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Biomedical subjects

R F Hamman

Publications and source records attributed to R F Hamman.

At least 127 records · Page 7Linked to original sources
PubMed1988

Reduced risk of IDDM among breast-fed children. The Colorado IDDM Registry.

The hypothesis that breast-feeding can provide protection against the development of insulin-dependent diabetes mellitus (IDDM) and would, therefore, be less common among subjects with IDDM was tested with a retrospective design. Cases (n = 268) were selected from the Colorado IDDM Registry and the Barbara Davis Center for Childhood Diabetes (Denver, CO). Two control groups were recruited, one from physicians' practices throughout Colorado (n = 291) and the second through random-digit dialing from the Denver area (n = 188). Cases were less likely to have been breast-fed than controls after adjustment for birth year, maternal age, maternal education, family income, race, and sex [adjusted odds ratio (OR) = 0.70; 95% confidence interval (CI) = 0.50-0.97]. This finding was consistent for both control groups and by birth-year intervals. A greater decrease in risk of IDDM was seen among subjects who had been breast-fed to an older age (for breast-feeding duration of greater than or equal to 12 mo, adjusted OR = 0.54, 95% CI = 0.27-1.08). The amount of IDDM that might be explained by breast-feeding habits (population percentage attributable risk) ranged from 2 to 26%, varying according to the breast-feeding prevalence reported in other studies. Replication of this work in different populations, controlled for the strong secular trends in breast-feeding habits, is critical before the hypothesis of protection is accepted.

Breast Feeding↗
PubMed1988

Prevalence of asymptomatic bacteriuria in subjects with NIDDM in San Luis Valley of Colorado.

This study examined whether non-insulin-dependent diabetic (NIDDM) subjects have an increased prevalence of asymptomatic bacteriuria compared with subjects with normal glucose tolerance. Diabetic (n = 206) and normal (n = 418) subjects were identified from a defined geographic area in the San Luis Valley of southern Colorado. Presence of asymptomatic bacteriuria was determined by testing the subjects' urine with a reagent-strip test for nitrite and leukocyte esterase (Chemstrip LN). The ability of the Chemstrip LN to detect bacteriuria was evaluated by comparing its results with those from urine culture on a subsample of subjects. There were 7 control and 12 diabetic subjects with bacteriuria as measured by the Chemstrip LN. The prevalence of urinary tract colonization among diabetic compared with control subjects was increased 3.5-fold (95% confidence interval 1.4-8.6). Adjustment for confounding by age, sex, ethnicity, and county of residence resulted in an adjusted prevalence ratio of 4.4 (95% confidence interval 1.1-17.4). Among diabetic subjects, prevalence of bacteriuria increased with longer disease duration but was not affected by measures of glucose control. We conclude that NIDDM increases the prevalence of bacterial colonization of the urine and, therefore, probably also increases the risk of symptomatic urinary tract infection.

Bacteriuria↗
PubMed1988

Seasonality comparisons among groups using incidence data.

A new test using incidence data is developed for testing whether two or more groups have the same seasonal pattern. The method fits sine waves to the data with a fundamental period of one cycle per year, and has the possibility of using higher harmonics, when necessary, to adequately model the data. The seasonal pattern can, therefore, have an arbitrary shape. The method allows for different length time intervals and different size populations at risk in the time intervals. Maximum likelihood estimation, based on the Poisson distribution, is used to determine the parameters of the model. Likelihood ratio tests and Akaike's information criterion (AIC) are used to determine the number of harmonics, and to test hypotheses. This method has been used to test for seasonal patterns in the incidence of insulin-dependent diabetes mellitus (IDDM) in Colorado among persons aged 0-17 years. Comparisons of seasonal patterns are made between males and females, and three age groups, each controlling for the other effect as in analysis of variance. Other potential applications of this approach are also discussed. A basic program is available for an IBM-PC to carry out these analyses.

Adolescent↗
PubMed1987

Sexual and reproductive risk factors for invasive squamous cell cervical cancer.

A case-control study of 418 women with invasive squamous cell cervical cancer and 704 population controls enabled evaluation of risk factors for this relatively rare cancer. Consistent with an infectious etiology was a pronounced effect of multiple sexual partners, with those reporting 10 or more partners being at a significant threefold excess risk. Early first intercourse also was associated with some residual effect on risk, although the relationship was not linear, nor the explanation readily apparent. Those with multiple births were at significantly elevated risks, even after adjustment for sexual parameters. Menstrual and hygiene factors, including use of tampons, vaginal deodorants, and douching products, were not consistently related to risk. Histories of specific infections involving the genital tract were poor predictors of risk, since few women provided positive responses, but those with nonspecific diseases were at a significant twofold excess risk.

