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Biomedical subjects

S M Haffner

Publications and source records attributed to S M Haffner.

At least 253 records · Page 14Linked to original sources
PubMed1990

Functional impairment in Mexican Americans and non-Hispanic whites with diabetes.

There are virtually no data available describing the functional status of diabetic individuals. We therefore measured functional status using the Sickness Impact Profile (SIP) in 393 diabetic subjects and 486 nondiabetic control subjects identified from the San Antonio Heart Study, a population-based study of diabetes among Mexican Americans and non-Hispanic whites. The SIP is a validated instrument that assesses the presence of health-related behavior changes and activity restrictions in 12 different categories. Functional impairment, defined as a SIP score of 2.0% or greater, was present among 36.6% of diabetic subjects. Following adjustments for age, Mexican Americans were 1.63 times more likely to experience functional impairment that non-Hispanic whites, although this difference was not statistically significant (95% confidence interval: 0.92-2.89). The categories in which subjects experienced impairment varied widely, but the category with the highest prevalence of impairment was "eating" (greater than 40%). The prevalence of functional impairment was 45.9% among diabetic subjects with vascular complications, 31.8% among diabetic subjects without complications, and 16.7% among nondiabetic control subjects. Among all diabetic subjects impairment increased with age, duration of diabetes, fasting glucose, and BMI, and with insulin use and the presence of hypertension. In a multiple logistic regression model these factors (with the exception of insulin use) remained associated with the presence of functional impairment even after adjustment for the presence of vascular complications. If the factors responsible for this excess of functional impairment can be identified, an intervention might be designed which can lead to improvement in the quality of life for diabetic individuals.

Adult↗
PubMed1990

Increased testosterone in type I diabetic subjects with severe retinopathy.

Diabetic retinopathy rarely occurs before puberty, suggesting that changes in sex hormones may influence the development of this condition. The authors measured serum testosterone, estradiol, DHEA-S, and sex hormone binding globulin levels in 26 men and 22 women with type I diabetes from the Wisconsin Epidemiologic Study of Diabetic Retinopathy (WESDR), a population-based study of diabetic complications. The mean age was 23 years and the mean duration of diabetes was 14 years. Subjects with proliferative or preproliferative retinopathy (greater than or equal to retinopathy level 51-80) were matched by duration of diabetes (+/- 2 years) and sex to subjects with minimal or no retinopathy (less than or equal to retinopathy level 21). Seven stereoscopic retinal photographs of each eye were obtained and photographs were read by the University of Wisconsin Reading Center. Serum testosterone concentrations were significantly higher in male diabetic subjects with proliferative retinopathy (648 +/- 36 ng/dl) than in male diabetic subjects with minimal or no retinopathy (512 +/- 43 ng/dl) (P = 0.017). No other statistically significant differences in sex hormones between subjects with and without proliferative retinopathy were observed. Although these results should be regarded as preliminary because of the small number of subjects, they support the hypothesis that testosterone concentrations may be associated with the development of retinopathy in type I diabetic patients.

Adolescent↗
PubMed1990

The relationship of insulin sensitivity and metabolic clearance of insulin to adiposity and sex hormone binding globulin.

Previous studies have shown that sex hormone binding globulin (SHBG) is negatively associated with insulin concentrations in premenopausal women. We determined insulin sensitivity (SI) and clearance (KI) in 8 non-obese men and 13 nonobese premenopausal women using the minimal model of Bergman and colleagues. Insulin clearance and insulin sensitivity were strongly correlated (p less than 0.05). SHBG was positively correlated with SI (i.e., individuals with high levels of SHBG had greater insulin sensitivity) in both men (r = .738, p less than 0.05) and women (r = .577, p less than 0.06). Insulin clearance was also positively correlated with SHBG in men (r = .619) and in women (r = .476) (0.05 less than p less than 0.10). Since obese subjects have both lower SHBG concentrations and decreased insulin sensitivity, we examined the effect of correcting for adiposity by partial correlation analyses. SHBG was not associated with KI after adjustment for BMI. SHBG was still positively correlated with SI in both men (r = .708) (p less than 0.06) and women (r = 0.541) (p less than 0.06), suggesting that the relationship between SHBG and insulin sensitivity is not confounded by obesity. Thus, the relationship of androgenicity with insulin sensitivity (but not insulin clearance) was independent of adiposity.

