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Biomedical subjects

T K Welty

Publications and source records attributed to T K Welty.

At least 73 records · Page 4Linked to original sources
PubMed1992

Risk factors for coronary heart disease in diabetic and nondiabetic Native Americans. The Strong Heart Study.

The Strong Heart Study is a study of cardiovascular disease and its risk factors among diabetic and nondiabetic Native Americans. The study includes 12 tribes in Arizona, Oklahoma, and North and South Dakota. Phase I, initiated in October 1988, included a mortality survey to determine CVD death rates in individuals 35-74 yr old between 1984 and 1988, and a medical record review to determine rates of myocardial infarction and stroke for individuals ages 45-74 during the same time. In addition, a physical examination was performed on persons 45-74 yr old to measure the prevalence of cardiovascular and peripheral vascular diseases and known and suspected risk factors. In Phase II, CVD mortality and morbidity rates will be determined in the examined cohort by surveillance. CVD risk factors, changes in risk factors over time, and the relationship between risk factors and CVD incidence will be assessed longitudinally. This study provides data on the relative importance of cardiovascular risk factors in nondiabetic and diabetic Native Americans and will provide insight into possible variations in the quantitative or qualitative importance of CVD risk factors among diverse population groups.

Adult↗
PubMed1992

The benefits of isoniazid chemoprophylaxis and risk factors for tuberculosis among Oglala Sioux Indians.

In a case-control study of 92 Indian patients, 46 with active tuberculosis (cases) and 46 tuberculin reactors without the disease (control subjects), significantly more control subjects than patients had prior adequate isoniazid chemoprophylaxis. While the Indian Health Service recommends treating all tuberculin reactors with isoniazid prophylaxis, most (75%) of our tuberculosis (TB) cases could have been prevented if the guidelines of the American Thoracic Society had been followed. Diabetes, alcohol abuse, and chronic renal failure were risk factors for active TB. Despite marked reductions in TB morbidity and mortality rates among American Indians and Alaska Natives over the past 30 years, their TB rates are still two to three times higher than overall United States and white rates. Enhanced TB control programs with an emphasis on preventive therapy for patients at risk for developing active disease, especially those with diabetes and chronic renal failure, could decrease the incidence and eventually eliminate TB among American Indians and Alaska Natives.

Adult↗
PubMed1991

Health implications of obesity in American Indians and Alaska Natives.

American Indians and Alaska Natives (AI/ANs) are experiencing an epidemic of diabetes, increasing rates of coronary artery disease and hypertension, and poor survival rates for breast cancer that are likely partially attributable to the increasing prevalence of obesity over the past generation. Obesity may also contribute to the high rates of gallstones and to adverse outcomes of pregnancy in AI/ANs. Although overall mortality was not associated with obesity in Pima Indians (except in the most obese men), the relationship of obesity to longevity in other AI/AN groups is not known. Further study of the specific health effects of obesity in various groups of AI/ANs are needed. In the meantime, community-based programs to prevent obesity and its sequelae should be implemented in all AI/AN communities.

Alaska↗
PubMed1990

The Strong Heart Study. A study of cardiovascular disease in American Indians: design and methods.

