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.
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.
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: 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: 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.
Early life factors may influence pulmonary function. We measured forced expiratory volume in 1 second (FEV(1)) in 1985-1986 and 2, 5, and 10 years later in approximately 4,000 black and white men and women initially aged 18-30 years. We estimated the age pattern of FEV(1) according to family smoking status, early diagnosis of asthma, early smoking initiation, adult asthma, and cigarette smoking. FEV(1) followed a quadratic pattern from age of peak through age 40. The pattern varied by race and sex. Early smoking initiation was associated with a faster decrease in FEV(1). Smoking by family members was related to early life asthma and may have contributed to faster FEV(1) decrease by encouraging behaviors such as heavier smoking or earlier smoking initiation. Prevalence of smoking was 28% when no family member smoked, compared with 59% when four or more members smoked. The FEV(1) decline was 8.5% in never-smokers without asthma; 10.1% in nonsmoking individuals diagnosed with asthma; and 11.1% in baseline smokers who smoked 15 or more cigarettes per day. The combination of asthma and heavier smoking was synergistic (17.8% decline). This study delineates an increased rate of decline in those with asthma or in those who smoke cigarettes and implicates early life exposures as contributing to the faster rate of FEV(1) decline.
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Although albumin excretion rate is commonly estimated by using albumin/creatinine ratio (A/C), gender and race differences in creatinine excretion may bias this estimate. The authors optimize the use of an untimed (spot) urine specimen among 3,371 Blacks and Whites aged 28-40 years in the Coronary Artery Risk Development in Young Adults Study in 1995-1996. Using three 24-hour collections during the year 5 examination, they determined k = 0.68 x 0.88 in Black men, 0.88 in Black women, 0.68 in White men, and 1.0 in White women to reflect gender and race differences in creatinine excretion. The authors then computed A/C adjusted for race and sex differences in creatinine excretion (A/kC) by using an untimed urine sample in the year 10 examination. A/kC >or= 25 mg/g (194 cases of microalbuminuria and 26 cases of clinical grade albuminuria) was more common among Blacks (9.1%) than among Whites (4.2%) and among men (8.2%) than among women (5.0%). Use of the unadjusted A/C underestimated the prevalence of microalbuminuria among men by 52% and among Blacks by 26%. Adjustment of A/C permitted more accurate estimation of albumin excretion rate. Men and Blacks have a higher albumin excretion rate than do women and Whites and may thereby have an increased risk of microvascular and macrovascular disease.
We examined the association between whole-grain intake and incident upper aerodigestive tract cancer in a cohort of 34,651 postmenopausal, initially cancer-free women. We also studied established risk factors for upper aerodigestive cancers, including fruit and vegetable intake, smoking and alcohol intake. A mailed questionnaire at baseline in 1986 included a food-frequency questionnaire and assessment of other cancer risk factors. During the 14-year follow-up period, 169 women developed cancer of the upper aerodigestive tract. For all upper aerodigestive cancers together, significant inverse associations were observed for the highest compared to the lowest tertile of whole grains [relative risk (RR) = 0.53, 95% confidence interval (CI) 0.34-0.81] and yellow/orange vegetables (RR = 0.58, 95% CI 0.39-0.87). In addition, those in the highest compared to lowest tertile of fiber intake from whole grain were less likely to develop upper aerodigestive tract cancer (RR = 0.56, 95% CI 0.37-0.84); fiber intake from refined grain was not significantly associated with upper aerodigestive tract cancer. Findings were generally similar for oropharyngeal (n = 53), laryngeal (n = 21), nasopharyngeal/salivary (n = 18), esophageal (n = 21) and gastric (n = 56) cancers, though numbers of cases were too small for statistical testing within individual cancers. These findings confirm previous observations that high intake of fruits and vegetables and that intake of whole grains and the fiber derived from them may reduce risk of upper aerodigestive tract cancers.
CONTEXT: Components of the insulin resistance syndrome (IRS), including obesity, glucose intolerance, hypertension, and dyslipidemia, are major risk factors for type 2 diabetes and heart disease. Although diet has been postulated to influence IRS, the independent effects of dairy consumption on development of this syndrome have not been investigated. OBJECTIVE: To examine associations between dairy intake and incidence of IRS, adjusting for confounding lifestyle and dietary factors. DESIGN: The Coronary Artery Risk Development in Young Adults (CARDIA) study, a population-based prospective study. SETTING AND PARTICIPANTS: General community sample from 4 US metropolitan areas of 3157 black and white adults aged 18 to 30 years who were followed up from 1985-1986 to 1995-1996. MAIN OUTCOME MEASURE: Ten-year cumulative incidence of IRS and its association with dairy consumption, measured by diet history interview. RESULTS: Dairy consumption was inversely associated with the incidence of all IRS components among individuals who were overweight (body mass index > or =25 kg/m(2)) at baseline but not among leaner individuals (body mass index < 25 kg/m(2)). The adjusted odds of developing IRS (2 or more components) were 72% lower (odds ratio, 0.28; 95% confidence interval, 0.14-0.58) among overweight individuals in the highest (> or =35 times per week, 24/102 individuals) compared with the lowest (<10 times per week, 85/190 individuals) category of dairy consumption. Each daily occasion of dairy consumption was associated with a 21% lower odds of IRS (odds ratio, 0.79; 95% confidence interval, 0.70-0.88). These associations were similar for blacks and whites and for men and women. Other dietary factors, including macronutrients and micronutrients, did not explain the association between dairy intake and IRS. CONCLUSIONS: Dietary patterns characterized by increased dairy consumption have a strong inverse association with IRS among overweight adults and may reduce risk of type 2 diabetes and cardiovascular disease.
