Racial differences in incidence of juvenile-onset type 1 diabetes: epidemiologic studies in southern California

Racial and ethnic differences in cardiovascular disease and outcome in type 1 diabetes patients

INTRODUCTION

Type 1 diabetes mellitus (T1DM) has increased dramatically over the last two decades with global variation greater than 350-fold difference reflecting the ethnic, racial, and geographical variation. Diabetic patients remain at a higher risk of cardiovascular mortality than those without diabetes. Therefore, it is vital for clinicians to have in-depth knowledge of T1DM statistics and their impact on people health and health resources.

AREAS COVERED

This review will cover the epidemiologic characteristics of T1DM and the influence of race, ethnicity, and geographical variation on the incidence and the outcome. The minority populations health disparities in the clinical presentation and outcomes among youth with T1DM, the long-term glycemic control patterns in racially and ethnically diverse youth, and the long-term influence of these factors on cardiovascular outcomes will be elucidated. The PubMed database was searched using the terms: T1DM ± incidence, Race, ethnicity, and Genetic.

EXPERT OPINION

Understanding the epidemiological characteristics of T1DM including race, ethnicity and the genetic predisposition will help to develop guidelines target these higher risk patients of an unfavorable outcome. Further research and interventional strategies to identify infants at genetic risk of T1DM may help to prevent, stop or retard the destructive autoimmune process leading to T1DM.

Ethnic differences in the incidence of type 1 diabetes in Norway: a register-based study using data from the period 2002-2009

BACKGROUND

Few studies have looked at variation in type 1 diabetes incidence between immigrant groups within a country.

OBJECTIVE

To investigate differences in incidence rates of childhood-onset type 1 diabetes between immigrant groups and ethnic Norwegians, and their contribution to the number of incident cases of type 1 diabetes in Norway.

SUBJECTS

The study includes 2221 individuals with newly onset type 1 diabetes diagnosed during 2002-2009 in children of 0-14 yr in Norway registered in the nationwide and population-based Norwegian Childhood Diabetes Registry.

METHODS

Incident cases were classified in seven groups based on country of maternal birth and three age groups. Statistics Norway provided the corresponding population sizes. Incidence rates were compared by Poisson regression.

RESULTS

The overall incidence rate was 34.0 cases per 100,000 person-years (95% CI: 32.6, 35.5). There were large variations in incidence across the immigrant groups (p < 0.001), ranging from 6.8 per 100,000 person-years (95% CI: 1.9-17.5) for South/East Asians to 26.0 cases per 100,000 person-years (95% CI: 11.9-49.3) for sub-Saharan Africans. The differences remained significant after adjusting for age and gender.

CONCLUSIONS

There are large variations in the rate of incidence of type 1 diabetes across the ethnic groups, and several immigrant groups have significantly lower incidence than ethnic Norwegians. Immigrant groups contributed ca. 5% of the total cases of type 1 diabetes and influence the overall incidence in Norway only to a small extent.

Race and association with disease manifestations and mortality in scleroderma: a 20-year experience at the Johns Hopkins Scleroderma Center and review of the literature

