Intervention Study In Children Research Articles

Association between change in self-reported sugar intake and a sugar biomarker (δ13C) in children at increased risk for type 1 diabetes.

We examined whether change in added sugar intake is associated with change in δ13C, a novel sugar biomarker, in thirty-nine children aged 5-10 years selected from a Colorado (USA) prospective cohort of children at increased risk for type 1 diabetes. Reported added sugar intake via FFQ and δ13C in erythrocytes were measured at two time points a median of 2 years apart. Change in added sugar intake was associated with change in the δ13C biomarker, where for every 1-g increase in added sugar intake between the two time points, there was an increase in δ13C of 0⋅0082 (P = 0⋅0053), independent of change in HbA1c and δ15N. The δ13C biomarker may be used as a measure of compliance in an intervention study of children under the age of 10 years who are at increased risk for type 1 diabetes, in which the goal was to reduce dietary sugar intake.

Alcohol consumption and serum metabolite concentrations in young women.

Alcohol consumption is an established breast cancer risk factor, though further research is needed to advance our understanding of the mechanism underlying the association. We used global metabolomics profiling to identify serum metabolites and metabolic pathways that could potentially mediate the alcohol-breast cancer association. A cross-sectional analysis of reported alcohol consumption and serum metabolite concentrations was conducted among 211 healthy women 25-29years old who participated in the Dietary Intervention Study in Children 2006 Follow-Up Study (DISC06). Alcohol-metabolite associations were evaluated using multivariable linear mixed-effects regression. Alcohol was significantly (FDR p < 0.05) associated with several serum metabolites after adjustment for diet composition and other potential confounders. The amino acid sarcosine, the omega-3 fatty acid eicosapentaenoate, and the steroid 4-androsten-3beta,17beta-diol monosulfate were positively associated with alcohol intake, while the gamma-tocopherol metabolite gamma-carboxyethyl hydroxychroman (CEHC) was inversely associated. Positive associations of alcohol with 2-methylcitrate and 4-androsten-3beta,17beta-diol disulfate were borderline significant (FDR p < 0.10). Metabolite set enrichment analysis identified steroids and the glycine pathway as having more members associated with alcohol consumption than expected by chance. Most of the metabolites associated with alcohol in the current analysis participate in pathways hypothesized to mediate the alcohol-breast cancer association including hormonal, one-carbon metabolism, and oxidative stress pathways, but they could also affect risk via alternative pathways. Independent replication of alcohol-metabolite associations and prospective evaluation of confirmed associations with breast cancer risk are needed.

Pubertal timing and breast density in young women: a prospective cohort study

BackgroundEarlier age at onset of pubertal events and longer intervals between them (tempo) have been associated with increased breast cancer risk. It is unknown whether the timing and tempo of puberty are associated with adult breast density, which could mediate the increased risk.MethodsFrom 1988 to 1997, girls participating in the Dietary Intervention Study in Children (DISC) were clinically assessed annually between ages 8 and 17 years for Tanner stages of breast development (thelarche) and pubic hair (pubarche), and onset of menses (menarche) was self-reported. In 2006–2008, 182 participants then aged 25–29 years had their percent dense breast volume (%DBV) measured by magnetic resonance imaging. Multivariable, linear mixed-effects regression models adjusted for reproductive factors, demographics, and body size were used to evaluate associations of age and tempo of puberty events with %DBV.ResultsThe mean (standard deviation) and range of %DBV were 27.6 (20.5) and 0.2–86.1. Age at thelarche was negatively associated with %DBV (p trend = 0.04), while pubertal tempo between thelarche and menarche was positively associated with %DBV (p trend = 0.007). %DBV was 40% higher in women whose thelarche-to-menarche tempo was 2.9 years or longer (geometric mean (95%CI) = 21.8% (18.2–26.2%)) compared to women whose thelarche-to-menarche tempo was less than 1.6 years (geometric mean (95%CI) = 15.6% (13.9–17.5%)).ConclusionsOur results suggest that a slower pubertal tempo, i.e., greater number of months between thelarche and menarche, is associated with higher percent breast density in young women. Future research should examine whether breast density mediates the association between slower tempo and increased breast cancer risk.

Reduced psychiatric symptoms at 6 and 12 months' follow-up of psychotherapeutic and psychoeducative group interventions for children exposed to intimate partner violence.

