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Biomedical subjects

C M Burchfiel

Publications and source records attributed to C M Burchfiel.

68 records · Page 4Linked to original sources
PubMed1994

Fish consumption may limit the damage of smoking on the lung.

High fish consumption is characteristic of Japanese-American men of the Honolulu Heart Program (HHP). Analyses of data from the Atherosclerosis Risk in Communities (ARIC) study suggest high fish intake protects the lung against smoking damage. Measurements of forced expiratory volume in 1 s (FEV1) and smoking status in the HHP cohort were done at the first examination in 1965-68. Among 8,006 men, 45 to 68 yr, 6,346 had acceptable spirograms. Within current smokers, 1,545 men consumed fish less than twice a week, and 1,264 ate fish twice a week or more. Controlling for cigarettes/d, age, height, and daily calories, separate regression models indicated an average decrease of -10.1 ml for each additional yr of smoking (95% Confidence Interval [CI]: -13.6, -6.5) at low levels of fish intake, and a decrease of -4.4 ml (95% CI: -8.2, -0.6) at high levels. The coefficients were significantly different (p = 0.03). These differences reflect a predicted FEV1 144 ml (95% CI: 62, 227) higher in the high fish group at > or = 40 yr of smoking, but no difference at < or = 35 yr. Similar analyses were conducted for cigarettes/d. On average, the FEV1 decline for each additional cigarette/d was not significantly different among subjects with low versus high fish intake. However, the predicted FEV1 at < or = 30 cigarettes/d was 52 ml (95% CI: 17, 87) higher in the high fish consumption group. No significant difference in FEV1 was noted between groups at > 30 cigarettes/d. These findings suggest that the protective role of fish is "saturated" at higher "doses" of cigarette smoking.

Aged↗
PubMed1994

Comparison of the causes of late death following aortic and mitral valve replacement. VA Co-operative Study on Valvular Heart Disease.

This report examines and compares the causes of late non-surgical death in 146 of 690 (21%) patients undergoing isolated aortic valve replacement (AVR) and in 79 of 273 (29%) patients undergoing mitral valve replacement (MVR) over a five year follow up period. The distribution of valve related, cardiac but not valve-related and non-cardiac deaths was 43%, 23% and 34% respectively for AVR and 65%, 29% and 6% respectively for MVR; the difference between these distributions was statistically significant. The specific causes of valve related deaths included bleeding (11% vs. 5% for MVR vs. AVR), systemic embolization (6% vs. 4% for MVR vs. AVR), endocarditis (14% vs. 8% for MVR vs. AVR), valve regurgitation (8% vs. 5% for MVR vs. AVR) and valve obstruction (3% vs. 5% for MVR vs. AVR). Sudden death (less than one hour from the onset of acute symptoms) accounted for 23% of deaths for MVR and 16% for AVR. The deaths due to congestive heart failure with normal prosthetic valve function were 13% and 8% for MVR and AVR respectively. Non-cardiac causes accounted for only 6% of MVR deaths but 34% of AVR deaths (p < 0.001). There was no significant difference in the late mortality between mechanical and bioprosthetic valves in the aortic position (24% vs. 22%), but the cumulative rate of late deaths was higher in patients with the Björk-Shiley than with the Hancock valve in the mitral position (41% vs. 25%, p < 0.02). In conclusion, about one quarter of patients surviving either aortic or mitral valve replacement died within five years.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1993

Association of diabetes mellitus with coronary atherosclerosis and myocardial lesions. An autopsy study from the Honolulu Heart Program.

