Identical and Nonidentical Twins: Risk and Factors Involved in Development of Islet Autoimmunity and Type 1 Diabetes

OBJECTIVE

There are variable reports of risk of concordance for progression to islet autoantibodies and type 1 diabetes in identical twins after one twin is diagnosed. We examined development of positive autoantibodies and type 1 diabetes and the effects of genetic factors and common environment on autoantibody positivity in identical twins, nonidentical twins, and full siblings.

RESEARCH DESIGN AND METHODS

Subjects from the TrialNet Pathway to Prevention Study (N = 48,026) were screened from 2004 to 2015 for islet autoantibodies (GAD antibody [GADA], insulinoma-associated antigen 2 [IA-2A], and autoantibodies against insulin [IAA]). Of these subjects, 17,226 (157 identical twins, 283 nonidentical twins, and 16,786 full siblings) were followed for autoantibody positivity or type 1 diabetes for a median of 2.1 years.

RESULTS

At screening, identical twins were more likely to have positive GADA, IA-2A, and IAA than nonidentical twins or full siblings (all P < 0.0001). Younger age, male sex, and genetic factors were significant factors for expression of IA-2A, IAA, one or more positive autoantibodies, and two or more positive autoantibodies (all P ≤ 0.03). Initially autoantibody-positive identical twins had a 69% risk of diabetes by 3 years compared with 1.5% for initially autoantibody-negative identical twins. In nonidentical twins, type 1 diabetes risk by 3 years was 72% for initially multiple autoantibody-positive, 13% for single autoantibody-positive, and 0% for initially autoantibody-negative nonidentical twins. Full siblings had a 3-year type 1 diabetes risk of 47% for multiple autoantibody-positive, 12% for single autoantibody-positive, and 0.5% for initially autoantibody-negative subjects.

CONCLUSIONS

Risk of type 1 diabetes at 3 years is high for initially multiple and single autoantibody-positive identical twins and multiple autoantibody-positive nonidentical twins. Genetic predisposition, age, and male sex are significant risk factors for development of positive autoantibodies in twins.

Low-Dose Anti-Thymocyte Globulin (ATG) Preserves β-Cell Function and Improves HbA1c in New-Onset Type 1 Diabetes

OBJECTIVE

A pilot study suggested that combination therapy with low-dose anti-thymocyte globulin (ATG) and pegylated granulocyte colony-stimulating factor (GCSF) preserves C-peptide in established type 1 diabetes (T1D) (duration 4 months to 2 years). We hypothesized that 1) low-dose ATG/GCSF or 2) low-dose ATG alone would slow the decline of β-cell function in patients with new-onset T1D (duration <100 days).

RESEARCH DESIGN AND METHODS

A three-arm, randomized, double-masked, placebo-controlled trial was performed by the Type 1 Diabetes TrialNet Study Group in 89 subjects: 29 subjects randomized to ATG (2.5 mg/kg intravenously) followed by pegylated GCSF (6 mg subcutaneously every 2 weeks for 6 doses), 29 to ATG alone (2.5 mg/kg), and 31 to placebo. The primary end point was mean area under the curve (AUC) C-peptide during a 2-h mixed-meal tolerance test 1 year after initiation of therapy. Significance was defined as one-sided P value < 0.025.

RESULTS

The 1-year mean AUC C-peptide was significantly higher in subjects treated with ATG (0.646 nmol/L) versus placebo (0.406 nmol/L) (P = 0.0003) but not in those treated with ATG/GCSF (0.528 nmol/L) versus placebo (P = 0.031). HbA_1c was significantly reduced at 1 year in subjects treated with ATG and ATG/GCSF, P = 0.002 and 0.011, respectively.

CONCLUSIONS

Low-dose ATG slowed decline of C-peptide and reduced HbA_1c in new-onset T1D. Addition of GCSF did not enhance C-peptide preservation afforded by low-dose ATG. Future studies should be considered to determine whether low-dose ATG alone or in combination with other agents may prevent or delay the onset of the disease.

A Type 1 Diabetes Genetic Risk Score Predicts Progression of Islet Autoimmunity and Development of Type 1 Diabetes in Individuals at Risk

OBJECTIVE

We tested the ability of a type 1 diabetes (T1D) genetic risk score (GRS) to predict progression of islet autoimmunity and T1D in at-risk individuals.

RESEARCH DESIGN AND METHODS

We studied the 1,244 TrialNet Pathway to Prevention study participants (T1D patients' relatives without diabetes and with one or more positive autoantibodies) who were genotyped with Illumina ImmunoChip (median [range] age at initial autoantibody determination 11.1 years [1.2-51.8], 48% male, 80.5% non-Hispanic white, median follow-up 5.4 years). Of 291 participants with a single positive autoantibody at screening, 157 converted to multiple autoantibody positivity and 55 developed diabetes. Of 953 participants with multiple positive autoantibodies at screening, 419 developed diabetes. We calculated the T1D GRS from 30 T1D-associated single nucleotide polymorphisms. We used multivariable Cox regression models, time-dependent receiver operating characteristic curves, and area under the curve (AUC) measures to evaluate prognostic utility of T1D GRS, age, sex, Diabetes Prevention Trial-Type 1 (DPT-1) Risk Score, positive autoantibody number or type, HLA DR3/DR4-DQ8 status, and race/ethnicity. We used recursive partitioning analyses to identify cut points in continuous variables.

RESULTS

Higher T1D GRS significantly increased the rate of progression to T1D adjusting for DPT-1 Risk Score, age, number of positive autoantibodies, sex, and ethnicity (hazard ratio [HR] 1.29 for a 0.05 increase, 95% CI 1.06-1.6; P = 0.011). Progression to T1D was best predicted by a combined model with GRS, number of positive autoantibodies, DPT-1 Risk Score, and age (7-year time-integrated AUC = 0.79, 5-year AUC = 0.73). Higher GRS was significantly associated with increased progression rate from single to multiple positive autoantibodies after adjusting for age, autoantibody type, ethnicity, and sex (HR 2.27 for GRS >0.295, 95% CI 1.47-3.51; P = 0.0002).

