Biomedical subjects

Bernard Rosner

Publications and source records attributed to Bernard Rosner.

At least 55 records · Page 3Linked to original sources

PubMed2004

Clinical trial of docosahexaenoic acid in patients with retinitis pigmentosa receiving vitamin A treatment.

OBJECTIVE: To determine whether a therapeutic dose of docosahexaenoic acid (DHA), an omega-3 fatty acid, will slow the course of retinal degeneration in adult patients with retinitis pigmentosa who are also receiving vitamin A. DESIGN: Randomized, controlled, double-masked trial of 221 patients, aged 18 to 55 years, evaluated over a 4-year interval. Patients were given either 1200 mg/d of docosahexaenoic acid or control capsules. All were given 15 000 IU/d of vitamin A (given as retinyl palmitate). Randomization considered genetic type and baseline dietary omega-3 fatty acid intake. MAIN OUTCOME MEASURES: The primary outcome measure was the total point score for the 30-2 program of the Humphrey field analyzer; secondary outcome measures were the total point score for the 30-2 and 30/60-1 programs combined, 30-Hz electroretinogram amplitude, and Early Treatment Diabetic Rentinopathy Study visual acuity. RESULTS: No significant differences in decline in ocular function were found between the docosahexaenoic acid plus vitamin A (DHA + A) group and control plus vitamin A (control + A) group over a 4-year interval among all 221 randomized patients or among the 208 patients who completed all 4 follow-up visits. The mean annual rate of loss of sensitivity for the Humphrey Field Analyzer 30-2 program was 37 dB for the DHA + A group and 38 dB for the control + A group (P =.88). For the Humphrey Field Analyzer 30-2 and 30/60-1 programs combined, the mean annual rates of loss of field sensitivity were 57 dB for the DHA + A group and 60 dB (P =.73) for control + A group. No toxic adverse effects were observed. No significant differences by treatment group assignment were observed within genetic types or within the category of baseline omega-3 fatty acid intake. CONCLUSION: In patients assigned to receive 15 000 IU/d of vitamin A, this randomized trial showed that 1200 mg/d of docosahexaenoic acid supplementation over a 4-year interval did not, on average, slow the course of disease in patients with retinitis pigmentosa.

Administration, Oral↗

PubMed2004

Further evaluation of docosahexaenoic acid in patients with retinitis pigmentosa receiving vitamin A treatment: subgroup analyses.

OBJECTIVE: To determine whether docosahexaenoic acid will slow the course of retinal degeneration in subgroups of patients with retinitis pigmentosa who are receiving vitamin A. DESIGN: A cohort of 208 patients with retinitis pigmentosa, aged 18 to 55 years, were randomly assigned to 1200 mg of docosahexaenoic acid plus 15 000 IU/d of vitamin A given as retinyl palmitate (DHA + A group) or control fatty acid plus 15 000 IU/d of vitamin A (control + A group) and followed up over 4 years. Seventy percent of the patients in each group were taking vitamin A, 15 000 IU/d, prior to entry. We compared rates of decline in ocular function in the DHA + A vs control + A groups among the subgroups defined by use or nonuse of vitamin A prior to entry. We also determined whether decline in ocular function was related to red blood cell phosphatidylethanolamine docosahexaenoic acid level, dietary omega-3 fatty acid intake, or duration of vitamin A use. Main outcome measures were Humphrey Field Analyzer visual field sensitivity, 30-Hz electroretinogram amplitude, and visual acuity. RESULTS: Among patients not taking vitamin A prior to entry, those in the DHA + A group had a slower decline in field sensitivity and electroretinogram amplitude than those in the control + A group over the first 2 years (P =.01 and P =.03, respectively); these differences were not observed in years 3 and 4 of follow-up or among patients taking vitamin A prior to entry. In the entire cohort, red blood cell phosphatidylethanolamine docosahexaenoic acid level was inversely related to rate of decline in total field sensitivity over 4 years (test for trend, P =.05). This was particularly evident over the first 2 years among those not on vitamin A prior to entry (test for trend, P =.003). In the entire control + A group, dietary omega-3 fatty acid intake was inversely related to loss of total field sensitivity over 4 years (intake, <0.20 vs > or =0.20 g/d; P =.02). The duration of vitamin A supplementation prior to entry was inversely related to rate of decline in electroretinogram amplitude (P =.008). CONCLUSIONS: For patients with retinitis pigmentosa beginning vitamin A therapy, addition of docosahexaenoic acid, 1200 mg/d, slowed the course of disease for 2 years. Among patients on vitamin A for at least 2 years, a diet rich in omega-3 fatty acids (> or =0.20 g/d) slowed the decline in visual field sensitivity.