While the excess risk of clinical cardiovascular disease among persons with diabetes mellitus is well established, most autopsy studies have not been able to elucidate reasons for the excess, to assess potential selection bias, or to adjust for other cardiovascular risk factors. The purpose of this study was to examine the predictive relation between diabetes and autopsy evidence of coronary atherosclerosis and myocardial lesions. Among 8,006 Japanese-American men examined at baseline in 1965-1968 as part of the Honolulu Heart Program, 7,591 were free of cardiovascular disease, and 1,515 of these men died over a 17-year follow-up period. Protocol autopsies were performed for 83 diabetic men and 159 nondiabetic men. Diabetes status was defined using self-reported history and treatment at several examinations, as well as physician diagnoses during hospitalization between 1965 and 1984. An excess of coronary artery atherosclerosis, assessed by mean panel score (3.4 vs. 3.0, p = 0.017) and percentage of intimal surface with raised lesions (56.6% vs. 47.4%, p = 0.024), was present among diabetic men but diminished to nonsignificant levels (3.3 vs. 3.0, p = 0.102, and 53.9% vs. 48.8%, p = 0.183, respectively) after adjustment for other cardiovascular risk factors. Myocardial lesions (acute, healing, or fibrotic) occurred significantly more frequently among diabetics than among nondiabetics (77.7% vs. 63.4%, p = 0.035), even after adjustment for other risk factors. Potential autopsy selection bias assessed in several ways appeared minimal. Among men with mild atherosclerosis, diabetics had more small and large myocardial lesions than did nondiabetics, although differences were not statistically significant (p < 0.10). It appears that the more adverse risk factor profile among diabetics accounts for some of the observed excess of coronary atherosclerosis. However, diabetes was independently associated with myocardial lesions, and these findings suggest a role for nonatherosclerotic mechanisms, such as clotting abnormalities or microvascular disease, in accounting for the excess clinical heart disease found in persons with diabetes.

Aged↗
PubMed1992

The roles of insulin, obesity, and fat distribution in the elevation of cardiovascular risk factors in impaired glucose tolerance. The San Luis Valley Diabetes Study.

The objective of this study was to determine whether a less favorable risk factor pattern for cardiovascular disease among persons with impaired glucose tolerance could be explained by fasting insulin, obesity, and/or a central distribution of body fat. Between 1984 and 1988, cardiovascular risk factors were examined cross-sectionally in Hispanic and non-Hispanic white participants in the San Luis Valley Diabetes Study who had either impaired (n = 173) or normal (n = 1,107) glucose tolerance. Sex-specific analysis of covariance models were constructed to adjust risk factor levels for age, age and insulin, and age, insulin, body mass index, and centrality index. Both males and females with impaired glucose tolerance had higher age-adjusted mean diastolic blood pressures, heart rates, uric acid levels, and triglyceride levels and lower levels of high density lipoprotein (HDL) cholesterol and HDL3 cholesterol than normal subjects; differences were significant for all risk factors except HDL cholesterol and HDL3 cholesterol in males. Differences in diastolic blood pressure in males, and differences in heart rate and triglyceride in both sexes, remained significant after adjustment for all covariates. However, differences in uric acid in males and differences in diastolic blood pressure and HDL3 cholesterol in females were attenuated to borderline significance levels. Differences in uric acid and HDL cholesterol in females were diminished to nonsignificant levels, especially after adjustment for obesity-related measures. With few exceptions, fasting insulin did not appear to play a major role in accounting for differences in these risk factors. With adjustment, ethnic differences (Hispanic vs. non-Hispanic white) were smaller and were statistically significant less often than differences observed between impaired and normal glucose tolerant groups. The authors concluded that hyperinsulinemia, obesity, and a central body fat distribution accounted for some, but usually not all, of the less favorable cardiovascular risk factor pattern found in subjects with impaired glucose tolerance.

Adult↗
PubMed1992

General mortality and respiratory cancer among a cohort of male chemical workers in California.

