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Biomedical subjects

D T Lackland

Publications and source records attributed to D T Lackland.

At least 37 records · Page 2Linked to original sources
PubMed1998

Cosmic radiation and magnetic field exposure to airline flight crews.

BACKGROUND: Flight crews are exposed to elevated levels of cosmic radiation and to magnetic fields generated by the aircraft's electrical system. The purpose of this study was to quantify these two occupational exposures. METHODS: Magnetic fields were measured during 37 flights (23 in the cockpit and 14 in the cabin) using an Emdex Lite personal dosimeter. All cockpit measurements were taken on the B737/200. Cabin measurements were taken in several aircraft types, including the B737, B757, DC9, and L1011. Cosmic radiation was computer estimated for 206 flights using the Federal Aviation Administration's program CARI-3C. RESULTS: Magnetic field levels in the cockpit had a mean value of approximately 17 milliGauss (mG), while cabin measurements were lower (mean values of approximately 3 or less in economy, 6 in first class, 8 in front serving areas). Cosmic radiation equivalent dose rates to bone marrow and skeletal tissue ranged from 0.3 to 5.7 microsieverts per hour. CONCLUSIONS: Elevated magnetic field levels in front serving areas and the cockpit suggest the need for further study to evaluate long-term exposure to flight crew members who work in these areas. Cosmic radiation levels are well below occupational limits for adults, but may require some pregnant flight crew members to adjust their flying time or routes.

Aerospace Medicine↗
PubMed1998

Mortality among US commercial pilots and navigators.

The airline industry may be an occupational setting with specific health risks. Two environmental agents to which flight crews are known to be exposed are cosmic radiation and magnetic fields generated by the aircraft's electrical system. Other factors to be considered are circadian disruption and conditions specific to air travel, such as noise, vibration, mild hypoxia, reduced atmospheric pressure, low humidity, and air quality. This study investigated mortality among US commercial pilots and navigators, using proportional mortality ratios for cancer and noncancer end points. Proportional cancer mortality ratios and mortality odds ratios were also calculated for comparison to the proportional mortality ratios for cancer causes of death. Results indicated that US pilots and navigators have experienced significantly increased mortality due to cancer of the kidney and renal pelvis, motor neuron disease, and external causes. In addition, increased mortality due to prostate cancer, brain cancer, colon cancer, and cancer of the lip, buccal cavity, and pharynx was suggested. Mortality was significantly decreased for 11 causes. To determine if these health outcomes are related to occupational exposures, it will be necessary to quantify each exposure separately, to study the potential synergy of effects, and to couple this information with disease data on an individual basis.

Aerospace Medicine↗
PubMed1998

The geographic variation in stroke incidence in two areas of the southeastern stroke belt: the Anderson and Pee Dee Stroke Study.

BACKGROUND AND PURPOSE: South Carolina and the southeastern United States have maintained the highest stroke mortality in the country. The Anderson and Pee Dee Stroke Study is an assessment of cerebrovascular disease incidence in 2 geographically defined communities in the stroke belt. METHODS: Strokes were identified in the Anderson and Pee Dee areas of South Carolina. All hospitalized and out-of-hospital deaths occurring during 1990 among the residents of these 2 areas were included. Strokes were classified by an independent panel of neurologists using a standard protocol that included specific criteria for stroke and subtypes. RESULTS: The overall age-adjusted stroke incidence rates (per 100 000 population) were significantly higher in the Pee Dee population (293.1) compared with Anderson (211.2). The geographic differences were more dramatic in the younger age groups of 35 to 64 years. Likewise, incidence rates for blacks were nearly twice the rates for whites. The rates in the Pee Dee were higher than the rates from other studies in the United States and other parts of the world. Although the stroke subtypes did not vary between the 2 regions, race-sex differences were identified. CONCLUSIONS: High stroke incidence and disease rates persist for all 4 race-sex groups in the Southeast and reflect similar risks as mortality rates. However, geographic variability in stroke rates suggests that the pattern of disease in the region is not so much a "belt" of increased stroke in contiguous areas but rather more a "necklace" of different levels of risk. These results should be useful in the identification of factors associated with this geographic enigma.

Adult↗
PubMed1998

Strategies for cardiovascular disease prevention: importance of public and community health programs.

