Association of sedentary and physical activity behaviours with body composition: a genome-wide association and Mendelian randomisation study

Objectives

Studies suggest that body composition can be independently improved through physical activity (PA). We performed a Mendelian randomisation (MR) study to test the incremental benefits of sedentary behaviour and various PA exposures on body composition outcomes as assessed by anthropometric indices, lean body mass (kg), body fat (%) and visceral adipose tissue (VAT) (kg).

Methods

Genetic instruments were identified for both self-reported and accelerometer-measured sedentary behaviour and PA. Outcomes included anthropometric and dual-energy X-ray absorptiometry measures of adiposity, extracted from the UK Biobank and the largest available consortia. Multivariable MR (MVMR) included educational attainment as a covariate to address potential confounding. Sensitivity analyses were evaluated for weak instrument bias and pleiotropic effects.

Results

We did not identify consistent associations between genetically predicted self-reported and accelerometer-measured sedentary behaviour and body composition outcomes. All analyses for self-reported moderate PA were null for body composition outcomes. Genetically predicted PA at higher intensities was protective against VAT in MR and MVMR analyses of both accelerometer-measured vigorous PA (MVMR β=-0.15, 95% CI: -0.24 to -0.07, p<0.001) and self-reported participation in strenuous sports or other exercises (MVMR β=-0.27, 95% CI: -0.52 to -0.01, p=0.034) was robust across several sensitivity analyses.

Conclusions

We did not identify evidence of a causal relationship between genetically predicted PA and body composition, with the exception of a putatively protective effect of higher-intensity PA on VAT. Protective effects of PA against VAT may support prior evidence of biological pathways through which PA decreases risk of downstream cardiometabolic diseases.

Obesity, Height, and Serum Androgen Metabolism among Postmenopausal Women in the Women's Health Initiative Observational Study

BACKGROUND

Anthropometric measures, including obesity, are important risk factors for breast and endometrial cancers in postmenopausal women. It is unknown whether these risk factors are associated with androgen metabolism, another risk factor for these cancers.

METHODS

Using baseline data from 1,765 postmenopausal women in the Women's Health Initiative Observational Study, we conducted a cross-sectional analysis examining associations between anthropometric measures [current body mass index (BMI), waist-to-hip ratio (WHR), height, and recalled BMI at age 18) and serum androgen metabolites. Twelve androgens/androgen metabolites were quantified using LC-MS/MS. Geometric means of androgen/androgen metabolite concentrations were estimated using linear regression, adjusting for potential confounders and stratified by hormone therapy (HT) use.

RESULTS

Regardless of HT use, higher current BMI (≥30 vs. <25 kg/m2) was associated with higher serum concentrations of dehydroepiandrosterone sulfate (DHEAS), 5α-reduced glucuronide metabolites [androsterone-glucuronide (ADT-G), 5α-androstane-3α,17β diol-3-glucuronide (3α-diol-3G), 3α-diol-17-glucuronide (3α-diol-17G)], and DHEAS:DHEA ratio (all P trend ≤ 0.02). BMI was also positively associated with unconjugated estrone:androstenedione and unconjugated estradiol:testosterone ratios among never/former HT users (all P trend < 0.001) but not among current users (P-int < 0.001). WHR was positively associated with adrenal androgens and 5α-reduced glucuronide metabolites in obese women only (BMI ≥ 30 kg/m2; all P-trend ≤ 0.01). BMI at age 18 was inversely associated with adrenal androgens (DHEA, DHEAS, androstenedione, testosterone) and 5α-reduced glucuronide metabolites in never/former HT users (all P trend < 0.06). Height was not associated with androgen metabolites.

CONCLUSIONS

Current BMI is associated with androgen metabolism among postmenopausal women.

IMPACT

This study contributes to our understanding of the link between obesity and cancer risk in postmenopausal women.

Prevalence and predictors of peripheral neuropathy after breast cancer treatment

Background

Many of the 3.8 million breast cancer survivors in the United States experience long‐term side effects of cancer therapy including peripheral neuropathy (PN). We assessed the prevalence and predictors of PN among women with breast cancer followed in the Women's Health Initiative's Life and Longevity After Cancer survivorship cohort.

Methods

The study population included 2420 women with local (79%) or regional (21%) stage disease. Presence of PN was based on the reports of “nerve problems and/or tingling sensations” after treatment and PN severity was assessed using the Functional Assessment of Cancer Therapy‐Gynecologic Oncology Group/Neurotoxicity instrument. Logistic regression analysis was used to evaluate the socio‐demographic and clinical factors associated with PN prevalence and severity.