PURPOSE: To determine trends in the incidence of cardiovascular disease in Japan, we examined observational data on coronary heart disease, stroke, and cardiovascular risk factors among urban Japanese working men. SUBJECTS AND METHODS: The surveyed population included all male employees aged 40 to 59 years who worked for eight industrial companies in Osaka, the second largest metropolitan city in Japan. Surveillance for cardiovascular disease and risk factors was conducted from 1963 to 1994. RESULTS: The age-adjusted incidence of coronary heart disease increased from 0.4 per 1000 person-years during 1963 to 1970, to 1.5 per 1000 person-years during 1979 to 1986, and then plateaued until 1987 to 1994 (P for trend = 0.002), whereas the incidence of stroke declined from 1.2 per 1,000 person-years during 1971 to 1978, to 0.6 per 1,000 person-years in 1987 to 1994 (P for trend = 0.02). The age-adjusted mean (+/- SD) total cholesterol level, which was 4.87 +/- 2.88 mmol/L during 1963 to 1966, increased to 5.11 +/- 0.62 mmol/L during 1982 to 1983 (P <0.001), and 5.09 +/- 0.75 mmol/L during 1990 to 1991. Both mean systolic and diastolic blood pressures increased by 1 mm Hg between the periods of 1966 to 1967 and 1982 to 1983, and declined below the 1966 to 1967 levels during 1990 to 1991. The prevalence of smoking declined from 72% during 1975 to 1976, to 58% during 1990 to 1991 (P for trend <0.001). CONCLUSION: Although these findings were limited to urban middle-aged men, the increase in serum cholesterol is likely to attenuate the reduction in future rates of coronary heart disease in Japan that would have been expected to result from the declining prevalence of smoking.
PURPOSE: We performed this study to see: 1) whether gamma-glutamyltransferase (GGT) was a predictor for hypertension irrespective of amount of alcohol consumption; and 2) whether the relationship between alcohol consumption and blood pressure (BP) was different depending on GGT. METHODS: This study included 8170 healthy male workers in a steel manufacturing company who had undergone health examinations in both 1994 and 1998. RESULTS: The adjusted relative risk (RR) for hypertension over four years among those with GGT >or=30 U/L at baseline was 1.6 (95% confidence interval (CI): 1.1-2.4), compared to those with GGT < 30 U/L. This relationship was shown only in drinkers. Among subjects with GGT < 30U/L, no matter how much the subjects drank, the risk of hypertension in drinkers was similar with that of non-drinkers. However, among those with GGT >or=30 U/L, adjusted RRs for light, moderate, and heavy drinkers compared to non-drinkers were 1.4 (95% CI: 0.5-4.5), 5.2 (95% CI: 1.5-18.0), and 5.3 (95% CI: 1.0-27.6). CONCLUSIONS: This study showed that elevated GGT could be a predictor for hypertension in drinkers and the relationship between alcohol consumption and hypertension was shown only among those with GGT >or= 30 U/L at baseline. These findings suggest that increased serum GGT levels may reflect individual susceptibility to the blood pressure raising effect of alcohol.
OBJECTIVE: Catechins are bioactive flavonoids present in tea, fruits, and vegetables. Previous epidemiological studies regarding tea and cancer risk were inconclusive, possibly because catechins are also present in other plant foods. We investigated whether a high intake of catechins are associated with cancer incidence among postmenopausal women. METHODS: A cohort of 34,651 postmenopausal cancer-free women aged 55-69 years were followed from 1986 to 1998. At baseline, data on diet, medical history, and lifestyle were collected. Incident cancers were obtained through linkage with a cancer registry. Cox proportional hazards analysis was used to estimate risk ratios. RESULTS: After adjustment for potential confounders, catechin intake was inversely associated with rectal cancer incidence only (risk ratios from lowest to highest quartile: 1.00, 0.93, 0.73, and 0.55; p for trend 0.02). Non-significant inverse trends were found for cancer of the upper digestive tract, pancreas, and for hematopoietic cancers. Catechins derived primarily from fruits, (+)-catechin and (-)-epicatechin, tended to be inversely associated with upper digestive tract cancer, whereas catechins derived from tea were inversely associated with rectal cancer. CONCLUSIONS: Among several cancers studied, our data suggest that catechin intake may protect against rectal cancer. The distinct effects found for catechins derived from solid foods (fruits) and beverages (tea) may be due to differences in bioavailability or metabolism of the catechins, or to their interactions with other dietary components.