Adipose Tissue↗
PubMed1990

Risk factors for cardiovascular mortality in Mexican Americans and non-Hispanic whites. San Antonio Heart Study.

A lower cardiovascular mortality in Mexican-American men than in non-Hispanic white men has been consistently observed. In contrast, no such ethnic difference has been observed in women. To determine whether this sex-ethnicity interaction in mortality is matched by a corresponding sex-ethnicity interaction in cardiovascular risk factors, the authors compared risk factors between 3,301 Mexican Americans and 1,877 non-Hispanic whites from the San Antonio Heart Study, a population-based study of cardiovascular disease and diabetes conducted in San Antonio, Texas (1979-1988). In both men and women, triglycerides, systolic and diastolic blood pressures, and body mass index (weight (kg)/height (m)2) were higher and high-density lipoprotein cholesterol was lower in Mexican Americans than in non-Hispanic whites. Although Mexican-American men were more likely than non-Hispanic white men to be smokers, Mexican Americans of both sexes smoked, on average, fewer cigarettes per day than non-Hispanic whites. Cardiovascular risk scores, which were constructed from Framingham Study risk equations to summarize the combined effect of multiple risk factors, were higher in Mexican Americans than in non-Hispanic whites of both sexes. The cardiovascular risk profile was less favorable for both Mexican Americans who grew up in Mexico and Mexican Americans who grew up in San Antonio. Although it is possible that in their younger years Mexican Americans had a more favorable cardiovascular risk profile, these results may also indicate that some protective factor, either genetic or life-style, is present in Mexican-American males but absent in non-Hispanic white males.

Adult↗
PubMed1990

Increased prevalence of clinical gallbladder disease in subjects with non-insulin-dependent diabetes mellitus.

The association between non-insulin-dependent diabetes mellitus (NIDDM) and the prevalence of gallbladder disease remains controversial. The authors investigated this association in 1,250 men and 1,656 women from the San Antonio Heart Study (1984-1988) a population-based study of diabetes and cardiovascular disease. A total of 68% of the subjects were Mexican American, a population at high risk for both gallbladder disease and NIDDM. Gallbladder disease was assessed by self-report, and the prevalence of diabetes was determined using National Diabetes Data Group criteria. NIDDM was significantly associated with gallbladder disease in Mexican-American men and women and in non-Hispanic white women. After adjustment for age, body mass index, ratio of waist-to-hip circumference, and ethnicity, using multiple logistic regression, the odds of gallbladder disease in women was 1.6 times higher if NIDDM was present (odds ratio = 1.60, 95% confidence interval 1.08-2.37). Mexican-American women also had a significantly increased prevalence of gallbladder disease relative to non-Hispanic white women (odds ratio = 2.21, 95% confidence interval 1.50-3.28). In nondiabetic women, fasting insulin was significantly related to prevalence of gallbladder disease in univariate analyses, but not in multivariate analyses. The authors conclude that women with diabetes have an increased prevalence of gallbladder disease relative to nondiabetic women and that this association is not explained by the greater adiposity or unfavorable body fat distribution of the diabetic subjects.

Adult↗
PubMed1990

Decreased prevalence of hypertension in Mexican-Americans.

Relatively few studies of hypertension have been carried out in Mexican-Americans, a population characterized by high rates of obesity and non-insulin-dependent diabetes mellitus. We therefore compared the prevalence of hypertension according to four different definitions in 3,297 Mexican-Americans and in 1,873 non-Hispanic whites from the San Antonio Heart Study, a population-based study of cardiovascular disease and diabetes. By all four definitions, the crude prevalence of hypertension in both sexes was lower in Mexican-Americans than in non-Hispanic whites, although only two of the eight pairwise comparisons were statistically significant. However, after adjusting for the potentially confounding effects of age, body mass index, and non-insulin-dependent diabetes mellitus, Mexican-Americans did have a statistically significant lower prevalence of both systolic and diastolic hypertension than did non-Hispanic whites in both sexes (odds ratios ranging from 0.66 to 0.71 depending on the definition of hypertension). The cause of this lower prevalence is unknown, but study of this ethnic group with elevated levels of risk factors for hypertension (obesity, hyperinsulinemia, and diabetes) may provide additional insights into the etiology of hypertension.