Administration, Oral↗

PubMed2004

Associations of plasma homocysteine and the methylenetetrahydrofolate reductase C677T polymorphism with carotid intima media thickness among South Asian, Chinese and European Canadians.

BACKGROUND: Few studies have evaluated the associations of plasma homocysteine concentration, the methylenetetrahydrofolate reductase (MTHFR) C677T genotype and B vitamin concentration with intima media thickness (IMT) in multiethnic populations. METHODS: In the Study of Health Assessment and Risk in Ethnic groups (SHARE), we measured carotid IMT, fasting serum folate, serum B12, plasma pyridoxal-5'-phosphate (PLP) and plasma homocysteine and determined the MTHFR C677T genotype in a cross-sectional study of 818 South Asian, Chinese and European Canadians without previous history of CVD, cancer or diabetes during 1996-1998. RESULTS: Plasma homocysteine was inversely related to serum folate, serum B12, plasma PLP, B vitamin supplement use and Chinese ethnicity, and was positively associated with hypertension, smoking, IMT, MTHFR 677T/T genotype and South Asian ethnicity. Although ethnicity was not a statistically significant modifier, among carriers of the MTHFR 677T/T genotype with serum folate < or =14 nmol/L compared to >14 nmol/L, plasma homocysteine was significantly higher among South Asians (50.9% increase, P < 0.001) and Europeans (52.4% increase, P < 0.001) but not Chinese (11.0% increase, P > 0.05). Plasma homocysteine > 11.7 micromol/L was associated with a 5.9% (95% CI: 1.9%, 10.0%) increase in IMT (approximately 0.04 mm) in the pooled-data analyses with similar increases noted in the ethnic-specific analyses. The 677T/T genotype was not associated with a significant change in IMT in the pooled-data analyses (2.7%; 95% CI: -1.7%, 7.2%) nor in ethnic-specific analyses compared to other genotypes, although there were only 63 677T/T homozygotes. CONCLUSION: The combination of lower serum folate and the MTHFR 677T/T genotype is associated with increased plasma homocysteine among South Asians and Europeans, but the association is not evident among Chinese possibly because their serum folate may not have been low enough to compromise MTHFR activity. Plasma homocysteine > 11.7 micromol/L appears to be associated with a clinically important increase in IMT.

Asia, Southeastern↗

PubMed2004

Methods to evaluate risks for composite end points and their individual components.

OBJECTIVE: Both randomized and observational studies commonly examine composite end points, but the literature on model development and criticism in this setting is limited. STUDY DESIGN AND SETTING: We examined approaches for evaluating heterogeneity in the effects of risk factors for different components of the end point, and determining the impact of heterogeneity on the ability to predict the composite end point. A specific example considered the composite cardiovascular disease end point in the Physicians' Health Study that occurred in 1,542 (myocardial infarction, n = 716; stroke, n = 557; cardiovascular death, n = 269) of 16,688 participants with complete information on baseline covariates. The strategy compared alternative polytomous logistic regression models assuming different effects of risk factors on components of the end point and a comparable logistic model assuming common effects. RESULTS: Likelihood ratio tests identified heterogeneity in the effects of age, alcohol consumption, and diabetes across components of the outcome, but comparability in the effects of other risk factors. However, a model assuming uniform effects explained over 90% of the log-likelihood change in the best polytomous model, and the two models also performed similarly based on a comparison of ROC curves. CONCLUSION: The overall strategy may be helpful for evaluating the validity of a composite end point analysis and identifying heterogeneity in risk factors.