Results

Initial breast cancer treatment included surgery‐only (21%), surgery and radiation (53%), or surgery and chemotherapy (±radiation) (26%). Overall, 17% of women reported PN occurring within days (30%), months (46%), or years (24%) after treatment and 74% reported ongoing symptoms at a median of 6.5 years since diagnosis. PN was reported by a larger proportion of chemotherapy recipients (33%) compared to those who had surgery alone (12%) or surgery+radiation (11%) (p < 0.0001). PN was reported more commonly by women treated with paclitaxel (52%) and docetaxel (39%), versus other chemotherapy (17%) (p < 0.0001). In multivariable analyses, treatment type (chemotherapy vs. none; OR, 95% CI: 3.31, 2.4–4.6), chemotherapy type (taxane vs. no‐taxane; 4.74, 3.1–7.3), and taxane type (paclitaxel vs. docetaxel; 1.59, 1.0–2.5) were associated with higher odds of PN.

Conclusion

PN is an important long‐term consequence of taxane‐based chemotherapy in breast cancer survivors.

Predictive Value of DXA Appendicular Lean Mass for Incident Fractures, Falls, and Mortality, Independent of Prior Falls, FRAX, and BMD: Findings from the Women's Health Initiative (WHI)

In the Women's Health Initiative (WHI), we investigated associations between baseline dual-energy X-ray absorptiometry (DXA) appendicular lean mass (ALM) and risk of incident fractures, falls, and mortality (separately for each outcome) among older postmenopausal women, accounting for bone mineral density (BMD), prior falls, and Fracture Risk Assessment Tool (FRAX® ) probability. The WHI is a prospective study of postmenopausal women undertaken at 40 US sites. We used an extension of Poisson regression to investigate the relationship between baseline ALM (corrected for height2 ) and incident fracture outcomes, presented here for major osteoporotic fracture (MOF: hip, clinical vertebral, forearm, or proximal humerus), falls, and death. Associations were adjusted for age, time since baseline and randomization group, or additionally for femoral neck (FN) BMD, prior falls, or FRAX probability (MOF without BMD) and are reported as gradient of risk (GR: hazard ratio for first incident fracture per SD increment) in ALM/height2 (GR). Data were available for 11,187 women (mean [SD] age 63.3 [7.4] years). In the base models (adjusted for age, follow-up time, and randomization group), greater ALM/height2 was associated with lower risk of incident MOF (GR = 0.88; 95% confidence interval [CI] 0.83-0.94). The association was independent of prior falls but was attenuated by FRAX probability. Adjustment for FN BMD T-score led to attenuation and inversion of the risk relationship (GR = 1.06; 95% CI 0.98-1.14). There were no associations between ALM/height2 and incident falls. However, there was a 7% to 15% increase in risk of death during follow-up for each SD greater ALM/height2 , depending on specific adjustment. In WHI, and consistent with our findings in older men (Osteoporotic Fractures in Men [MrOS] study cohorts), the predictive value of DXA-ALM for future clinical fracture is attenuated (and potentially inverted) after adjustment for femoral neck BMD T-score. However, intriguing positive, but modest, associations between ALM/height2 and mortality remain robust. © 2021 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Influence of Changes in Soft Tissue Composition on Changes in Bone Strength in Peripubertal Girls: The STAR Longitudinal Study

Obesity and osteoporosis remain two major public health concerns. Soft tissue composition and bone are interrelated; however, it is still not well understood how changes in adiposity during adolescence affect bone development. The aim of this study was to assess how changes in DXA-derived total body lean mass (TBLM) and total body fat mass (TBFM) associate with 2-year changes in bone outcomes at the 20% femur, 66% tibia, 66% radius, and 4% tibia, as measured by pQCT, during the years surrounding the onset of menarche in a cohort of 9- to 12-year-old (baseline) adolescent girls (70% Hispanic). From baseline to 2-year follow-up, girls showed statistically significant increases in all bone outcomes, except radial endosteal circumference. In separate linear regression models, change in TBLM and change in TBFM were both positively associated with 2-year changes in bone outcomes at all measured bone sites, after controlling for relevant covariates. However, when change in TBLM and change in TBFM were included in the same model, change in TBLM was the predominant predictor of bone outcomes, explaining 4% to 14% of the variance in bone strength outcomes. Change in TBFM remained a positive predictor of tibia polar strength strain index (SSI_p) (2% variance explained). A significant interaction between change in TBFM and menarcheal status was identified at the radius for SSI_p and indicated that greater gains in TBFM were beneficial for SSI_p in girls that were premenarcheal at baseline but detrimental for girls who were postmenarcheal at baseline. The overall findings suggest that changes in TBLM during the peripubertal years have a greater influence on bone outcomes than changes in TBFM. While gains in TBFM might benefit the weight bearing 66% tibia, greater gains in TBFM may be detrimental to bone development at the non-weight bearing 66% radius after the onset of menarche. © 2020 American Society for Bone and Mineral Research (ASBMR).

