Alan M. Robson

Nutrient Intake and Blood Pressure in the Dietary Intervention Study in Children

Delineating the role that diet plays in blood pressure levels in children is important for guiding dietary recommendations for the prevention of hypertension. The purpose of this study was to investigate relationships between dietary nutrients and blood pressure in children. Data were analyzed from 662 participants in the Dietary Intervention Study in Children who had elevated low-density lipoprotein cholesterol and were aged 8 to 11 years at baseline. Three 24-hour dietary recalls, systolic pressure, diastolic pressure, height, and weight were obtained at baseline, 1 year, and 3 years. Nutrients analyzed were the micronutrients calcium, magnesium, and potassium; the macronutrients protein, carbohydrates, total fat, saturated fat, polyunsaturated fat, and monounsaturated fat; dietary cholesterol; and total dietary fiber. Baseline and 3-year longitudinal relationships were examined through multivariate models on diastolic and systolic pressures separately, controlling for height, weight, sex, and total caloric intake. The following associations were found in longitudinal analyses: analyzing each nutrient separately, for systolic pressure, inverse associations with calcium (P < .05); magnesium, potassium, and protein (all P < .01); and fiber (P < .05), and direct associations with total fat and monounsaturated fat (both P < .05); for diastolic pressure, inverse associations with calcium (P < .01); magnesium and potassium (both P < .05), protein (P < .01); and carbohydrates and fiber (both P < .05), and direct associations with polyunsaturated fat (P < .01) and monounsaturated fat (P < .05). Analyzing all nutrients simultaneously, for systolic pressure, direct association with total fat (P < .01); for diastolic pressure, inverse associations with calcium (P < .01) and fiber (P < .05), and direct association with total and monounsaturated fats (both P < .05). Results from this sample of children with elevated low-density lipoprotein cholesterol indicate that dietary calcium, fiber, and fat may be important determinants of blood pressure level in children.

Higher Self-reported Physical Activity Is Associated With Lower Systolic Blood Pressure: The Dietary Intervention Study in Childhood (DISC)

OBJECTIVE. Children participating in a dietary clinical trial were studied to (1) assess physical activity patterns in boys and girls longitudinally from late childhood through puberty and (2) determine the association of level of physical activity on systolic blood pressure, low-density lipoprotein cholesterol, and BMI. PATIENTS AND METHODS. In the Dietary Intervention Study in Childhood, a randomized clinical trial of a reduced saturated fat and cholesterol diet in 8- to 10-year-olds with elevated low-density lipoprotein, a questionnaire that determined time spent in 5 intensity levels of physical activity was completed at baseline and at 1 and 3 years. An estimated-metabolic-equivalent score was calculated for weekly activity; hours per week were calculated for intense activities. We hypothesized that weekly self-reported physical activity would be associated with lower systolic blood pressure, low-density lipoprotein, and BMI over 3 years. Longitudinal data analyses were performed for each outcome (systolic blood pressure, low-density lipoprotein, and BMI) by using generalized estimating equations with estimated-metabolic-equivalent score per week as the independent variable adjusted for visit, gender, and Tanner stage (BMI was included in models for systolic blood pressure and low-density lipoprotein). RESULTS. The initial study cohort comprised 663 youths (362 boys [mean age: 9.7 years] and 301 girls [mean age: 9.0 years), of whom 623 (94%) completed the 3-year visit. For every 100 estimated-metabolic-equivalent hours of physical activity, there was a decrease of 1.15 mmHg of systolic blood pressure. There was a 1.28 mg/dL decline in low-density lipoprotein for a similar energy expenditure. For BMI, an analysis of intense physical activity showed that for every 10 hours of intense activity, there was a trend toward significance with a 0.2 kg/m2 decrease. CONCLUSIONS. Children with elevated cholesterol levels who lead a more physically active lifestyle have lower systolic blood pressure and a trend toward lower low-density lipoprotein over a 3-year interval. Long-term participation in intense physical activity may reduce BMI as well.