Adult↗

PubMed2004

Breastfeeding during infancy and the risk of cardiovascular disease in adulthood.

BACKGROUND: Numerous studies have reported associations between the type of feeding during infancy and subsequent cardiovascular risk factors. Only 2 studies have evaluated the relation between having been breastfed and the risk of adult cardiovascular events. METHODS: We examined this association among 87,252 female participants of the longitudinal Nurses' Health Study. Participants (all born between 1921 and 1946) reported in 1992 whether and for how long they were breastfed. During 8 years of follow up, there were 1099 cases of coronary heart disease and 940 strokes among women who knew whether they had been breastfed. We used proportional hazards models to estimate hazard ratios for cardiovascular events, adjusting for changing adult risk factors. RESULTS: Compared with women who were never breastfed, women who were breastfed had hazard ratios of 0.92 (95% confidence interval = 0.80-1.05) for coronary heart disease and 0.91 (0.79-1.06) for stroke, after adjustment for age, birthweight, and smoking. When body mass index was also included in the model, the results were similar. Looking within subgroups of stroke, hazard ratios were 0.86 (0.70-1.07) for ischemic stroke and 1.01 (0.70-1.46) for hemorrhagic stroke. Comparing women who were breastfed at least 9 months with those who were not breastfed, the hazard ratios were 0.84 (0.69-1.03) for coronary heart disease and 1.00 (0.81-1.23) for stroke. Breastfeeding history was not associated with high blood pressure in adulthood. CONCLUSIONS: These data suggest, but cannot establish, that breastfeeding in infancy may be associated with a small reduction in risk of ischemic cardiovascular disease in adulthood.

Adult↗

PubMed2004

Lung cancer in railroad workers exposed to diesel exhaust.

Diesel exhaust has been suspected to be a lung carcinogen. The assessment of this lung cancer risk has been limited by lack of studies of exposed workers followed for many years. In this study, we assessed lung cancer mortality in 54,973 U.S. railroad workers between 1959 and 1996 (38 years). By 1959, the U.S. railroad industry had largely converted from coal-fired to diesel-powered locomotives. We obtained work histories from the U.S. Railroad Retirement Board, and ascertained mortality using Railroad Retirement Board, Social Security, and Health Care Financing Administration records. Cause of death was obtained from the National Death Index and death certificates. There were 43,593 total deaths including 4,351 lung cancer deaths. Adjusting for a healthy worker survivor effect and age, railroad workers in jobs associated with operating trains had a relative risk of lung cancer mortality of 1.40 (95% confidence interval, 1.30-1.51). Lung cancer mortality did not increase with increasing years of work in these jobs. Lung cancer mortality was elevated in jobs associated with work on trains powered by diesel locomotives. Although a contribution from exposure to coal combustion products before 1959 cannot be excluded, these results suggest that exposure to diesel exhaust contributed to lung cancer mortality in this cohort. Key words: diesel exhaust, lung cancer, occupational exposure.

Adult↗

PubMed2004

Epidemiology of urinary melatonin in women and its relation to other hormones and night work.