CONCLUSIONS

The T1D GRS independently predicts progression to T1D and improves prediction along T1D stages in autoantibody-positive relatives.

Food image-induced brain activation is not diminished by insulin infusion

Background/Objective

The obesity epidemic appears to be driven in large part by our modern environment inundated by food cues, which may influence our desire to eat. While insulin decreases food intake in both animals and humans, the effect of insulin on motivation for food in the presence of food cues is not known. Therefore, the aim of this study was to evaluate the effect of an intravenous insulin infusion on the brain response to visual food cues, hunger and food craving in non-obese human subjects.

Subjects/Methods

Thirty-four right-handed healthy non-obese subjects (19F/15M, age: 29±8 yrs.; BMI: 23.1±2.1 kg/m2) were divided in two groups matched by age, and BMI: the Insulin Group (18 subjects) underwent a hyperinsulinemic-euglycemic-clamp, and the control group (16 subjects) received an intravenous saline infusion, while viewing high and low-calorie food and non-food pictures during a functional MRI scan. Motivation for food was determined via analogue scales for hunger, wanting and liking ratings.

Results

Food images induced brain responses in the hypothalamus, striatum, amygdala, insula, ventromedial prefrontal cortex (PFC), dorsolateral PFC, and occipital lobe (whole brain correction, P<0.05). Wanting (P<0.001) and liking (P<0.001) ratings were significantly higher for the food than the non-food images, but not different between insulin and saline infusion groups. Hunger ratings increased throughout the MRI scan and correlated with preference for high-calorie food pictures (r=0.70; P<0.001). However neither brain activity nor food craving were affected by hyperinsulinemia or hormonal status (leptin and ghrelin levels) (P=NS).

Conclusion

Our data demonstrate that visual food cues induce a strong response in motivation/reward and cognitive-executive control brain regions in non-obese subjects, but that these responses are not diminished by hyperinsulinemia per se. These findings suggest that our modern food cue saturated environment may be sufficient to overpower homeostatic hormonal signals, and thus contribute to the current obesity epidemic.

Severe sepsis in the emergency department - an observational cohort study from the university hospital of the West Indies

OBJECTIVE

To describe the incidence, treatment and outcomes of patients with severe sepsis and septic shock in a setting where early goal directed therapy (EGDT) is not routinely performed.

METHOD

An observational study of all adult patients admitted from the emergency department (ED) of the University Hospital of the West Indies (UHWI) with a diagnosis of severe sepsis and septic shock from July 5, 2007 to September 1, 2008 was conducted. Baseline parameters, treatment patterns and in-hospital outcomes were evaluated.

RESULTS

A total of 58 011 patients were seen and 762 (1.3%) had sepsis, 117 (15.4%) of whom were classified as severe sepsis or septic shock. Mean (SD) age was 59.2 (23.3) years and 49% were female. Medical history included hypertension (29%), diabetes mellitus (26%), stroke (8%), heart failure (6%) and HIV (6%). The most common sources of sepsis were pneumonia (67%) and urinary tract infection (46%). Median, interquartile range (IQR) time from triage to antibiotic administration was 126 (88, 220) minutes and antibiotics were given to 65.7% within three hours. Overall, organisms were sensitive to empirical antibiotics in 69%. Median (IQR) lactate was 5.3 (4.5, 7.5) mmol/L. Most patients (95%) were admitted to the ward; 1% went to the intensive care unit (ICU) and 2% died in the ED. Mean (SD) length of hospital stay was 9.5 (10.3) days. In-hospital mortality was 25% and survival correlated inversely with age (rpb = -0.25; p = 0.006).

CONCLUSION

Despite a lack of EGDT, sepsis treatment patterns were consistent with "best-practice" and mortality was lower than international comparators.

Year in diabetes 2012: The diabetes tsunami

Diabetes affects more than 300 million individuals globally, contributing to significant morbidity and mortality worldwide. As the incidence and prevalence of diabetes continue to escalate with the force of an approaching tsunami, it is imperative that we better define the biological mechanisms causing both obesity and diabetes and identify optimal prevention and treatment strategies that will enable a healthier environment and calmer waters. New guidelines from the American Diabetes Association/European Association of the Study of Diabetes and The Endocrine Society encourage individualized care for each patient with diabetes, both in the outpatient and inpatient setting. Recent data suggest that restoration of normal glucose metabolism in people with prediabetes may delay progression to type 2 diabetes (T2DM). However, several large clinical trials have underscored the limitations of current treatment options once T2DM has developed, particularly in obese children with the disease. Prospects for reversing new-onset type 1 diabetes also appear limited, although recent clinical trials indicate that immunotherapy can delay the loss of β-cell function, suggesting potential benefits if treatment is initiated earlier. Research demonstrating a role for the central nervous system in the development of obesity and T2DM, the identification of a new hormone that simulates some of the benefits of exercise, and the development of new β-cell imaging techniques may provide novel therapeutic targets and biomarkers of early diabetes detection for optimization of interventions. Today's message is that a diabetes tsunami is imminent, and the only way to minimize the damage is to create an early warning system and improve interventions to protect those in its path.

Pancreatic perfusion of healthy individuals and type 1 diabetic patients as assessed by magnetic resonance perfusion imaging

AIMS/HYPOTHESIS

Loss of pancreatic beta cell mass and function leads to the development of diabetes mellitus. Currently there is no technical way to non-invasively image islet function and mass. Murine models suggest that islets are highly vascularised organs that make a significant contribution to the total pancreatic blood flow. The current study was undertaken to test with arterial spin labelling (ASL) magnetic resonance imaging if islet mass and/or stimulation of human pancreatic islets by hyperglycaemia can differentially increase whole-pancreas perfusion, thereby distinguishing non-diabetic from type 1 diabetic patients.

