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Biomedical subjects

Johanna T Dwyer

Publications and source records attributed to Johanna T Dwyer.

At least 19 recordsLinked to original sources
PubMed2006

Vitamin supplement intake is related to dietary intake and physical activity: The Child and Adolescent Trial for Cardiovascular Health (CATCH).

OBJECTIVE: To explore the relationship of multiple-vitamin supplement use with selected food groups, physical activity, lifestyle behaviors, and weight status. SUBJECTS AND METHODS: Two thousand seven hundred sixty-one adolescents in the 12th grade who participated in the fourth Child and Adolescent Trial for Cardiovascular Health study had height and weight measured and completed health behavior survey and food frequency questionnaires. Logistic regression models were used to determine the likelihood of supplement use with health and activity behaviors and dietary intake. RESULTS: Prevalence of multiple-vitamin supplement use among adolescents was 25% and varied by sex and race/ethnicity. Supplement users had higher mean daily intakes of most food groups, but lower intakes of total fat and saturated fat than nonusers. Higher food index scores were positively associated with the likelihood of using multiple-vitamin supplements. Supplement users were more likely to be physically active, participate in team and organized sports, and less likely to be overweight and to watch more than an hour of television per day. CONCLUSIONS: Adolescents who use multiple vitamin supplements have more healthful dietary and lifestyle behaviors than nonusers. Further study on supplement use by adolescents, including other types of supplements used and reasons for use, is warranted.

Adolescent↗
PubMed2006

Hemodialysis timing, survival, and cardiovascular outcomes in the Hemodialysis (HEMO) Study.

BACKGROUND: The timing of medical therapies has been shown to influence the outcomes and side effects of treatments for disease. This report examines the extent to which hemodialysis treatment time of day was associated with cardiovascular mortality and morbidity and all-cause mortality in a secondary analysis of the Hemodialysis Study. METHODS: Dialysis start time defined dialysis shift: morning beginning between 0400 and 0930 hours (n = 822); midday, between 0930 and 1530 hours (n = 851); and evening, between 1530 and 2200 hours (n = 172). Outcome measures included all-cause mortality, cardiac death, composite end point of all-cause mortality or first cardiac hospitalization, and composite end point of first cardiac hospitalization or cardiac death. RESULTS: Morning hemodialysis was associated with a lower likelihood of cardiovascular events compared with the evening shift in all-cause mortality or first cardiac hospitalization (evening versus morning, relative risk [RR], 1.29; 95% confidence interval [CI], 1.01 to 1.65; P = 0.043), as well as first cardiac hospitalization or cardiac death (evening versus morning, RR, 1.44; 95% CI, 1.11 to 1.89; P = 0.007). No differences were noted in the other 2 outcomes, and there was no statistically significant difference between the morning and midday shifts. Although crude mortality rates were greater in the midday compared with morning (RR, 1.21; 95% CI, 1.05 to 1.39; P = 0.008), this association was attenuated after adjustment (RR, 1.04; 95% CI, 0.89 to 1.22; P = 0.64). CONCLUSION: Making extensive adjustment for patient characteristics, this report does not support the association of lower all-cause mortality with morning hemodialysis or a particular benefit for older patients.

Cardiovascular Diseases↗
PubMed2006

The 2005 Dietary Guidelines for Americans Adherence Index: development and application.

The sixth edition of the Dietary Guidelines for Americans (DGA) was released in January 2005, with revised healthy eating recommendations for all adult Americans. We developed the 2005 Dietary Guidelines Adherence Index (DGAI) as a measure of adherence to the key dietary intake recommendations. Eleven index items assess adherence to energy-specific food intake recommendations, and 9 items assess adherence to "healthy choice" nutrient intake recommendations. Each item was scored from a minimum of 0 to a maximum of 1, depending on the degree of adherence to the recommendation. A score of 0.5 was given for partial adherence on most items or for exceeding the recommendation for energy-dense food items. The DGAI was applied to dietary data collected at the fifth examination of the Framingham Heart Study Offspring Cohort. The mean DGAI score was 9.6 (range 2.5-17.50). Those with higher DGAI scores were more likely to be women, older, multivitamin supplement users, and have a lower BMI and less likely to be smokers. The DGAI demonstrated a reasonable variation in this population of adult Americans, and by design this index was independent of energy consumption. The DGAI also demonstrated face validity based on the observed associations of the index with participant characteristics. Given these attributes, this index should provide a useful measure of diet quality and adherence to the new 2005 Dietary Guidelines for Americans.

