Richard F. Hamman

Ankle brachial index combined with Framingham risk score to predict cardiovascular events and mortality - A meta-analysis

CONTEXTnPrediction models to identify healthy individuals at high risk of cardiovascular disease have limited accuracy. A low ankle brachial index (ABI) is an indicator of atherosclerosis and has the potential to improve prediction.nnnOBJECTIVEnTo determine if the ABI provides information on the risk of cardiovascular events and mortality independently of the Framingham risk score (FRS) and can improve risk prediction.nnnDATA SOURCESnRelevant studies were identified. A search of MEDLINE (1950 to February 2008) and EMBASE (1980 to February 2008) was conducted using common text words for the term ankle brachial index combined with text words and Medical Subject Headings to capture prospective cohort designs. Review of reference lists and conference proceedings, and correspondence with experts was conducted to identify additional published and unpublished studies.nnnSTUDY SELECTIONnStudies were included if participants were derived from a general population, ABI was measured at baseline, and individuals were followed up to detect total and cardiovascular mortality.nnnDATA EXTRACTIONnPrespecified data on individuals in each selected study were extracted into a combined data set and an individual participant data meta-analysis was conducted on individuals who had no previous history of coronary heart disease.nnnRESULTSnSixteen population cohort studies fulfilling the inclusion criteria were included. During 480,325 person-years of follow-up of 24,955 men and 23,339 women, the risk of death by ABI had a reverse J-shaped distribution with a normal (low risk) ABI of 1.11 to 1.40. The 10-year cardiovascular mortality in men with a low ABI (< or = 0.90) was 18.7% (95% confidence interval [CI], 13.3%-24.1%) and with normal ABI (1.11-1.40) was 4.4% (95% CI, 3.2%-5.7%) (hazard ratio [HR], 4.2; 95% CI, 3.3-5.4). Corresponding mortalities in women were 12.6% (95% CI, 6.2%-19.0%) and 4.1% (95% CI, 2.2%-6.1%) (HR, 3.5; 95% CI, 2.4-5.1). The HRs remained elevated after adjusting for FRS (2.9 [95% CI, 2.3-3.7] for men vs 3.0 [95% CI, 2.0-4.4] for women). A low ABI (< or = 0.90) was associated with approximately twice the 10-year total mortality, cardiovascular mortality, and major coronary event rate compared with the overall rate in each FRS category. Inclusion of the ABI in cardiovascular risk stratification using the FRS would result in reclassification of the risk category and modification of treatment recommendations in approximately 19% of men and 36% of women.nnnCONCLUSIONnMeasurement of the ABI may improve the accuracy of cardiovascular risk prediction beyond the FRS.

The Burden of Diabetes Mellitus Among US Youth: Prevalence Estimates From the SEARCH for Diabetes in Youth Study

OBJECTIVE. Our goal was to estimate the prevalence of diabetes mellitus in youth <20 years of age in 2001 in the United States, according to age, gender, race/ethnicity, and diabetes type. METHODS. The SEARCH for Diabetes in Youth Study is a 6-center observational study conducting population-based ascertainment of physician-diagnosed diabetes in youth. Census-based denominators for 4 geographically based centers and enrollment data for 2 health plan-based centers were used to calculate prevalence. Age-, gender-, and racial/ethnic group-specific prevalence rates were multiplied by US population counts to estimate the total number of US youth with diabetes. RESULTS. We identified 6379 US youth with diabetes in 2001, in a population of ∼3.5 million. Crude prevalence was estimated as 1.82 cases per 1000 youth, being much lower for youth 0 to 9 years of age (0.79 cases per 1000 youth) than for those 10 to 19 years of age (2.80 cases per 1000 youth). Non-Hispanic white youth had the highest prevalence (1.06 cases per 1000 youth) in the younger group. Among 10- to 19-year-old youth, black youth (3.22 cases per 1000 youth) and non-Hispanic white youth (3.18 cases per 1000 youth) had the highest rates, followed by American Indian youth (2.28 cases per 1000 youth), Hispanic youth (2.18 cases per 1000 youth), and Asian/Pacific Islander youth (1.34 cases per 1000 youth). Among younger children, type 1 diabetes accounted for ≥80% of diabetes; among older youth, the proportion of type 2 diabetes ranged from 6% (0.19 cases per 1000 youth for non-Hispanic white youth) to 76% (1.74 cases per 1000 youth for American Indian youth). We estimated that 154369 youth had physician-diagnosed diabetes in 2001 in the United States. CONCLUSIONS. The overall prevalence estimate for diabetes in children and adolescents was ∼0.18%. Type 2 diabetes was found in all racial/ethnic groups but generally was less common than type 1, except in American Indian youth.

Executive Cognitive Abilities and Functional Status Among Community‐Dwelling Older Persons in the San Luis Valley Health and Aging Study

OBJECTIVES: The purpose of this study was to evaluate the contribution of the executive cognitive functions to self‐reported and observed performance of activities of daily living and instrumental activities of daily living.

Prevalence of overweight and obesity in youth with diabetes in USA: the SEARCH for Diabetes in Youth study.

Liu LL, Lawrence JM, Davis C, Liese AD, Pettitt DJ, Pihoker C, Dabelea D, Hamman R, Waitzfelder B, Kahn HS. Prevalence of overweight and obesity in youth with diabetes in USA: the SEARCH for Diabetes in Youth Study.

Incidence of insulin-dependent diabetes mellitus in Colorado.