METHODS

We assessed pancreatic blood flow using ASL at baseline, during a hyperglycaemia clamp study (glucose at 11 mmol/l) and during recovery to euglycaemia.

RESULTS

Seventeen healthy volunteers and seven type 1 diabetic patients were studied. In healthy volunteers we observed no change in pancreatic blood flow during the three phases of the study. A trend for an increase in blood flow was observed in the two control tissues, the liver and kidney. Similarly, there was no significant difference in blood flow during the three stages (baseline, hyperglycaemia and recovery) in diabetic patients and there was no significant difference observed between diabetic patients and normal volunteers.

CONCLUSIONS/INTERPRETATION

Our data suggest that in humans neither increased demand nor islet mass has a substantial influence on pancreatic perfusion. It is possible, however, that the current state-of-the art imaging technology employed in this study might not be sensitive enough to distinguish between a true effect and noise.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00280085.

The association of birth weight with arterial stiffness at mid-adulthood: the Bogalusa Heart Study

BACKGROUND

Birth weight has been found to predict cardiovascular morbidity and mortality. Pulse wave velocity (PWV), a marker of arterial stiffness, has been associated with cardiovascular risk factors. An association between birth weight and blood pressure (BP) has previously been reported. In this study, the association of birth weight with PWV, and the relationship between birth weight, pulse wave velocity and BP in mid-adulthood were investigated.

METHODS

The Bogalusa Heart Study (BHS) is a population-based longitudinal study to investigate the natural development of cardiovascular risk factors. In the 2001 survey, brachial-ankle PWV (baPWV) was measured as an indicator of arterial stiffness. Of the 1203 participants in that survey, 707 had complete data on birth weight and PWV, which were utilised for this study.

RESULTS

In this study, birth weight was inversely correlated with baPWV, pulse pressure, and systolic and diastolic BP (r = -0.10; r = -0.10; r = -0.13 and r = -0.09, respectively; p< or =0.01 for all). After adjustment, birth weight was inversely associated with baPWV. On average, baPWV decreased by 0.23 m/s (95% CI -0.44 to -0.03 m/s) for each 1 kg increase in birth weight. Birth weight (inversely) and baPWV were independently associated with systolic BP (B = -2.05; 95% CI -3.27 to -0.84 and B = 2.99; 95% CI 2.58 to 3.40 respectively).

CONCLUSIONS

Lower birth weight is associated with higher baPWV. The link between birth weight and systolic BP may be partially explained by the association of birth weight with PWV.

Medical management of hyperglycaemia in type 2 diabetes mellitus: a consensus algorithm for the initiation and adjustment of therapy: a consensus statement from the American Diabetes Association and the European Association for the Study of Diabetes

The consensus algorithm for the medical management of type 2 diabetes was published in August 2006 with the expectation that it would be updated, based on the availability of new interventions and new evidence to establish their clinical role. The authors continue to endorse the principles used to develop the algorithm and its major features. We are sensitive to the risks of changing the algorithm cavalierly or too frequently, without compelling new information. An update to the consensus algorithm published in January 2008 specifically addressed safety issues surrounding the thiazolidinediones. In this revision, we focus on the new classes of medications that now have more clinical data and experience.

[Management of hyperglycemia in type 2 diabetes: a consensus algorithm for the initiation and adjustment of therapy. (A consensus statement from the American Diabetes Association and the European Association for the Study of Diabetes)]

This Russian translation and reprint of the original article published with authors permissions. Original article published in the Diabetes Care. 2006;29(8). Translation to Russian prepared by Yu. Sych. An abridged version of the article was prepared by A. Gorbovskaya. These recommendations and the algorithm are based on data from clinical studies of various treatment options for type 2 diabetes and on the personal experience of consensus participants, taking into account the main goal of treatment - to achieve and maintain glucose levels as close as possible to glycemia in healthy people. The lack of evidence of high levels of glycemia obtained in comparative clinical trials with a direct comparison of different treatment options for diabetes remains the main obstacle to isolating one main class of drugs or combination of drugs that have advantages over others.

The association of birth weight with developmental trends in blood pressure from childhood through mid-adulthood: the Bogalusa Heart study

Low birth weight has been found to be associated with cardiovascular mortality and morbidity and with an adverse profile of several cardiovascular risk factors. The inverse association between birth weight and blood pressure was consistently reported from many populations. Using longitudinal data from the Bogalusa Heart Study (Louisiana), the authors investigated the association between birth weight and progression of blood pressure through early adulthood, comparing that relation between African Americans and Whites. Birth data of 2,275 participants, screened two or more times in the Bogalusa Heart Study between 1973 and 2001, were retrospectively obtained from birth certificates and were linked to their clinical, laboratory, and socioeconomic and lifestyle data in the Bogalusa Heart Study data sets. Birth weight was inversely associated with systolic blood pressure, diastolic blood pressure, and pulse pressure (p<or=0.01 for all). For every 1-kg increase in birth weight, systolic blood pressure dropped by 1.9 mmHg (95% confidence interval: -2.6, -1.3), diastolic blood pressure by 0.7 mmHg (95% confidence interval: -1.2, -0.2), and pulse pressure by 1.2 mmHg (95% confidence interval: -1.7, -0.7). The interaction of birth weight with ethnicity was not significant for any outcome. Birth weight was inversely associated with later blood pressure. The strength of that association did not differ between African Americans and Whites.

Influence of acute alcohol ingestion on the hormonal responses to modest hypoglycaemia in patients with Type 1 diabetes

AIMS

To determine whether mild alcohol intoxication (45-50 mg/dl) influences counterregulatory hormone responses to moderate hypoglycaemia (2.8 mmol/l)in patients with Type 1 diabetes.