OBJECTIVE: Light exposure during night work suppresses melatonin production, and night work has been associated with an increased cancer risk. There is little information, however, about the interrelationships of night work, urinary melatonin levels, and levels of plasma steroid hormones in women. METHOD: We examined the reproducibility of morning urinary measurements of 6-sulfatoxymelatonin over a 3-year period in 80 premenopausal women. We assessed correlations between average urinary melatonin and plasma steroid hormone levels and evaluated potential associations between night work and hormone levels, using current and long-term shift work information from two large, prospective cohorts, the Nurses' Health Study cohorts. RESULTS: The intraclass correlation for creatinine-adjusted 6-sulfatoxymelatonin was 0.72 (95% confidence interval, 0.65, 0.82). We found significantly increased levels of estradiol after longer durations of night work (geometric mean levels of estradiol, 8.8 pg/mL for women who never worked night shifts versus 10.1 pg/mL for women who worked 15 or more years of night shifts; P for trend = 0.03). We observed a significant inverse association between increasing number of nights worked within the 2 weeks preceding urine collection and urinary melatonin levels (r = -0.30, P = 0.008), but no association of recent night work with estradiol (r = 0.10, P = 0.41). CONCLUSION: A single morning urinary melatonin measurement is a reasonable marker for long-term melatonin levels among premenopausal women. Women who work on rotating night shifts seem to experience changes in hormone levels that may be associated with the increased cancer risk observed among night-shift workers.

Adult↗

PubMed2003

Antioxidant intake and primary open-angle glaucoma: a prospective study.

The relation between dietary antioxidant intake and primary open-angle glaucoma risk was examined in participants aged over 40 years in the Nurses' Health Study (n = 76,200) and the Health Professionals Follow-up Study (n = 40,284). They were followed biennially from 1980 and 1986, respectively, to 1996, during periods when they received an eye examination. Dietary intakes were measured repeatedly from 1980 in the Nurses' Health Study and from 1986 in the Health Professionals Follow-up Study using validated food frequency questionnaires. The authors analyzed 474 self-reported glaucoma cases confirmed by medical chart review to have primary open-angle glaucoma with visual field loss. The authors used Cox proportional hazards models for cohort-specific multivariate analyses, and results were pooled using random effects models. The pooled multivariate rate ratios for primary open-angle glaucoma comparing the highest versus lowest quintile of cumulative updated intake were 1.17 (95% confidence interval (CI): 0.87, 1.58) for alpha-carotene, 1.10 (95% CI: 0.82, 1.48) for beta-carotene, 0.95 (95% CI: 0.70, 1.29) for beta-cryptoxanthin, 0.82 (95% CI: 0.60, 1.12) for lycopene, 0.92 (95% CI: 0.69, 1.24) for lutein/zeaxanthin, 1.05 (95% CI: 0.59, 1.89) for vitamin C, 0.97 (95% CI: 0.62, 1.52) for vitamin E, and 1.11 (95% CI: 0.82, 1.51) for vitamin A. In conclusion, the authors did not observe any strong associations between antioxidant consumption and the risk of primary open-angle glaucoma.

Adult↗

PubMed2003

Meat, fish and egg intake and risk of breast cancer.

Intakes of animal protein, meat, and eggs have been associated with breast cancer incidence and mortality in ecological studies, but data from long-term prospective studies are limited. We therefore examined these relationships in the Nurses' Health Study. We followed 88,647 women for 18 years, with 5 assessments of diet by food frequency questionnaire, cumulatively averaged and updated over time. We calculated the relative risks (RR) and 95% confidence intervals (95% CI) for risk of developing invasive breast cancer, over categories of nutrient and food intake. During follow-up, 4,107 women developed invasive breast cancer. Compared to the lowest quintile of intake, the RR and 95% CI for the highest quintile of intake were 1.02 (0.92-1.14) for animal protein, 0.93 (0.83-1.05) for red meat and 0.89 (0.79-1.00) for all meat. Results did not differ by menopausal status or family history of breast cancer. We found no evidence that intake of meat or fish during mid-life and later was associated with risk of breast cancer.

Adult↗

PubMed2003

Progression of age-related macular degeneration: association with dietary fat, transunsaturated fat, nuts, and fish intake.

