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Biomedical subjects

D T Lackland

Publications and source records attributed to D T Lackland.

At least 19 recordsLinked to original sources
PubMed2006

Nuclear magnetic resonance-determined lipoprotein subclass profile in the DCCT/EDIC cohort: associations with carotid intima-media thickness.

AIMS: To relate nuclear magnetic resonance lipoprotein subclass profiles (NMR-LSP) and other lipoprotein-related factors with carotid intima-media thickness (IMT) in Type 1 diabetes. METHODS: Lipoprotein-related factors were determined in sera (obtained in 1997-1999) from 428 female [age 39 +/- 7 years (mean +/- SD)] and 540 male (age 40 +/- 7 years) Diabetes Control and Complications Trial (DCCT)/Epidemiology of Diabetes Interventions and Complications (EDIC) participants. NMR quantifies chylomicrons, three very low-density lipoprotein (VLDL) subclasses, intermediate density lipoprotein (IDL), three low-density lipoprotein (LDL) subclasses, two high-density lipoprotein (HDL) subclasses, mean VLDL, LDL and HDL size, and LDL particle concentration. Conventional lipids, ApoA1, ApoB and Lp(a) and in vitro LDL oxidizibility were also measured. IMT was determined (in 1994-1995) using high-resolution B-mode ultrasound. Relationships between IMT and lipoproteins were analysed by multiple linear regression, controlling for age, diabetes-related factors, and cardiovascular disease (CVD) risk factors. RESULTS: IMT associations with lipoproteins were stronger for the internal than the common carotid artery, predominantly involving LDL. Internal carotid IMT was positively (P < 0.05) associated with NMR-based LDL subclasses and particle concentration, and with conventional LDL-cholesterol and ApoB in both genders. Common carotid IMT was associated, in men only, with large VLDL, IDL, conventional LDL cholesterol and ApoB. CONCLUSIONS: NMR-LSP reveals significant associations with carotid IMT in Type 1 diabetic patients, even 4 years after IMT measurement. NMR-LSP may aid early identification of high-risk diabetic patients and facilitate monitoring of interventions. Longer DCCT/EDIC cohort follow-up will yield CVD events and IMT progression, permitting more accurate assessment of pre-morbid lipoprotein profiles as determinants of cardiovascular risk in Type 1 diabetes.

Adult↗
PubMed2004

Sarcoidosis: social predictors of severity at presentation.

To determine relationships among social predictors and sarcoidosis severity at presentation, demographic characteristics, socioeconomic status, and barriers to care, A Case-Control Etiologic Study of Sarcoidosis (ACCESS) was set up. Patients self-reported themselves to be Black or White and were tissue-confirmed incident cases aged > or =l8-yrs-old (n=696) who had received uniform assessment procedures within one of 10 medical centres and were studied using standardised questionnaires and physical, radiographical, and pulmonary function tests. Severity was measured by objective disease indicators, subjective measures of dyspnoea and short form-36 subindices. The results of the study showed that lower income, the absence of private or Medicare health insurance, and other barriers to care were associated with sarcoidosis severity at presentation, as were race, sex, and age. Blacks were more likely to have severe disease by objective measures, while women were more likely than males to report subjective measures of severity. Older individuals were more likely to have severe disease by both measures. In conclusion, it was found that low income and other financial barriers to care are significantly associated with sarcoidosis severity at presentation even after adjusting for demographic characteristics of race, sex, and age.

Adult↗
PubMed2001

A current assessment of rurally linked exposures as potential risk factors for sarcoidosis.

PURPOSE: To identify and quantify the risk of developing sarcoidosis associated with specific rural exposures previously recognized as potential risk factors for this disease. METHODS: A matched case-control design was carried out with a 2-to-1 ratio of controls to cases. Case exposure histories were determine from a detailed questionnaire collecting self-reported information covering the period from birth through disease development and comparing that to exposure histories for the corresponding period in age-, race-, and gender-matched controls identified using Random Digit Dial survey methodology. Conditional logistic regression was used to analyze the matched data while controlling for several baseline variables. RESULTS: A number of exposures were found to be univariately associated with the development of sarcoidosis including: the use of wood stoves, the use of fireplaces, the use of nonpublic water supplies, and living or working on a farm. A dose-response gradient was detected from exposure to wood stoves and fireplaces continued to be significantly associated with sarcoidosis in multivariable models. CONCLUSIONS: The results of this study provide further support for the hypothesis that behaviors associated with rural living play some role in the development of sarcoidosis. This study further suggests that exposures involving the handling or burning of wood such as using wood stoves or fireplaces for home heating may, in part, explain this rural association.