Association of Sedentary Time and Incident Heart Failure Hospitalization in Postmenopausal Women

BACKGROUND

The 2018 US Physical Activity Guidelines recommend reducing sedentary behavior (SB) for cardiovascular health. SB's role in heart failure (HF) is unclear.

METHODS

We studied 80 982 women in the Women's Health Initiative Observational Study, aged 50 to 79 years, who were without known HF and reported ability to walk ≥1 block unassisted at baseline. Mean follow-up was 9 years for physician-adjudicated incident HF hospitalization (1402 cases). SB was assessed repeatedly by questionnaire. Time-varying total SB was categorized according to awake time spent sitting or lying down (≤6.5, 6.6-9.5, >9.5 h/d); sitting time (≤4.5, 4.6-8.5, >8.5 h/d) was also evaluated. Hazard ratios and 95% CI were estimated using Cox regression.

RESULTS

Controlling for age, race/ethnicity, education, income, smoking, alcohol, menopausal hormone therapy, and hysterectomy status, higher HF risk was observed across incremental tertiles of time-varying total SB (hazard ratios [95% CI], 1.00 [referent], 1.15 [1.01-1.31], 1.42 [1.25-1.61], trend P<0.001) and sitting time (1.00 [referent], 1.14 [1.01-1.28], 1.54 [1.34-1.78], trend P<0.001). The inverse trends remained significant after further controlling for comorbidities including time-varying myocardial infarction and coronary revascularization (hazard ratios: SB, 1.00, 1.11, 1.27; sitting, 1.00, 1.09, 1.37, trend P<0.001 each) and for baseline physical activity (hazard ratios: SB 1.00, 1.10, 1.24; sitting 1.00, 1.08, 1.33, trend P<0.001 each). Associations with SB exposures were not different according to categories of baseline age, race/ethnicity, body mass index, physical activity, physical functioning, diabetes, hypertension, or coronary heart disease.

CONCLUSIONS

SB was associated with increased risk of incident HF hospitalization in postmenopausal women. Targeted efforts to reduce SB could enhance HF prevention in later life.

Association of objectively measured physical activity and bone health in children and adolescents: a systematic review and narrative synthesis

The influence of day-to-day physical activity on bone in adolescence has not been well characterized. Forty articles were identified that assessed the relationship between accelerometry-derived physical activity and bone outcomes in adolescents. Physical activity was positively associated with bone strength in peri-pubertal males, with less consistent evidence in females. Physical activity (PA) is recommended to optimize bone development in childhood and adolescence; however, the influence of day-to-day PA on bone development is not well defined. The aim of this review was to describe the current evidence for objectively measured PA on bone outcomes in healthy children and adolescents. MEDLINE, Embase, Cochrane Library, Scopus, Web of Science, CINAHL, PsycInfo, and ClinicalTrials.gov were searched for relevant articles up to April 2020. Studies assessing the relationship between accelerometry-derived PA and bone outcomes in adolescents (6-18 years old) were included. Two reviewers independently screened studies for eligibility, extracted data, and rated study quality. Forty articles met inclusion criteria (25 cross-sectional, 15 longitudinal). There was significant heterogeneity in accelerometry methodology and bone outcomes measured. Studies in males indicated a significant, positive relationship between moderate to vigorous PA (MVPA) and bone outcomes at the hip and femur, particularly during the peri-pubertal years. The results for MVPA and bone outcomes in females were mixed. There was a paucity of longitudinal studies using pQCT and a lack of data regarding how light PA and/or impact activity influences bone outcomes. The current evidence suggests that objectively measured MVPA is positively associated with bone outcomes in children and adolescents, especially in males. However, inconsistencies in methodology make it difficult to determine the amount and type of PA that leads to favorable bone outcomes. Given that the majority of research has been conducted in Caucasian adolescents, further research is needed in minority populations.

Physical activity, sedentary time, and longitudinal bone strength in adolescent girls

The association between baseline physical activity and sedentary time with 2-year longitudinal bone strength was evaluated. The effect of physical activity on bone depended on maturity status. Sedentary time did not negatively impact bone outcomes, regardless of maturity. Maturity should be considered when developing exercise interventions to improve bone outcomes.

