PubMed Health⌕ Search

Biomedical subjects

S M Haffner

Publications and source records attributed to S M Haffner.

At least 199 records · Page 11Linked to original sources
PubMed1993

Is there an ethnic difference in the effect of risk factors for diabetic retinopathy?

Mexican Americans have an increased prevalence and incidence of non-insulin-dependent diabetes mellitus (NIDDM). In addition, Mexican American diabetic subjects have an increased prevalence of retinopathy relative to Caucasian diabetic subjects. In Mexican American diabetic subjects, established risk factors may have a stronger effect on diabetic retinopathy, compared to Caucasian diabetic subjects. In this report, we compare the effect of established risk factors (age at examination, gender, age at diagnosis of diabetes, duration of diabetes, glycemia, type of therapy, systolic and diastolic blood pressure, and hypertension prevalence) between Caucasian diabetic subjects (n = 478), a low-risk population for NIDDM (Wisconsin Epidemiologic Study of Diabetic Retinopathy), and Mexican American diabetic subjects (n = 231), a high-risk population for NIDDM (San Antonio Heart Study). Retinopathy was classified into two categories (any or none) as assessed by seven standard stereoscopic retinal photographs read at the University of Wisconsin Reading Center. Mexican American diabetic subjects in Texas had an increased prevalence of any retinopathy (odds ratio = 1.71, 95% confidence interval: 1.25, 2.34), compared to Caucasian diabetic subjects in Wisconsin. Longer duration of diabetes, more severe glycemia, earlier age at diagnosis, and insulin therapy were associated with diabetic retinopathy in both Mexican Americans and Caucasians. Socioeconomic status was not associated with prevalence of retinopathy. Moreover, the effect of risk factors for retinopathy was similar in both ethnic groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Performance of semiquantitative food frequency questionnaires in international comparisons. Mexico City versus San Antonio, Texas.

International dietary comparisons present a number of methodologic difficulties. We developed two semiquantitative food frequency questionnaires for use in Mexico City and San Antonio, Texas. The Mexico City questionnaire contained 85 food items and the San Antonio questionnaire contained 108. Thirty-six items were common to both questionnaires. The questionnaires were administered to 128 Mexican Americans, 35 to 64 years old, residing in a low-income barrio neighborhood of San Antonio and to 644 similarly aged Mexicans residing in a low-income "colonia" of Mexico City. Major differences in fat and carbohydrate intake as a percent of total kilocalories were observed between the two study groups, with Mexico City residents consuming approximately 18 to 21% of calories from fat and 68 to 72% from carbohydrate compared to 29 to 33% from fat and 48 to 52% from carbohydrate for Mexican Americans from San Antonio. Both of these differences were highly statistically significant (P < 0.001). A number of arguments support the validity of these findings. First, the distribution of high- and low-fat foods was similar on both questionnaires. Also, of the top-ten foods (as contributors to total kilocalorie intake) in San Antonio, seven were high in fat (> 30% of kilocalories), whereas this was true of only three of the top-ten foods in Mexico City.

Adult↗
PubMed1993

Sex hormones and the incidence of severe retinopathy in male subjects with type I diabetes.

BACKGROUND: Diabetic retinopathy rarely occurs before puberty, suggesting that changes in sex hormones may influence the development of this condition. METHODS: The authors measured total testosterone, free testosterone, sex hormone-binding globulin, estradiol, and dehydroepiandrosterone-sulfate levels in 44 men with type I diabetes participating in the 1984 to 1986 re-examination phase of the Wisconsin Epidemiologic Study of Diabetic Retinopathy, a population-based study of diabetic complications. The mean age was 32.7 years, and the mean duration of diabetes was 15.4 years. Subjects who progressed to proliferative or preproliferative retinopathy 6 years later (cases, n = 22) were compared with subjects who had little or no progression (controls, n = 22). Both groups were matched on initial level of retinopathy. Seven stereoscopic retinal photographs of each eye were obtained at both examinations, and the photographs were read by the University of Wisconsin Reading Center. RESULTS: Sex hormone-binding globulin concentrations (nmol/l) were significantly lower (reflecting increased androgenicity) in cases than in controls (22.4 +/- 11.4 versus 32.5 +/- 19.8; P = 0.04). No other statistically significant differences in hormone levels were observed. CONCLUSION: Neither serum testosterone nor other sex hormones were related to the incidence of severe retinopathy. The relationship to low-serum sex hormone-binding globulin suggests that increased androgenicity may be associated with the progression of retinopathy in male subjects with type I diabetes.