Long-term follow-up studies of interventions for children exposed to intimate partner violence are few, and the sustainability of their outcomes often remains unexplored and uncertain. Current research including follow-up assessment suggests that treatment gains may be maintained or continue post termination. In addition some children may show increased levels of symptoms. The present effectiveness study investigated the long-term outcomes of two established group interventions for children exposed to intimate partner violence and their non-offending parent. The study included 50 children, 24 girls and 26 boys, aged 4 to 13 years attending a psychotherapeutic child and adolescent mental health service intervention and a psychoeducative community-based intervention. Background information, child and parental mental health problems, trauma symptoms, and exposure to violence were assessed pre- and post treatment and at 6 and 12 months' follow-up. Sustained treatment gains and late improvements in children's internalizing and externalizing symptoms and in symptoms of traumatic stress were recorded from post treatment to the follow-up assessments (p = .004- .044; d = 0.29-0.67). No significant increase in symptoms was reported. Additionally, very little continued or renewed child exposure to violence was reported. The results of the study indicate that the children did benefit from the two interventions studied and that the outcomes of reduced child symptoms and protection from exposure to violence were sustainable. Children with severe trauma symptoms benefited the most, though maternal psychological problems may for some have hindered recovery. Clinical implications are discussed.

Efficacy of very low-energy diets for weight loss: a systematic review of intervention studies in children and adolescents with obesity

Efficacy of very low-energy diets for weight loss: a systematic review of intervention studies in children and adolescents with obesity

Efficacy of very low-energy diet programs for weight loss: A systematic review with meta-analysis of intervention studies in children and adolescents with obesity.

The objective of this review was to evaluate the efficacy and safety of very low-energy diet (VLED) programs for weight loss in children and adolescents with obesity. Six electronic databases were searched identifying 24 eligible studies (16 pre-post studies, four nonrandomized trials, two randomized controlled trials [RCTs], and two chart reviews) published up to October 2018. Studies were in English, implemented a VLED (≤3360kJF/day [≤800kcal/day] or <50% estimated energy requirements) in 5- to 18-year-olds with obesity, and reported at least one weight-related outcome. Weight-related outcomes significantly improved postintervention in all studies. Meta-analysis of 20 studies indicated a mean 10.1kg (95% confidence interval [CI], 8.7-11.4kg, P<0.001; I2 =92.3%) weight loss following interventions lasting 3 to 20weeks. Moderator analysis indicated greater weight loss in adolescent-only studies (10-18years) and formulated meal replacement interventions and inpatient settings. Meta-analysis of seven studies reporting weight at follow-up (5-14.5months from baseline) indicated 5.3 kg mean weight loss (CI, 2.5-8.0kg, P<0.001; I2 =50.6%). Details of adverse events were limited. VLED programs are effective for treating children and adolescents with obesity. However, conclusions on their safety cannot be drawn from the existing literature at this time. Future studies should include long-term follow-up with ongoing support and comprehensive monitoring of all adverse events.

A prebiotic intervention study in children with autism spectrum disorders (ASDs)

BackgroundDifferent dietary approaches, such as gluten and casein free diets, or the use of probiotics and prebiotics have been suggested in autistic spectrum disorders in order to reduce gastrointestinal (GI) disturbances. GI symptoms are of particular interest in this population due to prevalence and correlation with the severity of behavioural traits. Nowadays, there is lack of strong evidence about the effect of dietary interventions on these problems, particularly prebiotics. Therefore, we assessed the impact of exclusion diets and a 6-week Bimuno® galactooligosaccharide (B-GOS®) prebiotic intervention in 30 autistic children.ResultsThe results showed that children on exclusion diets reported significantly lower scores of abdominal pain and bowel movement, as well as lower abundance of Bifidobacterium spp. and Veillonellaceae family, but higher presence of Faecalibacterium prausnitzii and Bacteroides spp. In addition, significant correlations were found between bacterial populations and faecal amino acids in this group, compared to children following an unrestricted diet. Following B-GOS® intervention, we observed improvements in anti-social behaviour, significant increase of Lachnospiraceae family, and significant changes in faecal and urine metabolites.ConclusionsTo our knowledge, this is the first study where the effect of exclusion diets and prebiotics has been evaluated in autism, showing potential beneficial effects. A combined dietary approach resulted in significant changes in gut microbiota composition and metabolism suggesting that multiple interventions might be more relevant for the improvement of these aspects as well as psychological traits.Trial registrationNCT02720900; registered in November 2015.

Intake of dietary carbohydrates in early adulthood and adolescence and breast density among young women.

