Hypertension and OMICS, quo vadis.
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Biomedical subjects
Publications and source records attributed to David R Jacobs.
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The authors tested the hypothesis that consumption of whole grain is associated with greater insulin sensitivity and lower body mass index (BMI) (weight (kg)/height (m)(2)) in adolescents and that this association is stronger among the heaviest adolescents. Two 127-item food frequency questionnaires were administered at the mean ages of 13 years (standard deviation 1.2) and 15 years (standard deviation 1.3) to 285 Minnesota adolescents who underwent two euglycemic insulin clamp studies 2 years apart as part of a protocol evaluating the influence of insulin resistance on development of adverse cardiovascular disease risk factors. Intake of whole grain was examined for associations with BMI and insulin sensitivity (measured as milligrams of glucose uptake per kilogram of lean body mass (M(lbm)) per minute). After adjustment for age, gender, race, Tanner stage, and energy intake, mean BMI was 23.6 for adolescents consuming less than serving/day of whole-grain foods, 22.6 for -1 servings/day, and 21.9 for more than 1 servings/day (p = 0.05). After adjustment for age, gender, race, Tanner stage, energy intake, BMI, and physical activity, M(lbm) was 11.6, 12.3, and 13.2 mg/kg/minute, respectively, in the three whole grain intake groups (p = 0.02). This relation was stronger among adolescents with higher BMIs (p = 0.001). Whole grain intake was associated with greater insulin sensitivity and lower BMI in adolescents, especially among the heaviest persons.
BACKGROUND AND PURPOSE: Chronic infections, including periodontal infections, may predispose to cardiovascular disease. The present study investigates the relationship of periodontal disease and tooth loss with subclinical atherosclerosis. METHODS: We enrolled 711 subjects with a mean age of 66+/-9 years and no history of stroke or myocardial infarction in the Oral Infections and Vascular Disease Epidemiology Study. Subjects received a comprehensive periodontal examination, extensive in-person cardiovascular disease risk factor measurements, and a carotid scan using high-resolution B-mode ultrasound. Regression models were adjusted for conventional risk factors (age, sex, smoking, diabetes, systolic blood pressure, low- and high-density lipoprotein cholesterol, race-ethnicity, education, physical activity) and markers of cultural background, healthy lifestyle, and psychosocial health. RESULTS: Measures of both current and cumulative periodontitis became more severe as tooth loss increased. A significant association was observed between tooth loss levels and carotid artery plaque prevalence. Among those with 0 to 9 missing teeth, 46% had carotid artery plaque, whereas among those with >or=10 missing teeth, carotid artery plaque prevalence was approximately 60% (P<0.05). CONCLUSIONS: Our data suggest that tooth loss is a marker of past periodontal disease in this population and is related to subclinical atherosclerosis, thereby providing a potential pathway for a relationship with clinical events.
OBJECTIVE: This study characterizes whole grain consumption among a nationally representative sample of US children and adolescents. DESIGN: Data used in this study were collected as part of the 1994-1996 US Department of Agriculture Continuing Survey of Food Intakes by Individuals (CSFII). SUBJECTS/SETTING: CSFII was designed to obtain a nationally representative sample of noninstitutionalized persons of all ages residing in the United States. Analyses reported in this article are limited to participants aged 2 to 18 years with two days of dietary recall data (n=4,802). Foods reported in the survey were quantified in servings as defined by the Food Guide Pyramid using the US Department of Agriculture Pyramid Servings Database, which contains reference data for each food reported in CSFII in servings per 100 g for 30 Pyramid food groups, including whole grain and total grain. STATISTICAL ANALYSES: Means, frequencies, and logistic regression analyses were conducted as appropriate. RESULTS: Average whole grain intake ranged from 0.8 servings per day for preschool-aged children to 1.0 servings per day for adolescents. Ready-to-eat cereals, corn and other chips, and yeast breads were found to be the major food sources of whole grains accounting for 30.9%, 21.7%, and 18.1% of whole grain intake respectively among those aged two to 18 years. APPLICATIONS/CONCLUSIONS: Given the apparent low level of whole grain intake among most children and adolescents in the United States, interventions are needed to increase intake of whole-grain foods.
