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Biomedical subjects

David R Jacobs

Publications and source records attributed to David R Jacobs.

137 records · Page 8Linked to original sources
PubMed2002

Variation in newborn size according to pregnancy weight change by trimester.

BACKGROUND: The timing of maternal weight change in pregnancy may be an important determinant of the newborn's size. OBJECTIVE: The purpose was to identify effects of maternal weight change by trimester on newborn size, under the hypothesis that low weight gain early in pregnancy predicts proportionately smaller newborns. DESIGN: Women planning to become pregnant were followed by clinic visits and questionnaires through delivery. This study includes 389 women and their singleton infants born at a gestational age of > or = 241 d. RESULTS: In multiple regression analyses including a variety of potential confounders, maternal weight gain in the first and second trimesters predicted newborn weight (1-kg weight gain in the first trimester predicted a 31-g increase in newborn weight, P < 0.0007, and 1-kg weight gain in the second trimester predicted a 26-g increase in newborn weight, P < 0.007), but weight gain in the third trimester did not. Newborn ponderal index (in kg/m(3)) was predicted by weight gain in the first (1-kg weight gain predicted an added 0.21 units, P < 0.0003) and third (1-kg weight gain predicted an added 0.12 units, P < 0.03) trimesters but not in the second trimester. Newborn weight was 211 g lower (P < 0.006) and ponderal index 1.2 units lower (P < 0.02) in infants born to women who lost weight in the first trimester. CONCLUSIONS: The use of measured prepregnancy weight in tests of the effect on newborn size of weight gain by time in pregnancy produces different results than does the use of recalled prepregnancy weight. Maternal weight change in the first trimester of pregnancy more strongly influences newborn size than does weight change in the second or third trimester.

Adult↗
PubMed2002

An evaluation of the Dietary Guidelines for Americans in relation to cancer occurrence.

BACKGROUND: Although scientific knowledge regarding the influence of nutritional factors on health and disease serves as the basis for specific recommendations included in the Dietary Guidelines for Americans, limited empirical epidemiologic data are available to verify that adherence to the cluster of nutrition-related behaviors included in the Dietary Guidelines will reduce the incidence of disease. OBJECTIVE: We examined the association of compliance with the Dietary Guidelines and incident cancers. DESIGN: Data from a population-based cohort of postmenopausal women (n = 34 708) were examined. A dietary guidelines index was derived as a summary measure of compliance with the Dietary Guidelines, and the association of this index and cancer incidence was examined for all cancers combined and for site-specific cancers with > 100 events. RESULTS: For all cancers combined, the relative risks associated with the upper 4 quintiles of the dietary guidelines index in reference to the bottom quintile were 0.95 (95% CI: 0.87, 1.05) for quintile 2, 0.88 (95% CI: 0.80, 0.97) for quintile 3, 0.88 (95% CI: 0.80, 0.96) for quintile 4, and 0.85 (95% CI: 0.77, 0.93) for quintile 5 (P for trend < 0.01). Similar patterns in relative risks were found for cancers of the colon, bronchus and lung, breast, and uterus. In contrast, ovarian cancer incidence was positively associated with the dietary guidelines index. CONCLUSION: Our findings suggest that adherence to the cluster of nutrition-related behaviors included in the Dietary Guidelines for Americans may be associated with a lower risk of cancer.

Age Factors↗
PubMed2002

A systematic screening of total antioxidants in dietary plants.