Adult↗
PubMed1986

Higher than expected prevalence of multiple sclerosis in northern Colorado: dependence on methodologic issues.

A population-based study of multiple sclerosis (MS) was conducted in 2 northern Colorado counties in 1982 to determine MS prevalence, to compare the rates with recent North American surveys and to compare the methods used in these studies. Provisional cases were identified from: the patient rolls of MS service organizations, chart reviews in 2 neurology practices, a survey of physicians and a review of hospital discharge diagnoses. Crude-point prevalence for the 2-county region was 84 per 100,000. The age-adjusted rate was higher than the rate for the region above the 37th parallel projected from data in a 1976 national survey, but was comparable to rates obtained in localized surveys conducted in the northern tier of the country. The methodological results revealed that the highest yield sources were the MS service organizations and the neurology practice chart reviews. MS prevalence surveys which neglect these methods may underestimate MS prevalence by as much as 20-40%.

Adult↗
PubMed1985

Adult respiratory distress syndrome. Prognosis after onset.

In 88 patients with the adult respiratory distress syndrome, clinical, laboratory, cardiopulmonary, and demographic data collected on the day of onset of the syndrome were used to identify predictors of survivorship and mortality. Variables that individually were associated with mortality were then analyzed simultaneously by the Cox proportional hazards function and by multiple discriminant function using a step-up procedure. Four variables taken singly were significantly associated with mortality. These were the presence of less than 10% band forms on the initial peripheral blood smear, persistent acidemia with arterial pH less than 7.40, calculated HCO-3 less than 20 mg/dl, and blood urea nitrogen greater than 65 mg/dl. After eliminating those variables that did not contribute significantly to mortality in the presence of the others, only low band forms, low pH, and low HCO-3 were significantly associated with increased mortality. These findings illustrate the continued high mortality rate in the syndrome and indicate possible systemic aberrations that contribute to its severity.

Adult↗
PubMed1985

The effect of insulin treatment on insulin secretion and insulin action in type II diabetes mellitus.

We have studied the effects of 3 wk of continuous subcutaneous insulin infusion (CSII) on endogenous insulin secretion and action in a group of 14 type II diabetic subjects with a mean (+/-SEM) fasting glucose level of 286 +/- 17 mg/dl. Normal basal and postprandial glucose levels were achieved during insulin therapy at the expense of marked peripheral hyperinsulinemia. During the week of posttreatment evaluation, the subjects maintained a mean fasting glucose level of 155 +/- 11 mg/dl off insulin therapy, indicating a persistent improvement in carbohydrate homeostasis. Adipocyte insulin binding and in vivo insulin dose-response curves for glucose disposal using the euglycemic clamp technique were measured before and after therapy to assess the effect on receptor and postreceptor insulin action. Adipocyte insulin binding did not change. The insulin dose-response curve for overall glucose disposal remained right-shifted compared with age-matched controls, but the mean maximal glucose disposal rate increased by 74% from 160 +/- 14 to 278 +/- 18 mg/m2/min (P less than 0.0005). The effect of insulin treatment on basal hepatic glucose output was also assessed; the mean rate was initially elevated at 159 +/- 8 mg/m2/min but fell to 90 +/- 5 mg/m2/min in the posttreatment period (P less than 0.001), a value similar to that in control subjects. Endogenous insulin secretion was assessed in detail and found to be improved after exogenous insulin therapy. Mean 24-h integrated serum insulin and C-peptide concentrations were increased from 21,377 +/- 2766 to 35,584 +/- 4549 microU/ml/min (P less than 0.01) and from 1653 +/- 215 to 2112 +/- 188 pmol/ml/min (P less than 0.05), respectively, despite lower glycemia. Second-phase insulin response to an intravenous (i.v.) glucose challenge was enhanced from 170 +/- 53 to 1022 +/- 376 microU/ml/min (P less than 0.025), although first-phase response remained minimal. Finally, the mean insulin and C-peptide responses to an i.v. glucagon pulse were unchanged in the posttreatment period, but when glucose levels were increased by exogenous glucose infusion to approximate the levels observed before therapy and the glucagon pulse repeated, responses were markedly enhanced. Simple and multivariate correlation analysis showed that only measures of basal hepatic glucose output and the magnitude of the postbinding defect in the untreated state could be related to the respective fasting glucose levels in individual subjects.(ABSTRACT TRUNCATED AT 400 WORDS)

Adipose Tissue↗
PubMed1983

Adult respiratory distress syndrome: risk with common predispositions.

