Objective habitual physical activity and estradiol levels in obese Latina adolescents

Advances in Diet and Physical Activity in Breast Cancer Prevention and Treatment

There is currently a growing interest in diets and physical activity patterns that may be beneficial in preventing and treating breast cancer (BC). Mounting evidence indicates that indeed, the so-called Mediterranean diet (MedDiet) and regular physical activity likely both help reduce the risk of developing BC. For those who have already received a BC diagnosis, these interventions may decrease the risk of tumor recurrence after treatment and improve quality of life. Studies also show the potential of other dietary interventions, including fasting or modified fasting, calorie restriction, ketogenic diets, and vegan or plant-based diets, to enhance the efficacy of BC therapies. In this review article, we discuss the biological rationale for utilizing these dietary interventions and physical activity in BC prevention and treatment. We highlight published and ongoing clinical studies that have applied these lifestyle interventions to BC patients. This review offers valuable insights into the potential application of these dietary interventions and physical activity as complimentary therapies in BC management.

Objective and Self-Reported Measures of Physical Activity and Sex Hormones: Women's Lifestyle Validation Study

Background: The relationship between specific characteristics of physical activity (PA) (eg, intensity, type, frequency) with sex hormones is uncertain. The authors evaluated the association between characteristics of PA and circulating sex hormones. Methods: This was a cross-sectional analysis of the Women's Lifestyle Validation Study (n = 493). Total PA, light-intensity PA (LPA), and moderate- to vigorous-intensity PA (MVPA) were assessed by accelerometry (a) and self-report (sr). Self-report was used to assess PA type (ie, aerobic, weight training) and exercise frequency. Dehydroepiandrosterone sulfate, testosterone, and sex hormone-binding globulin (SHBG) were assayed among all women; estradiol was assayed in postmenopausal women not currently on hormone therapy. Results: Estradiol was inversely associated and SHBG positively associated with MVPA and LPA (estradiol: β = -0.15 per SD increase, P ≤ .01 for a-MVPA and a-LPA; SHBG: a-MVPA β = 0.20 per SD increase, P ≤ .01, a-LPA β = 0.15, P < .01). By type, aerobic activity and weight training were each independently associated with estradiol and SHBG. Controlling for body mass index attenuated all associations for estradiol, and to a lesser extent SHBG. PA was not associated with testosterone levels. Conclusions: Multiple aspects of PA were independently associated with sex hormones; associations varied some by activity intensity and type, and were attenuated after accounting for body mass index.

Salivary Pubertal Hormones, Sleep Disturbance, and an Evening Circadian Preference in Adolescents: Risk Across Health Domains

PURPOSE

Puberty influences biological and psychological development during adolescence. This includes a shift toward an evening circadian preference, which is characterized by greater physical and mental activity at night compared to the morning. This study examines how pubertal hormones are related to risk across key health domains among adolescents with an evening circadian preference.

METHODS

Participants were adolescents with an evening circadian preference (n = 165, 96 female and 69 male, mean age = 14.8) from an NICHD-funded study. Hormones included testosterone, dehydroepiandrosterone (DHEA), and estradiol (females only). Sleep measures included weeknight total sleep time and weeknight bedtime. Circadian preference was assessed with the Children's Morningness-Eveningness Preferences Scale. Health domains included emotional, cognitive, behavioral, social, and physical health.

RESULTS

For female adolescents, estradiol was related to higher risk in the emotional domain. Among female adolescents with later bedtimes, higher estradiol was associated with higher behavioral domain risk (specifically alcohol and substance use). For male adolescents with a more extreme evening circadian preference, higher DHEA and testosterone were associated with higher behavioral domain risk, specifically greater alcohol and substance use or sensation seeking (DHEA only). Among female adolescents with a more extreme evening circadian preference, higher DHEA was associated with greater physical health risk.

CONCLUSIONS

Pubertal hormones may be associated with heightened risk across select health domains. Specifically, higher levels of hormones may contribute to increased risk for alcohol and substance use as well as sensation seeking in the context of an evening circadian preference.

Comparison of accelerometer measured levels of physical activity and sedentary time between obese and non-obese children and adolescents: a systematic review

Background

Obesity has been hypothesized to be associated with reduced moderate-to-vigorous physical activity (MVPA) and increased sedentary time (ST). It is important to assess whether, and the extent to which, levels of MVPA and ST are suboptimal among children and adolescents with obesity. The primary objective of this study was to examine accelerometer-measured time spent in MVPA and ST of children and adolescents with obesity, compared with MVPA recommendations, and with non-obese peers.

Methods

An extensive search was carried out in Medline, Cochrane library, EMBASE, SPORTDiscus, and CINAHL, from 2000 to 2015. Study selection and appraisal: studies with accelerometer-measured MVPA and/or ST (at least 3 days and 6 h/day) in free-living obese children and adolescents (0 to 19 years) were included. Study quality was assessed formally. Meta-analyses were planned for all outcomes but were precluded due to the high levels of heterogeneity across studies. Therefore, narrative syntheses were employed for all the outcomes.

Results

Out of 1503 records, 26 studies were eligible (n = 14,739 participants; n = 3523 with obesity); 6/26 studies involved children aged 0 to 9 years and 18/26 involved adolescents aged 10.1 to19 years. In the participants with obesity, the time spent in MVPA was consistently below the recommended 60 min/day and ST was generally high regardless of the participant’s age and gender. Comparison with controls suggested that the time spent in MVPA was significantly lower in children and adolescents with obesity, though differences were relatively small. Levels of MVPA in the obese and non-obese were consistently below recommendations. There were no marked differences in ST between obese and non-obese peers.