Cohort mortality and nested case-control studies were conducted involving 2,901 men employed 1 year or more between 1940 and 1986 at any of four California facilities of a major chemical company. Employees experienced fewer deaths from each of the major causes than were expected based on U.S., California, and local county mortality rates. Respiratory cancer was significantly elevated in one socioeconomic category comprised of operators (SMR = 157, 95% CI = 109-220). The 34 cases who died from respiratory cancer and 136 matched controls, all of whom were operators, were included in a nested case-control study. Departments in which subjects had worked were grouped into 13 work assignment or product categories by an industrial hygienist without knowledge of case-control status. Smoking habits and other occupational exposures were ascertained by telephone interview from subjects or surrogate-responders. As expected, current cigarette smoking was strongly related to respiratory cancer. After adjustment for smoking, cases were significantly more likely than controls to have ever worked in one of the 13 work areas (supervision, services, and business support). However, no dose-response relationship was evident with duration of employment in this work area and the departments involved were associated with plant security and not chemical production. Results were similar when a 15-year latency period was assumed. These findings suggest that the excess of respiratory cancer mortality among operators was most likely due to differences in cigarette smoking or other factors not ascertained, rather than to a specific occupational exposure.

Adult↗
PubMed1992

Prevalence of back pain and joint problems in a manufacturing company.

To estimate prevalence of back pain and joint problems in employees of a chemical manufacturing company, a questionnaire was administered during medical surveillance examinations between 1987 and 1989. Among 5903 employees completing the questionnaire 35.4% reported back or joint pain during the past year. Back pain lasting 30 days or more occurred in 5.3% of employees, while joint pain and/or swelling occurred in 19.3% of employees. A physician visit was involved for 10.5% and 11.1% of employees reporting back pain and joint problems respectively. A trend of increasing prevalence with increasing age was significant (P less than .001) for all musculoskeletal outcomes. Unadjusted prevalence of back pain and joint problems was significantly higher among men and among whites. After adjusting for age, race, and occupation using logistic regression, the difference in prevalence for the two sexes was diminished or reversed. Similarly, differences in race were diminished when other variables were controlled. Differences in prevalence by occupation were attenuated after adjustment for age, gender, and race. Back pain tended to be reported more frequently for managers, back pain and joint problems for technicians, and back pain requiring physician visit for craftsmen. Self-reported back pain and joint problems during the previous year vary more by age and occupation and less by gender and race in this employed population.

Adult↗
PubMed1990

Left atrial dimension and risk of systemic embolism in patients with a prosthetic heart valve. Department of Veterans Affairs Cooperative Study on Valvular Heart Disease.

The relation between left atrial dimension measured by M-mode echocardiography and systemic embolization after valve replacement was examined prospectively among 397 patients with a prosthetic valve enrolled in the Department of Veterans Affairs Cooperative Study on Valvular Heart Disease. Baseline characteristics including several measures of left atrial enlargement were compared for 31 patients who developed systemic embolism and 366 who did not develop embolism during a 5 year follow-up period. Variables that were significantly related to left atrial dimension or systemic embolization in univariate analyses were included with several others in a multiple logistic regression model. The incidence rate of systemic embolism was more than three times higher after mitral valve replacement than after aortic valve replacement (4.4 and 1.3 per 100 patient-years, respectively); this difference persisted after adjustment for other factors. Univariate analysis indicated a threefold higher incidence of systemic embolism in patients with a left atrial dimension greater than or equal to 4 cm compared with that in patients with a dimension less than 4 cm (3 versus 1 per 100 patient-years, respectively). However, when the effect of valve location (mitral versus aortic) was taken into account using either univariate or multivariate techniques, left atrial dimension was found not to be associated with systemic embolism. In multivariate analysis, atrial fibrillation, age, ejection fraction and location of the prosthetic valve were significantly associated with embolism. Results of this multicenter study suggest that left atrial dimension is not independently related to the development of systemic embolism in patients undergoing valve replacement.

Aortic Valve↗
PubMed1990

Cardiovascular risk factors and impaired glucose tolerance: the San Luis Valley Diabetes Study.