Effects of Diet and Sexual Maturation on Low-Density Lipoprotein Cholesterol During Puberty The Dietary Intervention Study in Children (DISC)

BACKGROUND The Dietary Intervention Study in Children (DISC) is a multicenter, randomized, controlled clinical trial designed to examine the efficacy and safety of a dietary intervention to reduce serum LDL cholesterol (LDL-C) in children with elevated LDL-C. METHODS AND RESULTS The effects of dietary intake of fat and cholesterol and of sexual maturation and body mass index (BMI) on LDL-C were examined in a 3-year longitudinal study of 663 boys and girls (age 8 to 10 years at baseline) with elevated LDL-C levels. Multiple linear regression was used to predict LDL-C at 3 years. For boys, LDL-C decreased by 0.018 mmol/L for each 10 mg/4.2 MJ decrease in dietary cholesterol (P<.05). For girls, no single nutrient was significant in the model, but a treatment group effect was evident (P<.05). In both sexes, BMI at 3 years and LDL-C at baseline were significant and positive predictors of LDL-C levels. In boys, the average LDL-C level was 0.603 mmol/L lower at Tanner stage 4+ than at Tanner stage 1 (P<.01). In girls, the average LDL-C level was 0.274 mmol/L lower at Tanner stage 4+ than at Tanner stage 1 (P<.05). CONCLUSIONS In pubertal children, sexual maturation, BMI, dietary intervention (in girls), and dietary cholesterol (in boys) were significant in determining LDL-C. Sexual maturation was the factor associated with the greatest difference in LDL-C. Clinicians screening for dyslipidemia or following dyslipidemic children should be aware of the powerful effects of pubertal change on measurements of lipoproteins.

Height, adiposity and body fat distribution and breast density in young women

IntroductionBreast density is one of the strongest risk factors for breast cancer, but determinants of breast density in young women remain largely unknown.MethodsAssociations of height, adiposity and body fat distribution with percentage dense breast volume (%DBV) and absolute dense breast volume (ADBV) were evaluated in a cross-sectional study of 174 healthy women, 25 to 29 years old. Adiposity and body fat distribution were measured by anthropometry and dual-energy X-ray absorptiometry (DXA), while %DBV and ADBV were measured by magnetic resonance imaging. Associations were evaluated using linear mixed-effects models. All tests of statistical significance are two-sided.ResultsHeight was significantly positively associated with %DBV but not ADBV; for each standard deviation (SD) increase in height, %DBV increased by 18.7% in adjusted models. In contrast, all measures of adiposity and body fat distribution were significantly inversely associated with %DBV; a SD increase in body mass index (BMI), percentage fat mass, waist circumference and the android:gynoid fat mass ratio (A:G ratio) was each associated significantly with a 44.4 to 47.0% decrease in %DBV after adjustment for childhood BMI and other covariates. Although associations were weaker than for %DBV, all measures of adiposity and body fat distribution also were significantly inversely associated with ADBV before adjustment for childhood BMI. After adjustment for childhood BMI, however, only the DXA measures of percentage fat mass and A:G ratio remained significant; a SD increase in each was associated with a 13.8 to 19.6% decrease in ADBV. In mutually adjusted analysis, the percentage fat mass and the A:G ratio remained significantly inversely associated with %DBV, but only the A:G ratio was significantly associated with ADBV; a SD increase in the A:G ratio was associated with an 18.5% decrease in ADBV.ConclusionTotal adiposity and body fat distribution are independently inversely associated with %DBV, whereas in mutually adjusted analysis only body fat distribution (A:G ratio) remained significantly inversely associated with ADBV in young women. Research is needed to identify biological mechanisms underlying these associations.

Adolescent Diet and Subsequent Serum Hormones, Breast Density, and Bone Mineral Density in Young Women: Results of the Dietary Intervention Study in Children Follow-up Study