INTRODUCTION

Physical activity during adolescence is important to obtain peak bone mass; however, adolescents are increasingly sedentary, potentially increasing risk for osteoporosis later in life. The aim of this study was to assess the association of physical activity and sedentary time with 2-year longitudinal bone outcomes in adolescent females (69% Hispanic/31% non-Hispanic).

METHODS

Bone strength was assessed at the 66% tibia, 20% femur, and 66% radius of 9- to 12-year-old girls (n = 131) using peripheral quantitative computed tomography at baseline and 2-year follow-up. Physical activity and sedentary time were assessed via accelerometry. Linear regression analyses were used to assess whether baseline vigorous physical activity (VPA), moderate physical activity (MPA), light physical activity (LPA), or sedentary time predict longitudinal bone outcomes, adjusting for relevant confounders.

RESULTS

Significant interactions were found between maturity offset and physical activity. In weight-bearing bones, significant interactions were primarily identified between VPA and maturity offset. Interactions indicated that VPA was associated with favorable bone outcomes at the tibia and femur in girls further past the age of PHV. However, this favorable effect was not observed in girls closer to the age of PHV. At the radius, interactions were primarily observed between LPA and maturity offset. Again, LPA was more beneficial for girls further past the age of PHV. Sedentary time did not significantly influence bone outcomes.

CONCLUSION

The effects of physical activity on bone may be dependent on maturity. Therefore, physical activity interventions, with attention to maturity status, may be required to optimize bone strength in girls.

Walking Volume and Speed Are Inversely Associated With Incidence of Treated Hypertension in Postmenopausal Women

Few studies have evaluated hypertension incidence in relation to walking, which is a common physical activity among adults. We examined the association between walking and hypertension incidence in 83 435 postmenopausal women who at baseline were aged 50 to 79 years, without known hypertension, heart failure, coronary heart disease, or stroke, and reported the ability to walk at least one block without assistance. Walking volume (metabolic equivalent hours per week) and speed (miles per hour) were assessed by questionnaire. Incident physician-diagnosed hypertension treated with medication was ascertained through annual questionnaires. During a mean 11-year follow-up, 38 230 hypertension cases were identified. After adjustment for covariates including nonwalking activities, a significant inverse association with hypertension was observed across categories of baseline walking volume (0 [referent], >0-3.5, 3.6-7.5, and >7.5 metabolic equivalent hours per week), hazard ratio: 1.00 (referent), 0.98, 0.95, 0.89; trend P<0.001. Faster walking speeds (<2, 2-3, 3-4, and >4 miles per hour) also were associated with lower hypertension risk, hazard ratio: 1.00 (referent), 1.07, 0.95, 0.86, 0.79; trend P<0.001. Further adjustment for walking duration (h/wk) had little impact on the association for walking speed (hazard ratio: 1.00 [referent], 1.08, 0.96, 0.86, 0.77; trend P<0.001). Significant inverse associations for walking volume and speed persisted after additional control for baseline blood pressure. Results for time-varying walking were comparable to those for baseline exposures. This study showed that walking at guideline-recommended volumes (>7.5 metabolic equivalent hours per week) and at faster speeds (≥2 miles per hour) is associated with lower hypertension risk in postmenopausal women. Walking should be encouraged as part of hypertension prevention in older adults.

Race-specific associations of 25-hydroxyvitamin D and parathyroid hormone with cardiometabolic biomarkers among US white and black postmenopausal women

BACKGROUND

Concentrations of 25-hydroxyvitamin D [25(OH)D] tend to be lower in African Americans than in non-Hispanic whites, but whether adding information on parathyroid hormone (PTH) can help explain the higher cardiometabolic risk among African Americans is unknown.

OBJECTIVES

This study examined race (black/white)-specific independent and joint associations of 25(OH)D and PTH with cardiometabolic biomarkers including high-sensitivity C-reactive protein (hs-CRP), estimated glomerular filtration rate (eGFR), and homeostasis model assessment of insulin resistance (HOMA-IR) and β-cell function (HOMA-B).

METHODS

Among 1500 white and 1300 black postmenopausal women without cardiovascular disease from the Women's Health Initiative Observational Study, a weighted linear regression analysis and a novel penalized spline-based semiparametric model with contour plots, accounting for possible nonlinear relations and interactions simultaneously, were used to investigate the race-specific independent and joint associations of 25(OH)D and PTH with each biomarker.