Available data indicate that cardiovascular disease has become the leading cause of death in American Indians. However, limited information is available on cardiovascular disease incidence, prevalence, and risk factors in this population. Reported cardiovascular disease rates vary greatly among groups in different geographic areas. These rates have been obtained from studies of varying sizes and different methodologies. The Strong Heart Study, which uses standardized methodology, is designed to estimate cardiovascular disease mortality and morbidity rates and the prevalence of known and suspected cardiovascular disease risk factors in American Indians. The study population consists of 12 tribes in three geographic areas: an area near Phoenix, Arizona, the southwestern area of Oklahoma, and the Aberdeen area of North and South Dakota. The study includes three components. The first is a mortality survey to estimate cardiovascular disease mortality rates for 1984-1988 among tribal members aged 35-74 years, and the second is a morbidity survey to estimate incidence of both first and first or recurrent hospitalized myocardial infarction and stroke (cerebrovascular disease) among tribal members aged 45-74 years in 1984-1988, and the third is a clinical examination of 4,500 tribal members aged 45-74 years in order to estimate the prevalence of cardiovascular disease and its associations with risk factors. Family history, diet, alcohol and tobacco consumption, physical activity, degree of acculturation, and socioeconomic status are assessed in personal interviews. The physical examination includes measurements of body fat, body circumferences, and blood pressure, an examination of the heart and lungs, an evaluation of peripheral vascular disease, and a 12-lead electrocardiogram. Laboratory measurements include fasting and postload glucose, insulin, fasting lipids, apoproteins, fibrinogen, and glycated hemoglobin. Also measured are serum and urine creatinine and urinary albumin. DNA from lymphocytes is isolated and stored for future genetic studies.

Adult↗
PubMed1990

Sudden unexplained infant deaths among American Indians and whites in North and South Dakota.

Differences in risk factors for sudden unexplained infant death (SUID) were studied among American Indian and White infants in North and South Dakota. From 1977 to 1984, the incidence of SUID was 3.9 times higher among Indians compared with Whites. Indian SUID cases appeared to die at a slightly younger age than Whites, and the association of male gender and young maternal age with SUID was weak or absent among Indians. Low maternal education and late or no prenatal care were strongly related to SUID in both races. The Indian-White risk ratio was unaltered by adjustment for birthweight and maternal age but declined to 2.5 (95% confidence intervals = 1.9, 3.4) when adjusted for maternal education and trimester prenatal care began.

Age Factors↗
PubMed1990

Hepatitis transmission among the Sioux Indians of South Dakota.

Hepatitis A continues to occur in cyclical community-wide epidemics on the Indian reservations of South Dakota. In June 1985 a population-based serosurvey for viral hepatitis involving 120 households was conducted at the Pine Ridge and Rosebud Sioux Indian reservations in South Dakota. The serosurvey was performed shortly after a large hepatitis A epidemic on the Pine Ridge reservation in 1983-84, and immediately before a large hepatitis A epidemic on the Rosebud reservation in 1985-86. The overall seroprevalence for antibodies to hepatitis A virus (anti-HAV) was 76.2 percent (Pine Ridge reservation 80.5 percent, Rosebud reservation 72.0 percent, relative risk = 1.12, 95 percent confidence interval = 1.01, 1.24). For age groups 0 to 4 years, 54.2 percent and 36.1 percent of children were seropositive at Pine Ridge and Rosebud, respectively. Seropositivity rose rapidly with age; by age 40, more than 90 percent of persons at both Pine Ridge and Rosebud were anti-HAV positive. Only 1.1 percent of persons tested were positive for hepatitis B markers. Anti-HAV seroprevalence rates in both communities are similar to rates observed in developing countries. The surprisingly high anti-HAV seroprevalence among young children at Rosebud, where clinical hepatitis A had been virtually absent in the previous seven years, indicates that high-grade silent transmission was taking place during the interepidemic period.

Adolescent↗
PubMed1990

Determinants of blood pressure in Navajo adolescents.

Hypertension is becoming more common among Navajo people, especially among young men. In a group of 580 Navajo adolescents, we looked for factors associated with variations in blood pressure level. Using our criteria, 11.1% of adolescent males and 1.6% of females had an elevated screening blood pressure. In males, blood pressure was a function of age only, and not significantly related either to obesity (body mass index) or measures of acculturation and personal adjustment. In females, blood pressure was not related to age, but was associated with body mass index. Systolic pressure in females was also associated with poor personal adjustment. Level of acculturation (by our index) had no bearing on blood pressure level in this population.

Acculturation↗
PubMed1989

Increased chromosome fragility as a consequence of blood folate levels, smoking status, and coffee consumption.