Adult↗
PubMed1990

Incidence of type II diabetes in Mexican Americans predicted by fasting insulin and glucose levels, obesity, and body-fat distribution.

Few data exist on predictors of non-insulin-dependent (type II) diabetes mellitus. We examined body mass index (BMI), ratio of subscapular-to-triceps skin fold (centrality index), and fasting glucose and insulin concentrations as predictors of decompensation to type II diabetes in Mexican Americans, a population at high risk for this disorder. Twenty-eight of 474 initially nondiabetic Mexican Americans developed type II diabetes after 8 yr of follow-up. Converters to diabetes were older and had higher BMIs, centrality indices, and fasting glucose and insulin concentrations than nonconverters. Subjects in the highest quartile of the insulin distribution had 6.6 times the risk of developing type II diabetes as subjects in the remaining three quartiles combined (95% confidence interval [CI] = 3.14-13.7). In multivariate analysis, fasting glucose (odds ratio [OR] = 5.80, 95% CI = 2.57-13.1) and insulin (OR = 3.12, 95% CI = 1.36-7.14) remained significantly related to conversion to diabetes. However, BMI and centrality index, which were significantly related to conversion in the univariate analysis, were no longer significant in the multivariate analysis once glucose and insulin concentrations were taken into consideration, suggesting that the effect of these variables may be mediated by insulin resistance. Nearly half of the incident cases developed in a subset of the population who were simultaneously in the highest quartile of both fasting insulin and glucose concentrations (population-attributable risk 44.2%). Our results support the insulin resistance/pancreatic exhaustion theory of type II diabetes.

Adipose Tissue↗
PubMed1990

Essential hypertension: an insulin-resistant state.

Epidemiological evidence supports a link between hyperinsulinemia and blood pressure. In nondiabetic, normotensive individuals, the male sex, age, obesity, and body fat distribution all are associated with higher systolic and diastolic blood pressure and with higher plasma insulin concentrations. Nevertheless, when accounting for the above physiological variables, blood pressure still is independently related to plasma insulin. In the general population, hypertensive individuals have multiple metabolic abnormalities (glucose intolerance, hyperinsulinemia, and dyslipidemia). A striking pattern of overlap exists among obesity, diabetes, and hypertension. Physiological studies (euglycemic insulin clamp) have shown that essential hypertension per se is a state of insulin resistance: lean, nondiabetic subjects with untreated hypertension have a mean 40% reduction in the ability of physiological hyperinsulinemia to stimulate whole-body glucose uptake. Other insulin actions (suppression of hepatic glucose output, lipolysis, lipid oxidation, and promotion of K+ uptake) are conspicuously preserved. In perfused forearm studies, local (intra-arterial) hyperinsulinemia induces subnormal rates of glucose uptake and glycogen synthesis in the skeletal muscle of individuals with essential hypertension. In the San Antonio Heart Study, parental history of non-insulin-dependent diabetes mellitus (NIDDM) is associated with hyperinsulinemia and higher blood pressure and serum lipid levels in nondiabetic probands. In this biethnic population, however, hyperinsulinemia and NIDDM are more prevalent (approximately threefold) among Mexican-Americans than non-Hispanic whites, but hypertension is more prevalent among the latter.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Pressure↗
PubMed1990

Overweight and mortality in Mexican Americans.