Adult↗
PubMed2005

Self-reported appetite, hospitalization and death in haemodialysis patients: findings from the Hemodialysis (HEMO) Study.

BACKGROUND: Anorexia is an important cause of protein-energy malnutrition (PEM) in haemodialysis patients. We investigated whether self-reported appetite was associated with death and hospitalization in subjects enrolled in the Hemodialysis (HEMO) Study. METHODS: The HEMO Study was a 7-year, multicentre, randomized trial (N = 1846), which examined the effects of dialysis dose and membrane flux on mortality and morbidity. Three questions from the Appetite and Diet Assessment Tool (ADAT) were used to determine whether appetite had changed over time in the randomized treatment groups. The relations among ADAT scores, dietary protein and energy intakes, biochemical and anthropometric measures, and quality of life were assessed. We used Cox proportional hazards models to evaluate the relative risks of death and hospitalization associated with static and dynamic ADAT scores, adjusted for demographic factors, dose and flux assignments, and co-morbidity. RESULTS: The average length of follow-up was 2.84 years. After adjusting for demographic factors and randomized treatment assignments, there was a significant association between poorer self-reported appetite and death (RR 1.52, 95% CI 1.16-1.98); however, the association became non-significant with further adjustment for co-morbidity (RR 1.23, 95% CI 0.94-1.62). Poorer appetite was unequivocally associated with increased hospitalization rates (multivariable RR 1.35, 95% CI 1.13-1.61). The longitudinal effect of worsening appetite from baseline to 1 year was not associated with mortality or hospitalization rate after adjusting for co-morbidity. CONCLUSIONS: The association between appetite and death was confounded by co-morbidity. Self-reported appetite was associated with hospitalization rate in haemodialysis patients and, thus, it may be a useful screening tool for this outcome. Patients who report poor or very poor appetites should be monitored, and they should receive more comprehensive nutritional assessments.

Adolescent↗
PubMed2005

Dietary supplements in weight reduction.

We summarize evidence on the role of dietary supplements in weight reduction, with particular attention to their safety and benefits. Dietary supplements are used for two purposes in weight reduction: (a) providing nutrients that may be inadequate in calorie-restricted diets and (b) for their potential benefits in stimulating weight loss. The goal in planning weight-reduction diets is that total intake from food and supplements should meet recommended dietary allowance/adequate intake levels without greatly exceeding them for all nutrients, except energy. If nutrient amounts from food sources in the reducing diet fall short, dietary supplements containing a single nutrient/element or a multivitamin-mineral combination may be helpful. On hypocaloric diets, the addition of dietary supplements providing nutrients at a level equal to or below recommended dietary allowance/adequate intake levels or 100% daily value, as stated in a supplement's facts box on the label, may help dieters to achieve nutrient adequacy and maintain electrolyte balance while avoiding the risk of excessive nutrient intakes. Many botanical and other types of dietary supplements are purported to be useful for stimulating or enhancing weight loss. Evidence of their efficacy in stimulating weight loss is inconclusive at present. Although there are few examples of safety concerns related to products that are legal and on the market for this purpose, there is also a paucity of evidence on safety for this intended use. Ephedra and ephedrine-containing supplements, with or without caffeine, have been singled out in recent alerts from the Food and Drug Administration because of safety concerns, and use of products containing these substances cannot be recommended. Dietitians should periodically check the Food and Drug Administration Web site ( www.cfsan.fda.gov ) for updates and warnings and alert patients/clients to safety concerns. Dietetics professionals should also consult authoritative sources for new data on efficacy as it becomes available ( ods.od.nih.gov ).

Anti-Obesity Agents↗
PubMed2005

Dietitian involvement in the neonatal intensive care unit: more is better.