Chromosome fragility in 96 h, low-folate cultures was found to be associated with smoking status, coffee consumption, and blood folate level. The higher proportion of cells with chromosome aberrations in cigarette smokers was attributable to lower red cell folate levels in smokers compared with nonsmokers. There was a positive linear relationship between the average cups of coffee consumed per day and the proportion of cells with aberrations. This association was independent of the effects of smoking and red cell folate level. These data suggest that smoking history, coffee consumption, and red cell folate level are important considerations for the design and interpretation of fragile site studies in cancer cytogenetics.

Chromosome Aberrations↗
PubMed1989

Complete culture medium is better than low folate medium for detecting increased chromosome aberrations in smokers in 48-h lymphocyte cultures.

We compared chromosome breakage in parallel, 48-h lymphocyte cultures established from smokers and nonsmokers using minimal essential medium (MEM) and MEM without folate (MEM-FA). There was a statistically significant, higher frequency of aberrations for smokers than for nonsmokers in cells cultured in MEM, but not in those cultured in MEM-FA. Thus, these data support the recommendation of the World Health Organization (1985) that population monitoring studies for exposure assessment should not use a low folate medium.

Adult↗
PubMed1989

Acute myocardial infarction and sudden death in Sioux Indians.

While some Indian tribes have low rates of acute myocardial infarction, Northern Plains Indians, including the Sioux, have rates of morbidity and mortality from acute myocardial infarction higher than those reported for the United States population in general. In a review of diagnosed cases of acute myocardial infarction over a 3-year period in 2 hospitals serving predominantly Sioux Indians, 8% of cases were found misclassified, and 22% failed to meet rigorous diagnostic criteria, although the patients did indeed have ischemic heart disease. Patients had high frequencies of complications and risk factors and a fatality rate of 16% within a month of admission. Sudden deaths likely due to ischemic heart disease but in persons not diagnosed as having acute myocardial infarction by chart review occurred 3 times more frequently than deaths occurring within a month of clinical diagnosis.

Adult↗
PubMed1988

Increased sister chromatid exchange associated with smoking and coffee consumption.

Sister chromatid exchange (SCE) is a very sensitive cytogenetic assay for detecting exposure to chemical mutagens and carcinogens. One application of SCE is the monitoring of populations believed to be exposed to such agents. We have, however, relatively little knowledge about common lifestyle factors that may influence SCE and therefore complicate any study designed to examine the effects of exposure to genotoxins. In this study, we assessed the effect of cigarette smoking and coffee consumption on SCE. Smoking was associated with an increase of approximately 2 SCEs per cell and a decrease in cell proliferation. A positive linear relationship between SCE and coffee consumption was also observed. This effect was similar for smokers and nonsmokers. Additionally, the folic acid content of cell culture medium seemed to affect neither SCE nor cell proliferation.

Adult↗
PubMed1986

Effects of exposure to salty drinking water in an Arizona community. Cardiovascular mortality, hypertension prevalence, and relationships between blood pressure and sodium intake.

A high level of sodium (440 mg/L) in the water supply of Gila Bend, Ariz, caused concern because of apparently elevated rates of hypertension in Gila Bend Papago Indians. We surveyed 342 Gila Bend Papago Indians and 375 non-Indians from July to September 1983. Participants 25 years of age and older were interviewed for health risk factors, water consumption, and dietary sodium and calcium intake and had height, weight, blood pressure, and urinary sodium and potassium levels measured. No consistent associations were found between any of the sodium values and systolic or diastolic blood pressure. Mean blood pressures for the Gila Bend whites were lower in most age groups than in comparison US white populations. The prevalence rates of hypertension in Gila Bend were not significantly higher than national rates.

Adolescent↗
PubMed1986

Acute myocardial infarction among Navajo Indians, 1976-83.