The Geriatric Research Center (GRC) table of desirable weights is based on the mortality experience of holders of 4.2 million policies issued by 25 life insurance companies in the USA and Canada. The GRC table defines optimum weight-for-height as the weight range which is associated with below average mortality for a given age and height group. People who fall outside this range, i.e. overweight or underweight, experience above average mortality for their age and height group. We classified 3176 Mexican Americans and 1841 non-Hispanic whites who participated in the San Antonio Heart Study according to the GRC table and found that Mexican Americans were less likely than non-Hispanic whites to be underweight and more likely to be overweight. The two effects did not offset one another, however, and fewer Mexican Americans were found to be in the 'just right' range. If the mortality experience of the population which generated the GRC table (largely non-Hispanic) applied to Mexican Americans, these results imply that Mexican Americans should have higher mortality rates than non-Hispanic whites. Vital statistics data from the state of Texas for the years 1979-81, however, fail to corroborate this prediction. Beyond age 45 years, an age range in which obesity and obesity-related disorders would be expected to exert an important influence on mortality, age-specific and age-adjusted all cause mortality was at last as good if not better in Mexican Americans than in non-Hispanic whites. These results could not be explained by ethnic differences in body fat distribution, since fat was less favorably distributed in Mexican Americans.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Lack of awareness and treatment of hyperlipidemia in type II diabetes in a community survey.

Cardiovascular disease is the leading cause of morbidity, disability, and death among patients with type II (non-insulin-dependent) diabetes mellitus. Moreover, hyperlipidemia is also common among these patients. Despite this, there are virtually no data regarding the level of awareness and treatment of hyperlipidemia among diabetic subjects at the community level. We therefore examined 374 Mexican-Americans and 86 non-Hispanic whites with type II diabetes identified in an epidemiologic survey that involved 3279 Mexican-Americans and 1847 non-Hispanic whites who resided in San Antonio, Tex. More than 40% of the diabetic subjects were hyperlipidemic according to the criteria of the National Cholesterol Education Program, and an additional 23% had hypertriglyceridemia and/or low levels of high-density lipoprotein cholesterol. By contrast, less than one fourth of the nondiabetic subjects were hyperlipidemic. Only approximately 25% of non-Hispanic whites with diabetes were aware of their hyperlipidemia, and less than 10% were receiving treatment. Awareness and treatment were even less frequent among Mexican-Americans with diabetes. Community physicians should be encouraged to give early attention to the management of lipid disorders in their diabetic patients.

Adult↗
PubMed1989

Dietary intake and the prevalence of gallbladder disease in Mexican Americans.

Mexican Americans have a high prevalence of gallbladder disease. We examined the contribution of ethnic preferences in food intake to the risk of gallbladder disease in Mexican Americans and non-Hispanic whites. Participants in a population-based health survey were questioned about any history of gallbladder disease, and were interviewed to determine their dietary intake. After adjusting for age, body mass index, and ethnic group, we found that women with the highest intake of total fat and linoleic acid had reduced risks of gallbladder disease, although an opposite trend was observed in men. High levels of sucrose intake and low levels of cholesterol intake were associated with an increased risk for both sexes, but the odds ratios were not statistically significant. Although Mexican Americans and non-Hispanics differed in their intake of several nutrients, the elevated risk of gallbladder disease in Mexican American women was unchanged after ethnic differences in food intake were taken into account. Although the dietary preferences of Mexican Americans as reflected in 24-h diet recall interviews do not appear to explain their high prevalence of gallbladder disease, this finding should be interpreted with caution because of methodologic limitations in measuring habitual food intake.

Adult↗
PubMed1989

Central adiposity and gallbladder disease in Mexican Americans.

Obesity is widely recognized as a risk factor for gallstones. However, to the authors' knowledge, only one study has examined the effect of body fat distribution on the prevalence of gallbladder disease. Mexican Americans are a population characterized by both a high prevalence of gallbladder disease and an unfavorable body fat distribution. The authors examined whether central adiposity (as measured by the ratio of subscapular-to-triceps skinfold) was related to clinically evident gallbladder disease in 1,202 Mexican Americans and 908 non-Hispanic whites in the San Antonio Heart Study from 1979 to 1982. After adjustment for overall adiposity (as measured by body mass index) and the ratio of subscapular-to-triceps skinfold, an increased prevalence of gallbladder disease was still observed in Mexican-American women. Both body mass index and the ratio of subscapular-to-triceps skinfold were positively and independently associated with gallbladder disease in women, while in men, body mass index, but not the subscapular-to-triceps skinfold ratio, was associated with gallbladder disease. Central adiposity is also related to the adverse pattern of cardiovascular risk factors observed in women with gallbladder disease.