OBJECTIVES: To examine the relation of leptin to insulin resistance, as measured by euglycemic insulin clamp, and insulin resistance syndrome factors in thin and heavy children. RESEARCH METHODS AND PROCEDURES: Anthropometrics, insulin, blood pressure, and leptin were measured in 342 11- to 14-year-old children (189 boys, 153 girls, 272 white, 70 black). Insulin sensitivity (M) was determined by milligrams glucose uptake per kilogram per minute and expressed as M/lean body mass (Mlbm). Children were divided by median BMI (boys = 20.5 kg/m(2); girls = 21.4 kg/m(2)) into below-median (thin) and above-median (heavy) groups. Correlation coefficients between log-leptin and components of insulin resistance syndrome were adjusted for Tanner stage, gender, and race. RESULTS: BMI was related to leptin in boys (r = 0.70, p < 0.001) and girls (r = 0.75, p < 0.001). Leptin was higher in girls than boys (32.6 vs. 12.3 ng/mL, p = 0.0001). Leptin levels increased in girls and decreased in boys during puberty, paralleling the changes in body fat. Leptin was significantly correlated with insulin, Mlbm, triglycerides, and blood pressure in heavy children and only with insulin in thin children. After adjustment for body fat, the correlations remained significant for insulin and Mlbm in heavy children and with insulin in thin children. DISCUSSION: Significant associations were found between leptin and insulin resistance in children, and these associations were attenuated by adjustment for adiposity. These findings at age 13 likely have long-term consequences in the development of the obesity-insulin resistance-related cardiovascular risk profile.
The epidemic of type 2 diabetes among children, adolescents and adults is increasing along with the increasing prevalence of overweight and obesity. Overweight is the most powerful modifiable risk factor for type 2 diabetes. Intake of wholegrain foods may reduce diabetes risk. Three prospective studies in 160000 men and women examined the relationship of whole-grain or cereal-fibre intake with the risk of type 2 diabetes. Each study used a mailed Willett food-frequency questionnaire and similar methods of quantifying wholegrain foods and cereal fibre. The self-reported incident diabetes outcome was more reliably determined in the two studies of health-care professionals than in the study of Iowa women. Risk for incident type 2 diabetes was 21-27% lower for those in the highest quintile of whole-grain intake, and 30-36% lower in the highest quintile of cereal-fibre intake, each compared with the lowest quintile. Risk reduction persisted after adjustment for the healthier lifestyle found among habitual whole-grain consumers. Observations in non-diabetic individuals support an inverse relationship between whole-grain consumption and fasting insulin levels. In feeding studies in non-diabetic individuals insulin resistance was reduced using whole grains or diets rich in whole grains. Glucose control improved with diets rich in whole grains in feeding studies of subjects with type 2 diabetes. There is accumulating evidence to support the hypothesis that whole-grain consumption is associated with a reduced risk of incident type 2 diabetes; it may also improve glucose control in diabetic individuals.
BACKGROUND: Blood lipids can influence fat-soluble antioxidant concentrations and confound their interpretation as indicators of antioxidant intake status and disease risk. OBJECTIVES: The objectives were to identify lipoproteins that can confound the interpretation of serum fat-soluble antioxidants, to evaluate the amount of the confounding, and to recommend a method for standardizing blood concentrations of fat-soluble antioxidants. DESIGN: Several methods of lipid standardization of fat-soluble antioxidants were evaluated in a large cohort of young adults with the use of both cross-sectional and longitudinal data analysis. RESULTS: Tocopherol and carotenoid concentrations were associated with plasma total cholesterol and its components, LDL, HDL, and VLDL cholesterol (estimated as plasma total triacylglycerols/5), some of which were independent predictors for all of the fat-soluble antioxidants. Among supplement nonusers, the most amphipathic (polar) of the antioxidants (alpha-tocopherol, gamma-tocopherol, and zeaxanthin plus lutein) and lycopene were associated strongly with these lipid fractions (R(2) = 0.09, 0.40). Consistent with a causal association in which blood antioxidant concentrations change as blood lipid concentrations change, similar relations were found for changes in blood antioxidant and lipid concentrations over a 7-y period. Concentrations of the remaining carotenoids (beta-cryptoxanthin, alpha-carotene, and beta-carotene) had a weaker association with plasma lipoproteins (R(2) < 0.06). Similar relations were found for supplement users. CONCLUSIONS: The simultaneous adjustment of the concentrations of tocopherols, zeaxanthin plus lutein, and lycopene for VLDL, HDL, and LDL cholesterol is recommended. This method is practical and can provide a basis for the standardization of carotenoid and tocopherol concentrations.