Cardiovascular risk factor patterns were examined cross-sectionally in 856 Hispanic and Anglo subjects aged 20-74 years enrolled in the population-based San Luis Valley Diabetes Study of Colorado. Risk factor levels and prevalence were compared for 279 individuals with non-insulin-dependent diabetes mellitus, 89 with impaired glucose tolerance, and 488 with normal glucose tolerance. Sex-specific comparisons of continuous risk factors were made by diabetic status and ethnicity, adjusting for age using two-way analysis of covariance; similar comparisons of discrete variables were made using logistic regression. A number of vascular, metabolic, lipid, obesity-related, family history, and life-style risk factors for cardiovascular disease were examined. In general, biologic risk factors tended to be more strongly associated with diabetic status, while life-style risk factors varied more by ethnicity. Age-adjusted levels of systolic and diastolic blood pressure, hypertension history, triglyceride, and body mass index were lowest among normal subjects, intermediate for those with impaired glucose tolerance, and highest in subjects with non-insulin-dependent diabetes mellitus, while the trend was reversed for high density lipoprotein (HDL) cholesterol and its subfractions. Hispanics had lower serum uric acid levels and greater central obesity than Anglos; they were less likely to have a Type A personality, less physically active at work, and more likely to be a current smoker than Anglos. Hispanic males had a lower body mass index and a higher HDL cholesterol level than Anglo males. These results indicate that an adverse cardiovascular risk factor pattern is present not only in subjects with non-insulin-dependent diabetes mellitus but also in subjects with impaired glucose tolerance who are at increased risk of developing diabetes. This suggests that an adverse risk factor pattern may develop concurrently with or prior to the onset of impaired glucose tolerance. Future prospective studies will help to clarify the temporal sequence involved in the development of adverse cardiovascular risk factor patterns and impaired glucose tolerance.

Adult↗
PubMed1987

Comparison of outcome after valve replacement with a bioprosthesis versus a mechanical prosthesis: initial 5 year results of a randomized trial.

The Veterans Administration Cooperative Study on Valvular Heart Disease was organized to compare survival and incidence of valve-related complications between patients receiving a bioprosthesis (the Hancock porcine heterograft) and a mechanical prosthesis (the Björk-Shiley spherical disc valve). Five hundred seventy-five patients undergoing single aortic or mitral valve replacement were randomized at surgery to one of the two valve types. At an average follow-up of 5 years (range 3 to 8) there are no statistically significant differences in survival between patients with the two valve types in the aortic valve replacement group. There is a statistically nonsignificant trend toward improved survival in patients undergoing mitral valve replacement with a bioprosthesis compared with a mechanical prosthesis (5 year survival probability was 0.70 +/- 0.05 and 0.58 +/- 0.06, respectively). Fatal and nonfatal valve-related complications occurred significantly less frequently in patients with a bioprosthesis compared with a mechanical prosthesis for both mitral and aortic valve replacement. Five year complication-free probability was 0.67 +/- 0.05 and 0.45 +/- 0.06, respectively, for patients with mitral valve replacement and 0.63 +/- 0.04 and 0.53 +/- 0.04, respectively, for those with aortic valve replacement. The difference in overall complication rates was largely due to the increased number of clinically significant but nonfatal bleeding episodes in patients receiving a mechanical prosthesis. Adjustment for differences in baseline characteristics between patients receiving a mitral mechanical prosthesis and a mitral bioprosthesis reduced the statistical significance of the difference in both mortality and complications.

Aortic Valve↗
PubMed1986

Passive smoking in childhood. Respiratory conditions and pulmonary function in Tecumseh, Michigan.

The relationship of passive smoking to respiratory conditions and pulmonary function was assessed using a cross-sectional design in the defined population of Tecumseh, Michigan. The study population was made up of 3,482 children who were 0 to 19 yr of age at the 1962-1965 examination and for whom questionnaire information was available for both parents. Nearly 62% of children in this age group were exposed at the time of examination to at least 1 parent who smoked. Passive exposure to cigarette smoke was associated with an elevated prevalence of phlegm, wheeze, asthma, and chest colds among males and wheeze, bronchitis, and chest colds among females. Using logistic regression, offspring were shown to be 1.5 to 2.0 times more likely to have a respiratory condition if both their parents currently smoked than if both parents never smoked. FEV1, and FVC among males and Vmax50 among females were significantly lower by 5% in nonsmokers 10 to 19 yr of age whose parents were current smokers compared with similar offspring of never smoking parents. Respiratory conditions were generally more frequent and the level of lung function was generally lower for males from households where only mothers smoked compared with males from households where only fathers smoked, although sample size was limited. In females similar relationships were less consistent. Differences tended to be larger and more often significant for males than for females when respiratory symptoms and illnesses were examined.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1981

Increased incidence and prevalence of multiple sclerosis in Los Alamos County, New Mexico.