Adult↗
PubMed1993

LDL size and subclass pattern in a biethnic population.

Recently, the presence of small, dense low-density lipoprotein (LDL) has been recognized as a risk factor for coronary heart disease. There has been little work on correlates of LDL size in population-based studies and none in Mexican Americans. We examined the relationship of LDL size and pattern to anthropometric and metabolic variables in 466 Mexican Americans and non-Hispanic whites in the San Antonio Heart Study. LDL size in Angstrom units was significantly lower in Mexican Americans (255.8 +/- 0.6) than in non-Hispanic whites (257.9 +/- 0.7) (P = 0.041) after adjustment for gender and age. The percentage of subjects with pattern B tended to be higher in Mexican Americans than in non-Hispanic whites (40.0% versus 34.4%, respectively), although this difference did not reach statistical significance. In univariate analysis, LDL size was significantly associated with glucose (r = -.20), insulin (r = -.19), male gender (r = -.20), total cholesterol (r = -.22), high-density lipoprotein cholesterol (HDL-C) (r = .53), and triglyceride concentrations (r = -.63). In multivariate analyses, higher triglyceride, insulin, and glucose concentrations, lower HDL-C, and male gender were independent correlates of smaller, denser LDL. Correlates of LDL size were similar in Mexican Americans and non-Hispanic whites. Our results confirm previous reports that triglyceride and HDL-C concentrations are the most important variables associated with LDL size. The additional findings of independent effects of male gender, glucose, and insulin concentrations suggest that sex hormones and the insulin resistance syndrome may also play an important role.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Glucose↗
PubMed1993

Cardiovascular risk factors in non-insulin-dependent diabetic subjects with microalbuminuria.

In subjects with insulin-dependent diabetes mellitus, microalbuminuria has been associated with increased triglyceride and lipoprotein (a) (Lp[a]) concentrations and increased blood pressure. However, few studies have examined whether this association is present in subjects with non-insulin-dependent diabetes mellitus (NIDDM). We measured lipids, lipoproteins, Lp(a), blood pressure, and albumin excretion in 234 subjects with NIDDM from the San Antonio Heart Study, a population-based study of diabetes and cardiovascular disease. Seventy-two subjects had microalbuminuria (> or = 30 mg/dl). These subjects had increased systolic and diastolic blood pressures and higher fasting glucose concentrations relative to subjects without microalbuminuria. However, there were no significant differences between subjects with and without microalbuminuria with respect to lipids, lipoproteins, Lp(a), self-reported myocardial infarction, obesity, or body fat distribution. Subjects with diabetic retinopathy had increased microalbuminuria. In multivariate analysis both glycemia and blood pressure continued to be significantly related to the presence of microalbuminuria. We conclude that NIDDM subjects with microalbuminuria have elevated blood pressure and more severe glycemia but do not have a significantly more atherogenic pattern of lipids, lipoproteins, or Lp(a) than subjects without microalbuminuria.

Albuminuria↗
PubMed1993

Level of control of hypertension in Mexican Americans and non-Hispanic whites.