BACKGROUND: Recent epidemiologic study results showed that subjects who had high intakes of whole-grain foods had lower risks of death and heart disease than did subjects who had low intakes. However, the findings were inconsistent for fruit and vegetable intake. OBJECTIVE: The relations of whole-grain, refined-grain, and fruit and vegetable intakes with the risk of total mortality and the incidence of coronary artery disease (CAD) and ischemic stroke were studied in the Atherosclerosis Risk in Communities (ARIC) cohort (baseline: age 45-64 y, n = 15,792). DESIGN: Proportional hazards regression analyses were used to assess the relations of whole-grain, refined-grain, and fruit and vegetable intakes with the risk of death and the incidence of CAD and ischemic stroke, with adjustment for age, sex, ethnicity, energy intake, and cardiovascular disease risk factors. Dietary intakes were assessed by using a food-frequency questionnaire. RESULTS: Over an 11-y follow-up period, whole-grain intake was inversely associated with total mortality and incident CAD. The relative hazards of death for quintiles 2-5 of fruit and vegetable intake were 1.08 (95% CI: 0.88, 1.33), 0.94 (0.75, 1.17), 0.87 (0.68, 1.10), and 0.78 (0.61, 1.01), respectively; P for trend = 0.02. An inverse association between fruit and vegetable intake and CAD was observed among African Americans but not among whites (P for interaction = 0.01). The risk of ischemic stroke was not significantly related to whole-grain, refined-grain, or fruit and vegetable consumption. CONCLUSION: These observational findings suggest a beneficial effect of whole-grain and fruit and vegetable consumption on the risks of total mortality and incident CAD but not on the risk of ischemic stroke.
Evidence is synthesized that foods and food patterns act synergistically to influence the risk of several chronic diseases. Whole-grain consumption and risk of disease are presented as a model of food synergy. Food synergy is defined as additive or more than additive influences of foods and food constituents on health. Risk appears to be lower with consumption of whole grain than of refined grain; that is, benefit accrues when all edible parts of the grain are included (bran, germ, and endosperm). It appears that phytochemicals that are located in the fiber matrix, in addition to or instead of the fiber itself, are responsible for the reduced risk. Risk is further reduced if whole-grain foods are consumed in a diet otherwise high in plant foods. To gain full understanding of the pathways by which food synergies work, it is desirable to use several "top down" approaches, starting with the larger units, namely foods or food patterns, and working down to smaller units that provide protection from disease. Study of foods, food patterns, and individual nutrients or food components in reducing disease risk is seen as complementary. Epidemiologic, clinical trial, and in vitro approaches to such research are needed.