Carbohydrateintake increases postprandial insulin secretion and may affect breast density, a strong risk factor for breast cancer, early in life. We examined associations of adolescent and early adulthood intakes of total carbohydrates, glycemic index/load, fiber, and simple sugars with breast density among 182 young women. Diet was assessed using three 24-h recalls at each of five Dietary Intervention Study in Children (DISC) clinic visits when participants were age 10-19years and at the DISC06 Follow-Up Study clinic visit when participants were age 25-29years. Associations between energy-adjusted carbohydrates and MRI-measured percent dense breast volume (%DBV) and absolute dense breast volume (ADBV) at 25-29years were quantified using multivariable-adjusted mixed-effects linear models. Adolescent sucrose intakes and premenarcheal total carbohydrates intakes were modestly associated with higher %DBV (mean %DBVQ1 vs Q4, 16.6 vs 23.5% for sucrose; and 17.2 vs 22.3% for premenarcheal total carbohydrates, all Ptrend ≤ 0.02), but not with ADBV. However, adolescent intakes of fiber and fructose were not associated with %DBV and ADBV. Early adulthood intakes of total carbohydrates, glycemic index/load, fiber, and simple sugars were not associated with %DBV and ADBV. Insulinemic carbohydrate diet during puberty may be associated with adulthood breast density, but our findings need replication in larger studies. Clinical Trials Registration ClinicalTrials.gov Identifier, NCT00458588 April 9, 2007; NCT00000459 October 27, 1999.

Maternal supplementation alone with Lactobacillus rhamnosus HN001 during pregnancy and breastfeeding does not reduce infant eczema.

In a randomized placebo-controlled trial, we previously found that the probiotic Lactobacillus rhamnosus HN001 (HN001) taken by mothers from 35weeks of gestation until 6months post-partum if breastfeeding and their child from birth to age 2years halved the risk of eczema during the first 2years of life. We aimed to test whether maternal supplementation alone is sufficient to reduce eczema and compare this to our previous study when both the mother and their child were supplemented. In this 2-centre, parallel double-blind, randomized placebo-controlled trial, the same probiotic as in our previous study (HN001, 6×109 colony-forming units) was taken daily by mothers from 14-16weeks of gestation till 6months post-partum if breastfeeding, but was not given directly to the child. Women were recruited from the same study population as the first study, where they or their partner had a history of treated asthma, eczema or hay fever. Women were randomized to HN001 (N=212) or placebo (N=211). Maternal-only HN001 supplementation did not significantly reduce the prevalence of eczema, SCORAD≥10, wheeze or atopic sensitization in the infant by 12months. This contrasts with the mother and child intervention study, where HN001 was associated with reductions in eczema (hazard ratio (HR): 0.39, 95% CI 0.19-0.79, P=.009) and SCORAD (HR=0.61, 95% 0.37-1.02). However, differences in the HN001 effect between studies were not significant. HN001 could not be detected in breastmilk from supplemented mothers, and breastmilk TGF-β/IgA profiles were unchanged. Maternal probiotic supplementation without infant supplementation may not be effective for preventing infant eczema.

Definiciones y métodos de entrenamiento de la inhibición en la niñez, desde una perspectiva neuropsicológica. Una revisión sistemática

The structure and nature of the inhibition is discussed. However, it is recognized that inhibition is important for the performance of children in formal and informal education during the pre-school and school stages. Therefore, intervention studies have been developed, aimed at knowing the plasticity of its functioning and influencing other skills in which it participates. Consequently, this work intends to carry out a systematic review of process-based inhibitory intervention studies in children with typical development. We analyze practical aspects related to the effectiveness of the intervention and theoretical aspects, explaining the model that sustains each intervention and its specific contributions related to the nature of the inhibition construct. It is a contribution insufficiently treated in the literature about inhibition, which is important given the discrepancies on the construct. The analysis tries to draw conclusions that could be considered in the design and evaluation of the effectiveness of future inhibitory training programs.