Adult↗
PubMed2001

Predicting patient intent to return from satisfaction scores.

This study describes the development of a patient satisfaction assessment instrument used at the Medical University of South Carolina Outpatient Services clinics. Three years of responses were analyzed and a logistic regression model is presented to identify components of care that predict patient intent to return for additional care. Waiting time and understanding doctor's explanation were the only items that were significant predictors of intent to return. Additionally, the calculated probability of a return visit was used to calculate the potential impact of changes in mean satisfaction scores on the number of patient visits to the hospital ambulatory clinics.

Health Care Surveys↗
PubMed2001

Health among commercial airline pilots.

BACKGROUND: The airline pilot works within a complex exposure environment that may present physiological challenges to long-term health. METHODS: This study investigated self-reported disease outcomes among a large group of active and retired commercial airline pilots in the United States and Canada. A survey methodology was used, including the collection of historical information. RESULTS: Of 10,678 surveys mailed, 6609 were returned (6533 men, 63 women). Given the limitations of survey methodology, increased disease rates among pilots were suggested for melanoma, motor neuron disease, and cataracts. However, rates for other diseases were in general lower than those for the U.S. population. CONCLUSIONS: Further study has been initiated to verify and follow reported cases, to expand the study to a larger group, and to collect more in-depth information on flight histories, occupational exposures, and lifestyle factors.

Adolescent↗
PubMed2001

Non-invasive measurement of blood pressures in the Yucatan micropig (Sus scrofa domestica), with and without midazolam-induced sedation.

Current literature suggests that the effects of midazolam, a water-soluble benzodiazepine, on blood pressure in swine are minimal. The hypothesis of the study reported here was that a light sedative dose would induce a decrease in blood pressure in this species. Healthy female Yucatan Micropigs (n = 20), 16 to 30 (mean, 22) kg, aged four six months, were individually placed in a humane restraint sling and allowed to acclimate. Systolic (SBP), diastolic (DBP), and mean (MBP) blood pressures (mmHg) and heart rate (HR; beats per min [bpm]) were measured by use of oscillometry. The pressure cuff was placed at the base of the tail, and five sets of values were recorded at five-min intervals, beginning at 10 and ending 30 min after cuff placement. Following a three- to four-day rest period, this procedure was repeated with the addition of a dose of 0.5 mg of midazolam HCl/kg of body weight given intramuscularly at the time of cuff placement. A paired one-way Student's t-test was used to compare the means of the five measures between control and midazolam treatment. Mean (+/- SD) differences for SBP, DBP, MBP, and HR were 18.9 (+/- 3.97), 17.8 (+/- 5.27), and 18.6 (+/- 5.09) mmHg and 20.7 (+/- 3.73) bpm, respectively. All four parameters were significantly reduced in the midazolam-sedated group (P < 0.001). The maximal decrease in SBP, DBP, and MBP occurred at 15 and 20 min after dosing. Mean values based on the means of the five measures were 128 (+/- 12.6), 80 (+/- 9.4), and 99 (+/- 9.2) mmHg and 135 (+/- 17.4) bpm, and 109 (+/- 15.4), 63 (+/- 12.6), and 80 (+/- 13.6) mmHg and 115 (+/- 15.5) bpm for SBP, DBP, MBP, and HR in the control (n = 20) and midazolam (n = 20) groups, respectively. The control values can serve as normal oscillometric values for this age, sex, and breed of Micropig. We conclude that midazolam, given intramuscularly at a sedative dosage, negatively affects cardiovascular parameters measured by use of a blood pressure cuff, in sexually mature female Micropigs, compared with values in untreated pigs, which is similar to reports for humans.