We found that from 1976 through 1983 the incidence of acute myocardial infarction (AMI) diagnosed among Navajo Indians remained low (0.5 per 1,000 persons age 30 years or more), although the incidence in women appears to be climbing. Navajo AMI patients are more likely to be hypertensive and diabetic than age- and sex-matched patients with gallbladder disease. Twenty-four per cent die within one month of AMI.

Adolescent↗
PubMed1986

Plague.

Successful treatment of plaque depends on early diagnosis, institution of effective antibiotics (streptomycin, chloramphenicol, tetracycline or gentamicin) and adequate supportive care. To reduce mortality, therapy should be started in patients suspected of having plague while diagnostic procedures are under way. If persons with acute febrile illness (especially regional lymphadenitis) have been in plague-endemic areas within the week preceding the onset of illness, the diagnosis of plague should be considered.

Anti-Bacterial Agents↗
PubMed1985

Nineteen cases of plague in Arizona. A spectrum including ecthyma gangrenosum due to plague and plague in pregnancy.

We review the cases of 19 successfully treated plague patients, with emphasis on the clinical and epidemiologic features of the disease. Proper staining and culturing of bubo aspirates; prompt institution of streptomycin, chloramphenicol or tetracycline therapy in presumptive cases, and supportive care are the crucial factors in the treatment of plague. This disease should be considered in patients in a toxic condition who have lymphadenitis, pneumonia or septic shock and who have been in endemic areas within the past ten days.

Adolescent↗
PubMed1983

Immunogenicity of a Haemophilus influenzae type b vaccine in combination with diphtheria-pertussis-tetanus vaccine in infants.

Seventy-eight Navajo infants (one to two months of age) were randomly assigned to one of two vaccination groups: one group (40 infants) was scheduled to receive three doses of diphtheria-pertussis-tetanus (DPT) vaccine and the other (38 infants) to receive DPT combined with Haemophilus influenzae type b polyribosyl-ribitol phosphate (DPT + PRP vaccine). In the latter vaccine, pertussis antigen served as an adjuvant for PRP. Sixty-seven infants (37 who received DPT vaccine and 30 who received DPT + PRP vaccine) completed the protocol. Local and systemic reactions were equally frequent in the two groups. Fifty percent of the infants who received DPT + PRP vaccine had definite antibody responses to PRP after three doses, and 13% had possible responses. Of the infants who received DPT vaccine, 14% and 8% had definite and possible responses, respectively; three of five infants with definite responses were infected with H influenzae type b or cross-reacting organisms, as determined by pharyngeal cultures. The immune response did not appear to be suppressed by the presence of maternal antibody.

Antibodies, Bacterial↗
PubMed1983

Gasoline sniffing and lead toxicity in Navajo adolescents.

During a 6-year period, 23 Navajo adolescents were hospitalized 47 times for presumed lead intoxication secondary to gasoline sniffing. Most patients were male (87%) and sniffed gasoline as a social activity, more frequently in spring and summer. Sixty-five percent of the patients first presented with toxic encephalopathy. Of total episodes, 31% involved asymptomatic lead overload; 31% involved tremor, ataxia, and other neurologic signs; and 38% involved encephalopathy with disorientation and hallucinations. Free erythrocyte protoporphyrin levels were not consistently high, although blood lead levels were all elevated. One death occurred. Approximately 11% of 537 Navajo adolescents said they inhaled gasoline for enjoyment at least occasionally. Among 147 junior high school students, blood lead levels averaged 18 +/- 6 micrograms/dL with no values greater than 40 micrograms/dL. Three of these students had elevated zinc protoporphyrin levels and all three were anemic. No correlation was found between levels of blood lead or zinc protoporphyrin and whether or not the youth reported sniffing gasoline. However, sniffing gasoline was associated with poor school performance and delinquent behavior. Although apparently many Navajo adolescents experiment with gasoline inhalation, only a few engage in this activity frequently enough to develop either asymptomatic or symptomatic lead overload.

Adolescent↗