A 1-year survey of patients in three hospitals identified 936 patients who had one predisposition and 57 who had several predispositions to the adult respiratory distress syndrome. From the total predisposed population of 993 patients, 68 subsequently developed the syndrome. An additional 20 patients developed the syndrome from causes other than eight identified predispositions, to bring the total of patients studied to 88. A highly significant difference (p less than 0.0001) was found in the incidence rates of the syndrome between patients with one and several predispositions (5.8 versus 24.6 per 100 patients). Within 72 hours of onset of predisposition, 89.5% of patients who developed the syndrome had been intubated and placed on mechanical ventilation. Fifty-seven of the 88 patients (64.8%) with the syndrome died. By the 14th day 90% of deaths had occurred. There were no age- or sex-specific differences in either incidence or mortality rates. Case fatality rates of the syndrome were high in all predisposed groups.

Adult↗
PubMed1982

Busulfan versus hydroxyurea in long-term therapy of chronic myelogenous leukemia.

Survival of patients with chronic myeloid leukemia seen in the University of Colorado Leukemia Clinic were reviewed with respect to therapy. A total of 55 patients seen consecutively through mid 1980 were included in this study. Of these patients 30 were treated with busulfan, 14 were treated with hydroxyurea and 11 received under modalities. Busulfan treated patients who are now deceased, have had a median survival of 35 months (range, 13-108) and actuarial analysis shows the total busulfan treated population to have an expected median survival of 48 months. Hydroxyurea treated patients who are still alive have been followed for a median period of 69 months (range, 25-136 months) and a projected median survival for periods of 56 and 90 months, respectively. These data suggest that hydroxyurea may be an important treatment modality in the treatment of chronic myelogeous leukemia.

Adolescent↗
PubMed1981

Patterns of mortality in the the Old Order Amish. I. Background and major causes of death.

The major causes of death were studied in the Old Order Amish people in three settlements in Indiana, Ohio and Pennsylvania to determine if lifestyle and genetic isolation altered their mortality risk compared to neighboring non-Amish. The Amish are a conservative religious group who live in farm settlements, use horses for work and travel, exercise vigorously, and avoid cigarettes and alcohol. They are reproductively isolated and highly inbred. Death certificates and Amish censuses were used to determine mortality risks, which were summarized using age-adjusted mortality ratio (MRs). Amish mortality patterns were not systematically higher or lower than those of the non-Amish, but differed by age, sex, and cause. Amish males had slightly higher all-cause MRs as children and significantly lower MRs over the age of 40, due primarily to lower rates of cancer (MR = 0.44, age 40-69), and cardiovascular diseases (MR = 0.65, age 40-69). Amish females MRs for all causes of death were lower from age 10-39, not different from 40-69, and higher over age 69. MRs were not significantly different for all cancer sites combined in Amish women and they had higher cardiovascular mortality ratio aged 70 and over (MR =1.34). Other major causes of death were also examined. Because the Amish and other farming groups have similar mortality patterns, it is suggested that lifestyle may be the primary determinant of the overall mortality patterns in the Amish.

Adolescent↗
PubMed1978

Diabetes incidence and prevalence in Pima Indians: a 19-fold greater incidence than in Rochester, Minnesota.

The incidence and prevalence of diabetes mellitus were determined in 3733 Pima Indians aged 5 years or over by periodic examinations over a 10-year period. The examinations included modified glucose tolerance tests and medical record review. The age-sex adjusted prevalence rate was 21.1% (SE = 0.7%). Prevalence was low in childhood and plateaued at 40--50% in adults over 35 years of age. The age-sex adjusted incidence rate of 26.5 cases/1000 person-years (SE = 1.9) is the highest reported diabetes incidence known to the authors. Incidence increased from low levels in childhood to peak at age 40 (males) or 50 (females) and then gradually declined. Diabetes incidence was 19 times that in the predominantly white population of Rochester, Minnesota (95% confidence interval, 16 to 22 times). The high incidence rate was found despite using a more stringent diagnostic criterion than customarily employed, and was shown not be due to biased follow-up of subjects.

Adolescent↗
PubMed1976

Serum cholesterol levels in American (Pima) Indian children and adolescents.

