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.

Physical Activity and Incidence of Heart Failure in Postmenopausal Women

OBJECTIVES

This study prospectively examined physical activity levels and the incidence of heart failure (HF) in 137,303 women, ages 50 to 79 years, and examined a subset of 35,272 women who, it was determined, had HF with preserved ejection fraction (HFpEF) and HF with reduced EF (HFrEF).

BACKGROUND

The role of physical activity in HF risk among older women is unclear, particularly for incidence of HFpEF or HFrEF.

METHODS

Women were free of HF and reported ability to walk at least 1 block without assistance at baseline. Recreational physical activity was self-reported. The study documented 2,523 cases of total HF, and 451 and 734 cases of HFrEF and HFpEF, respectively, during a mean 14-year follow-up.

RESULTS

After controlling for age, race, education, income, smoking, alcohol, hormone therapy, and hysterectomy status, compared with women who reported no physical activity (reference group), inverse associations were observed across incremental tertiles of total physical activity for overall HF (hazard ratio [HR]: Tertile 1 = 0.89, Tertile 2 = 0.74, Tertile 3 = 0.65; trend p < 0.001), HFpEF (HR: 0.93, 0.70, 0.68; p < 0.001), and HFrEF (HR: 0.81, 0.59, 0.68; p = 0.01). Additional controlling for potential mediating factors included attenuated time-varying coronary heart disease (CHD) (nonfatal myocardial infarction, coronary revascularization) diagnosis but did not eliminate the inverse associations. Walking, the most common form of physical activity in older women, was also inversely associated with HF risks (overall: 1.00, 0.98, 0.93, 0.72; p < 0.001; HFpEF: 1.00, 0.98, 0.87, 0.67; p < 0.001; HFrEF: 1.00, 0.75, 0.78, 0.67; p = 0.01). Associations between total physical activity and HF were consistent across subgroups, defined by age, body mass index, diabetes, hypertension, physical function, and CHD diagnosis. Analysis of physical activity as a time-varying exposure yielded findings comparable to those of baseline physical activity.

CONCLUSIONS

Higher levels of recreational physical activity, including walking, are associated with significantly reduced HF risk in community-dwelling older women.

Association Between Sarcopenic Obesity and Falls in a Multiethnic Cohort of Postmenopausal Women

OBJECTIVES

To investigate associations between sarcopenia, obesity, and sarcopenic obesity and incidence of falls in a racially and ethnically diverse cohort of healthy postmenopausal women.

DESIGN

Prospective cohort study.

SETTING

Three Women's Health Initiative (WHI) clinical centers (Tucson-Phoenix, AZ; Pittsburgh, PA; Birmingham, AL).

PARTICIPANTS

Postmenopausal women aged 50 to 79 enrolled in the WHI who underwent bone and body composition scans using dual-energy x-ray absorptiometry at baseline (N = 11,020).

MEASUREMENTS

Sarcopenia was defined as the lowest 20th percentile of appendicular lean mass, correcting for height and body fat. Obesity was defined as a body fat percentage greater than 42%. Sarcopenic obesity was defined as co-occurrence of sarcopenia and obesity. The fall outcome was defined as falling 2 or more times in any year during 7 years of follow-up. The risk of falls associated with sarcopenic obesity were analyzed using log binomial regression models stratified according to age and race/ethnicity.

RESULTS

Sarcopenic obesity was associated with greater risk of falls in women aged 50 to 64 (relative risk (RR) = 1.35, 95% confidence interval (CI)=1.17-1.56) and 65 to 79 (RR = 1.21, 95% CI=1.05-1.39). Sarcopenic obesity related fall risk was higher in Hispanic women (RR = 2.40, 95% CI=1.56-3.67) than non-Hispanic white women (RR = 1.24, 95% CI=1.11-1.39).

CONCLUSION

In a multiethnic cohort of postmenopausal women, sarcopenic obesity-related fall risk was high in women younger than 65 and those age 65 and older. Sarcopenic obesity posed the highest risk for falls in Hispanic women. The findings support identification of causal factors and health disparities in sarcopenic obesity to customize fall prevention strategies and ameliorate this significant public health burden. J Am Geriatr Soc 66:2314-2320, 2018.