OBJECTIVE: Describe the level of registered dietitian (RD) involvement in neonatal intensive care units (NICUs) and associations with NICU nutrition practices. DESIGN: Questionnaires were mailed to 820 NICUs in the United States with two follow-up mailings to nonresponders. Abbreviated phone surveys were conducted with a random sample of 10% of nonresponders. A nutrition care score was devised based on a sum of 10 survey questions (range 0 to 10) to summarize the intensity of reported practices. SUBJECTS/SETTING: Directors of NICUs in the United States and RDs associated with them. STATISTICAL ANALYSES: Chi2, analysis of variance, Bonferroni and Duncan multiple range tests, regression. RESULTS: Respondents from 417 (54%) of the 772 NICUs eligible for the study provided completed questionnaires. Among NICUs responding, 76% involved RDs in care (41% employed full- or part-time RDs, 35% employed consult RDs), and 24% had no RD. NICUs with full- or part-time RDs provided fewer kilocalories and more protein parenterally, and more kilocalories and protein enterally. NICUs with less RD involvement were more likely to provide full-term infant feedings (eg, unfortified breast milk, full-term formula) to very-low-birth-weight infants. Mean nutrition care score varied with RD involvement from 4.6+/-1.7 (mean+/-standard deviation) for NICUs with a consult RD and 4.7+/-1.4 for NICUs employing no RD to 5.6+/-1.7 for NICUs with a full- or part-time RD (overall P<.001). CONCLUSIONS: More involvement of RDs in NICUs increased the intensity of important aspects of nutrition care that may improve outcomes of very-low-birth-weight infants in NICUs. These findings highlight the importance of RDs as NICU team members.

Analysis of Variance↗
PubMed2005

Are nutritional status indicators associated with mortality in the Hemodialysis (HEMO) Study?

BACKGROUND: The purpose of this study was to determine if indicators of nutritional status were associated with subsequent mortality in hemodialysis patients. METHODS: Twelve selected nutrition indicators were measured prior to randomization in the Mortality and Morbidity in Hemodialysis (HEMO) Study. Relative risks (RR) of mortality were assessed at <6 months and >6 months of follow-up using Cox regression after controlling for case mix, comorbidity, and treatment assignment (high vs. standard Kt/V and high vs. low membrane flux). RESULTS: Low values of most nutritional status indicators were associated with increased RR of mortality. RRs were greatest over the short term (<6 months) and diminished with increasing follow-up (>6 months). Increases in body mass index (BMI) at lower levels (e.g., < or =25 kg/m(2)) and increases in serum albumin at any level were associated with reduced short-term RR, even after adjusting for case mix, treatment assignment, and for the joint effects of equilibrated normalized protein catabolic rate, total cholesterol, and serum creatinine. For >6 months' follow-up, increases in values among those with lower levels of BMI and serum albumin (< or =3.635 g/dL) and increases in all serum creatinine levels were associated with lower RR. CONCLUSION: Nutrition indicators are associated with subsequent mortality in a time-dependent manner, with greatest effects at <6 months of follow-up. The RR for these indicators may also vary within different ranges of values.

Body Mass Index↗
PubMed2004

The effect of dialysis dose and membrane flux on nutritional parameters in hemodialysis patients: results of the HEMO Study.

BACKGROUND: The effect of standard or high dialysis dose and low or high dialysis flux on nutritional status was ascertained in 1846 maintenance hemodialysis patients enrolled in the HEMO Study. METHODS: Serum albumin levels, equilibrated protein catabolic rate, and postdialysis weight were obtained monthly, while adjusted protein and energy intake, self-reported appetite assessment, upper arm circumference, and calf circumference were obtained yearly. To account for patient attrition due to death or transfer, three statistical models were used to test the effects of the study interventions on longitudinal changes in nutritional parameters. RESULTS: During the first 3 years of follow-up, neither mean serum albumin levels, which declined by 0.21 g/dL, nor mean postdialysis weight, which declined by 2.7 kg, were significantly affected by either study intervention. Mean levels of all anthropometric measures declined during follow-up. For years 1, 2, and 3, the mean +/- SE declines in upper arm and calf circumferences were 0.35 +/- 0.16 cm (P= 0.031) and 0.31 +/- 0.13 (P= 0.015) cm less, respectively, in the high flux compared to the low flux group. Appetite scores and mean equilibrated protein catabolic rate also declined in all randomized groups; however, the average decline in equilibrated protein catabolic rate during years 1, 2, and 3 was 0.019 +/- 0.007 g/kg/day less in the high dose than the standard dose group (P= 0.007). There was no significant change in either mean energy or protein intake from diet records over time, and neither parameter was affected by the study interventions. CONCLUSION: Although the dose and flux interventions may subtly influence certain nutritional parameters, neither intervention prevented deterioration in nutritional status over time.

Adult↗
PubMed2004

Effects of hemodialysis dose and membrane flux on health-related quality of life in the HEMO Study.