Adult↗
PubMed1989

Metabolism of chylomicrons in subjects with dysbetalipoproteinaemia (type III hyperlipoproteinaemia).

These studies were conducted to investigate whether subjects with dysbetalipoproteinaemia (type III hyperlipoproteinaemia) can catabolize chylomicrons normally and if chylomicron catabolism is related to the triglyceride pool size. Iodinated postprandial plasma chylomicrons were injected into subjects with dysbetalipoproteinaemia (n = 7), subjects with endogenous hypertriglyceridaemia (n = 4), and normal subjects (n = 5). The subjects with dysbetalipoproteinaemia had VLDL-cholesterol/total triglyceride ratios greater than 0.35 and were deficient in isoapoE-3 and isoapoE-4. The decay of radioactivity in chylomicron apoB was measured and residence times (RT) were calculated by measuring the area under the radioactivity decay curve. The mean RT for chylomicron apoB in subjects with dysbetalipoproteinaemia was 17.4 +/- 3.5 h, which was significantly longer than in both subjects with endogenous hypertriglyceridaemia (4.8 +/- 2.1 h) and also in normal subjects (5.9 +/- 1.6 h). There was no significant correlation between chylomicron apoB RT and triglyceride levels in subjects with dysbetalipoproteinaemia or in other subjects. Thus, chylomicron apoB catabolism is retarded in subjects with dysbetalipoproteinaemia. The slow removal of chylomicron apoB in subjects with dysbetalipoproteinaemia does not seem to be attributable to an increased triglyceride pool size.

Adult↗
PubMed1989

Type II diabetes mellitus and polymorphism of insulin-receptor gene in Mexican Americans.

Resistance to insulin action is a well-established feature of type II (non-insulin-dependent) diabetes and is believed by many to contribute to the etiology of this condition. We therefore characterized restriction-fragment-length polymorphisms of the insulin-receptor gene with the restriction enzyme Rsa 1 in 242 Mexican Americans and non-Hispanic Whites with type II diabetes and 202 age-, sex-, and ethnicity-matched control subjects who participated in a population-based study in San Antonio. Alleles of 6.7 kilobases (kb) (A allele), 6.2 kb (B allele), and 3.4 kb (C allele) were identified. The C allele was observed in Mexican Americans only, where its frequency among nondiabetic control subjects was 17.7%. Diabetic Mexican Americans were twice as likely as control subjects to be homozygous for the C allele. The crude odds ratio for diabetes in CC homozygotes compared with the other two genotypes was 2.22, although this result was not statistically significant (chi 2 = 1.57, P = .21). The Mantel-Haenszel odds ratio, adjusting for age, however, indicated a 4.71-fold increased risk of diabetes among Mexican Americans with the CC genotype compared with Mexican Americans without this genotype (chi 2 = 5.38, P = .020). The age of onset of diabetes was also slightly younger in CC homozygote cases (45.4 +/- 9.2 yr) than in CX or XX cases (47.7 +/- 9.0 and 48.6 +/- 9.6 yr, respectively), although this difference was not statistically significant (P .467).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Effects of socioeconomic status on hyperglycemia and retinopathy levels in Mexican Americans with NIDDM.