Validation of Peripheral Quantitative Computed Tomography-Derived Thigh Adipose Tissue Subcompartments in Young Girls Using a 3 T MRI Scanner

The ability to assess skeletal muscle adipose tissue is important given the negative clinical implications associated with greater fat infiltration of the muscle. Computed tomography and magnetic resonance imaging (MRI) are highly accurate for measuring appendicular soft tissue and muscle composition, but have limitations. Peripheral quantitative computed tomography (pQCT) is an alternative that investigators find valuable because of its low radiation, fast scan time, and comparatively lower costs. The present investigation sought to assess the accuracy of pQCT-derived estimates of total, subcutaneous, skeletal muscle, intermuscular, and calculated intramuscular adipose tissue areas, and muscle density in the midthigh of young girls using the gold standard, 3 T MRI, as the criterion. Cross-sectional data were analyzed for 26 healthy girls aged 9-12 years. Midthigh soft tissue composition was assessed by both pQCT and 3 T MRI. Mean tissue area for corresponding adipose compartments by pQCT and MRI was compared using t tests, regression analysis, and Bland-Altman plots. Muscle density was regressed on MRI skeletal muscle adipose tissue, intermuscular adipose tissue, and intramuscular adipose tissue, each expressed as a percentage of total muscle area. Correlations were high between MRI and pQCT for total adipose tissue (r² = 0.98), subcutaneous adipose tissue (r² = 0.95), skeletal muscle adipose tissue (r² = 0.83), and intermuscular adipose tissue (r² = 0.82), and pQCT muscle density correlated well with both MRI skeletal muscle adipose tissue (r² = 0.70) and MRI intermuscular adipose tissue (r² = 0.70). There was a slight, but statistically significant underestimation by pQCT for total and subcutaneous adipose tissue, whereas no significant difference was observed for skeletal muscle adipose tissue. Both pQCT-estimated intramuscular adipose tissue and muscle density were weakly correlated with MRI-intramuscular adipose tissue. We conclude that pQCT is a valid measurement technique for estimating all adipose subcompartments, except for intramuscular adipose tissue, for the midthigh region in young/adolescent girls.

Anthropometry Versus Imaging for Prediction of Inflammation Among Hispanic Girls

OBJECTIVE

This study aimed to compare total and regional estimates of body composition, by direct and indirect techniques, for the optimal prediction of C-reactive protein (CRP) among young (aged 9-12 years) Hispanic girls (N = 232).

METHODS

Standard anthropometric techniques were used to measure height, weight, and waist circumference. Dual-energy X-ray absorptiometry (DXA) and peripheral quantitative computed tomography (pQCT) assessed body composition. Fasting serum CRP was measured by the AU5812 Clinical Chemistry Analyzer (Beckman Coulter, Brea, California). Associations between each total and regional body composition parameter and CRP were tested using linear regression (log-transformed, continuous CRP) and ordinal logistic regression (CRP < 1.0, ≥ 1.0-2.9, and ≥ 3.0 mg/L), controlling for maturation, dietary energy, physical activity, and medications.

RESULTS

All measures of total and regional body fat were positively associated with CRP (P < 0.0001) except for intermuscular fat by pQCT. There were no clinically relevant differences in their association with CRP between anthropometric (BMI; waist circumference) and DXA-derived (total fat and regional fat: trunk, gynoid, android fat, leg) measures of fat.

CONCLUSIONS

Measurement of body habitus in Hispanic girls, by multiple commonly available means, predicts CRP equally well.

Relationship between fat distribution and cardiometabolic risk in Hispanic girls

OBJECTIVE

In adults, certain body fat depots have greater impact on cardiometabolic risk than total adiposity. Whether similar relationships exist in children is uncertain. The aim of this study was to examine the relationships among dual x-ray absorptiometry (DXA) measures of body fat distribution and total body adiposity with cardiometabolic risk factors in Hispanic girls.