RESULTS

Black women had lower concentrations of 25(OH)D and higher PTH, HOMA-IR, HOMA-B, hs-CRP, and eGFR than white women (all P values < 0.0001). Lower 25(OH)D and higher PTH were each independently and jointly associated with higher HOMA-IR in both white and black women, whereas a similar joint relation with HOMA-B was observed in white women only. In contrast, PTH was nonlinearly associated with HOMA-B in black women and positively associated with hs-CRP in white women, independently of 25(OH)D. Whereas there was an inverse linear relation between PTH and eGFR in white women after accounting for 25(OH)D, PTH and 25(OH)D were jointly and nonlinearly associated with eGFR in black women.

CONCLUSIONS

We found that the joint association of 25(OH)D and PTH with β-cell function, systemic inflammation, and kidney function apparently differed between white and black women. Further studies are needed to determine whether differences in the vitamin D-PTH endocrine system contribute to racial disparities in cardiovascular health.

Exogenous hormone use, reproductive factors and risk of intrahepatic cholangiocarcinoma among women: results from cohort studies in the Liver Cancer Pooling Project and the UK Biobank

BACKGROUND

Intrahepatic cholangiocarcinoma (ICC) arises from cholangiocytes in the intrahepatic bile duct and is the second most common type of liver cancer. Cholangiocytes express both oestrogen receptor-α and -β, and oestrogens positively modulate cholangiocyte proliferation. Studies in women and men have reported higher circulating oestradiol is associated with increased ICC risk, further supporting a hormonal aetiology. However, no observational studies have examined the associations between exogenous hormone use and reproductive factors, as proxies of endogenous hormone levels, and risk of ICC.

METHODS

We harmonised data from 1,107,498 women who enroled in 12 North American-based cohort studies (in the Liver Cancer Pooling Project, LCPP) and the UK Biobank between 1980-1998 and 2006-2010, respectively. Cox proportional hazards regression models were used to generate hazard ratios (HR) and 95% confidence internals (CI). Then, meta-analytic techniques were used to combine the estimates from the LCPP (n = 180 cases) and the UK Biobank (n = 57 cases).

RESULTS

Hysterectomy was associated with a doubling of ICC risk (HR = 1.98, 95% CI: 1.27-3.09), compared to women aged 50-54 at natural menopause. Long-term oral contraceptive use (9+ years) was associated with a 62% increased ICC risk (HR = 1.62, 95% CI: 1.03-2.55). There was no association between ICC risk and other exogenous hormone use or reproductive factors.

CONCLUSIONS

This study suggests that hysterectomy and long-term oral contraceptive use may be associated with an increased ICC risk.

Perceptions of Cancer Causes, Prevention, and Treatment Among Navajo Cancer Survivors

Native Americans experience cancer-related health disparities. Yet, little is known about the current cancer experience in one of the largest Native American tribe, Navajo. A qualitative study of among Navajo cancer survivors, in which focus groups and individual interviews included questions related to perceptions of cancer causes, prevention, and treatment, allowed us to evaluate several aspects of the cancer experience from the Navajo perspective. An experienced, bilingual facilitator led the discussions using a standardized guide. Discussions were audio-recorded, documented by field notes, translated, as needed, and transcribed. NVivo software was used to summarize major themes according to the PEN-3 and health belief models. Navajo cancer survivors (N = 32) were both males (n = 13) and females (n = 19) that had been previously diagnosed with a variety of cancers: colorectal, breast, ovarian, cervical, esophageal, gall bladder, stomach, prostate, kidney, and hematologic. Many survivors had accurate knowledge of risk factors for cancer. Barriers to screening and clinical care included language, expense, geography, fear, lack of information, skepticism related to Western medicine, and treatment side effects. While some survivors experienced familial support, others were isolated from the family and community due to the perspective of cancer as a contagion. However, resilience, hope, trust in select community organizations, a desire to restore balance, and to support younger generations were positive attributes expressed regarding the treatment and recovery process. These evaluations need to be replicated across a larger cross-section of the Native cancer survivor community.

Abstract B002: Restoring Balance, a physical activity intervention for Native cancer survivors, preliminary analysis (NNR.14.192)