A predominantly plant-based diet reduces the risk for development of several chronic diseases. It is often assumed that antioxidants contribute to this protection, but results from intervention trials with single antioxidants administered as supplements quite consistently do not support any benefit. Because dietary plants contain several hundred different antioxidants, it would be useful to know the total concentration of electron-donating antioxidants (i.e., reductants) in individual items. Such data might be useful in the identification of the most beneficial dietary plants. We have assessed systematically total antioxidants in a variety of dietary plants used worldwide, including various fruits, berries, vegetables, cereals, nuts and pulses. When possible, we analyzed three or more samples of dietary plants from three different geographic regions in the world. Total antioxidants was assessed by the reduction of Fe(3+) to Fe(2+) (i.e., the FRAP assay), which occurred rapidly with all reductants with half-reaction reduction potentials above that of Fe(3+)/Fe(2+). The values, therefore, expressed the corresponding concentration of electron-donating antioxidants. Our results demonstrated that there is more than a 1000-fold difference among total antioxidants in various dietary plants. Plants that contain most antioxidants included members of several families, such as Rosaceae (dog rose, sour cherry, blackberry, strawberry, raspberry), Empetraceae (crowberry), Ericaceae (blueberry), Grossulariaceae (black currant), Juglandaceae (walnut), Asteraceae (sunflower seed), Punicaceae (pomegranate) and Zingiberaceae (ginger). In a Norwegian diet, fruits, berries and cereals contributed 43.6%, 27.1% and 11.7%, respectively, of the total intake of plant antioxidants. Vegetables contributed only 8.9%. The systematic analysis presented here will facilitate research into the nutritional role of the combined effect of antioxidants in dietary plants.

Antioxidants↗
PubMed2002

Relation of insulin resistance to blood pressure in childhood.

OBJECTIVE: To determine the relation between blood pressure and insulin resistance in children and the differences between fasting insulin and the insulin clamp in that relation. METHODS: Children were randomly selected after blood pressure screening of 12 043 fifth--eigth grade Minneapolis, Minnesota, students, with stratification by systolic blood pressure (SBP) percentile [half from the upper 25th percentile (high blood pressure) and half from the lower 75th percentile (low blood pressure)]. Euglycemic insulin clamps were performed with an insulin infusion rate of 1 mU/kg per min and a variable infusion of 20% glucose to maintain plasma glucose at 5.6 mmol/l (100 mg/dl). Insulin sensitivity (Mlbm) is defined as the amount of glucose required to maintain euglycemia (mg glucose infused/kg lean body mass (LBM)/min. RESULTS: Diastolic blood pressure was not significantly correlated with any of the body measurements or laboratory data. SBP was significantly correlated with virtually all measures of body size in males and females. SBP and Mlbm were not significantly correlated in either sex. The correlation between SBP and fasting insulin was significant for boys and girls, but became non-significant after adjustment for BMI. All measures of body fatness were significantly greater in the high blood pressure group, and a significant clustering effect for fasting insulin, BMI, triglycerides, and HDL-C was related to blood pressure. The clustering effect was similar when Mlbm was substituted for fasting insulin and was similar for boys, girls, blacks and whites. CONCLUSIONS: These results suggest that level of blood pressure in children is mediated through body fat and that insulin resistance, as determined by the insulin clamp, does not play a primary role at this age of development. Nevertheless, the clustering effect of the risk factors according to SBP grouping is consistent with an early relation of blood pressure to the insulin resistance syndrome.

Adipose Tissue↗
PubMed2002

Relationship of folate, vitamin B-6, vitamin B-12, and methionine intake to incidence of colorectal cancers.

It is hypothesized that diets deficient in folate, methionine, and vitamins B-6 and B-12 cause DNA hypomethylation and, as a result, increase risk of colorectal cancers. Furthermore, it is proposed that alcohol, a methyl group antagonist, increases risk of colorectal cancers among those with low intake of folate. Data from the Iowa Women's Health Study, a population-based cohort of incident cancer, were used to examine the relationship of folate, methionine, and vitamins B-6 and B-12 to occurrence of cancers of the colon (n = 598) and rectum (n = 123) over 13 yr of follow-up. There were no independent associations of folate, methionine, or vitamins B-6 and B-12 derived from a food frequency questionnaire with incidence of colon cancer. Adjusted relative risks (RRs) of rectal cancer were similar across categories of folate, vitamin B-12, and methionine intake, but RRs increased progressively with increasing intake of vitamin B-6 [P (for trend) = 0.03]. RRs suggested that incidence of cancer of the proximal colon was lower among those with 1) high folate and high vitamin B-12 intake [RR = 0.59, 95% confidence interval (CI) = 0.39-0.89] and 2) high folate and high vitamin B-6 intake (RR = 0.65, 95% CI = 0.50-0.84) than among those with the lowest intake of these nutrients. Incidence of cancer of the proximal colon was also somewhat lower among those with high folate and low alcohol intake (RR = 0.44, 95% CI = 0.22-0.89). Findings provide limited support for an association between dietary factors involved in DNA methylation and risk of cancers of the colon and rectum.