The incidence and prevalence of multiple sclerosis (MS) in Los Alamos County, New Mexico, were investigated because the number of reported cases appeared to have increased. The point prevalence on November 1, 1979, was 75.7 per 100,000, and average annual incidence rates for the period 1960-1969 and 1970-1979 were 3.4 and 3.7 per 100,000, respectively. The rates of MS in Los Alamos County were greater than expected from previous epidemiologic surveys of North America. The unusual ethnic composition and high socioeconomic level of the population probably contributed to the increases.

Adult↗
PubMedDate not supplied

Pulmonary function and ambient particulate matter: epidemiological evidence from NHANES I.

The relationship between pulmonary function and quarterly average levels of total suspended particulates (TSP) was examined for adults who resided in 49 of the locations where the First National Health and Nutrition Examination Survey (NHANES I) was conducted. Statistically significant relationships were observed between TSP levels and forced vital capacity (FVC) and forced expiratory volume at one second (FEV1.0). These relationships remained strong across several specifications and sample changes, e.g., exclusion of cities with two highest and two lowest TSP levels, restriction of sample to whites only. Anthropometric measurements and socioeconomic characteristics of the subjects were included in the analysis, and we restricted the sample to "never" smokers. The results indicate a 1 standard deviation increase (about 34 micrograms/m3) in TSP from the sample mean of 87 micrograms/m3 was associated with an average decrease in FVC of 2.25%. The results of this analysis also suggest that there is a threshold level (i.e., approximately 60 micrograms/m3 [quarterly average]) of TSP below which a relationship with pulmonary function ceases to exist.

Adult↗
PubMedDate not supplied

The role of insulin and body fat in associations of physical activity with lipids and lipoproteins in a biethnic population. The San Luis Valley Diabetes Study.

It has been postulated that the positive effects of physical activity on high density lipoprotein cholesterol (HDL-C) and HDL-C subfraction 2 (HDL-C2) are mediated through insulin action because increased activity lowers insulin levels and lower insulin levels are associated with higher HDL-C. These relations were evaluated in a rural population of Hispanic and non-Hispanic white (NHW) adults in Colorado. Included were 138 men and 152 women with normal glucose tolerance confirmed by World Health Organization criteria. Total physical activity was assessed by 7-day recall interviews. No significant associations were observed among women. Among men, activity was inversely associated with fasting insulin (r = -0.17, p less than 0.05). From analysis of covariance models including the interaction term activity x ethnicity, total HDL-C was 43.4 mg/dl (95% confidence interval [CI] = 39.1, 47.7) in the low tertile of activity and 50.4 mg/dl (95% CI = 46.3, 54.5) in the high tertile for NHW men, after adjustment for fasting insulin, fasting glucose, body mass index (BMI), waist to hip ratio (WHR), and age. For Hispanic men, adjusted HDL-C was 43.4 mg/dl (95% CI = 38.6, 48.2) and 49.1 mg/dl (95% CI = 44.0, 54.2) in the low and high tertiles, respectively. Adjusted HDL-C2 levels were 52% higher in the most compared with the least active NHW men, whereas there was no difference by activity for Hispanic men. Higher adjusted mean levels of HDL-C3 were observed for the high compared with the low activity tertile in both ethnic groups. Ethnicity-specific models showed that for NHW men, activity explained 12% (p = 0.01), fasting insulin explained 5% (p = 0.05), and BMI explained 6% (p = 0.04) of the variability in total HDL-C, after adjustment for fasting glucose, WHR, and age. These models confirmed that effects of insulin and body fat did not explain the observed associations between activity and total HDL-C and its subfractions.

Adipose Tissue↗