardial infarction in either sex, while serum iron and transferrin saturation were inversely associated with coronary heart disease in both sexes. Among men, the relative risk was 0.92 (95% CI 0.85-1.00) for a 5.4-mumol/liter increase in serum iron, while a relative risk of 0.91 (95% CI 0.83-1.00) was observed for a 10% increase in transferrin saturation. For women, the corresponding relative risks were 0.86 (95% CI 0.77-0.95) and 0.88 (95% CI 0.79-0.98), respectively. Dietary iron intake based on 24-hour recall was not associated with the two disease end points. These findings from a large national sample do not support the hypothesis of a positive iron-coronary heart disease relation.

Adult↗
PubMed1994

Carotenoids, tocopherols, and retinoids in human buccal mucosal cells: intra- and interindividual variability and storage stability.

The baseline, intra-, and interindividual variability as well as storage stability of carotenoids, tocopherols, and retinoids in human buccal mucosal cells were determined because this information is lacking. All the buccal mucosal cell samples were collected after an overnight fast. In the variability study, 154 subjects (median age 57.5 y) provided three samples each at 7-10-d intervals over a 1-mo period. In the stability study, 13 young volunteers provided four samples each before and during the 11 d of oral administration of beta-carotene, alpha-tocopherol, and vegetable juice; the cells were pooled and stored as a pellet at -80 degrees C. Eleven micronutrients were analyzed simultaneously with HPLC. The results indicated that 1) lycopene and beta-carotene were the two major carotenoids, retinol was not detected in most cell samples; 2) the intra-individual variability was small, but the interindividual variability was very large; 3) two measurements of micronutrient concentration in fasting buccal mucosal cells should be adequate to establish a representative baseline for each micronutrient; and 4) the micronutrients under the storage conditions were stable for > or = 8 mo.

Administration, Oral↗
PubMed1994

Illiteracy among Medicaid recipients and its relationship to health care costs.

Poor literacy is associated with poor health status, but whether illiteracy is also linked to higher medical care costs is unclear. We characterized the literacy skills of 402 randomly selected adult Medicaid enrollees to determine if there was an association between literacy skills and health care costs. Each subject's literacy skills were measured with a bilingual (English/Spanish) reading-assessment instrument. We also reviewed each subject's health care costs over the same one-year period. The mean reading level of this Medicaid population was at grade 5.6. Mean annual health care costs were $4,574 per person. There was no significant relationship between literacy and health care costs. While there are compelling reasons to improve poor reading skills among Medicaid enrollees, illiteracy in this population does not appear to contribute to the high cost of providing government-sponsored care.

Adolescent↗
PubMed1994

Two-year incidence of colon adenomas developing after tandem colonoscopy.

OBJECTIVES: We attempted to determine an accurate frequency of new polyp growth in a cohort of veteran male patients who were initially cleared of polyps by tandem colonoscopy. METHODS: Followup colonoscopy was performed 2 yr after tandem colonoscopy. A polyp was categorized as "new" if it was not located in a segment of the colon or rectum that had harbored a neoplastic polyp of the same histology at tandem colonoscopy, in contradistinction to lesions designated as "same-segment" polyps. RESULTS: Fifty-eight of 90 patients who had tandem colonoscopy as a part of a previous study were available for follow-up colonoscopy for 2 yr. Ninety-one percent had a history of benign neoplastic polyps or cancer. Neoplastic polyps were documented in 52% (95% CI, 45-74%) of patients at followup, and 38% (95% CI, 26-52%) were found to have a total of 31 "new" lesions. All new lesions were tubular adenomas. The largest number of new polyps in an individual patient was four, and the largest new lesion was 20 mm in size with a flat, linear configuration. Most (25/31) new polyps were < or = 5 mm, and the number of neoplastic polyps per patient at follow-up was less than at tandem colonoscopy. CONCLUSIONS: Approximately one-half of older, male patients with a history of neoplastic polyps will demonstrate neoplastic polyps at 2 yr. In at least one-third of patients, these appear to be new lesions. In some patients, de novo neoplastic polyps can grow to > or = 1 cm within 2 yr.

Adenoma↗
PubMed1993

Design and analysis of studies to reduce the incidence of colon polyps.

Decisions regarding the design and analysis of a phase III study to reduce the incidence of colorectal polyps must take into account two complicating factors: the possibility that polyps are missed during screening exams, and variable lengths of follow-up. In this paper we investigate the effects due to misclassification on the power of statistical tests to detect a change in polyp recurrence rates. We also use Monte Carlo studies to examine the relative efficiency of different methods of adjusting for variable times of follow-up.

Bias↗
PubMed1993

Cytogenetics and clinical correlations in breast cancer.

We describe an ongoing study examining the relevance of cytogenetic changes in primary and metastatic breast cancer. Tumors samples from breast cancer patients are karyotype using G-banding techniques, and all chromosomal findings, including the presence of structural and numeric clonal abnormalities, are documented in a dynamic patient data base. Information on essential clinical characteristics is collected, and patients are followed longitudinally for disease recurrence, progression, and survival. Statistical analyses will examine potential correlations between specific abnormalities and clinical features of the disease, and survival differences between patients will be examined as a function of karyotypic differences. We anticipate that this research will provide insights on the natural history of breast cancer and help direct the search for the underlying molecular mechanisms of tumor genesis and progression.

Adult↗
PubMed1992

The mangled extremity. Compartment syndrome and amputations.

Injuries that amputate, crush, or otherwise mangle an extremity are devastating. The possibilities of medical and psychologic disability, multiple operations, and protracted rehabilitation loom before these patients. Fortunately, expert care given by the emergency department physician maximizes the opportunity for success should the limb be replanted or revascularized. The first priority for the emergency department staff is the efficient and aggressive resuscitation of the patient. Only after this has been carried out and other life-threatening injuries addressed can attention be directed toward the injured limb. It is in the patient's best interest if the emergency department staff assumes that a mangled extremity will be replanted or revascularized. Advances in microsurgical technique and equipment have enabled surgeons to achieve salvage rates greater than 90%. Continued improvements in technique, equipment, rehabilitation, and patient selection will enable more patients to benefit from limb salvage procedures.

Amputation, Traumatic↗