METHODS

Measures of total percent body fat, percent of total fat within the android, gynoid, leg, and trunk regions, and cardiometabolic biomarkers (insulin, glucose, homeostatic model assessment of insulin resistance (HOMA-IR), triglycerides (TG), low and high lipoprotein cholesterol (LDL-C, HDL-C)) were obtained from 232 Hispanic girls (age 10.7 ±1.1 years). Regression models for each metabolic parameter were run against adiposity measures. Partial correlations of the adiposity measures were used to compare associations between adiposity measures and the cardiometabolic risk factors, controlling for somatic maturation.

RESULTS

Total and regional adiposity were significantly related with cardiometabolic risk factors (P < 0.05) except fasting glucose. The partial correlations of total and regional adiposity measures with each cardiometabolic biomarker were similar. More variance was explained for insulin and the HOMA-IR (33%-43%) than other risk factors. Partial correlations for the percentage of total fat in the gynoid and leg regions with insulin, HOMA-IR, TG, and LDL-C were negative, and positive with HDL-C.

CONCLUSION

Measures of total and regional fat perform similarly in predicting cardiometabolic risk in Hispanic girls. A higher proportion of fat distributed in the gynoid or leg region is associated with lower cardiometabolic risk.

Body composition and physical function in the Women's Health Initiative Observational Study

Physical function is critical for mobility and quality of life. We hypothesized that higher total lean mass is associated with higher physical function, and body fat inversely associated, among postmenopausal women. Women's Health Initiative Observational Study participants at Pittsburgh, PA; Birmingham, AL; and Tucson-Phoenix, AZ (1993–1998) completed dual-energy X-ray absorptiometry scans and the Rand SF-36 questionnaire at baseline and 3 y (N = 4526). Associations between quartiles (Q1–4) of lean or fat mass and physical function were tested using linear regression, adjusted for demographics, lifestyle factors, medical history, and scanner serial number. At baseline, participants had a mean ± SD age of 63.4 ± 7.4 y and BMI of 27.4 ± 5.8 kg/m². Higher percent lean mass was positively associated with physical function at baseline (Q4, 83.6 ± 0.6 versus Q1, 74.6 ± 0.7; p < 0.001), while fat mass (kg and %) was inversely associated (e.g., Q4, 73.7 ± 0.7 versus Q1, 84.2 ± 0.7 kg; p_trend < 0.001). Physical function had declined across the cohort at 3 y; the highest relative lean mass quartile at baseline conferred a lesser decline in physical function than the lowest (Q4, −3.3 ± 0.6 versus Q1–7.0 ± 0.6; p_trend < 0.001), while the highest fat mass quartile (% and kg) conferred greater decline (ex. Kg Q4, −6.7 ± 0.7 versus Q1–2.8 ± 0.6; p_trend < 0.001). Increased fat mass (≥5%), but not lean mass, was associated with lower physical function at 3 y (p < 0.001). Adiposity, as well as lean mass, requires consideration in the prediction of physical function among postmenopausal women over time.

•

Lean mass (%) is positively associated with physical function in menopause.

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Body fat is negatively associated with physical function in menopause.

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Decline in physical function is more rapid with gains in fat during menopause.

•

Body composition influence on functional decline is more evident among women <65 y.

Relative contributions of lean and fat mass to bone strength in young Hispanic and non-Hispanic girls

BACKGROUND

With the high prevalence of childhood obesity, especially among Hispanic children, understanding how body weight and its components of lean and fat mass affect bone development is important, given that the amount of bone mineral accrued during childhood can determine osteoporosis risk later in life. The aim of this study was to assess the independent contributions of lean and fat mass on volumetric bone mineral density (vBMD), geometry, and strength in both weight-bearing and non-weight-bearing bones of Hispanic and non-Hispanic girls.