Compared with non-Hispanic whites, Mexican Americans have a higher prevalence of diabetes, greater adiposity, and an unfavorable body fat distribution. The prevalence of hypertension, however, is similar or lower in Mexican Americans than in non-Hispanic whites. There is little information on the level of blood pressure control in Mexican Americans. We compared the mean blood pressure levels of Mexican American and non-Hispanic white hypertensive subjects in the San Antonio Heart Study, a population-based study of diabetes and cardiovascular disease. Hypertension was defined as one or more of a systolic blood pressure > or = 160 mm Hg, a diastolic blood pressure > or = 95 mm Hg, and current use of antihypertensive medications. Three hundred and fifty-eight Mexican Americans and 241 non-Hispanic whites met these criteria. Poor hypertension control was defined as a systolic blood pressure > or = 160, a diastolic blood pressure > or = 95 mm Hg, or both. After adjustment for age, gender, obesity, body fat distribution, and level of educational attainment, Mexican American hypertensive subjects were in significantly poorer control than non-Hispanic white hypertensive subjects. The reasons for their poorer control are unknown, but our findings emphasize the importance of hypertension in this ethnic group.

Adult↗
PubMed1993

Decreased sex hormone-binding globulin predicts noninsulin-dependent diabetes mellitus in women but not in men.

Sex hormones may influence risk factors for noninsulin-dependent diabetes mellitus (NIDDM). Decreased sex hormone-binding globulin (SHBG; an indirect measure of androgenicity) is associated with hyperinsulinemia and insulin resistance. We measured SHBG concentrations in 58 subjects who later converted to diabetes and 107 subjects who remained normoglycemic throughout the 8 yr of follow-up of the San Antonio Heart Study, a population-based study of diabetes and cardiovascular disease. Among premenopausal women, SHBG concentrations (nanomoles per L) were significantly lower in converters than in nonconverters (41.6 +/- 12.4 vs. 74.4 +/- 10.0; P = 0.004), but corresponding differences were not observed in postmenopausal women or in men. Since, however, analysis of variance suggested no significant interaction between menopausal status and conversion to NIDDM, we pooled pre- and postmenopausal women. Subsequent analysis indicated that SHBG concentrations predicted the development of NIDDM in women independently of glucose and insulin concentrations. We conclude that increased androgenicity, as assessed by decreased SHBG concentrations, is an important independent risk factor for NIDDM in women.

Adult↗
PubMed1993

Relationship of sex hormones to lipids and lipoproteins in nondiabetic men.

Although many studies show that increased androgenicity is associated with increased triglyceride (TG) and decreased high density lipoprotein cholesterol in both pre- and postmenopausal women, relatively few data are available on the association of sex hormones to lipids and lipoproteins in men. We examined the association of sex hormone-binding globulin (SHBG), total and free testosterone, dehydroepiandrosterone sulfate (DHEA-SO4), and estradiol with lipids and lipoproteins in 178 nondiabetic men from the San Antonio Heart Study, a population-based study of diabetes and cardiovascular disease. The TG concentration was significantly inversely related to SHBG (r = -0.22), free testosterone (r = -0.15), total testosterone (r = -0.22), and DHEA-SO4 (r = -0.16). High density lipoprotein (HDL) cholesterol was significantly positively correlated to SHBG (r = 0.21), free testosterone (r = 0.15), total testosterone (r = 0.17), and DHEA-SO4 (r = 0.16). Total testosterone was significantly related to total cholesterol (r = -0.17) and low density lipoprotein cholesterol (r = -0.15). After adjustment for age, body mass index, waist to hip ratio, and glucose and insulin concentrations, TG concentrations remained significantly related to SHBG (r = -0.20), free testosterone (r = -0.15), and DHEA-SO4 (r = -0.18), and HDL cholesterol remained significantly associated with SHBG (r = 0.17), free testosterone (r = 0.15), total testosterone (r = 0.14), and DHEA-SO4 (r = 0.16). In conclusion, we observed a less atherogenic lipid and lipoprotein profile with increased testosterone concentrations. This was not explained by differences in glucose or insulin concentrations. However, sex hormones explained only a small percentage of the variation in total TG and HDL cholesterol concentrations. These findings are in striking contrast to data from women, in whom increased androgenicity is strongly associated with increased TG and decreased HDL cholesterol levels.

Adult↗
PubMed1993

Incidence of NIDDM and impaired glucose tolerance in hypertensive subjects. The San Antonio Heart Study.