Although 11 million people in the United States have chronic renal insufficiency, little is known about ethnic/racial disparities for early-onset renal impairment. This study sought to determine whether there is an independent association between race/ethnicity and early-onset renal impairment and to identify other risk factors that might account for observed disparities. All Coronary Artery Risk Development in Young Adults subjects in which serum creatinine was measured at the year 15 examination were identified (n = 3554), excluding those who were pregnant at year 15. Potential risk factors at study entry (ages 18 to 30 yr, 1985 to 1986) included age, weight, gender, race/ethnicity, glucose, uric acid, and systolic BP. Renal impairment was defined as creatinine > or =1.5 mg/dl for men and > or = 1.2 mg/dl for women at year 15 (ages 33 to 45 yr). Fifty-two (2.7%) women and 39 (2.4%) men had renal impairment at the year 15 examination. In bivariate analyses, the odds of renal impairment among black women was estimated to be 2.4-fold that of white women, and among black men, the odds of renal impairment were 9.0-fold that of white men. In multivariate analysis, the odds of an elevated creatinine among black women compared with white women reduced to a nonsignificant 1.5-fold, whereas among men, the odds of an elevated creatinine among blacks was 11.4-fold that of whites. Although adjustment for baseline glucose levels accounted for much of the association between ethnicity and elevated creatinine among women, adjustment for weight, systolic BP, uric acid, glucose, and socioeconomic status did not account for the association between ethnicity and renal impairment among men. The data suggest that there are ethnic differences in the development of early-onset renal dysfunction. Among women, these differences are modest and largely accounted for by differences in glucose levels early in adult life. Differences in race/ethnicity related risk of early-onset renal impairment are particularly large among men and are not accounted for by the metabolic or socioeconomic factors evaluated.
PURPOSE: To determine the reliability and validity of physical activity monitors and self-report instruments suitable for young African-American girls. METHODS: A validation study was conducted by the Girls health Enrichment Multi-site Studies (GEMS) research team to compare an accelerometer with a pedometer and two self-report instruments for assessing physical activity in African-American girls, age 8-9 yr. Girls (N= 68) attended two clinic visits spaced 4 d apart. Each girl wore a MTI/CSA accelerometer (used as the criterion standard for validity) and a pedometer simultaneously for four consecutive days. Girls completed on two occasions a 24-h physical activity checklist of yesterday and usual activities, including sedentary activities (GEMS Activity Questionnaire, GAQ), and a 3-d computerized self-report instrument (Activitygram). RESULTS: Girls were (mean +/- SD) 9.0 +/- 0.6 yr old and had a body mass index of 19.4 kg x m. Reliability measured by intraclass correlations (ICC) and Pearson correlation coefficients (r) were calculated for the MTI/CSA (ICC = 0.37, P< 0.0001), pedometer (ICC = 0.08, = 0.094), Activitygram (ICC = 0.24) (P = 0.005), and GAQ for physical (r = 0.80, P< 0.0001) and sedentary (r = 0.3-0.5, P< 0.005) activities. Significant Pearson correlations between the MTI/CSA and the other instruments, as a measure of validity, were observed for the 4-d average pedometer score (r = 0.47, P< 0.0001), 3-d average Activitygram score (r = 0.37, P= 0.002), and the average of the two yesterday and two usual GAQ activity scores for a subset of 18 physical activities questions (r = 0.27, = 0.03; and r = 0.29,P = 0.02, respectively). The MTI/CSA was uncorrelated with single day scores from the three other instruments. CONCLUSION: The reliability of the instruments tested was acceptable, except the pedometer. Validity correlations were significant when more than one day was used. Self-report instruments need further development for improved reliability and validity.
BACKGROUND: Gamma-glutamyltransferase (GGT), which maintains cellular concentrations of glutathione, may be a marker of oxidative stress, and GGT itself may produce oxidative stress. We performed a prospective study to examine whether serum GGT predicts diabetes and hypertension. METHODS: Study participants were 4844 black and white men and women 18-30 years of age in 1985-1986; they were reexamined 2, 5, 7, 10, and 15 years later. Year 0 GGT cutpoints were 12, 17, 25, and 36 U/L (overall 25th, 50th, 75th, and 90th percentiles; the laboratory cutpoints for abnormal are 40 U/L in women and 50 U/L in men). We deleted 32 participants with prevalent diabetes and 140 participants with prevalent hypertension from the respective incidence analyses. RESULTS: After adjustment for study center, race, sex, and age in proportional hazards regression, the hazard ratios across year 0 GGT categories were 1.0, 1.6, 1.7, 4.0 (95% confidence interval, 2.0-8.1), and 5.5 (2.7-11.1) for 15-year incident diabetes and 1.0, 1.2, 1.7 (1.2-2.2), 2.3 (1.7-3.2), and 2.3 (1.7-3.2) for hypertension. Additional adjustment for year 0 alcohol consumption, body mass index, cigarette smoking, and physical activity attenuated this relationship, but GGT remained a significant predictor. CONCLUSIONS: Serum GGT within a range regarded as physiologically normal is associated with incident diabetes and hypertension. Considering known functionality of GGT, these associations are consistent with a role for oxidative stress in risk for diabetes and hypertension.