Experience suggests that African Americans may express autoimmune disease differently than other racial groups. In the context of systemic sclerosis (scleroderma), we sought to determine whether race was related to a more adverse expression of disease. Between January 1, 1990, and December 31, 2009, a total of 409 African American and 1808 white patients with scleroderma were evaluated at a single university medical center. While the distribution by sex was virtually identical in both groups, at 82% female, African American patients presented to the center at a younger mean age than white patients (47 vs. 53 yr; p < 0.001). Two-thirds of white patients manifested the limited cutaneous subset of disease, whereas the majority of African American patients manifested the diffuse cutaneous subset (p < 0.001). The proportion seropositive for anticentromere antibody was nearly 3-fold greater among white patients, at 34%, compared to African American patients (12%; p < 0.001). Nearly a third of African American (31%) patients had autoantibodies to topoisomerase, compared to 19% of white patients (p = 0.001). Notably, African American patients experienced an increase in prevalence of cardiac (adjusted odds ratio [OR], 1.6; 95% confidence interval [CI], 1.3-2.2), renal (OR, 1.6; 95% CI, 1.2-2.1), digital ischemia (OR, 1.5; 95% CI, 1.4-2.2), muscle (OR, 1.7; 95% CI, 1.3-2.3), and restrictive lung (OR, 6.9; 95% CI, 5.1-9.4) disease. Overall, 700 (32%) patients died (159 African American; 541 white). The cumulative incidence of mortality at 10 years was 43% among African American patients compared to 35% among white patients (log-rank p = 0.0011). Compared to white patients, African American patients experienced an 80% increase in risk of mortality (relative risk [RR], 1.8; 95% CI, 1.4-2.2), after adjustment for age at disease onset and disease duration. Further adjustment by sex, disease subtype, and scleroderma-specific autoantibody status, and for the socioeconomic measures of educational attainment and health insurance status, diminished these risk estimates (RR, 1.3; 95% CI, 1.0-1.6). The heightened risk of mortality persisted in strata defined by age at disease onset, diffuse cutaneous disease, anticentromere seropositivity, decade of care at the center, and among women. These findings support the notion that race is related to a distinct phenotypic profile in scleroderma, and a more unfavorable prognosis among African Americans, warranting heightened diagnostic evaluation and vigilant care of these patients. Further, we provide a chronologic review of the literature regarding race, organ system involvement, and mortality in scleroderma; we furnish synopses of relevant reports, and summarize findings.

COSINE: COndition-SpecIfic sub-NEtwork identification using a global optimization method

MOTIVATION

The identification of condition specific sub-networks from gene expression profiles has important biological applications, ranging from the selection of disease-related biomarkers to the discovery of pathway alterations across different phenotypes. Although many methods exist for extracting these sub-networks, very few existing approaches simultaneously consider both the differential expression of individual genes and the differential correlation of gene pairs, losing potentially valuable information in the data.

RESULTS

In this article, we propose a new method, COSINE (COndition SpecIfic sub-NEtwork), which employs a scoring function that jointly measures the condition-specific changes of both 'nodes' (individual genes) and 'edges' (gene-gene co-expression). It uses the genetic algorithm to search for the single optimal sub-network which maximizes the scoring function. We applied COSINE to both simulated datasets with various differential expression patterns, and three real datasets, one prostate cancer dataset, a second one from the across-tissue comparison of morbidly obese patients and the other from the across-population comparison of the HapMap samples. Compared with previous methods, COSINE is more powerful in identifying truly significant sub-networks of appropriate size and meaningful biological relevance.

AVAILABILITY

The R code is available as the COSINE package on CRAN: http://cran.r-project.org/web/packages/COSINE/index.html.

Incidence of type 1 diabetes in Philadelphia is higher in black than white children from 1995 to 1999: epidemic or misclassification?

OBJECTIVE

To determine the epidemiology of type 1 diabetes in children in Philadelphia, Pennsylvania, from 1995 through 1999 and compare these data with previous cohorts.

RESEARCH DESIGN AND METHODS

This is a report of a retrospective population-based registry maintained since 1985. Hospital records meeting the following criteria were reviewed: newly diagnosed type 1 diabetes, age 0-14 years, residing in Philadelphia at the time of diagnosis, and diagnosed from 1 January 1995 to 31 December 1999. The secondary source of validation was the School District of Philadelphia. Incidence rates by race and age were compared with 1985-1989 and 1990-1994 cohorts.

RESULTS

A total of 234 case subjects were identified, and the registry was determined to be 96% complete. The overall age-adjusted incidence rate in Philadelphia was 14.8 per 100,000/year. Incidence rates in Hispanic children (15.5 per 100,000/year) and white children (12.8 per 100,000/year) have been relatively stable over 15 years. The incidence in black children (15.2 per 100,000/year), however, has increased dramatically, rising 64% in children 5-9 years of age (14.9 per 100,000/year) and 37% in the 10- to 14-year age-group (26.9 per 100,000/year).

CONCLUSIONS

The overall incidence of type 1 diabetes in Philadelphia is increasing and is similar to other U.S. registries. These are the first data reporting a higher incidence in black children in a registry of children 0-14 years of age. The etiology of the marked increase in incidence in the black population is unknown and underscores the need to establish type 1 diabetes as a reportable disease, so that environmental risk factors may be thoroughly investigated.