METHODS

Seventeen subjects (14 male, age range 21-46 years) with Type 1 diabetes underwent four hyperinsulinaemic glucose clamps: euglycaemia with placebo; euglycaemia with alcohol (0.4 g/kg); hypoglycaemia (2.8 mmol/l for 65 min)with placebo; and hypoglycaemia (2.8 mmol/l for 65 min) with alcohol (0.4 g/kg). Arterialized venous blood samples were taken for measurement of insulin and counterregulatory hormones.

RESULTS

During hypoglycaemia, peak growth hormone concentrations were significantly lower after alcohol compared with placebo (14.3 +/- 2.9 vs.25.9 +/- 3.4 microg/l,P< 0.001) associated with reduced insulin sensitivity in both hypoglycaemia and euglycaemia studies.

CONCLUSIONS

We found an attenuated growth hormone response to hypoglycaemia associated with mild alcohol intoxication. Although this may potentially contribute to impaired recovery of glucose after hypoglycaemia in patients with Type 1 diabetes, it appears to be offset by a reduction in insulin action.

Origins of the "black/white" difference in blood pressure: roles of birth weight, postnatal growth, early blood pressure, and adolescent body size: the Bogalusa heart study

BACKGROUND

The determinants of differences in blood pressure that emerge in adolescence between black Americans of predominantly African descent and white Americans of predominantly European descent are unknown. One hypothesis is related to intrauterine and early childhood growth. The role of early blood pressure itself is also unclear. We tested whether differences in birth weight and in carefully standardized subsequent measures of weight, height, and blood pressure from 0 to 4 or 5 years were related to black/white differences in blood pressure in adolescence.

METHODS AND RESULTS

Two Bogalusa cohorts who had complete follow-up data on birth weights and early childhood and adolescent anthropometric and blood pressure measures were pooled. One hundred eighty-five children (48 black and 47 white boys and 41 black and 49 white girls) were followed up and studied after 15 to 17 years. Birth weights were a mean 443 and 282 g lower in black boys and girls, respectively, than in whites (P<0.001). Blood pressures in adolescence were 3.4/1.9 and 1.7/0.6 mm Hg higher, respectively, and tracked from early childhood. In regression analyses, birth weight accounted for the ethnic difference in adolescent blood pressure, which was also independently predicted, in decreasing impact order, by adolescent height, adolescent body mass index, and systolic blood pressure at 4 to 5 years and inversely by growth from 0 to 4 to 5 years.

CONCLUSIONS

If these results can be replicated in larger and independent samples, they suggest that efforts to improve intrauterine growth in black infants as well as lessen weight gain in adolescence might substantially reduce excess high blood pressure/hypertension in this ethnic group.

The regulatory role of DR4 in a spontaneous diabetes DQ8 transgenic model

MHC class II molecules are critical determinants of genetic susceptibility to human type 1 diabetes. In patients, the most common haplotype contains the DRA1*0101-DRB1*0401 (DR4) and DQA1*0301-DQB1*0302 (DQ8) loci. To assess directly the relative roles of HLA-DQ8 and DR4 for diabetes development in vivo, we generated C57BL/6 transgenic mice that lack endogenous mouse MHC class II molecules but express HLA-DQ8 and/or DR4. Neither HLA-DQ nor HLA-DR transgenic mice developed insulitis or spontaneous diabetes. However, when they were crossed to transgenic mice (C57BL/6) expressing the B7.1 costimulatory molecules on pancreatic beta cells that do not normally develop diabetes, T cells from these double transgenic mice were no longer tolerant to islet autoantigens. The majority of DQ8/RIP-B7 mice developed spontaneous diabetes, whereas only 25% of DR4/RIP-B7 mice did so. Interestingly, when DQ8 and DR4 were coexpressed (DQ8DR4/RIP-B7), only 23% of these mice developed diabetes, an incidence indistinguishable from the DR4/RIP-B7 mice. T cells from both DR4/RIP-B7 and DQ8DR4/RIP-B7 mice, unlike those from DQ8/RIP-B7 mice, exhibited a Th2-like phenotype. Thus, the expression of DR4 appeared to downregulate DQ8-restricted autoreactive T cells in DQ8DR4/RIP-B7 mice. Our data suggest that although both DQ8 and DR4 can promote spontaneous diabetes in mice with a non-autoimmune-prone genetic background, the diabetogenic effect of the DQ8 allele is much greater, whereas DR4 expression downregulates the diabetogenic effect of DQ8, perhaps by enhancing Th2-like immune responses.

Alcohol intake, type of beverage, and the risk of cerebral infarction in young women

BACKGROUND AND PURPOSE

The relationship between alcohol consumption and cerebral infarction remains uncertain, and few studies have investigated whether the relationship varies by alcohol type or is present in young adults. We examined the relationship between alcohol consumption, beverage type, and ischemic stroke in the Stroke Prevention in Young Women Study.

METHODS

All 59 hospitals in the greater Baltimore-Washington area participated in a population-based case-control study of stroke in young women. Case patients (n=224) were aged 15 to 44 years with a first cerebral infarction, and control subjects (n=392), identified by random-digit dialing, were frequency matched by age and region of residence. The interview assessed lifetime alcohol consumption and consumption and beverage type in the previous year, week, and day. ORs were obtained from logistic regression models controlling for age, race, education, and smoking status, with never drinkers as the referent.

RESULTS

Alcohol consumption, up to 24 g/d, in the past year was associated with fewer ischemic strokes (<12 g/d: OR 0.57, 95% CI 0. 38 to 0.86; 12 to 24 g/d: OR 0.38, 95% CI 0.17 to 0.86; >24 g/d: OR 0.95, 95% CI 0.43 to 2.10) in comparison to never drinking. Analyses of beverage type (beer, wine, liquor) indicated a protective effect for wine consumption in the previous year (<12 g/wk: OR 0.58, 95% CI 0.35 to 0.97; 12 g/wk to <12 g/d: OR 0.55, 95% CI 0.28 to 1.10; >/=12 g/d: OR 0.92, 95% CI 0.23 to 3.64).