Animals↗
PubMed2000

Low birth weights contribute to high rates of early-onset chronic renal failure in the Southeastern United States.

BACKGROUND: The southeastern United States is a region in which rates of cardiovascular and renal diseases are excessive. Within the Southeast, South Carolina has unusually high rates of end-stage renal disease (ESRD) in young people, with more than 70% of cases attributed to hypertension and diabetes. OBJECTIVE: To determine whether the increased vulnerability to early-onset ESRD might originate through impaired renal development in utero as measured by low birth weight. METHODS: Patients who were diagnosed with renal failure and undergoing dialysis from 1991 through 1996 were identified from the ESRD registry maintained by the Southeastern Kidney Council, Raleigh, NC. Birth weights reported on birth certificates were selected for the ESRD cases and non-ESRD controls who were born in South Carolina in 1950 and later. Birth weights were compared for 1230 cases and 2460 controls who were matched for age, sex, and race. RESULTS: Low birth weight was associated with ESRD among men and women as well as blacks and whites. Among people whose birth weight was less than 2.5 kg, the odds ratio for ESRD was 1.4 (95% confidence interval, 1.1-1.8) compared with people who weighed 3 to 3.5 kg. This association was present for renal failure resulting from diabetes, hypertension, and other causes. CONCLUSIONS: Low birth weights, which reflect adverse effects on development in utero, contribute to the early onset of ESRD in South Carolina. Since low birth weight increases the risk of ESRD from multiple causes, the data suggest that an adverse environment in utero impairs kidney development and makes it more vulnerable to damage from a range of pathological processes.

Adult↗
PubMed2000

Flight deck magnetic fields in commercial aircraft.

BACKGROUND: Airline pilots are exposed to magnetic fields generated by the aircraft's electrical system. The objectives of this study were (1) to directly measure flight deck magnetic fields in terms of personal exposure to the pilots when flying on different aircraft types over a 75-hour flight-duty month, and (2) to compare magnetic field exposures across flight deck types and job titles. METHODS: Measurements were taken using personal dosimeters carried by either the Captain or the First Officer on Boeing 737/200, Boeing 747/400, Boeing 767/300ER, and Airbus 320 aircraft. RESULTS: Approximately 1,008 block hours were recorded at a sampling frequency of 3 seconds. Total block time exposure to the pilots ranged from a harmonic geometric mean of 6.7 milliGauss (mG) for the Boeing 767/300ER to 12.7 mG for the Boeing 737/200. CONCLUSIONS: Measured flight deck magnetic field levels were substantially above the 0.8-1 mG level typically found in the home or office and suggest the need for further study to evaluate potential health effects of long-term exposure.

Aircraft↗
PubMed2000

Biochemical and metabolic effects of very-low-salt diets.

In cross-cultural studies, very low sodium intakes are associated with a low prevalence of hypertension and minimal increase of blood pressure with aging. Disorders of lipid and carbohydrate metabolism are rare. In short-term clinical studies, very low sodium intake (<50 mmol/d) has been associated with greater values for total and low-density lipoprotein cholesterol, fasting and post-glucose insulin, uric acid, plasminogen activator inhibitor-1, and activity of the renin-angiotensin system. Thus, the long-term safety of the very-low-salt diets suggested by these observations, in which sodium is one of many differences between population groups, is not entirely consonant with the short-term clinical trials data in which sodium is studied as an isolated intervention. This may reflect transient effects of abrupt and large changes in sodium consumption. Nevertheless, differences in diet composition and nutrient intake other than sodium including potassium, magnesium, and a range of antioxidants may also contribute to the discrepancies between ecological observations and clinical studies. Further research on the effects of selective changes of dietary sodium versus more global changes in diet composition on biochemical and hemodynamic variables could provide the basis for an even more effective public health policy.

Cholesterol↗
PubMed2000

Prevention education and evaluation in U.S. medical schools: a status report.