Cardiovascular diseases (CVD), principally coronary heart disease (CHD), stroke, and congestive heart failure, continue to be the leading cause of death claiming nearly 1,000,000 lives annually and accounting for more than 40% of the deaths in the United States (American Heart Association). While cardiovascular disease is often viewed as a problem of the elderly, 45% of heart attacks occur among individuals less than 65 years old. Moreover, CVD is the second leading cause of death for those 45 to 64 years of age and the third leading cause of death for those 25 to 44 years old. In economic terms, the annual direct and indirect costs of heart attack and stroke are approximately $259 billion or $492,444/second, in the United States alone. Thus, from a human and economic perspective, heart and vascular diseases are an enormous burden worthy of significant attention. This review is not intended to ignore the 50% decline in age-adjusted rates for heart attack and stroke events over the preceding three decades, as summarized by the recent report of the Joint National Committee on the Prevention, Detection, Evaluation and Treatment of High Blood Pressure (JNC VI). However, progress has halted as coronary heart disease and stroke mortality rates have reached a plateau in recent years and appear to be rising. Consequently, this is an excellent time for re-examining our approach to the prevention and treatment of CVD. In this article, readers will find an overview of the CVD prevention and treatment topics and not an in-depth analytical or epidemiological assessment of risk factors and outcomes. First, a macroscopic approach to reducing CVD is presented, followed by a discussion emphasizing the critical importance of public health and community-based programs in the effort to significantly reduce the burden of hypertension and related cardiovascular morbidity and mortality. Effective public health programs can play a pivotal role in raising awareness, and more importantly, in facilitating lifestyle change, entry and retention in the healthcare system, and compliance with non-pharmacological as well as drug therapy.

Cardiovascular Diseases↗
PubMed1998

Commun-I-Care: experience in the first four years.

The medically uninsured ("working poor") comprise roughly 10 percent of the citizens in South Carolina. These individuals are more likely than the insured to have chronic health conditions including hypertension, diabetes, and respiratory diseases. They appear to have poorer outcomes as as result of misallocation of health care resources from prevention to acute intervention. CIC is a novel program which represents an effort to coordinate the efficient utilization of existing resources to meet the non-emergent health care needs of the medically uninsured. The CIC program has enjoyed a successful beginning and, with the continued strong support of providers and sponsors, looks forward to exciting progress in the future.

Adolescent↗
PubMed1997

Hypertension-related morbidity and mortality in the southeastern United States.

Stroke mortality is higher in the Southeast compared with other regions of the United States. The prevalence of hypertension is also higher (black men = 35%, black women = 37.7%, white men = 26.5%, white women = 21.5%), and the proportion of patients whose hypertension is being controlled is poor, especially in white and black men. The prevalence of hypertension-related complications other than stroke is also higher in the Southeast. The five states with the highest death rates for congestive heart failure are all in the southern region. Of the 15 states with the highest rates of end-stage renal disease, 10 are in the Southeast. Obesity is very prevalent (24% to 28%) in the Southeast. Although Michigan tops the ranking for all states, 6 of the top 15 states are in the Southeast, as are 7 of the 10 states with the highest reported prevalence regarding no leisure-time physical activity. Similar to other areas of the United States, dietary sodium and saturated fat intake are high in the Southeast; dietary potassium intake appears to be relatively low. Other factors that may be associated with the high prevalence, poor control, and excess morbidity and mortality of hypertension-related complications in the Southeast include misperceptions of the seriousness of the problem, the severity of the hypertension, lack of adequate follow-up, reduced access to health care, the cost of treatment, and possibly, low birth weights. The Consortium of Southeastern Hypertension Control (COSEHC) is a nonprofit organization created in 1992 in response to a compelling need to improve the disproportionate hypertension-related morbidity and mortality throughout this region. The purpose of this position paper is to summarize the data that document the problem, the consequences, and possible causative factors.

Adult↗
PubMed1997

Hypertension-related mortality and morbidity in the southeast.

Geographic variations in adverse health outcomes have long been recognized in the United States, with specific focus on the southeastern region of the country. Cerebrovascular disease mortality rates have identified the Southeast as the "stroke belt" for decades, though rates are also high for other hypertension-related diseases including ischemic heart disease, diabetes, and end-stage renal disease. The increased cerebrovascular disease mortality in the Southeast has prompted intervention and research efforts. This paper provides a descriptive profile of the hypertensive end-organ diseases in this area to guide research efforts and to gauge changes in health outcomes and risks. In addition to mortality from stroke, this assessment identified excessive risks from diabetes, ischemic heart disease, and end-stage renal disease for some states in the Southeast. Trend variations in health outcomes were also detected.

Adolescent↗
PubMed1997

The effectiveness of topical anesthesia and vibration in alleviating the pain of oral injections.