We examined the incidence of insulin-dependent diabetes mellitus in children 0-17 years of age in Colorado from 1978 to 1988. Cases were ascertained from a statewide registry based on physician surveillance. A total of 1,376 children were diagnosed during this interval in a population averaging 860,000 children. The degree of ascertainment was estimated to be 93.3%. The age-adjusted incidence rate of insulindependent diabetes mellitus was 14.8/100,000 person-years. The rate was lower in individuals of Spanish origin (Hispanics) (8.7/100,000 person-years) compared with non-Hispanic individuals (15.5/100,000 person-years) (incidence rate ratio=0.6, 95% confidence interval=0.4-0.8). Incidence rates were higher in winter and lower in summer for children 5- 17 years old. Children diagnosed before the age of 5 years showed no significant seasonal pattern, although peak incidences were observed in autumn and spring. No temporal trend in diabetes incidence was observed overall or by ethnic group. The increasing insulin-dependent diabetes incidence reported by registries in Europe during this time period was not observed in Colorado. (Epidemiology 1992;3:232-238)

Seasonality comparisons among groups using incidence data

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

Indicators of Nutritional Risk in a Rural Elderly Hispanic and Non-Hispanic White Population: San Luis Valley Health and Aging Study

OBJECTIVEnTo describe the prevalence of nutritional risk factors among elderly residents in a rural Hispanic and non-Hispanic white population.nnnDESIGNnA geographically based survey of community-dwelling elderly adults.nnnSUBJECTS/SETTINGnFrom July 1993 to July 1995, all Hispanic persons older than 65 years and an age-stratified, random sample of 69% of non-Hispanic white persons, from 2 Colorado counties, were invited to participate in a study of functional impairment and disability (81% responded). After exclusion of 184 respondents who required a surrogate respondent and 8 with missing diet data, the study consisted of 1,006 subjects. Interviews included questions similar to the Nutrition screening Initiative checklist, a 21-item food frequency questionnaire, and anthropometric measures.nnnSTATISTICAL ANALYSES PERFORMEDnGender- and ethnicity-specific, age-adjusted prevalence for each risk factor was estimated by use of logistic regression.nnnRESULTSnHispanic participants were more likely than non-Hispanic whites to report inadequate intake of vegetables, problems with teeth or dentures that limited the kinds and amounts of food eaten, difficulty preparing meals, and lack of money needed to buy food. Hispanic women reported nutritional risk factors more often than Hispanic men, although anthropometric markers indicated that Hispanic men may be at higher risk of nutritional deficiency.nnnAPPLICATIONS/CONCLUSIONSnHispanic men and women had a higher prevalence of nutritional risk factors than non-Hispanic whites. Intervention programs targeting rural, elderly Hispanics should aim to ensure that basic nutrition needs (access to food, help preparing meals, and adequate dental care) are being met. Community programs to increase activity levels and consumption of nutrient-dense foods are recommended.

Abdominal obesity predicts declining insulin sensitivity in non-obese normoglycaemics: the Insulin Resistance Atherosclerosis Study (IRAS)

Aim:u2002 Cross‐sectional studies have demonstrated a relationship between obesity and insulin sensitivity (SI); however, there is a lack of evidence from longitudinal studies.

Association of antibodies to beta2-glycoprotein 1 with pregnancy loss and pregnancy-induced hypertension: a prospective study in low-risk pregnancy.

OBJECTIVEnTo determine whether higher levels of anti-beta2-glycoprotein 1 before 25 weeks gestation are independently associated with either pregnancy loss or pregnancy-induced hypertension.nnnMETHODSnSerum samples for the immunoglobulin (Ig) G and IgM isotypes of anti-beta2-glycoprotein 1, anticardiolipin antibody, and antiphosphatidylserine were collected from 325 low-risk nulliparas who presented for prenatal care before 25 weeks gestation. This cohort was followed prospectively for the development of pregnancy loss and pregnancy-induced hypertension.nnnRESULTSnThe adjusted odds ratios (OR) and 95% confidence intervals (CI) of elevated antiphospholipid antibody levels for pregnancy loss were: IgG anti-beta2-glycoprotein 1, OR 1.2 (CI 0.5, 2.8); IgG anticardiolipin antibody, OR 8.4 (CI 2.3, 31); and IgG antiphosphatidylserine, OR 5.2 (CI 1.4, 18.7). The relative risks of pregnancy loss for all IgG antiphospholipid antibodies were higher among women who had blood collected after 10 weeks gestation compared with those studied before 10 weeks gestation. However, there were only marginal differences in the attributable risks, suggesting that the impact of elevated levels of antiphospholipid antibodies might be similar in early and later stages of pregnancy. None of the antiphospholipid antibodies was associated with pregnancy-induced hypertension.nnnCONCLUSIONnIn this study, elevated levels of IgG anticardiolipin and IgG antiphosphatidylserine antibodies were markers of pregnancy loss, but an elevated level of anti-beta2-glycoprotein was not a strong predictor of fetal loss.

Prevalence of Disorders of Executive Cognitive Functioning among the Elderly: Findings from the San Luis Valley Health and Aging Study

The San Luis Valley Health and Aging Study is a population-based epidemiologic study of chronic illness and disability among Hispanic and non-Hispanic white persons over the age of 60 in two counties in rural southern Colorado, USA. Between 1993 and 1995, we examined the prevalence of impaired executive cognitive functioning in a sample of 1,313 individuals living both in the community and in nursing homes. Overall, 1 person in 3 was found to have at least mild impairment, while 1 in 6 had moderate to severe deficits. Increasing levels of executive functioning impairment were associated with lower education, advancing age, and Hispanic ethnicity. After controlling for education and acculturation, the differences by ethnic group were no longer significant.