BACKGROUND: Individuals with early or intermediate stages of age-related macular degeneration (AMD) make up a large, growing segment of the elderly population. Evidence is sparse regarding modifiable factors that may decrease the risk of progression to the advanced forms of AMD. OBJECTIVE: To advise patients with a high risk for advanced forms of AMD about preventive measures through our evaluation of the relationship between dietary fat intake and the progression of early or intermediate AMD to the advanced stages of the disease associated with visual loss. DESIGN: A prospective cohort study with an average follow-up time of 4.6 years. SETTING: A hospital-based clinical retinal practice specializing in macular degeneration. Patients The 261 participants were aged 60 years and older and had some sign of nonexudative AMD and visual acuity of 20/200 or better in at least 1 eye. Main Outcome Measure Progression to advanced AMD, which was defined as having geographic atrophy or neovascular disease. RESULTS: Higher total fat intake increased the risk of progression to the advanced forms of AMD, with a relative risk (RR) of 2.90 (95% confidence interval, 1.15-7.32) for the highest fat-intake quartile relative to the lowest fat-intake quartile, after controlling for other factors (P trend =.01). Animal fat intake was associated with a 2-fold increased risk of progression (RR, 2.29 for the highest quartile compared with the lowest quartile; 95% confidence interval, 0.91-5.72), although the trend for increasing risk with higher animal fat intake was not significant (P=.09). Higher vegetable fat intake had a stronger relationship with increased risk of AMD progression with an RR of 3.82 (95% confidence interval, 1.58-9.28) for the highest quartile compared with the lowest quartile (P trend =.003). Saturated, monounsaturated, polyunsaturated, and transunsaturated fats increased the likelihood of progression (RR, 2.09 and P trend =.08; RR, 2.21 and P trend =.04; RR, 2.28 and P trend =.04; RR, 2.39 and P trend =.008, respectively). Higher fish intake was associated with a lower risk of AMD progression among subjects with lower linoleic acid intake. Processed baked goods, which are higher in some of these fats, increased the rate of AMD progression approximately 2-fold, and nuts were protective. CONCLUSIONS: Among individuals with the early or intermediate stages of AMD, total and specific types of fat intake, as well as some fat-containing food groups, modified the risk of progression to advanced AMD. Fish intake and nuts reduced risk. Since advanced AMD is associated with visual loss and reduced quality of life, these preventive measures deserve additional research and greater emphasis.

Aged↗

PubMed2003

Progression of age-related macular degeneration: association with body mass index, waist circumference, and waist-hip ratio.

BACKGROUND: Individuals with early or intermediate stages of age-related macular degeneration (AMD) make up a large and growing segment of our elderly population. To advise these high-risk patients regarding preventive measures, we evaluated anthropomorphic, behavioral, and medical factors associated with progression to the advanced stages of AMD associated with visual loss. METHODS: The design was a prospective cohort study in a hospital-based retinal practice. The 261 participants were 60 years or older, with some sign of nonadvanced AMD and visual acuity of 20/200 or better in at least 1 eye. The average follow-up time was 4.6 years, and the total person-years of follow-up was 1198. Factors associated with rates of progression to advanced AMD were assessed by the Cox proportional hazards model. OUTCOME MEASURES: Progression to geographic atrophy and neovascular disease. RESULTS: Higher body mass index (calculated as weight in kilograms divided by the square of height in meters) increased the risk for progression to the advanced forms of AMD. Relative risk (RR) was 2.35 (95% confidence interval [CI], 1.27-4.34) for a body mass index of at least 30, and 2.32 (95% CI, 1.32-4.07) for a body mass index of 25 to 29, relative to the lowest category (<25) after controlling for other factors (P =.007 for trend). Higher waist circumference was associated with a 2-fold increased risk for progression (RR for the highest tertile compared with the lowest, 2.04; 95% CI, 1.12-3.72), with a significant trend for increasing risk with a greater waist circumference (P =.02). Higher waist-hip ratio also increased the risk for progression (RR, 1.84; 95% CI, 1.07-3.15) for the highest tertile compared with lowest (P =.02 for trend). More physical activity tended to be associated with a reduced rate of progression (25% reduction for 3 times per week vigorous activity vs none, P =.05 to P =.07). Relative risks for smoking ranged from 1.48 to 1.99, but were not statistically significant. CONCLUSIONS: Results provide new information regarding modifiable factors for individuals with the early or intermediate stages of this disease. Overall and abdominal obesity increased the risk for progression to advanced AMD, and more physical activity tended to decrease risk. These preventive measures deserve additional research and greater emphasis.