Abstract 1752: Dietary fat intake during adolescence and breast density among young women

Abstract BACKGROUND: Lack of association between fat intake and breast cancer risk in cohort studies might be attributed to disregard of temporal effects during adolescence when breasts develop and are particularly sensitive to stimuli. We prospectively examined associations between adolescent fat intakes and breast density. METHOD: Among 177 women who participated in the Dietary Intervention Study in Children, dietary intakes at ages 10-18 were assessed on five occasions by 24-hour recalls and averaged. We calculated geometric mean and 95% confidence intervals for MRI-measured breast density at ages 25-29 across quartiles of fat intake using linear mixed-effect regression. RESULTS: Comparing women in the extreme quartiles of adolescent fat intakes, percent dense breast volume (%DBV) was positively associated with saturated fat (mean = 16.4% vs. 21.5%; Ptrend&amp;lt;0.001). Conversely,%DBV was inversely associated with monounsaturated fat (25.0% vs. 15.8%; Ptrend&amp;lt;0.001) and the ratio of polyunsaturated fat to saturated fat (P/S ratio; 19.1% vs. 14.3%; Ptrend:&amp;lt;0.001). When examining intake by pubertal stages,%DBV was inversely associated with intake of polyunsaturated fat (20.8% vs. 16.4%; Ptrend = 0.04), long-chain omega-3 fat (17.8% vs. 15.8%; Ptrend&amp;lt;0.001), and P/S ratio (22.5% vs. 16.1%; Ptrend&amp;lt;0.001) before menarche, but not after. These associations observed with%DBV were consistently observed with absolute dense breast volume but not with absolute non-dense breast volume. CONCLUSIONS: In our study, adolescent intakes of higher saturated fat and lower mono- and polyunsaturated fat are associated with higher breast density measured approximately 15 years later. IMPACT: The fat subtype composition in adolescent diet may be important in early breast cancer prevention. Citation Format: Seungyoun Jung. Dietary fat intake during adolescence and breast density among young women. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1752.

Early Life Body Fatness, Serum Anti-Müllerian Hormone, and Breast Density in Young Adult Women

Emerging evidence suggests positive associations between serum anti-Müllerian hormone (AMH), a marker of ovarian function, and breast cancer risk. Body size at young ages may influence AMH levels, but few studies have examined this. Also, no studies have examined the relation of AMH levels with breast density, a strong predictor of breast cancer risk. We examined associations of early life body fatness, AMH concentrations, and breast density among 172 women in the Dietary Intervention Study in Children (DISC). Height and weight were measured at baseline (ages 8-10) and throughout adolescence. Serum AMH concentrations and breast density were assessed at ages 25-29 at the DISC 2006 Follow-up visit. We used linear mixed effects models to quantify associations of AMH (dependent variable) with quartiles of age-specific youth body mass index (BMI) Z-scores (independent variable). We assessed cross-sectional associations of breast density (dependent variable) with AMH concentration (independent variable). Neither early life BMI nor current adult BMI was associated with AMH concentrations. There were no associations between AMH and percent or absolute dense breast volume. In contrast, women with higher AMH concentrations had significantly lower absolute nondense breast volume (Ptrend < 0.01). We found no evidence that current or early life BMI influences AMH concentrations in later life. Women with higher concentrations of AMH had similar percent and absolute dense breast volume, but lower nondense volume. These results suggest that AMH may be associated with lower absolute nondense breast volume; however, future prospective studies are needed to establish temporality. Cancer Epidemiol Biomarkers Prev; 25(7); 1151-7. ©2016 AACR.

Dietary Fat Intake During Adolescence and Breast Density Among Young Women.

Lack of association between fat intake and breast cancer risk in cohort studies might be attributed to the disregard of temporal effects during adolescence when breasts develop and are particularly sensitive to stimuli. We prospectively examined associations between adolescent fat intakes and breast density. Among 177 women who participated in the Dietary Intervention Study in Children, dietary intakes at ages 10-18 years were assessed on five occasions by 24-hour recalls and averaged. We calculated geometric mean and 95% confidence intervals for MRI-measured breast density at ages 25-29 years across quartiles of fat intake using linear mixed-effect regression. Comparing women in the extreme quartiles of adolescent fat intakes, percent dense breast volume (%DBV) was positively associated with saturated fat (mean = 16.4% vs. 21.5%; Ptrend < 0.001). Conversely, %DBV was inversely associated with monounsaturated fat (25.0% vs. 15.8%; Ptrend < 0.001) and the ratio of polyunsaturated fat to saturated fat (P/S ratio; 19.1% vs. 14.3%; Ptrend < 0.001). When examining intake by pubertal stages, %DBV was inversely associated with intake of polyunsaturated fat (20.8% vs. 16.4%; Ptrend = 0.04), long-chain omega-3 fat (17.8% vs. 15.8%; Ptrend < 0.001), and P/S ratio (22.5% vs. 16.1%; Ptrend < 0.001) before menarche, but not after. These associations observed with %DBV were consistently observed with absolute dense breast volume but not with absolute nondense breast volume. In our study, adolescent intakes of higher saturated fat and lower mono- and polyunsaturated fat are associated with higher breast density measured approximately 15 years later. The fat subtype composition in adolescent diet may be important in early breast cancer prevention. Cancer Epidemiol Biomarkers Prev; 25(6); 918-26. ©2016 AACR.