BACKGROUND: It has been widely supposed that high dose and high flux hemodialysis would affect the quality as well as the length of life of patients treated by maintenance hemodialysis. The HEMO Study examined changes in health-related quality of life as a secondary study outcome. Specific hypotheses were that study interventions would affect physical functioning, vitality, Short Form-36 Health Survey (SF-36) physical and mental component summary scores, symptoms and problems associated with kidney disease, and sleep quality. METHODS: At baseline and annually, subjects responded to both the Index of Well-Being and the Kidney Disease Quality of Life-Long Form questionnaires. The interventions were assessed on the basis of their average effects over 3 years. RESULTS: At baseline, the SF-36 physical component summary score was lower than in healthy populations, but the mental component score was nearly normal. Over 3-year follow-up, physical health continued to decline; mental health and kidney disease-targeted scores remained relatively stable. The high dose hemodialysis intervention was associated with significantly less pain (4.49 points, P < 0.001) and higher physical component scores (1.23 points P= 0.007), but these effects were small compared to the natural variability in scores. High flux membranes were not associated with statistically significant differences in health-related quality of life. CONCLUSION: The HEMO Study results demonstrate the marked burden of chronic kidney failure and hemodialysis treatment on daily life. In this trial among patients undergoing maintenance three times a week hemodialysis, the SF-36 physical component summary score and pain scale showed significant but very small clinical effects favoring the higher dialysis dose. No clinically meaningful benefits or either the dose or flux interventions were observed for other indices of health-related quality of life.

Aged↗
PubMed2003

The impact of early transfer bias in a growth study among neonatal intensive care units.

BACKGROUND AND OBJECTIVE: Transfer of infants between hospitals or their discharge home may bias comparisons of the performance across neonatal intensive care units (NICUs). This study attempts to show the potential size of transfer bias in the context of a large cohort study and describe strategies for minimizing this type of bias. METHODS: To limit transfer bias in a neonatal growth study of extremely premature infants in six tertiary NICUs, we restricted eligibility to infants <30 weeks gestation at birth and substituted matched replacements for early transfers (infants transferred or discharged prior to day of life 16). RESULTS: The restriction strategy was successful, reducing the overall early transfer rate from 16.4 to 3.6% and the range of transfer rates among individual NICUs from 0.6-32.7% to 0-11.0%. Replacement by matched substitutes had a much smaller effect because of the small number of early transfers and our inability to match on all factors distinguishing early transfers. CONCLUSION: Sampling strategies to minimize infants lost to follow-up were more successful than replacement strategies in limiting transfer bias in a NICU growth study. Although complete elimination of bias is likely impossible, valid studies require efforts to minimize, quantify, and test the effect of transfer bias.

Bias↗
PubMed2003

Fat-sugar see-saw in school lunches: impact of a low fat intervention.

PURPOSE: To determine the long-term effects of a low fat intervention on sugar content in school lunches METHODS: We calculated contributions of total sugars, 6 specific sugars, and selected nutrients in National School Lunch Program meals served in 56 former intervention, 20 randomly selected control schools that had participated 3 years before in a low fat intervention, and 12 additional schools from neighboring school districts that had never been exposed to the intervention, whose goal was the lowering of total fat to under 30% of calories and saturated fat to under 10% calories. Analysis of variance adjusted for region was used to compare treatment groups. Pearson partial correlations controlling for the effects of region and treatment group were used to assess the strength of sugar and fat relationships. RESULTS: Three years after the low fat intervention, former intervention, control and unexposed schools lunches were similar in mean total sugars (25% of calories), and "added" sugars (e.g. sucrose, glucose, galactose, and maltose) at 15% of calories; and differed only in their lactose content. As percent of calories from fat or saturated fat in lunches decreased, that from sugars increased. Lunches that met reduced saturated fat goals were significantly higher than those not meeting goals in percent of calories from sugars both in meals as offered (27.6 +/- 0.3% vs. 26.2 +/- 0.3 SE p =.004) and as served (26.5 +/- 0.4 vs. 23.9 +/- 0.4 p =.009). Lunches meeting reduced total fat goals were significantly higher only in percent of calories from sugars as served. Seventy-five percent of total sugar in lunches offered was from chocolate milk, fruit/fruit juices, and white milk. More "added" sugar came from high micronutrient foods, such as fruit, fruit juices, and chocolate milk than from desserts and entrees. CONCLUSIONS: The existence of a fat-sugar "see-saw" makes it important to emphasize substitutions of fat and saturated fat with starches and fiber in school lunches.