Adipose Tissue↗

PubMed2003

Variability of full-field electroretinogram responses in subjects without diffuse photoreceptor cell disease.

PURPOSE: To evaluate test-retest variability in electroretinogram (ERG) responses in subjects without evidence of diffuse photoreceptor cell disease. DESIGN: Cohort study. PARTICIPANTS: Forty subjects without diffuse photoreceptor cell disease. METHODS: Serial ERGs were performed on 40 subjects (mean age at the time of first ERG: 54 years; range: 38-75 years) over a period of 2 to 6 years. These subjects participated in a study by a pharmaceutical company investigating the effects of certain drugs, used for gastrointestinal disorders, on retinal function. None of the subjects showed any evidence of progressive change in retinal function related to the medications. The ERG responses that were evaluated included amplitudes and implicit times for the dark-adapted rod-isolated and rod-dominant responses, light-adapted single flash response, and both light- and dark-adapted 31-Hz flicker responses. MAIN OUTCOME MEASURES: The data were analyzed by using analysis of variance methods, and a threshold criteria for significant change with 95% confidence was calculated for implicit times and an increase or decrease in ERG amplitudes. RESULTS: The threshold for significant change varied depending on the ERG stimulus. For the dark-adapted stimuli, a significant decrease in amplitude varied from 35% to 42% as compared with a variation of 53% to 73% for a significant increase. For the light-adapted stimuli, a significant decrease in amplitude varied by 52% as compared with a variation of 109% to 110% for a significant increase. The threshold for significant change for implicit times varied from 3.0 milliseconds to 8.7 milliseconds. CONCLUSIONS: The measured test-retest variability in ERG amplitudes and implicit times in subjects without diffuse photoreceptor cell disease underscores the importance of conducting similar comprehensive studies of variability in patients with acquired and hereditary retinal diseases. These data are also of value for monitoring disease progression and in future therapeutic trials.

Adult↗

PubMed2003

Breast cancer risk prediction with a log-incidence model: evaluation of accuracy.

OBJECTIVE: We examined whether a breast cancer risk prediction model other than the Gail et al. model performs better at discriminating between women who will and who will not develop the disease. METHODS: We applied the two published versions of the Rosner and Colditz log-incidence model of breast cancer, developed on data from the Nurses' Health Study, to the estimation of 5-year risk for the period 1992 to 1997 in the same cohort. The first version contained reproductive factors only, and the second version contained a more extensive list of risk factors. RESULTS: Both versions of the model fit well. The ratio of expected to observed numbers of cases (E/O) in the first version was 1.00 (95% confidence interval [CI] 0.93-1.07); for the extended version the E/O was 1.01 (95% CI 0.94-1.09). The age-adjusted concordance statistic was 0.57 for the first model version and 0.63 for the extended version. CONCLUSION: The discriminatory accuracy of the two versions was modest, although the addition of the variables in the extended version meaningfully increased the discriminatory accuracy of risk prediction over that found with the more parsimonious model.

Aged↗

PubMed2003

Prospective study of the association of changes in dietary intake, physical activity, alcohol consumption, and smoking with 9-y gain in waist circumference among 16 587 US men.