Mexican Americans have a threefold greater prevalence of non-insulin-dependent diabetes mellitus (NIDDM) than non-Hispanic Whites. Moreover, Mexican-American diabetic people have more severe hyperglycemia and diabetic retinopathy than non-Hispanic White diabetic people. Mexican Americans are predominantly of low socioeconomic status (SES), and low-SES Mexican Americans have a higher prevalence of NIDDM than higher-SES Mexican Americans. Therefore, we hypothesized that among diabetic people, low SES would be associated with more severe hyperglycemia and retinopathy. Three hundred forty-three Mexican Americans and 79 non-Hispanic Whites with NIDDM were identified from the San Antonio Heart Study, a population-based study of diabetes and cardiovascular disease. Hyperglycemia was assessed as the sum of the fasting, 1-h, and 2-h plasma glucose concentrations during a standard oral glucose tolerance test. Retinopathy was assessed by 7 standard stereoretinal photographs. SES was assessed with three indicators: Duncan's socioeconomic index, education, and income. Contrary to expectations, low SES was not associated with greater levels of hyperglycemia or grades of retinopathy.

Blood Glucose↗
PubMed1989

Proteinuria in Mexican Americans and non-Hispanic whites with NIDDM.

Mexican Americans have a threefold greater prevalence of non-insulin-dependent diabetes mellitus (NIDDM) than non-Hispanic Whites as found in the San Antonio Heart Study, a population-based study of diabetes and cardiovascular disease. In addition, Mexican-American diabetic subjects have higher levels of glycemia than non-Hispanic White diabetic subjects. We therefore hypothesized that the prevalence of clinical proteinuria would be greater among Mexican-American diabetic subjects (n = 317) than among non-Hispanic White diabetic subjects (n = 67). Clinical proteinuria, defined as greater than or equal to 1+ on the Ames Albustix test, was 2.82 times more prevalent in Mexican-American diabetic subjects compared with non-Hispanic White diabetic subjects adjusting for age and duration (95% confidence interval [CI] = 1.05, 7.55; P = .039). After controlling for other possible confounding variables (i.e., glycemia, systolic blood pressure, smoking, and insulin use), the excess of proteinuria in Mexican-American diabetic subjects was only slightly attenuated, although the statistical significance became borderline (odds ratio [OR] = 2.59, 95% CI = 0.91, 7.32; P = .072). The prevalence of microalbuminuria (greater than 30 mg/L) was also significantly higher in Mexican-American diabetic subjects than in non-Hispanic White diabetic subjects (OR = 3.54, 95% CI = 1.28, 9.81; P = .015). We also compared previously diagnosed Mexican-American diabetic subjects (n = 243) from San Antonio with previously diagnosed non-Hispanic White diabetic subjects in Wisconsin (n = 476).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Relationship of sex hormone binding globulin to overall adiposity and body fat distribution in a biethnic population.

Previous data have indicated that decreased sex hormone binding globulin (SHBG) is associated with increased overall and upper body adiposity and higher levels of glucose, insulin and triglyceride (TG) and decreased levels of high-density lipoprotein (HDL) cholesterol. Since Mexican Americans have greater overall and upper body adiposity, higher rates of non-insulin-dependent diabetes mellitus, higher TG and lower HDL levels than non-Hispanic whites, we postulated that they would also have lower levels of SHBG. We measured total testosterone and total estradiol using a commercial radioimmunoassy and SHBG using a dextran-coated charcoal technique in premenopausal women (61 Mexican American and 39 non-Hispanic white) as part of the San Antonio Heart Study, a population-based study of diabetes and cardiovascular risk factors. There were no significant ethnic differences in total testosterone or total estradiol. SHBG, however, was lower in Mexican American (0.285 micrograms/dl) than in non-Hispanic white women (0.429 micrograms/dl) (P = 0.009). After adjustment for body mass index (BMI), ratio of waist-to-hip circumference (WHR) and ratio of subscapular-to-triceps skinfolds (centrality index), SHBG remained lower in Mexican Americans (0.307 micrograms/dl) than in non-Hispanic whites (0.396 micrograms/dl), although this difference was no longer statistically significant (P = 0.083). BMI, WHR and centrality index were all negatively associated with SHBG (P less than 0.01). The lower levels of SHBG in premenopausal Mexican American women compared to non-Hispanic white women may reflect greater in-vivo androgenicity and may be related to a variety of metabolic abnormalities seen in this ethnic group.

Adipose Tissue↗