Hypertension often occurs in association with NIDDM and IGT. We examined the association of hypertension at baseline to the 8-yr incidence of NIDDM and IGT in 1471 subjects who participated in the San Antonio Heart Study. Subjects who were hypertensive at baseline had a higher incidence of NIDDM (8.9 vs. 4.9%, P = 0.041) and IGT (25.2 vs. 10.0%, P < 0.001) than subjects who were normotensive at baseline. After adjusting for age, sex, ethnicity, obesity, body fat distribution, fasting glucose, and insulin, this excess was eliminated for NIDDM, but not for IGT. Specifically, the adjusted OR for NIDDM in hypertensive versus normotensive patients was 0.73 (95% Cl 0.34-1.58), whereas the adjusted OR for IGT was 1.87 (95% Cl 1.08-3.22). The excess risk of NIDDM in hypertensive patients can be explained by their greater age, obesity, more unfavorable body fat distribution, and hyperinsulinemia, whereas the excess risk of IGT is independent of these factors.

Adult↗
PubMed1993

Predicting diabetes. Moving beyond impaired glucose tolerance.

We developed predictive models for type II diabetes using stepwise multiple logistic regression analyses of a cohort of 844 Mexican Americans and 641 non-Hispanic whites who were nondiabetic at baseline and who were then followed for 8 yr. Models were developed for the overall population and separately for each sex and ethnic group. For optimal models, the multiple logistic regression program selected potential risk factors from a panel of 5 categorical and 14 continuous demographic, anthropometric, metabolic, and hemodynamic variables. For reduced models, the list of candidate variables was restricted to those commonly used in ordinary clinical practice, i.e., skinfolds, and serum insulin and postural glucose load variables were excluded. For all models, the stepwise process selected a mixture of anthropometric, glucose, lipid, and hemodynamic variables. The top 15% of the risk continuum for each model was defined as high risk to compare the performance of the models with the performance of impaired glucose tolerance (15% prevalence) as a predictor of diabetes. The relative risk of being high risk ranged from 12.16 to 35.29, whereas the relative risk of having impaired glucose tolerance ranged from 7.11 to 10.0. The sensitivity of the multiple logistic regression models ranged from 67.7 to 83.3% compared with 56.5 to 62.1% for impaired glucose tolerance. The results indicate that multivariate predictive models perform at least as well, if not better than impaired glucose tolerance in predicting type II diabetes but need not require an oral glucose load. Moreover, the models highlight the complex metabolic and hemodynamic syndrome that precedes diabetes.

Adult↗
PubMed1993

Relationship of proinsulin and insulin to cardiovascular risk factors in nondiabetic subjects.

Recent data suggest that proinsulin is strongly associated with cardiovascular risk factors in diabetic subjects. However, this relationship has not been examined in nondiabetic subjects. Therefore, we examined the relation of proinsulin to lipids, obesity (body mass index), and waist-to-hip ratio in 260 nondiabetic individuals from the San Antonio Heart Study, a population-based study of diabetes and cardiovascular disease. Proinsulin was measured by radioimmunoassay, and insulin was measured by a Linco radioimmunoassay that does not cross-react with proinsulin. Fasting insulin was significantly associated with body mass index (0.42), waist-to-hip ratio (r = 0.30), triglyceride (r = 0.29), high-density lipoprotein cholesterol (r = -0.20), and systolic blood pressure (r = 0.16) but not significantly related to diastolic blood pressure (r = 0.11). Fasting proinsulin was significantly associated with body mass index (r = 0.19), waist-to-hip ratio (r = 0.25), triglyceride (r = 0.41), systolic blood pressure (r = 0.19), and diastolic blood pressure (r = 0.15). Proinsulin was more strongly related to increased triglyceride than insulin despite its weaker relationship to obesity. In multivariate analyses, proinsulin continued to be significantly related to triglyceride concentrations (explaining 23.1% of the variance) and to systolic blood pressure (explaining 4.0% of the variance), even after adjusting for insulin. These observations suggest that proinsulin should be measured in addition to insulin in epidemiological studies. Proinsulin may be a marker for metabolic decompensation in prediabetic subjects.