Aged↗
PubMed2002

Association between the insulin resistance of puberty and the insulin-like growth factor-I/growth hormone axis.

To test the hypothesis that the relative insulin resistance of puberty is associated with changes in IGF-I levels, we compared IGF-I, IGF binding protein-3 (IGFBP-3), and IGFBP-1 levels to insulin resistance [M(lbm), milligrams glucose used per kilogram of lean body mass (LBM) per minute] measured during euglycemic, hyperinsulinemic clamp studies in 342 children and adolescents. IGF-I levels rose and fell during the Tanner stages of puberty in a pattern that closely followed the rise and fall of insulin resistance. IGF-I levels were significantly related to M(lbm) in boys (P = 0.0006) and girls (P = 0.02). IGF-I was significantly related to fasting insulin levels only in girls (P = 0.006; boys, P = 0.26), and this relation was significantly influenced in girls by body fat (P = 0.007), with the strongest association between IGF-I and fasting insulin seen in thin girls. IGFBP-1 correlated negatively with insulin resistance in both boys (P = 0.0004) and girls (P = 0.04), whereas IGFBP-3 correlated positively with insulin resistance in boys (P = 0.0004) but not girls (P = 0.85). These data suggest that the GH/IGF-I axis is an important contributor to the insulin resistance of puberty.

Adolescent↗
PubMed2002

Neighborhood characteristics and components of the insulin resistance syndrome in young adults: the coronary artery risk development in young adults (CARDIA) study.

OBJECTIVE: To examine associations of neighborhood characteristics with six components of the insulin resistance syndrome (IRS) in young adults. RESEARCH DESIGN AND METHODS: Cross-sectional data from the Coronary Artery Risk Development in Young Adults (CARDIA) Study were used to examine associations of neighborhood characteristics with the IRS in 3,093 nondiabetic adults aged 28-40 years. Measures of BMI, fasting HDL cholesterol, triglycerides, insulin, glucose, and systolic blood pressure were combined into an IRS score. U.S. Census-derived neighborhood characteristics were summarized into a neighborhood socioeconomic score, with an increasing score signifying increasing socioeconomic advantage. RESULTS: Among white men and women, the IRS score was inversely related to neighborhood socioeconomic score. Neighborhood characteristics remained associated with the IRS score after controlling for personal income and education (adjusted mean differences for 95th vs. 5th percentile of neighborhood score: -0.24 standard deviation units [SE = 0.12] in men and -0.56 standard deviation units [SE = 0.10] in women). Among black participants, neighborhood score was inversely associated with IRS score in persons of high income and education (mean differences 95th vs. 5th percentile -0.54 [SE 0.26] in men and -0.52 [SE 0.26] in women) but positively associated or not associated with IRS score in persons of low income and education (mean differences 0.60 [SE 0.21] in men and 0.00 [SE 0.16] in women). CONCLUSIONS: The IRS score is associated with neighborhood characteristics as early as young adulthood. Features of residential environments may be related to the development of insulin resistance.

Adolescent↗
PubMed2002

Diet and risk of leukemia in the Iowa Women's Health Study.

Nearly 30,000 individuals ages over 21 years are diagnosed with leukemia each year in the United States. Other than benzene, radiation, and chemotherapy, which account for a small proportion of cases, there are few identified risk factors for adult leukemia. Although recent data from animal studies indicate a potentially protective role for dietary restriction in leukemogenesis, few data exist on dietary relationships in adult leukemia. Food frequency data collected at baseline (1986) were analyzed from the prospective Iowa Women's Health Study to begin to address the role of diet in adult leukemia. Data from 35,221 women ages 55-69 years were analyzed. A total of 138 women developed leukemia during the 14-year follow-up period of 1986 to 1999. With the exception of an inverse association (P trend = 0.08) with increasing consumption of all vegetables (relative risk, 0.56 and 95% confidence interval, 0.36-0.88; relative risk, 0.69 and 95% confidence interval, 0.44-1.07 for medium and high consumption, respectively), there was little evidence of an important role for other dietary factors in leukemogenesis. Analyses that excluded cases diagnosed in the first 2 years from baseline did not notably alter the results. Leukemia subgroups, including acute myeloid leukemia and chronic lymphoblastic leukemia, were also analyzed, but no statistically significant associations with dietary factors were revealed. This study provides evidence that increased vegetable consumption may decrease the risk of adult leukemia. However, given that our study focused on older women from a defined geographical area, analyses of prospective studies in other populations are needed to confirm or refute these results.