The Prevention Curriculum Assistance Program (PCAP) was initiated to help U.S. medical schools examine the extent to which they are evaluating the learning of medical students about disease prevention/health promotion. A survey was sent to all 144 allopathic and osteopathic medical schools, with an overall response rate of 68%. The results revealed more emphasis on teaching and evaluating the learning of medical students in the areas of clinical preventive services and quantitative methods, and less emphasis on the community dimensions of medical practice and health services organization and delivery. Written tests and unstructured observation are the most common methods of evaluation. Fewer than half of all respondents were satisfied with the quality of their assessment of student achievement in any of the four domains of prevention education. More than 30% expressed a desire to receive assistance with designing curricula and/ or evaluation methods in each of the four content areas examined. Several indicated their willingness to assist colleagues who want to improve their prevention curricula and/or measurement strategies. This study identified a need for more attention and support for prevention education and evaluation programs. Curriculum leaders can help by designating prevention a priority area and appointing faculty to be responsible for monitoring the content and quality of prevention teaching throughout the curriculum. Resources such as the Internet can be utilized to establish a network whereby medical schools can collaborate to improve their educational programs and evaluation methods in prevention.

Achievement↗
PubMed2000

Perspectives of those impacted: airline pilot's perspective.

The airline pilot operates within an environment that consists of circadian dysrhythmia, reduced atmospheric pressure, mild hypoxia, low humidity, and exposure to sound, vibration, cosmic-radiation, and magnetic-field exposure. These occupational exposures present physiological challenges to the long term health of the airline pilot. In particular, exposure to cosmic radiation and its carcinogenic potential have recently received considerable attention. Given the complexity of the environment and possible synergistic exposures, there is an immediate requirement for comprehensive research into both cosmic-radiation and magnetic-field exposures in airline pilots. In response, the Airline Pilots Association International in conjunction with the Medical University of South Carolina (Department of Biometry and Epidemiology) has initiated an extensive research program into these occupational exposures. These investigations include ground based calculations, flight-dose estimates, epidemiological survey and exposure assessment, and biological marker analysis.

Aircraft↗
PubMed2000

Short-term impact of a church-based approach to lifestyle change on cardiovascular risk in African Americans.

While lifestyle modification decreases cardiovascular risk, there are barriers to lifestyle education in usual clinical practice, especially among the medically underserved. To address this gap, "Lighten Up," a church-based lifestyle program was developed in collaboration with the local African-American Christian community. Lighten Up includes a baseline health assessment (week 1), eight educational sessions (weeks 2-9) combining study of scripture and a health message, a short-term health check (week 10) and a long-term health check (week 52). Baseline and 10 week risk factor data have been obtained in 133 African Americans from eight sites (83% women) and form the basis of this report. At baseline, 76% of participants had two or more modifiable risk factors (overweight, hypertension, borderline high cholesterol, or diabetes). The entire group had significant short-term reductions in weight (-2.3 pounds, P<.01), mean blood pressure (BP, -2.1 mm Hg, P<.05), and triglycerides (-11 mg/dl, P<.05). Risk factor improvement was greater among the 60 subjects who attended 75% or more of the educational sessions. In this group, weight fell 2.9+/-0.6 pounds (mean +/- SEM; P<.01), mean BP declined 3.8+/-1.2 mm Hg (P<.01), total cholesterol was lowered 6+/-4 mg/ dl (P = .12), and triglycerides were reduced 17+/-9 mg/dl (P = .05). Lighten Up is reaching a group with multiple cardiovascular risk factors that is not optimally managed by existing healthcare resources. Of the 133 participants, 70% attended half or more of the sessions, and several components of the risk factor cluster were favorably affected.

Black or African American↗
PubMed1999

Geographic variation in sarcoidosis in South Carolina: its relation to socioeconomic status and health care indicators.