METHODS

Bone vBMD, geometry, and strength were assessed at the 20% distal femur, the 4% and 66% distal tibia, and the 66% distal radius of the non-dominant limb of 326, 9- to 12-year-old girls using peripheral quantitative computed tomography (pQCT). Total body lean and fat mass were measured by dual-energy x-ray absorptiometry (DXA). Multiple linear regression was used to assess the independent relationships of fat and lean mass with pQCT bone measures while adjusting for relevant confounders. Potential interactions between ethnicity and both fat and lean mass were also tested.

RESULTS

Lean mass was a significant positive contributor to all bone outcomes (p < 0.05) with the exception of vBMD at diaphyseal sites. Fat mass was a significant contributor to bone strength at weight bearing sites, but did not significantly contribute to bone strength at the non-weight bearing radius and was negatively associated with radius cortical content and thickness. Bone measures did not significantly differ between Hispanic and non-Hispanic girls, although there was a significant interaction between ethnicity and fat mass with total bone area at the femur (p = 0.02) and 66% tibia (p = 0.005) as well as bone strength at the femur (p = 0.03).

CONCLUSION

Lean mass is the main determinant of bone strength for appendicular skeletal sites. Fat mass contributes to bone strength in the weight-bearing skeleton but does not add to bone strength in non-weight-bearing locations and may potentially be detrimental. Bone vBMD, geometry, and strength did not differ between Hispanic and non-Hispanic girls; fat mass may be a stronger contributor to bone strength in weight-bearing bones of Hispanic girls compared to non-Hispanic.

Effect of cardiometabolic risk factors on the relationship between adiposity and bone mass in girls

BACKGROUND/OBJECTIVE

Childhood obesity has been separately associated with cardiometabolic risk factors (CMRs) and increased risk of fracture. However, both augmented and compromised bone mass have been reported among overweight/obese children. Metabolic dysfunction, often co-existing with obesity, may explain the discrepancy in previous studies. The aim of this study was to examine whether the relationship between adiposity and dual-energy X-ray absorptiometry (DXA) derived bone mass differed in young girls with and without CMR(s).

SUBJECTS/METHODS

Whole-body bone and body composition measures by DXA and measures of CMR (fasting glucose, high-density lipoprotein cholesterol (HDL-C), triglyceride (TG), systolic and diastolic blood pressure, waist circumference (WC)) were obtained from 307, 9- to 12-year-old girls. Girls with 1 or ≥ 2 CMR(s) were considered to be at risk (vs. no CMR). Multiple linear regression was used to test the relationship of total fat mass with total body bone mineral content (BMC) after controlling for height, lean mass, CMR risk, and other potential confounders.

RESULTS

There was a significant interaction between CMR risk and total body fat mass. When girls were stratified by CMR group, all groups had a significant positive relationship between fat mass and BMC (p < 0.05), however, girls with ≥ 2 CMRs had a lower BMC for a given level of body fat. Total body fat was not significantly related to bone mineral density (p > 0.05).

CONCLUSION

Fat mass has a positive relationship with BMC even after controlling for lean mass. However, the positive relationship of fat mass with BMC may be attenuated if multiple CMRs are present.

Metabolic obesity phenotypes and risk of colorectal cancer in postmenopausal women

Obesity has been postulated to increase the risk of colorectal cancer by mechanisms involving insulin resistance and the metabolic syndrome. We examined the associations of body mass index (BMI), waist circumference, the metabolic syndrome, metabolic obesity phenotypes and homeostasis model-insulin resistance (HOMA-IR-a marker of insulin resistance) with risk of colorectal cancer in over 21,000 women in the Women's Health Initiative CVD Biomarkers subcohort. Women were cross-classified by BMI (18.5-<25.0, 25.0-<30.0 and ≥30.0 kg/m² ) and presence of the metabolic syndrome into 6 phenotypes: metabolically healthy normal weight (MHNW), metabolically unhealthy normal weight (MUNW), metabolically healthy overweight (MHOW), metabolically unhealthy overweight (MUOW), metabolically healthy obese (MHO) and metabolically unhealthy obese (MUO). Neither BMI nor presence of the metabolic syndrome was associated with risk of colorectal cancer, whereas waist circumference showed a robust positive association. Relative to the MHNW phenotype, the MUNW phenotype was associated with increased risk, whereas no other phenotype showed an association. Furthermore, HOMA-IR was not associated with increased risk. Overall, our results do not support a direct role of metabolic dysregulation in the development of colorectal cancer; however, they do suggest that higher waist circumference is a risk factor, possibly reflecting the effects of increased levels of cytokines and hormones in visceral abdominal fat on colorectal carcinogenesis.