CONCLUSIONS

Light to moderate alcohol consumption appears to be associated with a reduced risk of ischemic stroke in young women.

Homocyst(e)ine and risk of cerebral infarction in a biracial population : the stroke prevention in young women study

BACKGROUND AND PURPOSE

Genetic enzyme variation and vitamin intake are important determinants of blood homocyst(e)ine levels. The prevalence of common genetic polymorphisms influencing homocyst(e)ine levels varies by race, and vitamin intake varies by socioeconomic status. Therefore, we examined the effect of vitamin intake, race, and socioeconomic status on the association of homocyst(e)ine with stroke risk.

METHODS

All 59 hospitals in the greater Baltimore-Washington area participated in a population-based case-control study of stroke in young women. One hundred sixty-seven cases of first ischemic stroke among women aged 15 to 44 years were compared with 328 controls identified by random-digit dialing from the same region. Risk factor data were collected by standardized interview and nonfasting phlebotomy. Plasma homocyst(e)ine was measured by high-performance liquid chromatography and electrochemical detection.

RESULTS

Blacks and whites did not differ in median homocyst(e)ine levels, nor did race modify the association between homocyst(e)ine and stroke. After adjustment for cigarettes per day, poverty status, and regular vitamin use, a plasma homocyst(e)ine level of >/=7.3 micromol/L was associated with an odds ratio for stroke of 1.6 (95% CI, 1.1 to 2.5).

CONCLUSIONS

The association between elevated homocyst(e)ine and stroke was independent not only of traditional vascular risk factors but also of vitamin use and poverty status. The degree of homocyst(e)ine elevation associated with an increased stroke risk in young women is lower than that previously reported for middle-aged men and the elderly and was highly prevalent, being present in one third of the control group.

Elevated tissue plasminogen activator antigen and stroke risk: The Stroke Prevention In Young Women Study

BACKGROUND AND PURPOSE

Abnormalities in endogenous fibrinolysis are associated with an increased risk for stroke in men and older adults. We tested the hypothesis that elevated plasma tissue plasminogen activator (tPA) antigen, a marker for impaired endogenous fibrinolysis, is an independent risk factor for stroke in young women.

METHODS

Subjects were 59 nondiabetic females ages 15 to 44 years with cerebral infarction from the Baltimore-Washington area and 97 control subjects frequency-matched for age who were recruited by random-digit dialing from the same geographic area. A history of cerebrovascular disease risk factors was obtained by face-to-face interview. Plasma tPA antigen was measured by enzyme-linked immunosorbent assay.

RESULTS

Mean plasma tPA antigen levels were significantly higher in stroke patients than control subjects (4. 80+/-4.18 versus 3.23+/-3.67 ng/mL; P=0.015). After adjustment for age, hypertension, cigarette smoking, body mass index, and ischemic heart disease, there was a dose-response association between tPA antigen and stroke with a 3.9-fold odds ratio of stroke (95% CI, 1.2 to 12.4; P=0.03) for the upper quartile (>4.9 ng/mL) of tPA antigen compared with the lowest quartile. The dose-response relationship between tPA antigen and stroke was equally present in white and nonwhite women, and further adjustment for total and HDL cholesterol levels only modestly attenuated this association.

CONCLUSIONS

This population-based case-control study shows that elevated plasma tPA antigen level is independently associated with an increased risk for ischemic stroke in nondiabetic females 15 to 44 years of age. These findings support the hypothesis that impaired endogenous fibrinolysis is an important risk factor for stroke in young women.

Cerebral infarction in young adults: the Baltimore-Washington Cooperative Young Stroke Study

BACKGROUND

Few reports on stroke in young adults have included cases from all community and referral hospitals in a defined geographic region.

METHODS

At 46 hospitals in Baltimore City, 5 central Maryland counties, and Washington, DC, the chart of every patient 15 to 44 years of age with a primary or secondary diagnosis of possible cerebral arterial infarction during 1988 and 1991 was abstracted. Probable and possible etiologies were assigned following written guidelines.

RESULTS

Of 428 first strokes, 212 (49.5%) were assigned at least one probable cause, 80 (18.7%) had no probable cause but at least one possible cause, and 136 (31.8%) had no identified probable or possible cause. Of the 212 with at least one probable cause, the distribution of etiologies was cardiac embolism (31.1%), hematologic and other (19.8%), small vessel (lacunar) disease (19.8%), nonatherosclerotic vasculopathy (11.3%), illicit drug use (9.4%), oral contraceptive use (5.2%), large artery atherosclerotic disease (3.8%), and migraine (1.4%). There were an additional 69 recurrent stroke patients.

CONCLUSIONS

In this hospital-based registry within a region characterized by racial/ethnic diversity, cardiac embolism, hematologic and other causes, and lacunar stroke were the most common etiologies of cerebral infarction in young adults. Nearly a third of both first and recurrent strokes had no identified cause.

Effect of postmenopausal hormone therapy on lipoprotein(a) concentration. PEPI Investigators. Postmenopausal Estrogen/Progestin Interventions

BACKGROUND

Postmenopausal hormone therapy has been reported to decrease levels of lipoprotein (Lp)(a) in cross-sectional studies and small or short-term longitudinal studies. We report findings from a large, prospective, placebo-controlled clinical trial that allows a broad characterization of these effects for four regimens of hormone therapy.