Adult↗
PubMed1993

Lipoprotein(a) and diabetes. An update.

On the basis of the available data (much of which is contradictory), I suggest that the following might summarize the role of Lp(a) in diabetes currently. 1. Lp(a) in IDDM: Concentrations are probably elevated. Concentrations are probably related to metabolic control. Concentrations are increased with microalbuminuria. 2. Lp(a) in NIDDM: Concentrations are not elevated. Concentrations do not change with metabolic control. Too few data exist to make an assessment of relation of Lp(a) to microalbuminuria in NIDDM. 3. Lp(a) and CHD in diabetes: Little current evidence shows that Lp(a) is a risk factor for CHD in diabetes. More studies--especially prospective studies with larger numbers of subjects--need to be done.

Biomarkers↗
PubMed1993

Stability over time of modern diagnostic criteria for type II diabetes.

OBJECTIVE: To examine the long-term stability of the World Health Organization criteria for diabetes in the 8-yr follow-up of the San Antonio Heart Study. A problem with older criteria for diagnosing diabetes was that many individuals classified as having borderline or chemical diabetes reverted to nondiabetic status on follow-up. Few studies have addressed this issue among diabetic patients who meet the more stringent, modern National Diabetes Data Group or World Health Organization criteria. RESEARCH DESIGN AND METHODS: We studied 98 Mexican-American and 44 non-Hispanic white type II diabetic patients 8 yr after they were diagnosed according to World Health Organization criteria in a population-based epidemiological survey. Patients were classified as follows: whether they were on pharmacological treatment for diabetes at baseline, or, if not, whether they had a prior diagnosis of diabetes at the time of their baseline survey visit or were newly diagnosed. RESULTS: Of the 142 patients who met the study criteria for type II diabetes at baseline and whose status at follow-up was known, 20 (14.1%; 95% confidence interval 9.0-20.5%) no longer met criteria at follow-up 8 yr later. All but 2 of those who reverted to nondiabetic status were from the newly diagnosed group. Two of 20 had lost more than 5.0 kg over the 8 yr and an additional 5 had lost 2.5-5.0 kg. The 20 patients who reverted to nondiabetic status lacked many of the associated anthropometric, physiological, and metabolic findings of diabetes such as obesity, unfavorable body fat distribution, and dyslipidemia. Moreover, only one had proteinuria, and none had any grade of diabetic retinopathy at baseline. CONCLUSIONS: Epidemiological surveys that rely on a single oral glucose tolerance test to determine the prevalence of type II diabetes may overestimate prevalence by as much as 16% (95% confidence interval 10.5-23.6%) (142/122 = 1.16). The actual overestimate could well be less because some patients who truly have diabetes at baseline may be in remission at follow-up as a result of significant weight loss. Despite these difficulties, the modern National Diabetes Data Group and World Health Organization criteria are more stable than earlier criteria.

Adult↗
PubMed1993

Differences in the prevalence of diabetes and impaired glucose tolerance according to maternal or paternal history of diabetes.

OBJECTIVE: To determine whether diabetes risk is influenced by which parent (a parental history of diabetes is a well-documented risk factor for NIDDM) is reported to have diabetes. RESEARCH DESIGN AND METHODS: We compared the prevalence of NIDDM and IGT for 4914 subjects according to their parental history of diabetes (mother only, father only, both parents, neither parent). Subjects were drawn from the San Antonio Heart Study, a population-based survey of diabetes and cardiovascular risk factors conducted in Mexican American and non-Hispanic white individuals between 1979-1988. RESULTS: Men with a parental history of diabetes had a higher prevalence of both NIDDM and impaired glucose tolerance than men reporting no parental history of diabetes. Prevalence was equally high regardless of which parent, or whether both parents, had diabetes. In contrast, in women, only a maternal history of diabetes was associated with a higher prevalence of NIDDM and impaired glucose tolerance. Virtually no difference in NIDDM prevalence was found between women with a paternal-only history of diabetes and women with no parental history of diabetes. CONCLUSIONS: Results differed markedly between men and women. The reason for this sex difference is unclear. It may represent a measurement bias, a sex-specific environmental effect, or a genetic effect that is expressed or transmitted differently between the sexes.