Adolescent↗
PubMed2002

Effect of dialysis dose and membrane flux in maintenance hemodialysis.

BACKGROUND: The effects of the dose of dialysis and the level of flux of the dialyzer membrane on mortality and morbidity among patients undergoing maintenance hemodialysis are uncertain. METHODS: We undertook a randomized clinical trial in 1846 patients undergoing thrice-weekly dialysis, using a two-by-two factorial design to assign patients randomly to a standard or high dose of dialysis and to a low-flux or high-flux dialyzer. RESULTS: In the standard-dose group, the mean (+/-SD) urea-reduction ratio was 66.3+/-2.5 percent, the single-pool Kt/V was 1.32+/-0.09, and the equilibrated Kt/V was 1.16+/-0.08; in the high-dose group, the values were 75.2+/-2.5 percent, 1.71+/-0.11, and 1.53+/-0.09, respectively. Flux, estimated on the basis of beta2-microglobulin clearance, was 3+/-7 ml per minute in the low-flux group and 34+/-11 ml per minute in the high-flux group. The primary outcome, death from any cause, was not significantly influenced by the dose or flux assignment: the relative risk of death in the high-dose group as compared with the standard-dose group was 0.96 (95 percent confidence interval, 0.84 to 1.10; P=0.53), and the relative risk of death in the high-flux group as compared with the low-flux group was 0.92 (95 percent confidence interval, 0.81 to 1.05; P=0.23). The main secondary outcomes (first hospitalization for cardiac causes or death from any cause, first hospitalization for infection or death from any cause, first 15 percent decrease in the serum albumin level or death from any cause, and all hospitalizations not related to vascular access) also did not differ significantly between either the dose groups or the flux groups. Possible benefits of the dose or flux interventions were suggested in two of seven prespecified subgroups of patients. CONCLUSIONS: Patients undergoing hemodialysis thrice weekly appear to have no major benefit from a higher dialysis dose than that recommended by current U.S. guidelines or from the use of a high-flux membrane.

Adult↗
PubMed2002

Maintenance of lightweight correlates with decreased cardiovascular risk factors in early adolescence.

PURPOSE: To describe predictors of lightweight in 11-year-olds and how weight changes between ages 9-11 years affected selected cardiovascular risk factors. METHODS: Cohort study among an ethnically and geographically diverse group of 5098 nine-year-olds who participated in the Child and Adolescent Trial for Cardiovascular Health (CATCH) and were followed from 1991 to 1994 until age 11 years. Lightweight (body mass index [BMI] <15th percentile) was defined from gender- and age-adjusted data on the total population in the National Health and Nutrition Examination Survey I of 1971 to 1973. Weight (BMI) category at follow-up (age 11 years) was the dependent variable in the logistic regression. Gender, race/ethnicity, school site, weight category at baseline, and participation in the CATCH (intervention or control group) were examined for possible predictors. RESULTS: The prevalence of lightweight was much lower than the 15% expected at both ages 9 and 11 years; 4.7% for males (M) and 7.4% for females (F) and at age 11 years; 5.9% for M and 8.3% for F. Lightweight at age 9 years was the best predictor of lightweight at age 11 years (OR = 56.8; CI 41.3, 78.2). Normal-weight children who entered the overweight category exhibited striking adverse percent changes in serum cholesterol and in both serum high-density cholesterol and apolipoprotein B cholesterol levels. Among children in each weight group at age 9 years, the heavier children at age 11 years had higher percent changes in systolic blood pressure, and lower times on the 9-min run. Maintenance of lightweight was associated with the most favorable pattern of cardiovascular risk factors. Differences between groups were not found for percent change in total calorie intake or percentage of calories from fat. Normal-weight children who became overweight exhibited striking percentage increases in levels of serum cholesterol and in serum apolipoprotein B cholesterols. CONCLUSIONS: Population-based anticipatory guidance about weight should focus on all children in mid-childhood, not only those at the upper extremes of weight. These who are genetically lean and healthy should be encouraged to remain so. Maintenance or achievement of lightweight was associated with favorable changes in systolic blood pressure in CATCH children during early adolescence. Those below the 5th percentile should be assessed and treated if eating disorders, undernutrition, or chronic illness are present. Optimal weight and optimal health should not be confused.

Blood Pressure↗