Age Factors↗
PubMedDate not supplied

Fast-food habits, weight gain, and insulin resistance (the CARDIA study): 15-year prospective analysis.

BACKGROUND: Fast-food consumption has increased greatly in the USA during the past three decades. However, the effect of fast food on risk of obesity and type 2 diabetes has received little attention. We aimed to investigate the association between reported fast-food habits and changes in bodyweight and insulin resistance over a 15-year period in the USA. METHODS: Participants for the CARDIA study included 3031 young (age 18-30 years in 1985-86) black and white adults who were followed up with repeated dietary assessment. We used multiple linear regression models to investigate the association of frequency of fast-food restaurant visits (fast-food frequency) at baseline and follow-up with 15-year changes in bodyweight and the homoeostasis model (HOMA) for insulin resistance. FINDINGS: Fast-food frequency was lowest for white women (about 1.3 times per week) compared with the other ethnic-sex groups (about twice a week). After adjustment for lifestyle factors, baseline fast-food frequency was directly associated with changes in bodyweight in both black (p=0.0050) and white people (p=0.0013). Change in fast-food frequency over 15 years was directly associated with changes in bodyweight in white individuals (p<0.0001), with a weaker association recorded in black people (p=0.1004). Changes were also directly associated with insulin resistance in both ethnic groups (p=0.0015 in black people, p<0.0001 in white people). By comparison with the average 15-year weight gain in participants with infrequent (less than once a week) fast-food restaurant use at baseline and follow-up (n=203), those with frequent (more than twice a week) visits to fast-food restaurants at baseline and follow-up (n=87) gained an extra 4.5 kg of bodyweight (p=0.0054) and had a two-fold greater increase in insulin resistance (p=0.0083). INTERPRETATION: Fast-food consumption has strong positive associations with weight gain and insulin resistance, suggesting that fast food increases the risk of obesity and type 2 diabetes.

Adolescent↗
PubMedDate not supplied

Contemporary diagnosis and management of hypercholesterolemia in elderly acute myocardial infarction patients: a population-based study.

There are limited data regarding the diagnosis and treatment of hypercholesterolemia in elderly patients with acute myocardial infarction (AMI). The authors describe the in-hospital and discharge prescription patterns of lipid-lowering agents in patients hospitalized with an AMI, and identify factors associated with low rates of utilization of these therapies. The authors analyzed the Minnesota Heart Survey, a population-based surveillance project that retrospectively abstracted the medical records of patients hospitalized with AMI in 2001-2002 from 21 hospitals in the Minneapolis-St Paul metropolitan area. They identified 2773 patients 30 years and older with an AMI. The mean total cholesterol was 175+/-45 mg/dL, the mean low-density lipoprotein cholesterol was 104+/-38 mg/dL, and the mean high-density lipoprotein cholesterol was 44+/-14 mg/dL. Statins were prescribed at discharge to 74.6%, 63.2%, and 38.5% of patients younger than 65, 65-74, and 75 years and older, respectively (P<.0001). The utilization of statins was highly correlated with the administration of other standard AMI therapies-aspirin, beta-blockers, angiotensin-converting enzyme inhibitors/angiotensin receptor blockers, and reperfusion therapy-and was more prevalent among patients undergoing percutaneous coronary intervention than among those undergoing coronary artery bypass surgery. Elderly patients remain less likely to receive lipid-lowering therapy following an AMI. Greater attention is required to ensure that elderly AMI patients without contraindications are appropriately treated with lipid-lowering therapy.

Acute Disease↗