METHODS AND RESULT

The Postmenopausal Estrogen/Progestin Interventions study was a 3-year, placebo-controlled, randomized clinical trial to assess the effect of hormone regimens on cardiovascular disease risk factors in postmenopausal women 45 to 65 years of age. The active regimens were conjugated equine estrogens therapy at 0.625 mg daily, alone or in combination with each of three regimens of progestational agents: medroxyprogesterone acetate (MPA) at 2.5 mg daily (ie, continuous MPA), MPA at 10 mg days 1 to 12 (ie, cyclical MPA), and micronized progesterone at 200 mg days 1 to 12. Plasma levels of Lp(a) were measured at baseline (n = 366), 12 months (n = 354), and 36 months (n = 342). Assignment to hormone therapy resulted in a 17% to 23% average drop in Lp(a) concentrations relative to placebo (P<.0001), which was maintained across 3 years of follow-up. No significant differences were observed among the four active arms. Changes in Lp(a) associated with hormone therapy were positively correlated with changes in LDL cholesterol, total cholesterol, apolipoprotein B, and fibrinogen levels and were similar across subgroups defined by age, weight, ethnicity, and prior hormone use.

CONCLUSIONS

Postmenopausal estrogen therapy, with or without concomitant progestin regimens, produces consistent and sustained reductions in plasma Lp(a) concentrations.

Gin and tonic and reactive hypoglycemia: what is important-the gin, the tonic, or both?

The objectives of this study were to test the hypothesis that alcohol can cause reactive hypoglycemia by attenuating the release of counterregulatory hormones. The subjects were eight healthy volunteers (five men and three women, aged 20-40 yr). Each subject drank, using a randomized, double blind design 1) three large gin with regular tonics (0.5 g/kg alcohol and 60 g carbohydrate, mainly sucrose (G+T); 2) the same amount of alcohol with Slim-line tonic (0.5 g carbohydrate; G alone); and 3) regular tonic without alcohol (T alone). Glucose, insulin, and counterregulatory hormone levels and middle cerebral artery velocity (MCAV), an index of cerebral blood flow, were measured. Alcohol levels averaged 60-70 mg/dL. Peak insulin levels were similar in both studies in which regular tonic was consumed (95% confidence interval for difference, -6 to 22 microU/mL). After the ingestion of G+T, the blood glucose nadir was lower compared to that with T alone (3.35 vs. 3.87 mmol/L; P < 0.02) or G alone (3.35 vs. 3.95 mmol/L; P < 0.01). After drinking gin, subjects reported typical hypoglycemic warning symptoms unrelated to the prevailing glucose level. In both alcohol studies, there was marked blunting of GH release (P < 0.01). Despite a blood glucose nadir of 3.35 mmol/L, plasma epinephrine levels rose only slightly from 267 to 455 pmol/L (P = NS) after G+T. Ingestion of alcohol also caused a transient rise in right MCAV (P < 0.05) followed by a late drop in velocity in both cerebral hemispheres in the G+T study (P < 0.05). In otherwise healthy individuals a combination of gin and regular tonic can induce reactive hypoglycemia. Acute ingestion of alcohol impairs the epinephrine response and markedly suppresses the release of GH in response to a fall in blood glucose levels.

Validity of self-reported rheumatoid arthritis in elderly women

OBJECTIVE

To determine the validity of a self-reported physician diagnosis of rheumatoid arthritis (RA) in elderly women.

METHODS

Women with self-reported RA were contacted and permission requested to contact their physician. Physicians were mailed a questionnaire requesting information on the subject's arthritic condition. Hand radiographs obtained at study entry were read for changes of RA.

RESULTS

The self-reported diagnosis of RA could be confirmed in 26 (21%) individuals.

CONCLUSION

The positive predictive value of self-reported RA was low in this cohort. Caution needs to be exercised in the use and interpretation of self-report data concerning arthritic conditions in epidemiologic studies.

Traditional risk factors and ischemic stroke in young adults: the Baltimore-Washington Cooperative Young Stroke Study

OBJECTIVE

To determine the association of hypertension, diabetes, and cigarette smoking with incidence of ischemic stroke in young adults.

DESIGN

Case-control study.

SETTING

Population-based sample of cases and controls.

SUBJECTS

The study included 296 cases of incident ischemic stroke among black and white adults aged 18 to 44 years in central Maryland counties from the Baltimore-Washington Cooperative Young Stroke Study and 1220 black and white adults aged 18 to 44 years from the Maryland Behavioral Risk Factor Survey, a telephone survey of a random sample of the same region, to serve as controls.

MAIN OUTCOME MEASURES

Logistic regression models were developed to determine the age-adjusted odds ratios for each risk factor. Population-attributable risk percent were computed based on the odds ratios and prevalence of each risk factor.

RESULTS

The age-adjusted odds ratios (95% confidence intervals) for white men (WM), white women (WW), black men (BM), and black women (BW) were as follows: current cigarette smoking: WM, 2.0 (1.1-3.8), WW, 2.1 (1.1-4.3), BM, 3.3 (1.6-6.6), and BW, 2.2 (1.3-3.9); history of diabetes mellitus: WM, 22.9 (5.8-89.6), WW, 6.2 (1.9-20.2), BM, 4.2 (0.8-21.9), and BW, 3.3 (1.4-7.7); and history of hypertension: WM, 1.6 (0.7-3.2), WW, 2.5 (1.1-5.9), BM, 3.8 (1.8-7.9), and BW, 4.2 (2.4-7.5). The population-attributable risk percent (95% confidence intervals) were as follows: current cigarette smoking: WM, 22.6 (3.1-38.2), WW, 17.2 (4.0-34.0), BM, 40.5 (23.1-54.0), and BW, 29.1 (13.5-41.9); history of diabetes mellitus: WM, 19.0 (8.2-28.5), WW, 15.8 (3.8-26.3), BM, 13.2 (5.3-20.4), and BW, 22.1 (12.5-30.7); and history of hypertension: WM, 21.7 (6.2-34.6), WW, 21.3 (5.4-34.5), BM, 53.5 (39.0-64.4), and BW, 50.5 (37.1-61.1).

CONCLUSIONS

Hypertension, diabetes mellitus, and current cigarette smoking are important risk factors in a biracial young adult population. Cigarette smoking and hypertension, the 2 most modifiable risk factors, were particularly important risk factors in young blacks.