Background: Adolescent diet is hypothesized to influence breast cancer risk. We evaluated the long-term effects of an intervention to lower fat intake among adolescent girls on biomarkers that are related to breast cancer risk in adults. Methods: A follow-up study was conducted on 230 girls who participated in the Dietary Intervention Study in Children (DISC), in which healthy, prepubertal, 8 to 10 year olds were randomly assigned to usual care or to a behavioral intervention that promoted a reduced fat diet. Participants were 25 to 29 years old at follow-up visits. All tests of statistical significance are two-sided. Results: In analyses that did not take account of diet at the time of the follow-up visit, the only statistically significant treatment group difference was higher bone mineral content in intervention group participants compared with usual care group participants; their mean bone mineral contents were 2,444 and 2,377 g, respectively. After adjustment for current diet, the intervention group also had statistically significantly higher bone mineral density and luteal phase serum estradiol concentrations. Serum progesterone concentrations and breast density did not differ by treatment group in unadjusted or adjusted analyses. Conclusions: Results do not support the hypothesis that consumption of a lower fat diet during adolescence reduces breast cancer risk via effects on subsequent serum estradiol and progesterone levels, breast density, or bone mineral density. It remains unclear, however, if the results are specific to the DISC intervention or are more broadly applicable. Impact: Modest reductions in fat intake during adolescence are unlikely to lower later breast cancer risk via long-term effects on the biomarkers measured. Cancer Epidemiol Biomarkers Prev; 19(6); 1545–56. ©2010 AACR.

Adolescent Diet and Metabolic Syndrome in Young Women: Results of the Dietary Intervention Study in Children (DISC) Follow-Up Study

CONTEXT Childhood diet is hypothesized to influence development of chronic disease in adulthood. OBJECTIVE Our objective was to evaluate the long-term effects of a dietary intervention to reduce fat and increase fiber intake during childhood and adolescence on the prevalence of metabolic syndrome in young adult women. DESIGN A follow-up study was conducted in 2006-2008, 9 yr after termination of the Dietary Intervention Study in Children (DISC). SETTING The study took place at six DISC clinical centers in the United States. PARTICIPANTS A total of 230 (76%) DISC female participants who were 25-29 yr old and had not been pregnant or breastfeeding in the previous 3 months participated in the follow-up study. INTERVENTION There was no intervention between the end of the DISC trial and the follow-up visit. MAIN OUTCOME MEASURE Metabolic syndrome was the primary study endpoint planned before data collection and was hypothesized to be less common in the intervention group participants. RESULTS Metabolic syndrome was uncommon, and its prevalence did not differ by treatment group. However, after adjustment for nondietary variables, mean systolic blood pressures of intervention and control group participants were 107.7 and 110.0 mm Hg, respectively (P = 0.03), whereas mean fasting plasma glucose levels were 87.0 and 89.1 mg/dl, respectively (P = 0.01). Intervention group participants also had lower concentrations of large very-low-density lipoprotein particles, a marker of hepatic insulin resistance, compared with control group participants. Adjustment for current diet did not materially alter results. CONCLUSION Consumption of a diet lower in fat and higher in fiber during childhood and adolescence may benefit glycemic control and blood pressure long term.

Dietary Energy Density Is Positively Associated with Breast Density among Young Women

BACKGROUND Breast density is an established predictor of breast cancer risk, and there is considerable interest in associations of modifiable lifestyle factors, such as diet, with breast density. OBJECTIVE To determine whether dietary energy density (ED) is associated with percent dense breast volume (%DBV) and absolute dense breast volume (ADBV) in young women. DESIGN A cross-sectional analysis was conducted with women who participated in the Dietary Intervention Study in Children Follow-Up Study. %DBV and ADBV were measured by magnetic resonance imaging. Diet was assessed by three 24-hour recalls. Dietary ED (kilocalories/gram) was calculated using three methods: food only, food and caloric beverages, and food and all beverages. PARTICIPANTS/SETTING One hundred seventy-two women (aged 25 to 29 years) who were enrolled in the Dietary Intervention Study in Children Follow-Up Study. Participants who reported breast augmentation or reduction surgery or were pregnant or lactating within 3 months before breast density assessment were excluded. MAIN OUTCOME MEASURES ADBV and %DBV. STATISTICAL ANALYSES PERFORMED Multivariable linear mixed effects models were used. Final models were adjusted for race, smoking status, education, parity, duration of sex hormone use, whole body percent fat, childhood body mass index z score, and energy from beverages. RESULTS After adjustment, each 1 kcal/g unit increase in food-only ED was associated with a 25.9% (95% CI 6.2% to 56.8%) increase in %DBV (P=0.01). Childhood body mass index z score modified the association between food-only ED and %DBV such that a significant positive association was observed only in women who were heavier as children. Food-only ED was not associated with ADBV in all women, but a borderline significant positive association was observed in women who had higher childhood body mass index z scores. CONCLUSIONS This is the first report to suggest a potential role for dietary ED in breast density; the effects of long-term exposure to high-ED diets on breast cancer risk remain unknown.