Associations between ACE-Inhibitors, Angiotensin Receptor Blockers, and Lean Body Mass in Community Dwelling Older Women

Studies suggest that ACE-inhibitors (ACE-I) and angiotensin receptor blockers (ARBs) may preserve skeletal muscle with aging. We evaluated longitudinal differences in lean body mass (LBM) among women diagnosed with hypertension and classified as ACE-I/ARB users and nonusers among Women's Health Initiative participants that received dual energy X-ray absorptiometry scans to estimate body composition (n=10,635) at baseline and at years 3 and 6 of follow-up. Of those, 2642 were treated for hypertension at baseline. Multivariate linear regression models, adjusted for relevant demographics, behaviors, and medications, assessed ACE-I/ARB use/nonuse and LBM associations at baseline, as well as change in LBM over 3 and 6 years. Although BMI did not differ by ACE-I/ARB use, LBM (%) was significantly higher in ACE-I/ARB users versus nonusers at baseline (52.2% versus 51.3%, resp., p=0.001). There was no association between ACE-I/ARB usage and change in LBM over time. Reasons for higher LBM with ACE-I/ARB use cross sectionally, but not longitundinally, are unclear and may reflect a threshold effect of these medications on LBM that is attenuated over time. Nevertheless, ACE-I/ARB use does not appear to negatively impact LBM in the long term.

Physical Activity among Navajo Cancer Survivors: A Qualitative Study

Physical activity (PA) may improve quality of life and survival among cancer survivors; however, little is known about Navajo cancer survivor PA. We evaluated Navajo cancer survivor PA habits, barriers, and preferences through focus groups and interviews (n = 32). Transcripts were coded in NVivo and major themes summarized by consensus. Survivor exercise guidelines were largely unknown, but movement, resilience and life balance were valued. Most participants reported at ≥1 mode of current PA (n = 24; 71% walking, 46% work/homesteading). Barriers to PA included treatment side effects, limited access to programs, fear of "over doing it," and family/friends encouraging rest. Preferences for PA varied.

Initiating Exercise Interventions to Promote Wellness in Cancer Patients and Survivors

Exercise is associated with significant reductions in the recurrence and mortality rates of several common cancers. Cancer survivors who exercise can potentially benefit from reduced levels of fatigue, and improved quality of life, physical function, and body composition (ie, healthier ratios of lean body mass to fat mass). The amount of activity required to achieve protective effects is moderate (eg, walking 30 minutes per day at 2.5 miles per hour). However, many healthcare providers report a lack of awareness of the appropriate exercise recommendations across the phases of cancer survivorship, considerations regarding the timing of exercise interventions, and the ability to refer patients to exercise programs specifically aimed at cancer survivors. The American College of Sports Medicine notes that exercise is generally safe for most cancer survivors, and inactivity should be avoided. Their guidelines for exercise call for 150 minutes of moderate or 75 minutes of vigorous aerobic activity per week, and 2 days per week of resistance training (eg, with exercise bands or light weights). Survivors with lymphedema, peripheral neuropathy, breast reconstruction, central lines, and ostomies should follow specific precautions. Providing health professionals with the training and tools needed to provide adequate recommendations to their patients is essential to improving patient outcomes. To facilitate adherence among communities with the greatest need and poor access to services, cultural and environmental adaptations are critical.

Genetic Variant in ACVR2B Is Associated with Lean Mass

INTRODUCTION

Low lean mass (LM) is a risk factor for chronic disease, a major cause of disability and diminished quality of life, and is a heritable trait. However, relatively few specific genetic factors have been identified as potentially influencing this trait.