The goal of the research was to compare the effectiveness of vibration with that of a topical anesthetic in reducing the pain of local anesthetic injections. Injections were given adjacent to maxillary premolars in four locations in 61 patients. Before injection, sites received either placebo or topical anesthetic with or without vibration. Patients rated the injection pain on a five-point scale. The topical anesthetic caused a statistically significant decrease in pain values; however, the amount of decrease was of questionable clinical significance.

Adult↗
PubMed1996

Epidemiology of hypertension in African Americans.

Hypertension is more prevalent, appears at an earlier age, is more likely to be associated with end-organ complications, and is less likely to be treated with traditional therapies in African Americans compared to Americans of European descent. Epidemiological associations have been made between the excess burden of hypertension in this population group and some biological, psychosocial, and socioeconomic factors. These associations might be used as a starting point that guides research to identify the cause(s) for the higher proportion of African Americans with hypertension. At present, such associations can help in the design of risk factor intervention strategies.

Adolescent↗
PubMed1996

An international working party on assessing hypertension control in populations: a proposal.

Hypertension is a world-wide public health problem. High blood pressure control efforts have been and are being implemented in order to reduce this burden of unnecessary death and morbidity in most societies. Standard methods of assessment will be developed for the measurement of the goals and strategies of hypertension control in populations; and establishing the means for international comparisons of results. The products of the Working Party are expected to become an international guide and resource for the establishment and assessment of hypertension control.

Community Health Services↗
PubMed1995

Coronary disease mortality and risk factors in black and white men. Results from the combined Charleston, SC, and Evans County, Georgia, heart studies.

BACKGROUND: Epidemiologic studies begun in the southeastern United States in the 1960s indicated that the prevalence of coronary disease was two to three times greater among white men than black men and also showed an excess incidence of coronary disease among white men, although hypertension was twice as prevalent among blacks. This study was conducted to determine if racial differences exist in coronary heart disease mortality and coronary risk factors. METHODS: Data from the two population-based cohorts of the Charleston, SC, and Evans County, Georgia, Heart Studies were pooled to make comparisons of coronary disease mortality and its risk factors. A total of 726 black men and 1346 white men aged 35 years or older in 1960 in the combined cohort were followed up for 30 years. RESULTS: There were 125 deaths among the black men and 323 deaths among the white men attributable to coronary disease; the age-adjusted rates were 5.0 per 1000 person-years in the black men and 6.5 per 1000 person-years in white men. Black-white coronary mortality risk ratios were 0.8 when age adjusted and 0.7 when also adjusted for other cardiovascular risk factors. Elevated systolic blood pressure and cigarette smoking were significant predictors of coronary mortality in black and white men. Serum total cholesterol level was a statistically significant risk factor only in white men. Higher education level was significantly protective in black and white men. CONCLUSIONS: Black men experienced significantly less coronary disease mortality than white men. Except for cholesterol level, the risk factors for coronary mortality in black and white men were similar.

Adult↗
PubMed1995

Outcomes of black and white hypertensive individuals after 30 years of follow-up.

Outcomes of a 30-year follow-up for the participants of the Charleston Heart Study were studied with elevated blood pressure assessed using various classifications. The traditional categories of > or = 140/90 mmHg, > or = 160/95 mmHg and isolated systolic hypertension, as well as high normal and the four stages of high blood pressure were utilized in analyses. Prevalence rates of hypertension were, in general, higher among blacks compared to whites. Blacks had higher prevalence rates of hypertension and greater prevalence of high blood pressure at younger ages. Risk ratios were higher for black and white hypertensives than their normotensive counterparts. Blacks were found to have substantially higher population attributable risk proportions, particularly at the higher blood pressure categories. The results suggest that the standard clinical classifications of hypertension as related to mortality are appropriate for blacks and white.

Adult↗
PubMed1994

Is race related to glycemic control? An assessment of glycosylated hemoglobin in two South Carolina communities.

To consider the relationship between race and long-term glycemic control, as measured by glycosylated hemoglobin (GHb), we analyzed data from a community-based sample of 3175 adults in the South Carolina Cardiovascular Disease Prevention Project. A clinically meaningful difference for mean GHb levels (10.5 vs 8.4%, P < 0.001) was present between black people and white people reporting diabetes. Similarly, a significant association between race and GHb was present among people reporting "borderline diabetes" or no diabetes. Logistic regression confirmed this finding in all three diabetic categories, however, controlling for insulin use in the diabetic group reduced (P < 0.001) the association between GHb and race. These findings confirm that further improvements in glycemic control are necessary, especially for black patients and that black people not reporting diabetes have higher GHb levels compared to white people, possibly due to undiagnosed diabetes.

Adult↗
PubMed1993

Mortality rates and risk factors for coronary disease in black as compared with white men and women.