The changing spectrum of diabetes in Mexican American youth

Type 2 diabetes (T2DM) is now a pediatric disease. As in adults, it disproportionately affects ethnic and racial minorities, including Hispanics. The preponderance of Hispanics in south Texas are of Mexican American (MA) heritage. Over the past 16 years, we have accumulated a large cohort of children with diabetes. We have noted distinct differences in numerous parameters between MA children with T2DM and those with type 1 diabetes (T1DM). In order to explore these observations, we have reviewed the records of all children diagnosed with diabetes (n = 669) during the 9 years between January, 1990 and December, 1998 and seen by our pediatric diabetes group. In this cohort were 329 MA, 287 non-Hispanic whites (EA) and 53 African Americans. Compared to EA children with T1DM, MA children were more likely to have a parent with diabetes, to be hospitalized at the time of diagnosis and to lack health insurance. The differences between MA children with T1DM and T2DM were significant: specifically, children with T2DM were more likely to be female and pubertal with a body mass index >25 kg/m(2) and have acanthosis nigricans. Slightly more than 2/3 of the MA children with T2DM had at least one parent already diagnosed with T2DM. Less than 1/3 of the children with T2DM required hospitalization at the time of diagnosis and only a 1/4 have private health insurance. Over this 9-year interval, the apparent incidence of diabetes almost tripled in south Texas with the great majority of that increase due to the increasing numbers of children with T2DM.

Newborn HLA-DR,DQ genotype screening: age- and ethnicity-specific type 1 diabetes risk estimates

OBJECTIVE

Certain human leukocyte antigen (HLA)-DR,DQ genotypes have been associated with type 1 diabetes mellitus (T1DM) risk, although it is unknown whether the association is due to alleles, haplotypes, genotypes, the formation of heterodimers, or all of the above. To characterize the role of the HLA-DR,DQ genotype and ethnicity on the onset age of T1DM, we analyzed these factors in patients with T1DM and the general population.

METHODS

One thousand three hundred twenty-two well-characterized patients with T1DM were compared with 3339 children from the general population of Denver, Colorado, USA. Because of the extensive available data across age and ethnic groups, this study population is unique.

RESULTS

The HLA-DR3/4,DQB1*0302, DRX/4,DQB1*0302 (where X=1, 4, 8, and 9), and HLA--DR3/3 genotypes were associated with T1DM, supporting previous research. Additionally, the DR3/9 genotype showed a positive association with T1DM, which has not previously been described in Caucasian populations. The HLA-DR3/4*0302 genotype was most strongly associated with T1DM in diabetic individuals with the youngest onset age. Genotype frequencies were similar between Hispanics and non-Hispanic whites, except for the DR3/3 genotype, which was more likely to be found in non-Hispanic whites.

CONCLUSIONS

These results indicate that there are multiple alleles and genotypes associated with T1DM and that the risk associated with different genetic markers depends on the age of disease onset, suggesting that some markers may be involved in more rapid disease progression.

The epidemiology of type 1 diabetes in children in Philadelphia 1990-1994: evidence of an epidemic

OBJECTIVE

To determine the epidemiology of type 1 diabetes in children in Philadelphia from 1990 to 1994, and to identify whether an epidemic occurred during that time period.

RESEARCH DESIGN AND METHODS

This is a descriptive epidemiological study using a retrospective population-based registry in Philadelphia, PA, a city with large white, African-American, and Hispanic (Puerto Rican) populations. All hospitals in Philadelphia that admit children were identified. All charts meeting the following criteria were reviewed: 1) newly diagnosed type 1 diabetes, 2) children 0-14 years of age, 3) children residing in Philadelphia at the time of diagnosis, and 4) those diagnosed from 1 January 1990 to 31 December 1994. Standard type 1 diabetes registry data were abstracted from the charts. Ascertainment of the completeness of the hospital registry was validated by data from the Philadelphia School District. Communicable disease records were reviewed to identify epidemics from 1987 to 1995.

RESULTS

A total of 209 cases were identified, and the combined hospital and school registry was determined to be 96% complete. The overall age-adjusted incidence rate in Philadelphia was 13.3/100,000/year. The highest rate by race continues to be in the Hispanic population (15.5). The incidence in African-American children has increased markedly (12.8), particularly in the 10- to 14-year age-group (22.9). An epidemic of type 1 diabetes occurred from January to June 1993, approximately 2 years after a measles epidemic in Philadelphia.