BACKGROUND: Although it is known that abdominal obesity increases the risk of chronic diseases, prospective data examining the relation between lifestyle factors and the accumulation of abdominal adipose tissue are sparse. OBJECTIVE: The objective of the study was to determine the associations of changes in diet, physical activity, alcohol consumption, and smoking with 9-y waist gain among US men. DESIGN: A prospective cohort comprised 16 587 US men aged 40-75 y at baseline in 1986. Data on lifestyle factors were provided periodically with the use of self-reported questionnaires, and participants measured and reported their waist circumference in 1987 and 1996. RESULTS: In multivariate analyses, a 2% increment in energy intake from trans fats that were isocalorically substituted for either polyunsaturated fats or carbohydrates was significantly associated with a 0.77-cm waist gain over 9 y (P < 0.001 for each comparison). An increase of 12 g total fiber/d was associated with a 0.63-cm decrease in waist circumference (P < 0.001), whereas smoking cessation and a 20-h/wk increase in television watching were associated with a 1.98-cm and 0.59-cm waist gain, respectively (P < 0.001). Increases of 25 metabolic equivalent tasks (METs) * h/wk in vigorous physical activity and of >/= 0.5 h/wk in weight training were associated with 0.38-cm and 0.91-cm decreases in waist circumference, respectively (P < 0.001 for each comparison). These associations remained significant after further adjustment for concurrent change in body mass index. Changes in total fat and alcohol consumption and in walking volume were not significantly related to waist gain. CONCLUSIONS: Waist gain may be modulated by changes in trans fat and fiber consumption, smoking cessation, and physical activity.

Abdomen↗

PubMed2003

Relation between changes in intakes of dietary fiber and grain products and changes in weight and development of obesity among middle-aged women.

BACKGROUND: Although increased consumption of dietary fiber and grain products is widely recommended to maintain healthy body weight, little is known about the relation of whole grains to body weight and long-term weight changes. OBJECTIVE: We examined the associations between the intakes of dietary fiber and whole- or refined-grain products and weight gain over time. DESIGN: In a prospective cohort study, 74,091 US female nurses, aged 38-63 y in 1984 and free of known cardiovascular disease, cancer, and diabetes at baseline, were followed from 1984 to 1996; their dietary habits were assessed in 1984, 1986, 1990, and 1994 with validated food-frequency questionnaires. Using multiple models to adjust for covariates, we calculated average weight, body mass index (BMI; in kg/m(2)), long-term weight changes, and the odds ratio of developing obesity (BMI > or = 30) according to change in dietary intake. RESULTS: Women who consumed more whole grains consistently weighed less than did women who consumed less whole grains (P for trend < 0.0001). Over 12 y, those with the greatest increase in intake of dietary fiber gained an average of 1.52 kg less than did those with the smallest increase in intake of dietary fiber (P for trend < 0.0001) independent of body weight at baseline, age, and changes in covariate status. Women in the highest quintile of dietary fiber intake had a 49% lower risk of major weight gain than did women in the highest quintile (OR = 0.51; 95% CI: 0.39, 0.67; P < 0.0001 for trend). CONCLUSION: Weight gain was inversely associated with the intake of high-fiber, whole-grain foods but positively related to the intake of refined-grain foods, which indicated the importance of distinguishing whole-grain products from refined-grain products to aid in weight control.

Adult↗

PubMed2003

Incorporation of clustering effects for the Wilcoxon rank sum test: a large-sample approach.