OBJECTIVE: Nutritional status is associated with pulmonary health and survival in children with cystic fibrosis (CF). This study evaluated the weight gain pattern of children with CF in relation to the longitudinal trends of their pulmonary function. Our hypothesis was that children who experience continuous weight gain at a given rate will have better average forced expiratory volume in 1 second (FEV(1)) and change in FEV(1) than children who have weight gain patterns that deviate from this rate, even when total weight gain seems adequate. METHODS: Prospectively collected data were examined in 319 children, aged 6 to 8, who were routinely followed at the Minnesota Cystic Fibrosis Center. One to 67 measurements of weight (kg), height (cm), and FEV(1) (mL) were taken per child during this 2-year period. The data were analyzed by repeated measure regression analysis and by growth pattern analysis. RESULTS: At baseline, a 1-kg higher initial weight was associated with a 55-mL higher average FEV(1). During the follow-up period, a 1-kg gain in weight was associated with an increase in FEV(1) by 32 mL. Children who had a steady weight gain tended to experience greater increases in FEV(1) than children who experienced periodic losses in weight. CONCLUSIONS: We established that children who weigh more and who gain weight at an appropriate and uninterrupted rate have a better FEV(1) trajectory. Aggressive nutritional support to maintain growth in these children may therefore improve FEV(1), which can be taken as a surrogate for better lung health, and may ultimately lead to better survival.
OBJECTIVE: A relationship between birth weight and the insulin resistance syndrome has been reported in adults but has not been defined in adolescents. RESEARCH DESIGN AND METHODS: Data were analyzed in 296 children (132 girls and 164 boys) mean age 15.0 +/- 1.2 years who had euglycemic insulin clamp studies (intravenous administration of 1 mU. kg(-1). min(-1) of insulin balanced by a variable infusion of 20% glucose to maintain blood glucose at 100 mg/dl). Insulin sensitivity (M(LBM)) was determined by glucose uptake per kg lean body mass (LBM), and parents reported birth weight. RESULTS: Birth weight ranged from 1,021 to 4,848 g (mean +/- SD 3,433 +/- 551), with 4.0% <2,500 g. Fat mass and BMI had U-shaped relations with birth weight after adjustment for race, age, sex, and blood pressure. Lean mass index (lean mass/height squared) was stable across birth weight quartiles. Fasting insulin decreased nonsignificantly across birth weight quartiles but became significant after adjustment for adolescent weight (P = 0.008). Although M(LBM) was highest in the highest birth weight quartile, the pattern was not significant. Triglycerides tended to increase with birth weight, whereas LDL cholesterol (LDL-C) and HDL cholesterol (HDL-C) tended to decrease. Blood pressure was unrelated to birth weight. CONCLUSIONS: In this cohort, fat mass was greater in adolescents with low and high birth weight; fasting insulin was lower with higher birth weight after adjustment for adolescent weight. Insulin sensitivity increased nonsignificantly with birth weight.