METHODS

In this study, we selected 1493 single-nucleotide polymorphisms (SNP) in 155 candidate genes involved in anabolic, catabolic, growth hormone, and other related pathways and examined their association with LM, assessed by dual-energy x-ray absorptiometry, in a sample of 2760 non-Hispanic and Hispanic white postmenopausal women from the Women's Health Initiative (WHI) Observational Study. We assessed the replication of our top findings in a meta-analysis of 20 genome-wide association studies (n = 38,292) conducted by the Cohorts for Heart and Aging Research in Genomic Epidemiology Consortium Musculoskeletal Working Group.

RESULTS

We identified 32 SNPs that had nominally significant associations with LM in the WHI cohort. In the replication stage, we find that SNP rs2276541 in the activin A receptor, type IIB (ACVR2B), was significantly associated with LM (β = 0.15, P = 2.17 × 10). ACVR2B codes for a receptor for a negative regulator of skeletal muscle, myostatin, and has previously been identified in a candidate gene study as a determinant of skeletal muscle mass.

CONCLUSIONS

Our findings support a previously proposed role of ACVR2B allelic variation as a determinant of muscle mass and extend prior findings in men and women. Additional large-scale studies will be needed to confirm our findings in different populations.

Use of iDXA spine scans to evaluate total and visceral abdominal fat

OBJECTIVES

Abdominal fat may be a better predictor than body mass index (BMI) for risk of metabolically-related diseases, such as diabetes, cardiovascular disease, and some cancers. We sought to validate the percent fat reported on dual energy X-ray absorptiometry (DXA) regional spine scans (spine fat fraction, SFF) against abdominal fat obtained from total body scans using the iDXA machine (General Electric, Madison, WI), as previously done on the Prodigy model.

METHODS

Total body scans and regional spine scans were completed on the same day (N = 50). In alignment with the Prodigy-based study, the following regions of interest (ROI) were assessed from total body scans and compared to the SFF from regional spine scans: total abdominal fat at (1) lumbar vertebrae L2-L4 and (2) L2-Iliac Crest (L2-IC); (3) total trunk fat; and (4) visceral fat in the android region. Separate linear regression models were used to predict each total body scan ROI from SFF; models were validated by bootstrapping.

RESULTS

The sample was 84% female, a mean age of 38.5 ± 17.4 years, and mean BMI of 23.0 ± 3.8 kg/m² . The SFF, adjusted for BMI, predicted L2-L4 and L2-IC total abdominal fat (%; Adj. R² : 0.90) and total trunk fat (%; Adj. R² : 0.88) well; visceral fat (%) adjusted R² was 0.83. Linear regression models adjusted for additional participant characteristics resulted in similar adjusted R² values.

CONCLUSIONS

This replication of the strong correlation between SFF and abdominal fat measures on the iDXA in a new population confirms the previous Prodigy model findings and improves generalizability.

Body Mass Index, Waist Circumference, and Mortality in a Large Multiethnic Postmenopausal Cohort-Results from the Women's Health Initiative

OBJECTIVES

To determine whether the relationship between anthropometric measurements of obesity and mortality varies according to age, race, and ethnicity in older women.

DESIGN

Prospective cohort study of multiethnic postmenopausal women.

SETTING

Women's Health Initiative (WHI) observational study and clinical trials in 40 clinics.

PARTICIPANTS

Postmenopausal women aged 50-79 participating in WHI (N = 161,808).

MEASUREMENTS

Baseline height, weight, and waist circumference (WC) were measured, and body mass index (BMI) was calculated based on height and weight. Demographic, health, and lifestyle data from a baseline questionnaire were used as covariates. The outcome was adjudicated death (n = 18,320) during a mean follow-up of 11.4 ± 3.2 years.