Serum cholesterol levels from birth to adulthood in a population of North American (Pima) Indians are described and compared to those of Caucasian populations. Cholesterol levels at birth (mean +/- SEM, 87 +/- 2.6 mg/100 ml) were similar in Pimas and Caucasians, but levels in Pimas from 5 to 16 years (148 +/- 4.6 mg/100 ml) were 20 to 30 mg/100 ml lower than among most white populations. The levels showed little rise with age from 5 to 16, then rose significantly in both sexes from ages 17 to 25. Cholesterol levels in adult Pimas (190 +/- 1.5 mg/100 ml) were up to 50 to 60 mg/100 ml lower than in American whites, and showed little increase after age 25. Two cohorts of children followed prospectively for six years indicated that the prevalence data reflect sequential changes in the population. Cholesterol levels of those subjects were significantly correlated at the first and last examinations. The Pima, in contrast to Caucasian American populations, have relatively low levels of serum cholesterol and low rates of coronary heart disease, but evidence of a causal relationship with the latter remains to be established.

Adolescent↗
PubMed1975

The effect of menopause on serum cholesterol in American (Pima) Indian women.

Serum cholesterol levels in Pima Indian women were investigated to determine if menopause caused these levels to rise. The mean cholesterol values of 148 pre-menopausal women aged 34-54 when age-matched with 75 post-menopausal women were not significantly different. Sixty-five women passed through menopause while under observation and were examined sequentially for an average of 6.1 years. Their mean pre- and post-menopausal cholesterol levels of 182 +/- 5 mg/100 ml and 180 +/- 5 mg/100 ml were similar. Nor did menopause alter cholesterol levels in the subgroups of these patients with diabetes mellitus. Cholesterol levels in both Pima males and females showed no age-related rise, and were 20-30% lower than white populations. This study provides additional evidence against the postulated relationship between menopause and serum cholesterol.

Adult↗
PubMed1975

Asthma in schoolchildren. Demographic associations and peak expiratory flow rates compared in children with bronchitis.

The frequency of asthma in 10 971 school-children between the ages of 5 and 14 years was reported by their parents to be 3-8%. Of these, 20-7% were said to have had bronchitis, 5-9% pneumonia, and 4-7% eczema. Asthma was reported more commonly in boys than girls and was greatest in children of social classes I and II. One-third of the children were reported to have their first attack before the age of 2 years. Few (18%) first attacks started after the age of 5 years. There was no evidence that bronchitis predisposed to the later development of asthma, or vice versa. Within each age-sex group children with a history of asthma had lower peak expiratory flow rates than children who gave no such history. These diffences in PEFR were greater than for children with a history of bronchitis.

Adolescent↗
PubMedDate not supplied

Genetic variation in the apolipoprotein H (beta2-glycoprotein I) gene affects plasma apolipoprotein H concentrations.

Apolipoprotein H (apoH, protein; APOH, gene) is a single chain glycoprotein that exists in plasma both in a free form and in combination with lipoprotein particles. ApoH has been implicated in several physiologic pathways, including lipid metabolism, coagulation, and the production of antiphospholipid antibodies. The wide range of interindividual variation in plasma apoH levels is thought to be under genetic control, but its molecular basis is unknown. APOH displays a common structural polymorphism with the occurrence of three common alleles (APOH*1, APOH*2, and APOH*3), the APOH*2 allele being the most frequent in all populations. The relationship between the APOH polymorphism and plasma apoH levels is unknown. In this study, we have determined the impact of this APOH polymorphism on apoH levels in 455 normoglycemic non-Hispanic Whites (220 men and 235 women) from the San Luis Valley, Colorado. Mean plasma apoH levels, determined by capture enzyme-linked immunosorbent assay, were 20.0 +/- 0.2 mg/dl (range: 3.4-31.2 mg/dl) with no significant difference between men and women. In women, but not in men, age had a significant effect on plasma apoH levels explaining 3.4% of its phenotypic variance. ApoH levels also correlated positively with cholesterol (P = 0.015), HDL-cholesterol (P = 0.044), and triglyceride (P = 0.037) in women, but not in men. An analysis of variance (ANOVA) of adjusted plasma apoH levels showed significant association with the APOH polymorphism in both men and women (P < 0.0001), and the APOH polymorphism accounted for 11.4% and 13.6% of the variation in apoH levels in men and women, respectively. Compared with the APOH*1 and APOH*2 alleles, the APOH*3 allele was associated with significantly lower plasma apoH levels. At the molecular level, APOH*3 can be further subdivided into two distinct forms, called APOH*3W and APOH*3B. The APOH*3W form is more common in US Whites and is the result of a missense mutation at codon 316. An ANOVA for the codon 316 polymorphism revealed that this polymorphism is a major determinant of plasma apoH variation (P < 0.0001). This study indicates that common genetic variation in the APOH gene is a significant determinant of plasma apoH levels in non-Hispanics Whites and should be useful in evaluating the role of the APOH genetic variation in various metabolic pathways in which apoH has been implicated.

Adult↗