Curvularia urinary tract infection: a case report.

A healthy 5-year-old child had recurrent symptomatic urinary tract infections, the last of which was accompanied by black specks in her urine. These specks were identified asCurvularia species, a dermatiaceous mold. Symptoms resolved and fungi disappeared with long-term hydration, without specific antifungal treatment.

Youth and Young Adult Physical Activity and Body Composition of Young Adult Women: Findings from the Dietary Intervention Study in Children

This study prospectively investigates associations between youth moderate-to-vigorous-intensity physical activity (MVPA) and body composition in young adult women using data from the Dietary Intervention Study in Children (DISC) and the DISC06 Follow-Up Study. MVPA was assessed by questionnaire on 5 occasions between the ages 8 and 18 years and at age 25-29 years in 215 DISC female participants. Using whole body dual-energy x-ray absorptiometry (DXA), overall adiposity and body fat distribution were assessed at age 25-29 years by percent body fat (%fat) and android-to-gynoid (A:G) fat ratio, respectively. Linear mixed effects models and generalized linear latent and mixed models were used to assess associations of youth MVPA with both outcomes. Young adult MVPA, adjusted for other young adult characteristics, was significantly inversely associated with young adult %fat (%fat decreased from 37.4% in the lowest MVPA quartile to 32.8% in the highest (p-trend = 0.02)). Adjusted for youth and young adult characteristics including young adult MVPA, youth MVPA also was significantly inversely associated with young adult %fat (β=-0.40 per 10 MET-hrs/wk, p = .02) . No significant associations between MVPA and A:G fat ratio were observed. Results suggest that youth and young adult MVPA are important independent predictors of adiposity in young women.

Abstract 2827: Adolescent diet and serum hormones, breast density and bone mineral density in young adults: findings from the Dietary Intervention in Children (DISC) Follow-Up Study

Proceedings: AACR 101st Annual Meeting 2010‐‐ Apr 17‐21, 2010; Washington, DC Background: Adolescent diet is hypothesized to influence breast cancer risk, and we previously showed that an intervention to lower fat intake during adolescence was associated with lower serum estrogens and progesterone. We have now evaluated the long-term effects of this intervention on serum hormones, breast density and bone mineral density (BMD), biomarkers that are positively related to breast cancer risk in adults. Methods: We conducted a follow-up study of 230 girls who participated in 1988-1997 in the Dietary Intervention Study in Children (DISC), in which healthy, prepubertal 8-10 year olds with elevated low-density lipoprotein cholesterol were randomly assigned to usual care or to a behavioral intervention that promoted a reduced-fat diet. Follow-up visits were conducted in 2006-2008, when participants were 25-29 years old. Serum estradiol and progesterone were measured by radioimmunoassays, breast density was measured by magnetic resonance imaging, and whole body bone mineral content (BMC) and BMD were measured by dual x-ray absorptiometry (DXA). Analyses were performed using linear mixed models. All tests of statistical significance are two-sided. Results: In analyses that did not take account of current diet at the time of the follow-up visit, the only statistically significant (p=.04) treatment group difference was higher whole body BMC in the intervention group compared to the usual care group; their mean BMCs were 2,444g (95% confidence interval (CI)=2,391-2,496g) and 2,378g (95% CI=2,325-2,431g), respectively. After adjustment for current dietary intakes of fat and fiber, intervention group participants’ mean BMD was 1.19g/cm2 (95% CI=1.17-1.21g/cm2), which was statistically significantly (p=.01) higher compared to usual care group participants mean BMD of 1.16g/cm2 (95% CI=1.14-1.18g/cm2). Furthermore, mean luteal phase serum estradiol concentrations were statistically significantly (p=.02) higher in intervention group participants compared to usual care group participants after adjustment for current diet; their mean concentrations were 142pg/mL (95% CI=115-174pg/mL) and 97pg/mL (95% CI=76-122pg/mL), respectively. Serum progesterone concentrations and breast density did not differ by treatment group in unadjusted or adjusted analyses. Conclusion: Results do not support the hypothesis that consumption of a lower fat diet during adolescence reduces later breast cancer risk via effects on serum estradiol and progesterone, breast density or BMD. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2827.