Involvement of parents in intervention for childhood speech sound disorders: a review of the evidence.

Internationally, speech and language therapists (SLTs) are involving parents and providing home tasks in intervention for phonology-based speech sound disorder (SSD). To ensure that SLTs' involvement of parents is guided by empirical research, a review of peer-reviewed published evidence is needed. To provide SLTs and researchers with a comprehensive appraisal and analysis of peer-reviewed published intervention research reporting parent involvement and the provision of home tasks in intervention studies for children with phonology-based SSD. A systematic search and review was conducted. Academic databases were searched for peer-reviewed research papers published between 1979 and 2013 reporting on phonological intervention for SSD. Of the 176 papers that met the criteria, 61 were identified that reported on the involvement of parents and/or home tasks within the intervention. These papers were analysed using a quality appraisal tool. Details regarding the involvement of parents and home tasks were extracted and analysed to provide a summary of these practices within the evidence base. Parents have been involved in intervention research for phonology-based SSD. However, most of the peer-reviewed published papers reporting this research have provided limited details regarding what this involved. This paucity of information presents challenges for SLTs wishing to integrate external evidence into their clinical services and clinical decision-making. It also raises issues regarding treatment fidelity for researchers wishing to replicate published intervention research. The range of tasks in which parents were involved, and the limited details reported in the literature, present challenges for SLTs wanting to involve parents in intervention. Further high-quality research reporting more detail regarding the involvement of parents and home tasks in intervention for SSD is needed.

A Review of Intervention Studies for Children with Autism SpectrumDisorder: Focusing on PECS (Picture Exchange Communication System)

A Review of Intervention Studies for Children with Autism SpectrumDisorder: Focusing on PECS (Picture Exchange Communication System)

Body fatness during childhood and adolescence and breast density in young women: a prospective analysis.

IntroductionOverweight and obesity in childhood and adolescence are associated with reduced breast cancer risk, independent of adult body mass index (BMI). These associations may be mediated through breast density.MethodsWe prospectively examined associations of early life body fatness with adult breast density measured by MRI in 182 women in the Dietary Intervention Study in Children (DISC) who were ages 25–29 at follow-up. Height, weight, and other factors were measured at baseline (ages 8–10) and annual clinic visits through adolescence. We used linear mixed-effects models to quantify associations of percent breast density and dense and non-dense breast volume at ages 25–29 with quartiles of age-specific youth body mass index (BMI) Z-scores, adjusting for clinic, treatment group, current adult BMI, and other well-established risk factors for breast cancer and predictors of breast density.ResultsWe observed inverse associations between age-specific BMI Z-scores at all youth clinic visits and percent breast density, adjusting for current adult BMI and other covariates (all p values <0.01). Women whose baseline BMI Z-scores (at ages 8–10 years) were in the top quartile had significantly lower adult breast density, after adjusting for current adult BMI and other covariates [least squares mean (LSM): 23.4 %; 95 % confidence interval (CI): 18.0 %, 28.8 %] compared to those in the bottom quartile (LSM: 31.8 %; 95 % CI: 25.2 %, 38.4 %) (p trend <0.01). Significant inverse associations were also observed for absolute dense breast volume (all p values <0.01), whereas there were no clear associations with non-dense breast volume.ConclusionsThese results support the hypothesis that body fatness during childhood and adolescence may play an important role in premenopausal breast density, independent of current BMI, and further suggest direct or indirect influences on absolute dense breast volume.Clinical Trials Registration NumberNCT00458588; April 9, 2007Electronic supplementary materialThe online version of this article (doi:10.1186/s13058-015-0601-4) contains supplementary material, which is available to authorized users.