Physical activity has been shown to improve quality of life, body composition, metabolic and physical function, and survival among cancer survivors. However, no studies have focused on Native American cancer survivors. Methods: Native cancer survivors and family members were enrolled in a 12-week multi-site, randomized supervised and home-based physical activity intervention (n = 63). The intervention includes 1d/wk supervised resistance, aerobic, flexibility, and balance and 2-3 days/wk of home-based exercise. National guidelines for survivorship exercise training were culturally tailored based focus groups and interviews, as well as cultural expert program review by representatives from 10 tribes. Preliminary descriptive statistics (mean, SD) and six and twelve week changes in weight (kg), fat mass (%), HbA1c (%), fitness by 6min walk test (meters), and quality of life by PROMIS10 questionnaire score have been assessed by paired t-test for survivors only (n = 30). Though currently under powered, data collection is ongoing and will be updated as participants complete the 12-week intervention. Results: Participants were 58.4 ± 12.2 years of age. Tumor types were breast (n = 7), colorectal (n = 7), stomach (n = 2), lung (n = 2), and other varied cancers. Reasons for loss to follow-up were: repeat surgeries or change in clinical care plan (n=3), loss of family members (n=1), and loss of contact (n=3). Comorbidities for cancer survivors included: diabetes (n=7), cardiovascular disease (N=13). Twenty-two Native cancer survivors have completed six weeks of intervention and 14 Native cancer survivors have completed twelve weeks of intervention thus far. Weight loss was significant at six weeks (-1.0 ± 2.2kg; p=0.04), but not twelve weeks. Fitness and quality of life were improved by twelve weeks, 31.9 ± 132m and 1.6±0.4, respectively, though not significant. Conclusions: Tailored exercise programs present opportunities to restore health and balance among Native cancer survivors. This ongoing trial will provide important information on the effects of physical activity in Native cancer survivorship, unaddressed to date.

Citation Format: Jennifer W Bea, Hendrik de Heer, Taylor Lane, Brenda Charley, Etta Yazzie, Jennifer Hudson, Mishayla Mitchell, Betsy Wertheim, Anna Schwartz. Restoring Balance, a physical activity intervention for Native cancer survivors, preliminary analysis (NNR.14.192) [abstract]. In: Proceedings of the Twelfth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2019 Sep 20-23; San Francisco, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl_2):Abstract nr B002.

Peripheral neuropathy after breast cancer: An analysis of data from the Women’s Health Initiative Life and Longevity After Cancer cohort

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Background: There are over 3.8 million breast cancer survivors in the United States, and many experience long-term side effects from chemotherapy. Factors associated with peripheral neuropathy (PN), one troubling side effect, following breast cancer among women are unknown. Methods: We included 2,420 women enrolled in the Women’s Health Initiative and diagnosed prospectively with local or regional stage breast cancer and followed in the Life and Longevity After Cancer (LILAC) study. PN was assessed by response to the baseline LILAC questionnaire regarding the presence of “nerve problems, tingling sensations” after treatment. Data were collected on initial course of therapy (surgery, radiation, and chemotherapy) through Medicare linkage or the LILAC staging and treatment form. Chi-square and Wilcoxon rank-sum tests were used for univariate comparison of socio-demographics, clinical and diagnosis characteristics associated with the presence or absence of PN. Results: The sample included 1,913 women (79%) with local and 507 women (21%) with regional stage disease. Initial course of therapy included either surgery alone (21%), surgery and radiation (53%), or surgery and chemotherapy (+/- radiation) (26%). Seventeen percent of women reported experiencing PN days (30%), months (46%) or years (24%) following treatment. Three-quarters (74%) reported ongoing symptoms at the time of the LILAC survey. PN was reported by 33% of chemotherapy recipients, compared to 12% in the surgery alone group, and 11% in the group that received surgery and radiation (p<0.0001). The prevalence of PN was higher among women receiving regimens containing paclitaxel (52%) and docetaxel (39%), compared to those receiving other chemotherapy (17%) (p<0.0001). Conclusions: PN is an important complication of taxane-based chemotherapy. Further analysis will explore the relationship between socio-demographic, clinical and treatment on the development, timing of, and severity of PN after cancer directed therapy.

Short Sleep Is Associated With Low Bone Mineral Density and Osteoporosis in the Women's Health Initiative

Short sleep duration, recognized as a public health epidemic, is associated with adverse health conditions, yet little is known about the association between sleep and bone health. We tested the associations of usual sleep behavior and bone mineral density (BMD) and osteoporosis. In a sample of 11,084 postmenopausal women from the Women's Health Initiative (WHI; mean age 63.3 years, SD = 7.4), we performed a cross-sectional study of the association of self-reported usual hours of sleep and sleep quality (WHI Insomnia Rating Score) with whole body, total hip, femoral neck, and spine BMD using linear regression models. We also studied the association of sleep duration and quality with dual-energy X-ray absorptiometry (DXA)-defined low bone mass (T-score < -2.5 to <-1) and osteoporosis (T-score ≤ -2.5) using multinomial regression models. We adjusted for age, DXA machine, race, menopausal symptoms, education, smoking, physical activity, body mass index, alcohol use, physical function, and sleep medication use. In adjusted linear regression models, women who reported sleeping 5 hours or less per night had on average 0.012 to 0.018 g/cm² significantly lower BMD at all four sites compared with women who reported sleeping 7 hours per night (reference). In adjusted multinomial models, women reporting 5 hours or less per night had higher odds of low bone mass and osteoporosis of the hip (odds ratio [OR] = 1.22; 95% confidence interval [CI] 1.03-1.45, and 1.63; 1.15-2.31, respectively). We observed a similar pattern for spine BMD, where women with 5 hours or less per night had higher odds of osteoporosis (adjusted OR = 1.28; 95% CI 1.02-1.60). Associations of sleep quality and DXA BMD failed to reach statistical significance. Short sleep duration was associated with lower BMD and higher risk of osteoporosis. Longitudinal studies are needed to confirm the cross-sectional effects of sleep duration on bone health and explore associated mechanisms. © 2019 American Society for Bone and Mineral Research.