The Wilcoxon rank sum test is frequently used in statistical practice for the comparison of measures of location when the underlying distributions are far from normal or not known in advance. An assumption of the ordinary rank sum test is that individual sampling units are independent. In many ophthalmologic clinical trials, the Early Treatment for Diabetic Retinopathy Scale (ETDRS) is a principal endpoint used for measuring the level of diabetic retinopathy. This is an ordinal scale, and it is natural to consider the Wilcoxon rank sum test for the comparison of the level of diabetic retinopathy between treatment groups. However, under this design, unlike the usual Wilcoxon rank sum test, the subject is the unit of randomization, but the eye is the unit of analysis. Furthermore, a person will tend to have different, but correlated, ETDRS scores for fellow eyes. Thus, we propose a correction to the variance of the Wilcoxon rank sum statistic that accounts for clustering effects and that can be used for both balanced (same number of subunits per cluster) or unbalanced (different number of subunits per cluster) data, both in the presence or absence of ties, with p-value adjusted accordingly. In this article, we present large-sample theory and simulation results for this test procedure and apply it to diabetic retinopathy data from type I diabetics in the Sorbinil Retinopathy Trial.

Biometry↗

PubMed2003

Change in glycemic control predicts change in weight in adolescent boys with type 1 diabetes.

OBJECTIVE: To characterize the intraindividual relationships between changes in weight, glycosylated hemoglobin (HbA1c) levels, and reported total daily insulin dose between clinic visits in adolescent boys with type 1 diabetes (T1D). RESEARCH DESIGN AND METHODS: Intraindividual changes in HbA1c, anthropometric data, and reported total daily insulin dose between consecutive visits for 94 adolescent boys with T1D were analyzed. RESULTS: Average quarterly weight gain was 2.8 kg during periods of improving, 1.5 kg during periods of minimal change, and 0.8 kg during periods of worsening glycemic control (improving vs. minimal change p < 0.001; minimal change vs. worsening p = 0.11; improving vs. worsening p < 0.001). Analyzing the quarterly weight velocity according to change in reported total daily dose of insulin, we found significantly greater weight gain during intervals when the family reported a decreasing insulin dose compared to intervals when the family reported no change in insulin dose (p = 0.003). Conversely, weight change during periods of reported increasing insulin dose was similar to that when the family reported that the boy's insulin dose did not change. CONCLUSIONS: Quarterly weight velocity was correlated with degree of change in glycemic control between visits in adolescent boys with T1D. When weight loss or inadequate weight gain and worsening glycemic control occur, the possibility of insulin omission must be explored. Reviewing the adolescent's growth data and then the division of responsibilities for diabetes management within the family, clinicians must reconcile discrepancies between weight velocity and a reportedly adequate dose of insulin.

Adolescent↗

PubMed2003

Relation between dieting and weight change among preadolescents and adolescents.

OBJECTIVE: To assess whether dieting to control weight was associated with weight change among children and adolescents. METHODS: A prospective study was conducted of 8203 girls and 6769 boys who were 9 to 14 years of age in 1996, were in an ongoing cohort study, and completed at least 2 annual questionnaires between 1996 and 1999. Dieting to control weight, binge eating, and dietary intake were assessed annually from 1996 through 1998 with instruments designed specifically for children and adolescents. The outcome measure was age- and sex-specific z score of body mass index (BMI). RESULTS: In 1996, 25.0% of the girls and 13.8% of the boys were infrequent dieters and 4.5% of the girls and 2.2% of the boys were frequent dieters. Among the girls, the percentage of dieters increased over the following 2 years. Binge eating was more common among the girls, but in both sexes, it was associated with dieting to control weight (girls: infrequent dieters, odds ratio [OR]: 5.10; frequent dieters, OR: 12.4; boys: infrequent dieters, OR: 3.49; frequent dieters, OR: 7.30). During 3 years of follow-up, dieters gained more weight than nondieters. Among the girls, frequency of dieting was positively associated with increases in age- and sex-specific z scores of BMI (beta = 0.05 and beta = 0.04 for frequent and infrequent dieters vs nondieters). Among the boys, both frequent and infrequent dieters gained 0.07 z scores of BMI more than nondieters. In addition, boys who engaged in binge eating gained significantly more weight than nondieters. CONCLUSIONS: Although medically supervised weight control may be beneficial for overweight youths, our data suggest that for many adolescents, dieting to control weight is not only ineffective, it may actually promote weight gain.

Adolescent↗