RESULTS

Hazard ratios (HRs) and 95% confidence intervals (95% CIs) indicated that ethnicity and age modified (P < .01) the relationship between obesity and mortality. Underweight was associated with higher mortality, but overweight or slight obesity was not a risk factor for mortality in most ethnic groups except for Hispanic women in the obesity I category (HR = 1.42, 95% CI = 1.04-1.95). BMI was not or was only weakly associated with mortality in individuals aged 70-79 (HR = 0.90, 95% CI = 0.85-0.95 for overweight; HR = 0.98, 95 CI = 0.92-1.06 for obese I; HR = 1.11, 95% CI = 1.00-1.23 for obese II; HR = 1.08, 95% CI = 0.92-1.26 for obese III). In contrast, higher central obesity measured using WC was consistently associated with higher mortality in all groups.

CONCLUSION

Underweight is a significant risk factor for mortality in older women, and healthy BMI ranges may need to be specific for age, race, and ethnicity. The findings support a consistent relationship between central obesity and mortality.

Comparison of direct measures of adiposity with indirect measures for assessing cardiometabolic risk factors in preadolescent girls

Background

Childhood overweight and obesity remains high, contributing to cardiometabolic risk factors at younger ages. It is unclear which measures of adiposity serve as the best proxies for identifying children at metabolic risk. This study assessed whether DXA-derived direct measures of adiposity are more strongly related to cardiometabolic risk factors in children than indirect measures.

Methods

Anthropometric and DXA measures of adiposity and a comprehensive assessment of cardiometabolic risk factors were obtained in 288, 9–12 year old girls, most being of Hispanic ethnicity. Multiple regression models for each metabolic parameter were run against each adiposity measure while controlling for maturation and ethnicity. In addition, regression models including both indirect and direct measures were developed to assess whether using direct measures of adiposity could provide a better prediction of the cardiometabolic risk factors beyond that of using indirect measures alone.

Results

Measures of adiposity were significantly correlated with cardiometabolic risk factors (p < 0.05) except fasting glucose. After adjusting for maturation and ethnicity, indirect measures of adiposity accounted for 29-34% in HOMA-IR, 10-13% in TG, 14-17% in HDL-C, and 5-8% in LDL-C while direct measures accounted for 29-34% in HOMA-IR, 10-12% in TG, 13-16% in HDL-C, and 5-6% in LDL-C. The addition of direct measures of adiposity to indirect measures added significantly to the variance explained for HOMA-IR (p = 0.04).

Conclusion

Anthropometric measures may perform as well as the more precise direct DXA-derived measures of adiposity for assessing most CVD risk factors in preadolescent girls. The use of DXA-derived adiposity measures together with indirect measures may be advantageous for predicting insulin resistance risk.

Trial registration

NCT02654262. Retrospectively registered 11 January 2016.

Physical Activity Modifies the Association between Dietary Protein and Lean Mass of Postmenopausal Women

BACKGROUND

Maintenance of lean muscle mass and related strength is associated with lower risk for numerous chronic diseases of aging in women.

OBJECTIVE

Our aim was to evaluate whether the association between dietary protein and lean mass differs by physical activity level, amino acid composition, and body mass index categories.

DESIGN

We performed a cross-sectional analysis of a prospective cohort.

PARTICIPANTS/SETTING

Participants were postmenopausal women from the Women's Health Initiative with body composition measurements by dual-energy x-ray absorptiometry (n=8,298).

MAIN OUTCOME MEASURES

Our study measured percent lean mass, percent fat mass, and lean body mass index.

STATISTICAL ANALYSES PERFORMED

Linear regression models adjusted for scanner serial number, age, calibrated energy intake, race/ethnicity, neighborhood socioeconomic status, and recreational physical activity were used to determine the relationship between protein intake and body composition measures. Likelihood ratio tests and stratified analysis were used to investigate physical activity and body mass index as potential effect modifiers.

RESULTS

Biomarker-calibrated protein intake was positively associated with percent lean mass; women in the highest protein quintile had 6.3 percentage points higher lean mass than the lowest quintile (P<0.001). This difference rose to 8.5 percentage points for physically active women in the highest protein quintile (Pinteraction=0.023). Percent fat mass and lean body mass index were both inversely related to protein intake (both P<0.001). Physical activity further reduced percent fat mass (Pinteraction=0.022) and lean body mass index (Pinteraction=0.011). Leucine intake was associated with lean mass, as were branched chain amino acids combined (both P<0.001), but not independent of total protein. All associations were observed for normal-weight, overweight, and obese women.