It's Absolutely Relative: The Effect of Age on the BMI-Mortality Relationship in Postmenopausal Women

OBJECTIVE

The use of relative and absolute effect estimates has important implications for the interpretation of study findings. Likewise, examining additive and multiplicative interaction can lead to differing conclusions about the joint effects of two exposure variables. The aim of this paper is to examine the relationship between BMI and mortality on the relative and absolute scales and investigate interaction between BMI and age.

METHODS

Data from 68,132 participants in the Women's Health Initiative (WHI) study were used. The risk ratio and risk difference of BMI on mortality were estimated. A product term was also included to examine interaction between BMI and age on the multiplicative scale, and the relative excess risk of interaction was calculated to measure additive interaction.

RESULTS

Results demonstrated that the mortality risk ratio decreased as women aged, but the mortality risk difference increased as women aged. Evidence of additive and multiplicative interaction between age and BMI was found.

CONCLUSIONS

In postmenopausal women, the relative mortality risk associated with high BMI decreased with increasing age, but the absolute risk of high BMI increased with increasing age. This indicates the importance of considering the interaction between age and BMI to understand mortality risk in older women.

The Effects of Reverse Causality and Selective Attrition on the Relationship Between Body Mass Index and Mortality in Postmenopausal Women

Concerns about reverse causality and selection bias complicate the interpretation of studies of body mass index (BMI, calculated as weight (kg)/height (m)2) and mortality in older adults. The objective of this study was to investigate methodological explanations for the apparent attenuation of obesity-related risks in older adults. We used data from 68,132 participants in the Women's Health Initiative (WHI) clinical trial for this analysis. All of the participants were postmenopausal women aged 50-79 years at baseline (1993-1998). To examine reverse causality and selective attrition, we compared rate ratios from inverse probability of treatment- and censoring-weighted Poisson marginal structural models with results from an unweighted adjusted Poisson regression model. The estimated mortality rate ratios and 95% confidence intervals for BMIs of 30.0-34.9, 35.0-39.9 and ≥40.0 were 0.86 (95% confidence interval (CI): 0.77, 0.96), 0.85 (95% CI: 0.72, 0.99), and 0.88 (95% CI: 0.72, 1.07), respectively, in the unweighted model. The corresponding mortality rate ratios were 0.96 (95% CI: 0.86, 1.07), 1.12 (95% CI: 0.97, 1.29), and 1.31 95% CI: (1.08, 1.57), respectively, in the marginal structural model. Results from the inverse probability of treatment- and censoring-weighted marginal structural model were attenuated in low BMI categories and increased in high BMI categories. The results demonstrate the importance of accounting for reverse causality and selective attrition in studies of older adults.

Weight Management and Physical Activity for Breast Cancer Prevention and Control

Observational evidence has consistently linked excess adiposity and inactivity to increased breast cancer risk and to poor outcomes in individuals diagnosed with early-stage, potentially curable breast cancer. There is less information from clinical trials testing the effect of weight management or physical activity interventions on breast cancer risk or outcomes, but a number of ongoing trials will test the impact of weight loss and other lifestyle changes after cancer diagnosis on the risk of breast cancer recurrence. Lifestyle changes have additional benefits beyond their potential to decrease primary or secondary breast cancer risk, including improvements in metabolic parameters, reduction in the risk of comorbidities such as diabetes and heart disease, improvement of physical functioning, and mitigation of side effects of cancer therapy. Despite these myriad benefits, implementation of lifestyle interventions in at-risk and survivor populations has been limited to date. This article reviews the evidence linking lifestyle factors to breast cancer risk and outcomes, discusses completed and ongoing randomized trials testing the impact of lifestyle change in primary and secondary breast cancer prevention, and reviews efforts to implement and disseminate lifestyle interventions in at-risk and breast cancer survivor populations.