Adult↗
PubMed1993

Clinical gallbladder disease in NIDDM subjects. Relationship to duration of diabetes and severity of glycemia.

OBJECTIVE: To examine the relationship between the prevalence of gallbladder disease and severity of glycemia among diabetic individuals and to provide insight into whether the diabetes-gallstone association is a causal one, because NIDDM patients have an increased prevalence of clinical gallbladder disease. RESEARCH DESIGN AND METHODS: We examined 462 diabetic individuals identified during the San Antonio Heart Study, a population-based survey of diabetes and cardiovascular disease in Mexican Americans and non-Hispanic whites. Diabetes was diagnosed according to National Diabetes Data Group criteria. RESULTS: The prevalence of self-reported gallbladder disease was 34.2% in diabetic women and 7.2% in diabetic men. Although duration of diabetes was positively related to the prevalence of gallbladder disease (P < 0.01), type of therapy was not associated, and fasting glucose concentration was inversely associated with gallbladder disease. CONCLUSIONS: Factors other than hyperglycemia may account for the increased prevalence of gallbladder disease in diabetic subjects.

Adult↗
PubMed1993

Obesity, body fat distribution and sex hormones in men.

An unfavourable body fat distribution may cause metabolic abnormalities including diabetes and dyslipidemia. These effects may be mediated by alterations in sex hormones. In women the available data suggest that upper body adiposity is related to increased androgenicity (especially as indicated by low concentrations of sex hormone binding globulin). Few data, however, are available on these relationships in men. We therefore examined the association of total testosterone, free testosterone, oestradiol, dehydroepiandrosterone sulphate (DHEA-SO4) and sex hormone binding globulin (SHBG) to waist-to-hip ratio (WHR) and conicity index in 178 men from the San Antonio Heart Study, a population-based study of diabetes and cardiovascular disease. The conicity index is equal to the abdominal circumference divided by 0.109 x the square root of (weight/height). The conicity index and WHR were significantly inversely related to DHEA-SO4 and free testosterone. SHBG was only weakly associated with body mass index (r = -0.18, P < 0.05). After adjustment for age and body mass index, DHEA-SO4 remained inversely correlated with WHR (r = -0.22, P < 0.01) and conicity index (r = -0.31, P < 0.001) and free testosterone remained inversely associated with conicity index (r = -0.21, P < 0.01). Thus, in men, the association between unfavourable body fat distribution and increased androgenicity is inverse in contrast to the situation in women.

Adipose Tissue↗
PubMed1993

A comparison of three methods for assessing Amerindian admixture in Mexican Americans.

Epidemiologic studies have revealed that Mexican Americans experience an excess of non-insulin-dependent diabetes mellitus, gallbladder disease, and obesity relative to non-Hispanic whites. It has been hypothesized that the greater susceptibility of Mexican Americans to these disorders may be related to their greater degree of Amerindian genetic admixture. We evaluate the comparability of three different methods of assessing individual genetic admixture in Mexican Americans. Subjects were enrolled as part of the San Antonio Heart Study and were examined between 1979 and 1988 (n = 3301). Three different methods were used to assess Amerindian admixture: we queried subjects about their ancestors' ethnic origin, we measured subjects' skin color, and we estimated genetic admixture directly by analysis of polymorphic blood markers. These measures were generally poorly correlated with each other, with the highest correlations observed between skin color and proportion of Mexican-origin grandparents. In men, none of these three measures of genetic admixture was associated with the prevalence of diabetes, gallbladder disease, or obesity. In women, consistent positive associations were observed between admixture and all three diseases, regardless of the admixture measure used (ie, disease prevalence was higher among women with more Amerindian admixture). In both sexes, height was negatively correlated with all three measures of admixture, and admixture was also significantly correlated with body mass index and central adiposity in women. These data suggest that the three measures considered may assess different dimensions of admixture, but that for epidemiologic research, no one may be claimed to be superior to the others.

Adult↗