CONCLUSIONS

Protein consumption up to 2.02 g/kg body weight daily is positively associated with lean mass in postmenopausal women. Importantly, those that also engage in physical activity have the highest lean mass across body mass index categories.

Changes in physical activity, sedentary time, and risk of falling: The Women's Health Initiative Observational Study

Falling significantly affects quality of life, morbidity, and mortality among older adults. We sought to evaluate the prospective association between sedentary time, physical activity, and falling among post-menopausal women aged 50-79years recruited to the Women's Health Initiative Observational Study between 1993 and 1998 from 40 clinical centers across the United States. Baseline (B) and change in each of the following were evaluated at year 3 (Y3) and year 6 (Y6; baseline n=93,676; Y3 n=76,598; Y6 n=75,428): recreational physical activity (MET-h/wk), sitting, sleeping (min/day), and lean body mass by dual energy X-ray absorptiometry (subset N=6475). Falls per year (0, 1, 2, ≥3) were assessed annually by self-report questionnaire and then dichotomized as ≤1 and ≥2falls/year. Logistic regression models were adjusted for demographics, body mass index, fall history, tobacco and alcohol use, medical conditions, and medications. Higher baseline activity was associated with greater risk of falling at Y6 (18%; p for trend <0.0001). Increasing sedentary time minimally decreased falling (1% Y3; 2% Y6; p<0.05). Increasing activity up to ≥9MET-h/wk. (OR: 1.12, 95% CI: 1.03-1.22) or maintaining ≥9MET-h/wk. (OR: 1.20, 95% CI: 1.13-1.29) increased falling at Y3 and Y6 (p for trend <0.001). Adding lean body mass to the models attenuated these relationships. Physically active lifestyles increased falling among post-menopausal women. Additional fall prevention strategies, such as balance and resistance training, should be evaluated to assist post-menopausal women in reaching or maintaining levels of aerobic activity known to prevent and manage several chronic diseases.

Dual energy X-ray absorptiometry spine scans to determine abdominal fat in postmenopausal women

Body composition may be a better predictor of chronic disease risk than body mass index (BMI) in older populations.

OBJECTIVES

We sought to validate spine fat fraction (%) from dual energy X-ray absorptiometry (DXA) spine scans as a proxy for total abdominal fat.

METHODS

Total body DXA scan abdominal fat regions of interest (ROI) that have been previously validated by magnetic resonance imaging were assessed among healthy, postmenopausal women who also had antero-posterior spine scans (n = 103). ROIs were (1) lumbar vertebrae L2-L4 and (2) L2-Iliac Crest (L2-IC), manually selected by two independent raters, and (3) trunk, auto-selected by DXA software. Intra-class correlation coefficients evaluated intra and inter-rater reliability on a random subset (N = 25). Linear regression models, validated by bootstrapping, assessed the relationship between spine fat fraction (%) and total abdominal fat (%) ROIs.

RESULTS

Mean age, BMI, and total body fat were 66.1 ± 4.8 y, 25.8 ± 3.8 kg/m² and 40.0 ± 6.6%, respectively. There were no significant differences within or between raters. Linear regression models adjusted for several participant and scan characteristics were equivalent to using only BMI and spine fat fraction. The model predicted L2-L4 (Adj. R² : 0.83) and L2-IC (Adj. R² : 0.84) abdominal fat (%) well; the adjusted R² for trunk fat (%) was 0.78. Model validation demonstrated minimal over-fitting (Adj. R² : 0.82, 0.83, and 0.77 for L2-L4, L2-IC, and trunk fat, respectively).

CONCLUSIONS

The strong correlation between spine fat fraction and DXA abdominal fat measures make it suitable for further development in postmenopausal chronic disease risk prediction models. Am. J. Hum. Biol. 28:918-926, 2016. © 2016Wiley Periodicals, Inc.