OBJECTIVE: To assess the relationship between positional blood pressure change and 8-year incidence of hypertension in a biracial cohort of young adults. SUBJECTS AND METHODS: Participants from the Coronary Artery Risk Development in Young Adults (CARDIA) study with complete data from year 2 (1987-1988), year 5 (1990-1991), year 7 (1992-1993), and year 10 (1995-1996) examinations were included (N = 2781). Participants were classified into 3 groups based on their year 2 systolic blood pressure response to standing: drop, a decrease in systolic blood pressure of more than 5 mm Hg; same, a change of between -5 and +5 mm Hg; and rise, more than 5-mm Hg increase. RESULTS: The number of participants in each group was as follows: drop, 741; same, 1590; and rise, 450. The 8-year incidence of hypertension was 8.4% in the drop group, 6.8% in the same group, and 12.4% in the rise group (P < .001). Adjusted odds ratios for developing hypertension during the follow-up period in the rise group vs the same group were as follows: in black men, 2.85 (95% confidence interval [CI], 1.43-5.69), in black women, 2.47 (95% CI, 1.19-5.11), in white men, 2.17 (95% CI, 1.00-4.73), and in white women, 4.74 (95% CI, 1.11-20.30). CONCLUSIONS: A greater than 5-mm Hg increase in blood pressure on standing identified a group of young adults at increased risk of developing hypertension within 8 years. These findings support a physiologic link between sympathetic nervous system reactivity and risk of hypertension in young adults.
OBJECTIVE: This paper describes the development of an after-school obesity-prevention program for African-American girls, and presents findings from a 12-week pilot trial conducted by the University of Minnesota. This study was part of the GEMS project, created to test interventions designed to reduce excess weight gain in African-American girls. DESIGN: Two-arm parallel group, randomized controlled trial. Measures were taken at baseline and at 12 weeks follow up. SETTING: An after-school community program. PARTICIPANTS: Fifty-four African-American girls, 8- to 10-years of age, and their parents/caregivers. INTERVENTION: The after-school intervention was conducted twice a week for 12 weeks, and focused on increasing physical activity and healthy eating. A family component was also included. Girls in the control group received a program over 12 weeks unrelated to nutrition and physical activity. OUTCOMES: Measures included height and weight (body mass index), percent body fat (DEXA), physical activity, assessed using a CSA accelerometer and self-report, two 24-hour dietary recalls, and psycho-social and demographic variables. Parental data included demographic and psycho-social characteristics, and dietary measures. Additionally, process evaluation data on the intervention were collected. RESULTS: Recruitment goals were met. After adjustment for baseline level, follow-up BMI did not differ between the treatment groups, an expected finding, given that this was a pilot study. At 12 weeks follow up, differences between the intervention and control groups were in the hypothesized direction of change for most variables, among both the girls and their parents. Process evaluation results demonstrated that the program was well attended, and well received, by girls and parents. CONCLUSIONS: An after-school obesity prevention program for low-income African-American girls is a promising model for future efforts.
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The objective was to describe trends in cardiovascular risk factors between 1980-1982 and 1995-1997 in metropolitan Minneapolis-St. Paul, Minnesota. Four population-based surveys of 4,000-6,000 adults aged 25-74 years were conducted in 1980-1982, 1985-1987, 1990-1992, and 1995-1997 using consistent sampling strategies and protocols. The authors completed interviews and examinations to characterize cardiovascular risk factors. Blood samples were drawn and assayed for several analytes including total cholesterol. Although total cholesterol decreased 7-9 mg/dl during the 1980s, no further reduction was noted between 1990-1992 and 1995-1997. Hypercholesterolemia prevalence (total cholesterol of >240 mg/dl and/or use of lipid-lowering medication) fell between 1980-1982 and 1990-1992 but increased thereafter. Current cigarette smoking, systolic blood pressure, and hypertension prevalence decreased significantly between 1980-1982 and 1995-1997. Body mass index increased substantially across the four surveys. Although there was little change in the mean leisure-time physical activity, the proportion of the population not engaging in regular exercise increased between 1990-1992 and 1995-1997. Dietary fat decreased consistently from 1980-1982 to 1995-1997, while overall caloric intake rose 8% in women but not men. To conclude, the favorable trends in hypertension, cigarette smoking, and dietary fat consumption observed in Minneapolis-St. Paul from 1980-1982 to 1995-1997 were paralleled by less favorable recent trends in total cholesterol, hypercholesterolemia, adiposity, and physical activity.