Relationship of cardiometabolic risk biomarkers with DXA and pQCT bone health outcomes in young girls

BACKGROUND

Excess weight exerts the positive effect of mechanical loading on bone during development whereas obesity-related metabolic dysfunction may have a detrimental impact. In adults, the presence of metabolic syndrome and type 2 diabetes has been associated with compromised bone density, quality, and strength, and an increased incidence of fractures. The few studies that have investigated the role of cardio-metabolic disease risk biomarkers (CMR) on bone strength in children have given conflicting results. The aim of this study was to assess the combined and independent relationships of cardio-metabolic biomarkers with total body and regional bone parameters in young girls.

METHODS

In 306, 9-12 year old girls, measures of whole body fat and lean mass, areal bone mineral density (aBMD), bone mineral content (BMC), and bone area (BA) were obtained by dual-energy x-ray absorptiometry (DXA). Bone mineral density (vBMD), geometry, and strength of metaphyseal and diaphyseal regions of the femur and tibia and a diaphyseal region of the radius were measured using peripheral quantitative computed tomography (pQCT). Fasting serum measures of CMRs included, fasting glucose, insulin, homeostatic model assessment for insulin resistance (HOMA-IR), high-density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C), triglyceride (TG), systolic and diastolic blood pressure (SBP and DBP), and C-reactive protein (CRP). Multiple linear regression was used to assess the independent associations of a single CMR with total body and peripheral measures of bone strength after controlling for the other CMRs, plus total body soft tissue, and other relevant covariates. Also, a standardized total CMR composite score, calculated by standardizing to z-scores and then summing z-scores of each CMR biomarker, was regressed with total body and regional bone measures to assess the relationship of a cluster of risk factors with bone health.

RESULTS

Total CMR composite score had inverse associations (p < 0.001) with DXA total BMC and BA. Inverse associations (p < 0.05) of CMR risk score with pQCT regional bone measures occurred with total and trabecular BA at the 4% tibia. Of the individual CMRs, HOMA-IR and CRP were significant predictors of total body bone measures by DXA accounting for ~1-5% of the variance in BMC, BA, and/or aBMD. HOMA-IR was the main predictor of regional pQCT bone outcomes, accounting for the most variance in trabecular vBMD (2.6%) and BSI (3.8%) at the 4% tibia. Most markers of dyslipidemia (TG, HDL-C, LDL-C) and hypertension (SBP, DBP) were not associated (p > 0.05) with any total body or regional bone outcomes with the exception of the inverse relationship of LDL-C with total and trabecular BA and the positive relationship of DBP with cortical vBMD at the radius.

CONCLUSION

Of the obesity-related metabolic impairments, insulin resistance and chronic inflammation may compromise whole body bone development in young girls. In particular, trabecular bone, such as that found at the metaphysis of long bones, may be more susceptible to the detrimental effects associated with obesity-related metabolic dysfunction.

Nutritional Status, Body Mass Index, and the Risk of Falls in Community-Dwelling Older Adults: A Systematic Review and Meta-Analysis

OBJECTIVES

To evaluate the association between nutritional status, defined on the basis of a multidimensional evaluation, and body mass index (BMI) with the risk of falls and recurrent falls in community-dwelling older people.

DESIGN

Systematic literature review and meta-analysis.

SETTING AND PARTICIPANTS

Community-dwelling older adults.

MEASURES

A systematic literature review was conducted on prospective studies identified through electronic and hand searches until October 2017. A random effects meta-analysis was used to evaluate the relative risk (RR) of experiencing falls and recurrent falls (≥2 falls within at least 6 months) on the basis of nutritional status, defined by multidimensional scores. A random effects dose-response meta-analysis was used to evaluate the association between BMI and the risk of falls and recurrent falls.

RESULTS

People who were malnourished or those at risk for malnutrition had a pooled 45% higher risk of experiencing at least 1 fall than were those well-nourished (9510 subjects). Increased falls risk was observed in subjects malnourished versus well-nourished [RR 1.64, 95% confidence interval (CI) 1.18-2.28; 3 studies, 8379 subjects], whereas no substantial results were observed for risk of recurrent falls. A U-shaped association was detected between BMI and the risk for falls (P < .001), with the nadir between 24.5 and 30 (144,934 subjects). Taking a BMI of 23.5 as reference, the pooled RR of falling ranged between 1.09 (95% CI 1.04-1.15) for a BMI of 17, to 1.07 (95% CI 0.92-1.24) for a BMI of 37.5. No associations were observed between BMI and recurrent falls (120,185 subjects).

CONCLUSIONS/IMPLICATIONS

The results of our work suggest therefore that nutritional status and BMI should be evaluated when assessing the risk for falls in older age.