Conclusions

MVPA in children and adolescents with obesity tends to be well below international recommendations. Substantial effort is likely to be required to achieve the recommended levels of MVPA among obese individuals in obesity treatment interventions.

This systematic review has been registered on PROSPERO (International Database of Prospective Register Systematic Reviews; registration number CRD42015026882).

Electronic supplementary material

The online version of this article (10.1186/s12887-018-1031-0) contains supplementary material, which is available to authorized users.

Every exercise bout matters: linking systemic exercise responses to breast cancer control

Cumulative epidemiological evidence shows that regular exercise lowers the risk of developing breast cancer and decreases the risk of disease recurrence. The causality underlying this relation has not been fully established, and the exercise recommendations for breast cancer patients follow the general physical activity guidelines, prescribing 150 min of exercise per week. Thus, elucidations of the causal mechanisms are important to prescribe and implement the most optimal training regimen in breast cancer prevention and treatment. The prevailing hypothesis on the positive association within exercise oncology has focused on lowering of the basal systemic levels of cancer risk factors with exercise training. However, another rather overlooked systemic exercise response is the marked acute increases in several potential anti-cancer components during each acute exercise bout. Here, we review the evidence of the exercise-mediated changes in systemic components with the ability to influence breast cancer progression. In the first part, we focus on systemic risk factors for breast cancer, i.e., sex hormones, insulin, and inflammatory markers, and their adaptation to long-term training. In the second part, we describe the systemic factors induced acutely during exercise, including catecholamines and myokines. In conclusion, we propose that the transient increases in exercise factors during acute exercise appear to be mediating the positive effect of regular exercise on breast cancer progression.

Role of n-3 Polyunsaturated Fatty Acids and Exercise in Breast Cancer Prevention: Identifying Common Targets

Diet and exercise are recognized as important lifestyle factors that significantly influence breast cancer risk. In particular, dietary n-3 polyunsaturated fatty acids (PUFAs) have been shown to play an important role in breast cancer prevention. Growing evidence also demonstrates a role for exercise in cancer and chronic disease prevention. However, the potential synergistic effect of n-3 PUFA intake and exercise is yet to be determined. This review explores targets for breast cancer prevention that are common between n-3 PUFA intake and exercise and that may be important study outcomes for future research investigating the combined effect of n-3 PUFA intake and exercise. These lines of evidence highlight potential new avenues for research and strategies for breast cancer prevention.

Interventions to prevent adverse fetal programming due to maternal obesity during pregnancy

Maternal obesity is a global epidemic affecting both developed and developing countries. Human and animal studies indicate that maternal obesity adversely programs the development of offspring, predisposing them to chronic diseases later in life. Several mechanisms act together to produce these adverse health effects. There is a consequent need for effective interventions that can be used in the management of human pregnancy to prevent these outcomes. The present review analyzes the dietary and exercise intervention studies performed to date in both altricial and precocial animals, rats and sheep, with the aim of preventing adverse offspring outcomes. The results of these interventions present exciting opportunities to prevent, at least in part, adverse metabolic and other outcomes in obese mothers and their offspring.

Exercise in obese female rats has beneficial effects on maternal and male and female offspring metabolism

BACKGROUND

Maternal obesity (MO) impairs maternal and offspring health. Mechanisms and interventions to prevent adverse maternal and offspring outcomes need to be determined. Human studies are confounded by socio-economic status providing the rationale for controlled animal data on effects of maternal exercise (MEx) intervention on maternal (F0) and offspring (F1) outcomes in MO.

HYPOTHESIS

MO produces metabolic and endocrine dysfunction, increases maternal and offspring glucocorticoid exposure, oxidative stress and adverse offspring outcomes by postnatal day (PND) 36. MEx prevents these outcomes.

METHODS

F0 female rats ate either control or obesogenic diet from weaning through lactation. Half of each group wheel ran (from day ninety of life through pregnancy beginning day 120) providing four groups (n=8/group) – i) controls, ii) obese, iii) exercised controls and iv) exercised obese. After weaning, PND 21, F1 offspring ate a control diet. Metabolic parameters of F0 prepregnancy and end of lactation and F1 offspring at PND 36 were analyzed.

RESULTS

Exercise did not change maternal weight. Before breeding, MO elevated F0 glucose, insulin, triglycerides, cholesterol, leptin, fat and oxidative stress. Exercise completely prevented the triglyceride rise and partially glucose, insulin, cholesterol and oxidative stress increases. MO decreased fertility, recovered by exercise. At the end of lactation, exercise returned all metabolic variables except leptin to control levels. Exercise partially prevented MO elevated corticosterone. F1 Offspring weights were similar at birth. At PND 36 MO increased F1 male but not female offspring leptin, triglycerides and fat mass. In controls exercise reduced male and female offspring glucose, prevented the offspring leptin increase and partially the triglyceride rise.

CONCLUSIONS

MEx before and during pregnancy has beneficial effects on maternal and offspring metabolism and endocrine function occurring with no weight change in mothers and offspring indicating the importance of body composition rather than weight in evaluations of metabolic status.