BACKGROUND: Currently recognized risk factors for coronary artery disease have been identified primarily from investigations of white populations. In this investigation, we estimated mortality rates for coronary disease and for any cause and identified risk factors for death from coronary disease among whites and blacks. METHODS: Data collected over a 30-year period in the Charleston Heart Study were used to estimate mortality rates and quantify associations with risk factors assessed at the base-line examination in 1960 and 1961 of 653 white men, 333 black men, 741 white women, and 454 black women. RESULTS: There were no significant racial differences in the rate ratios for death from coronary disease; however, women had significantly lower death rates than men. Over the 30-year period, the mortality rates for coronary disease per 1000 person-years were 5.2 for white men (95 percent confidence interval, 4.1 to 6.3), 4.6 for black men (3.0 to 6.2), 2.1 for white women (1.6 to 2.6), and 3.2 for black women (2.3 to 4.0). Significant, or nearly significant, predictors of mortality due to coronary disease were systolic blood pressure in all four groups; serum cholesterol level among white men, white women, and black women; and smoking among white men, white women, and black men. Although the difference was not statistically significant, the risk of death from coronary disease was consistently increased among diabetics in all four groups. A higher level of education was predictive of lower rates of death due to coronary disease among white men and black women. For all causes of death taken together, the rates for blacks were higher than the rates for whites. The presence of hypertension, a history of smoking, and a history of diabetes were significant or nearly significant predictors of mortality from any cause in all four groups. CONCLUSIONS: Although the rates of death from coronary disease were somewhat lower among black men than white men and higher among black women than white women, the black:white mortality rate ratios were not statistically significant, and the major risk factors for mortality from coronary disease were similar in blacks and whites in the 30-year follow-up of the Charleston Heart Study.

Adult↗
PubMed1992

Leisure time physical activity: are there black/white differences?

BACKGROUND: Behavioral risk factor surveillance survey data collected during 1984 and 1985 in South Carolina were analyzed. METHODS: This article is based on telephone interviews conducted with 2,005 individuals (431 black, 1574 white), mean age, 45.1 years, selected by random-digit dialing. Information on the type, frequency, and duration of leisure time physical activity was used to estimate leisure time energy expenditure (kcal/week) averaged over the previous month. The median level of leisure time energy expenditure differed significantly (all P less than 0.001) by gender (men = 741, women = 421), age (six categories; youngest, 18-29 years = 780; oldest, 70+ = 301), annual household income (four categories; lowest, less than or equal to $10,000 = 300; highest, greater than $35,000 = 870), body mass index (kg/m2, less than or equal to 24.1 = 601, greater than or equal to 30.1 = 180), and race (black = 301, white = 601). RESULTS: Leisure time energy expenditure generally decreased with increasing age and body mass index and increased with increasing levels of education and income among all race/gender groups. Logistic regression analyses revealed that after adjustment for gender (if applicable), age, income, and body mass index, the variable race made a statistically significant contribution to the model, in the total sample (P less than .03) and for women P less than .001), but not for men. CONCLUSIONS: Our results suggest that blacks living in the South, particularly black women, have lower levels of leisure time physical activity compared with their white counterparts after control for several important confounders.

Adolescent↗
PubMed1992

A comparison of the effects of cholesterol on CHD mortality in black and white women: twenty-eight years of follow-up in the Charleston Heart Study.

The relationship between cholesterol and 28-year CHD mortality in women was evaluated in the Charleston Heart Study. Linear, quadratic, and cubic models were investigated using Cox proportional hazards regression analysis. In white women, the linear, quadratic, and cubic terms for cholesterol were significant suggesting an asymmetric J-shaped relationship. In black women, only the linear term in all three models was statistically significant suggesting an increasing CHD mortality rate with increasing cholesterol level. The lack of consistency of results by different statistical analyses in black women make conclusions concerning the nature of the relationship between cholesterol and CHD mortality less strong in black women than in white women. Compared with women having a cholesterol value equal to the mean of the group (241 mg/dl), white women having a cholesterol value one standard deviation above the mean (s = 52.5 mg/dl) had a 60% higher CHD mortality rate (hazard ratio = 1.6, 95% CI: 1.2-2.1). In black women, the estimated hazard ratio for a one standard deviation (s = 47.8 mg/dl) increase in cholesterol is 1.4 (95% CI: 1.03-1.8). The results suggest that the relationship of cholesterol to CHD mortality is different in white and black women. The relationship in white women appears to be curvilinear and represented by an asymmetric curve while the relationship in black women is not curvilinear and the overall pattern of association, while possibly linear, is equivocal.

Black People↗