Geographic patterns of sarcoidosis have been detected and studied on a global scale. However, the associations between these disease patterns and population characteristics have not been determined. The authors studied the geographic pattern of sarcoidosis in South Carolina and its relation to socioeconomic status (SES) and health status indicators. Hospitalization rates for the period 1985-1995 were used as geographic indicators of sarcoidosis. Rates were assessed for the 46 counties in South Carolina, adjusting for differences in SES, availability/accessibility of health care, diagnostic practices, and hospital utilization. Patterns in geographic variation were assessed based on physiographic characteristics and proximity to the Atlantic coastline. Significant variation was identified with an increase in sarcoidosis rates proximal to the Atlantic coastline. Population characteristics were identified that appeared to explain regional variation in sarcoidosis in Caucasians; however, regression analysis was unable to explain the regional differences in disease distribution by variation in SES, diagnostic practices, accessibility/availability, or hospital utilization in African Americans. These results suggest that the development of sarcoidosis is associated with a geographically linked risk factor in African Americans. This work supports the need for additional studies that will identify this risk factor(s).

Adult↗
PubMed1999

Impact of nativity and race on "Stroke Belt" mortality.

The southeastern region of the United States has been recognized for 6 decades as an area of excess cerebrovascular mortality rates. While the reasons for the disease variation remain an enigma, South Carolina has consistently been the forerunner of the "Stroke Belt." To determine the effects of nativity (birthplace) on stroke mortality rates in South Carolina, proportional mortality ratios (PMRs) were calculated for stroke deaths in South Carolina during 1980-1996 according to birthplace and stratified by gender, race, age, and educational status. The analyses revealed a graded risk of stroke by birthplace, with the highest PMRs (95% CI) among individuals born in South Carolina (104.8 [103.4 to 106.3]), intermediate PMRs in those born in the Southeast other than South Carolina (92.5 [90.2 to 94.9]), and lowest PMRs for those born outside the Southeast (77.4 [74.9 to 80.1]). The lower stroke PMRs for individuals born outside the Southeast were more striking in blacks (51.8 [45.2 to 59.3]) than in whites (84.9 [82.0 to 88.0]) and for men (73.3 [69.5 to 77.3]) than women (83.5 [79.9 to 87.3]). The findings, particularly in blacks, were not explainable by gender, differences in age, and/or markers of educational and socioeconomic status. These findings suggest that nativity is a significant risk marker for the geographic variation in stroke mortality. Moreover, the regional disparities for nativity and subsequent stroke mortality appear to be greater in blacks than in whites and for men than for women. An understanding of factors linking birthplace to risk for cerebrovascular mortality could facilitate efforts directed at stroke prevention.

Black or African American↗
PubMed1999

The dominant role of systolic hypertension as a vascular risk factor: evidence from the southeastern United States.

A high burden of hypertension-related cardiovascular disease remains an unfortunate hallmark in the southeastern United States (also known as the Stroke Belt). A convergence of factors related to aging, systolic blood pressure (BP), and hypertension control rates indicate that the Southeast burden will remain and probably increase well into the next century unless strategic initiatives are undertaken soon. More specifically, systolic BP, which is a major independent risk factor, increases as a function of age, whereas diastolic BP reaches a plateau. Given a selective immigration of elderly residents from other areas of the country, the Southeast is "aging" more rapidly. Thus, isolated systolic hypertension (ISH), which carries a very high relative risk, is likely to increase at a faster rate in the Southeast than in other areas of the U.S. Moreover, control rates for systolic BP are poorer than for diastolic BP. Hypertension control rates are also lower in elderly people than in younger patients with hypertension. In the absence of a paradigm shift in medical practice, control rates will decline as the prevalence of ISH rises in an aging population. The health and economic implications of an inadequate response to this challenge are imposing, particularly for the Southeast. On a positive note, the emerging recognition of systolic BP as a significant risk factor may lead to more appropriate recognition and higher rates of treatment and control. Randomized, controlled clinical trials have clearly established that treatment reduces BP in the elderly patient with ISH and combined systolic-diastolic hypertension. Moreover, treatment dramatically reduces hypertension-related cardiovascular complications among elderly patients with hypertension. In summary, the Southeast will lead the aging of the nation into the next century. The implications of this large demographic shift are likely to worsen rather than reduce the relative burden of cardiovascular disease in the Stroke Belt. Thus, a high priority should be given to the recognition, treatment, and control of systolic hypertension in the Southeast.

Adult↗