CONCLUSIONS

The overall incidence of type 1 diabetes in Philadelphia is similar to other U.S. registries. The incidence in the Hispanic population continues to be among the highest of any U.S. ethnic group. The marked increase in incidence in the African-American population may be due in part to misclassification of cases actually having type 2 diabetes. The 1993 epidemic may have been due to beta-cell autoimmunity triggered by the measles virus.

Long-term risk of IDDM in first-degree relatives of patients with IDDM

Due to a short observation period previous studies may have underestimated prevalence and recurrence risk of IDDM in relatives of IDDM patients. To obtain a more exact life-time risk estimate we identified 310 probands, representative of Danish IDDM patients, characterized by current age more than 50 years, age at onset 40 years or less and diabetes duration of more than 30 years. Family data were obtained from 291 probands. Mean "observation" times (age) (+/- SD) for siblings (n = 553) and offspring (n = 359) were 59.4 +/- 16.1 years and 33.8 +/- 8.8 years, respectively. Of the probands 73 (25.1%) had at least one first-degree relative with IDDM. Seventeen percent had at least one affected sibling. An increase from 10.4% to 22.4% of having first-degree relatives with IDDM among probands with age at onset below 20 years was observed during the period from proband at age 21 years up to 1 September 1992. Among affected siblings 48% of the second cases were affected more than 10 years after the first affected sibling. Using the life-table method cumulative recurrence risks from time of birth were calculated for siblings up to age 30 years of 6.4% and up to age 60 years of 9.6%. For offspring the risk up to age 34 years was 6.3%. In addition, we present a life-table method evaluating the cumulative recurrence risk from time of onset in the proband, as this is the most relevant when giving genetic counselling. In conclusion, the long-term risks of IDDM in siblings and offspring are high compared to that shown in previous reports.

Detecting and treating retinopathy in patients with type I diabetes mellitus. A health policy model

Diabetic retinopathy is the major cause of new cases of blindness among working-age Americans. The authors analyzed the medical and economic implications of alternative screening strategies for detecting retinopathy in a diabetic population. The approaches compared included dilated fundus examination at 6-, 12-, and 24-month intervals with and without fundus photography. Potential savings from screening and treatment are based on amounts paid by the federal government for blindness-related disability. Screening for and treating retinopathy in patients with type I diabetes mellitus was cost-effective using all screening strategies. Between 71,474 and 85,315 person years of sight and 76,886 and 94,705 person years of reading vision can be saved for each annual cohort of patients with type I diabetes mellitus when proper laser photocoagulation is administered. This results in a cost savings of $62.1 to $108.6 million. Annual examination of all diabetic patients and semi-annual examination of those with retinopathy was more effective than annual examination with fundus photography. This screening strategy is consistent with the Preferred Practice Pattern for Diabetic Retinopathy of the American Academy of Ophthalmology.

Cost effectiveness of current approaches to the control of retinopathy in type I diabetics

Diabetic retinopathy is a leading cause of blindness among working age Americans. The epidemiology of diabetic eye disease has been well described in population-based studies and the effects of laser treatment have been tested in randomized controlled trials. The authors have designed a computer simulation model using the published reports of these studies to predict the medical and economic effects of applying currently accepted methods for the control of diabetic retinopathy to the population of type I diabetics. Recommendations for screening are taken from the Public Health Committee of the American Academy of Ophthalmology. Treatment recommendations and treatment efficacy are drawn from the reports of the Diabetic Retinopathy Study (DRS) and the Early Treatment Diabetic Retinopathy Study (ETDRS). Costs of screening and treatment are drawn from published Medicare reimbursement data. Over a 60-year period, the model predicts that proliferative diabetic retinopathy (PDR) requiring panretinal photocoagulation (PRP) will eventually develop in 72% of type I diabetics and macular edema will develop in 42%. If these treatments are delivered as recommended in the clinical trials, the model predicts a cost of $966 per person-year of vision saved from proliferative retinopathy and $1118 per person-year of central acuity saved from macular edema. This is only one seventh of the $6900 average cost of 1 year of Social Security Disability for those disabled by vision loss. Therefore, this model supports the use of federally funded eye care to prevent blindness in medically uninsured diabetics.