The NHLBI workshop on Hypertension in Hispanic Americans, Native Americans, and Asian/Pacific Islander Americans

In June 1994, the National Heart, Lung, and Blood Institute held a workshop entitled "Epidemiology of Hypertension in Hispanic Americans, Native Americans, and Asian/Pacific Islander Americans." The studies that served as the basis for the workshop along with a summary of two workshop panel discussions are being published as a supplement by Public Health Reports. In this article, the authors present graphs that compare results across these studies with data for non-Hispanic whites, blacks, and Hispanics from the Third National Health and Nutrition Examination Survey. The graphs indicate differences in mean blood pressure levels within and among these three population groups; such differences are also apparent in comparisons of these groups with the U.S. white and black populations. Although they appear modest, these differences are sufficient to result in increased mortality rates in populations with higher levels of hypertension. Environmental influences appear to underlie most of these differences. In all of these populations, blood pressure control rates are poor. Based on these studies, hypertension prevention and control programs should be undertaken. Special emphasis should be placed on the underserved minority populations that were the focus of the workshop.

Putting it all together: summary of the NHLBI Workshop on the Epidemiology of Hypertension in Hispanic American, Native American, and Asian/Pacific Islander American Populations

THE AUTHORS OF THIS PAPER SUMMARIZED the major themes that emerged from a 2-day workshop entitled Epidemiology of Hypertension in Hispanic Americans, Native Americans, and Asian/Pacific Islander Americans, sponsored by the National Heart, Lung, and Blood Institute (NHLBI) in Washington, DC. Data from the papers were synthesized using seven points: similarities, variability within and between groups, lost prevention opportunities, emergence of explanatory variables, differences in types of data collected, missing or inconsistently reported data, and socioeconomic characteristics. Virtually all of the population groups demonstrated rises in blood pressure with age. These rises appear to be largely attributable to potentially modifiable risk factors, for example, high body mass index (BMI). Despite high levels of awareness, the levels of control of high blood pressure were poor in each population studied. Based on the themes that emerged from the data, we presented several recommendations to the workshop. One was that data be collected on these population groups repeatedly and in a standardized fashion. Another called for increased efforts aimed at control of high blood pressure in these groups. A third recommended major nationwide programmatic efforts aimed at the prevention and control of high blood pressure.

Blood pressure in minorities screened for the Multiple Risk Factor Intervention Trial (MRFIT)

THE AUTHORS PRESENT DATA FROM 361, 662 MEN ages 35 to 57, screened from 1973 to 1976 for possible participation in the Multiple Risk Factor Intervention Trial (MRFIT). Volunteers identified themselves as "white," "black," "Oriental," "Spanish American," "American Indian," or "other." They also noted if they were taking medication for diabetes. A trained technician measured blood pressure after participants had rested for 5 minutes, using the fifth Korotkoff sound to define diastolic pressure and averaging the second and third of three readings. Differences among the groups included the following: blacks had consistently higher systolic and diastolic blood pressure (SBP and DBP) than other groups; Orientals had slightly lower pressure than other nonblack groups; American Indians had somewhat higher pressure than other nonblack groups at ages 35 to 44 but lower at ages 45 to 54; Hispanics in Miami and Davis, California, had significantly higher SBP and DBP than whites in the same area; Orientals in California had significantly higher DBP (but not SBP) than whites in California.

Effect of acute and chronic caffeine use on the cerebrovascular, cardiovascular and hormonal responses to orthostasis in healthy volunteers

1. The effects of acute and chronic caffeine ingestion on supine- and tilt- (60 min at 70 degrees) induced changes in middle cerebral artery velocity (Vmca), heart rate, blood pressure and counter-regulatory hormone levels (catecholamines, growth hormone and cortisol) were studied in nine healthy volunteers. A double-blind, placebo-controlled design was used to study acute effects followed by an open study after 6 days of chronic caffeine use. 2. In the supine position, acute ingestion of caffeine (250 mg) was associated with a fall in Vmca [-11 cm/s, point estimate of difference versus placebo (95% confidence interval: -17, -6) cm/s, P < 0.001] and a rise in mean arterial pressure [+4 (1, 6) mmHg, P < 0.01] and plasma adrenaline levels [+138 (53, 223) pmol/l, P < 0.01]. After chronic caffeine use, the pressor and adrenaline responses, but not the drop in Vmca, were significantly attenuated. 3. On tilting to 70 degrees the fall in Vmca was greater with placebo than after acute caffeine ingestion [-10 (-14, -15) cm/s, P < 0.01], whereas increments (above supine values) in heart rate, mean arterial pressure and hormone levels were unchanged by caffeine. In contrast, the adrenaline [+126 (29, 282) pmol/l, P < 0.01] and noradrenaline [+0.6, 0.9) nmol/l, P < 0.05] responses to tilting were augmented after acute caffeine ingestion. Chronic caffeine supplementation did not alter the fall in Vmca associated with tilting, but significantly attenuated the adrenaline response (P < 0.01 compared with the acute study). 4. Acute caffeine ingestion and orthostasis are both associated with a reduction in Vmca and a rise in mean arterial pressure and adrenaline levels. The acute effects of caffeine on mean arterial pressure and adrenaline but not on Vmca are lost with sustained caffeine intake. These results suggest dissociation between the development of central and peripheral tolerance after chronic caffeine use.

Rationale, design, and conduct of the PEPI Trial. Postmenopausal Estrogen/Progestin Interventions

There is growing and consistent evidence that estrogen use in postmenopausal women is associated with a substantial reduction in the occurrence of cardiovascular disease. However, remarkably little is known about the biological mechanisms by which estrogen therapy may influence risk. Even less information is available on the cardiovascular effects of combined estrogen-progestin use. PEPI was not designed to test whether estrogen and estrogen-progestin therapy is efficacious in the prevention of cardiovascular disease, as a much larger trial with clinical disease outcomes is needed to answer that question. However, PEPI will provide critical evidence regarding the potential effectiveness of the various estrogen and estrogen/progestin regimens ni altering risk factors for cardiovascular disease in women. Detailed information on factors such as adherence, side effects, and general patient acceptability will also be ascertained. The main results from PEPI will provide the scientific community with information on the basic actions of estrogen and estrogen/progestin therapy on four biological systems believed to be causally associated with cardiovascular disease occurrence. Further, since the trial is designed to continue for 3 years, PEPI will be able to provide information on longer term as well as short-term effects on these systems. Finally, the results from PEPI should enable women and their physicians to select an optimal hormonal regimen, i.e., one that is acceptable, safe, and provides the most beneficial and least deleterious changes in cardiovascular and other risk factors.