Adolescent endogenous sex hormones and breast density in early adulthood

IntroductionDuring adolescence the breasts undergo rapid growth and development under the influence of sex hormones. Although the hormonal etiology of breast cancer is hypothesized, it remains unknown whether adolescent sex hormones are associated with adult breast density, which is a strong risk factor for breast cancer.MethodsPercentage of dense breast volume (%DBV) was measured in 2006 by magnetic resonance imaging in 177 women aged 25–29 years who had participated in the Dietary Intervention Study in Children from 1988 to 1997. They had sex hormones and sex hormone-binding globulin (SHBG) measured in serum collected on one to five occasions between 8 and 17 years of age. Multivariable linear mixed-effect regression models were used to evaluate the associations of adolescent sex hormones and SHBG with %DBV.ResultsDehydroepiandrosterone sulfate (DHEAS) and SHBG measured in premenarche serum samples were significantly positively associated with %DBV (all Ptrend ≤0.03) but not when measured in postmenarche samples (all Ptrend ≥0.42). The multivariable geometric mean of %DBV across quartiles of premenarcheal DHEAS and SHBG increased from 16.7 to 22.1 % and from 14.1 to 24.3 %, respectively. Estrogens, progesterone, androstenedione, and testosterone in pre- or postmenarche serum samples were not associated with %DBV (all Ptrend ≥0.16).ConclusionsOur results suggest that higher premenarcheal DHEAS and SHBG levels are associated with higher %DBV in young women. Whether this association translates into an increased risk of breast cancer later in life is currently unknown.Clinical trials registrationClinicalTrials.gov Identifier, NCT00458588 April 9, 2007; NCT00000459 October 27, 1999

Adolescent Endogenous Sex Hormones and Breast Density in Early Adulthood

Abstract During adolescence the breasts undergo rapid growth and development under the influence of sex hormones. Although the hormonal etiology of breast cancer is hypothesized, it remains unknown whether adolescent sex hormones are associated with adult breast density, which is a strong risk factor for breast cancer. METHODS: Percentage of dense breast volume (%DBV) was measured in 2006 by magnetic resonance imaging in 177 women aged 25–29 years who participated in the Dietary Intervention Study in Children from 1988–1997 and had sex hormones and sex hormone binding globulin (SHBG) measured in serum collected on 1–4 occasions between 8 and 17 years of age. Multivariable linear mixed-effect regression models were used to evaluate the associations of adolescent sex hormones and SHBG with %DBV. RESULTS: Dehydroepiandrosterone sulfate (DHEAS) and SHBG measured in premenarche serum samples were significantly positively associated with %DBV (all Ptrend ≤ 0.03) but not when measured in postmenarche samples (all Ptrend ≥ 0.42). The multivariable geometric mean of %DBV across quartiles of premenarcheal DHEAS and SHBG increased from 16.7% to 22.1% and from 14.1% to 24.3%, respectively. Estrogens, progesterone, androstenedione, and testosterone were not associated with %DBV pre- or post-menarche (all Ptrend ≥ 0.16). CONCLUSIONS: Our results suggest that higher DHEAS and SHBG levels during adolescence, particularly before the onset of menarche, are associated with higher%DBV in young women. Whether this association translates into an increased risk of breast cancer later in life is currently unknown.

Endogenous sex hormones and breast density in young women.

Breast density is a strong risk factor for breast cancer and reflects epithelial and stromal content. Breast tissue is particularly sensitive to hormonal stimuli before it fully differentiates following the first full-term pregnancy. Few studies have examined associations between sex hormones and breast density among young women. We conducted a cross-sectional study among 180 women ages 25 to 29 years old who participated in the Dietary Intervention Study in Children 2006 Follow-up Study. Eighty-five percent of participants attended a clinic visit during their luteal phase of menstrual cycle. Magnetic resonance imaging measured the percentage of dense breast volume (%DBV), absolute dense breast volume (ADBV), and absolute nondense breast volume (ANDBV). Multiple-linear mixed-effect regression models were used to evaluate the association of sex hormones and sex hormone-binding globulin (SHBG) with %DBV, ADBV, and ANDBV. Testosterone was significantly positively associated with %DBV and ADBV. The multivariable geometric mean of %DBV and ADBV across testosterone quartiles increased from 16.5% to 20.3% and from 68.6 to 82.3 cm(3), respectively (Ptrend ≤ 0.03). There was no association of %DBV or ADBV with estrogens, progesterone, non-SHBG-bound testosterone, or SHBG (Ptrend ≥ 0.27). Neither sex hormones nor SHBG was associated with ANDBV except progesterone; however, the progesterone result was nonsignificant in analysis restricted to women in the luteal phase. These findings suggest a modest positive association between testosterone and breast density in young women. Hormonal influences at critical periods may contribute to morphologic differences in the breast associated with breast cancer risk later in life.

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.