Fetal Doppler and behavioral responses during hypoglycemia induced with the insulin clamp technique in pregnant diabetic women

OBJECTIVE

This study was undertaken to assess human fetal behavior and fetal blood flow after insulin-induced symptomatic maternal hypoglycemia of sufficient magnitude to elicit counterregulatory hormones and a symptomatic response.

STUDY DESIGN

Plasma glucose was lowered from approximately 95 mg/dl to 45 mg/dl in decrements of 10 mg/dl every 40 minutes with the insulin clamp technique. In 10 insulin-dependent diabetic women in the third trimester, the fetus was studied by monitoring fetal heart rate and recording fetal body and breathing movements and by performing Doppler waveform analysis with real-time ultrasonography. Maternal levels of glucagon, cortisol, epinephrine, and growth hormone were measured at each plasma glucose level.

RESULTS

The mean number of fetal limb and body movements at the start of the study was 25 +/- 16 per 15 minutes, which increased to a mean of 38 +/- 28 at a glucose level of 60 mg/dl and then declined to a mean of 23 +/- 10 at a glucose level of approximately 45 mg/dl. These changes, however, did not achieve statistical significance. In addition, no significant reductions in fetal breathing movements or heart rate were observed, although maternal epinephrine and growth hormone levels were significantly (p < 0.001) increased. No consistent changes in Doppler velocity waveforms were observed.

CONCLUSION

These data suggest that fetal well-being remains unaltered in spite of moderate maternal hypoglycemia in diabetic women.

Correlates of bone mineral density in the postmenopausal estrogen/progestin interventions trial

We assessed the cross-sectional relationship of age, menopausal years, body mass, previous estrogen use, and ethnic background to bone mineral status in a sample of 875 healthy postmenopausal women at the time they were recruited from the community to participate in a multicenter clinical trial. The women were 1-10 years postmenopause, 45-64 years of age, and had not received estrogen replacement therapy within 3 months of enrollment. Of the participants, 89% were white, 69% had a spontaneous menopause, and 53% had a history of previous estrogen replacement therapy. Bone mineral density (BMD) of the lumbar spine (L2-4) and proximal femur was measured by dual-energy x-ray absorptiometry. Results were consistent with a significant negative linear regression of BMD on age or years from menopause. Body mass index (BMI) correlated significantly with BMD at all sites (L 2-4 r = 0.28; femoral neck r = 0.34, p < 0.0001). BMD adjusted for age and BMI were higher at both sites in women who had taken estrogen versus those who had not (L2-4 0.976 +/- 0.009 versus 0.932 +/- 0.01; femoral neck 0.740 +/- 0.006 versus 0.708 +/- 0.008, p < 0.05). Adjusted BMD also increased with duration of ERT. Parity was negatively associated with L2-4 BMD (p = 0.03) but did not correlate significantly with BMD at the femoral neck. Black women had the highest L2-4 BMD, and Hispanic women had the highest femoral neck BMD, even when results were adjusted for age and BMI. When data were corrected for differences in bone size, these interethnic differences were no longer significant. We conclude that increased body mass is positively correlated with BMD, and this may confer a degree of skeletal protection to heavier postmenopausal women. Exposure for 5 years to exogenous estrogen is associated with significantly increased age- and BMI-adjusted BMD.

Reproductive correlates of bone mass in elderly women. Study of Osteoporotic Fractures Research Group

Results from previous studies of reproductive factors and bone density have been conflicting; some demonstrate a beneficial effect, but others show a detrimental effect on bone density. The present study investigates the association of parity, lactation, and menstruation with radial bone density in 2230 white women, 65 years of age and older. Bone density was assessed by single-photon absorptiometry. Linear multiple regression was utilized to determine if reproductive factors were associated with radial bone density. The number of births, duration of menstrual bleeding, age at menarche, and years menstruating were significant independent predictors of postmenopausal bone density of the radius. A 1.4% increase in distal radius bone density was observed with each additional birth. Women who began menstruation at age 9 had 6.3% higher bone density than women who began at age 16. Women who menstruated for 3 days during each menstrual cycle had 2.8% less distal radius bone density than women who bled for 7 days. Each decade of menstruation was associated with a 2% greater distal radius bone density. No difference in bone density was demonstrated for women who breast-fed and women who did not. Length of the menstrual cycle, amount of menstrual flow, and irregularity of the menstrual cycle were not significantly associated with radial bone mineral density. In conclusion, pregnancy and menstruation are associated with postmenopausal bone density of the radius.

The University of Maryland experience in integrating preventive medicine into the clinical medicine curriculum

Lifestyle risk factors play a major role in the etiology of premature mortality, morbidity, and disability in the United States. Numerous professional groups as well as the Surgeon General of the Public Health Service have recommended that increased attention be devoted to training medical students and physicians to improve their knowledge and skills in health promotion and disease prevention. Such training is critical for attaining many of the "Healthy People 2000" objectives. For a variety of reasons, however, most medical schools have had difficulty in successfully integrating preventive medicine into their clinical curriculums. This article describes the critical elements that allowed the faculty at the University of Maryland School of Medicine to accomplish this goal through its fourth year clinical preventive medicine course. The strategies employed in this course may serve as a model for other institutions to achieve the integration of preventive medicine into their clinical curriculums.