Energy requirements in the eighth decade of life

Development and validation of age-specific predictive equations for total energy expenditure and physical activity levels for older adults

BACKGROUND

Predicting energy requirements for older adults is compromised by the underpinning data being extrapolated from younger adults.

OBJECTIVES

To generate and validate new total energy expenditure (TEE) predictive equations specifically for older adults using readily available measures (age, weight, height) and to generate and test new physical activity level (PAL) values derived from 1) reference method of indirect calorimetry and 2) predictive equations in adults aged ≥65 y.

METHODS

TEE derived from "gold standard" methods from n = 1657 (n = 1019 females, age range 65-90 y), was used to generate PAL values. PAL ranged 1.28-2.05 for males and 1.26-2.06 for females. Physical activity (PA) coefficients were also estimated and categorized (inactive to very active) from population means. Nonlinear regression was used to develop prediction equations for estimating TEE. Double cross-validation in a randomized, sex-stratified, age-matched 50:50 split, and leave one out cross-validation were performed. Comparisons were made with existing equations.

RESULTS

Equations predicting TEE using the Institute of Medicine method are as follows: For males, TEE = -5680.17 - 17.50 × age (years) + PA coefficient × (6.96 × weight [kilograms] + 44.21 × height [centimeters]) + 1.13 × resting metabolic rate (RMR) (kilojoule/day). For females, TEE = -5290.72 - 8.38 × age (years) + PA coefficient × (9.77 × weight [kilograms] + 41.51 × height [centimeters]) + 1.05 × RMR (kilojoule/day), where PA coefficient values range from 1 (inactive) to 1.51 (highly active) in males and 1 to 1.44 in females respectively. Predictive performance for TEE from anthropometric variables and population mean PA was moderate with limits of agreement approximately ±30%. This improved to ±20% if PA was adjusted for activity category (inactive, low active, active, and very active). Where RMR was included as a predictor variable, the performance improved further to ±10% with a median absolute prediction error of approximately 4%.

CONCLUSIONS

These new TEE prediction equations require only simple anthropometric data and are accurate and reproducible at a group level while performing better than existing equations. Substantial individual variability in PAL in older adults is the major source of variation when applied at an individual level.

Determining total energy expenditure in 3–6-year-old Japanese pre-school children using the doubly labeled water method

The doubly labeled water (DLW, 2H218O) method for calculating the total production of CO2 over several days is currently considered to be the most accurate technique for the measurement of total energy expenditure (TEE), and the results obtained using this method have been used to review energy requirements. Presently, there is limited data available on TEE in Japanese children. The objective of this study was to assess the TEE in pre-school Japanese children using the DLW method. We used a cross-sectional population of 140 children (69 boys and 71 girls) aged 3–6 years. TEE was measured using the DLW method over 8 days under free-living conditions. The average weights (kg) of the boys and girls were 15.6 ± 2.5 and 15.0 ± 2.1 for the 3–4 years old and 19.8 ± 3.8 and 19.6 ± 2.7 for the 5–6 years old, respectively. The corresponding TEE (kcal/day) was 1260.9 ± 357.8 and 1265.2 ± 408.0, and 1682.3 ± 489.0 and 1693.1 ± 473.3, respectively, showing a significant difference with respect to age. Furthermore, TEE per body weight (kcal/kg/day) was 83.2 ± 29.2 and 84.9 ± 26.6, and 85.4 ± 23.2 and 86.7 ± 22.6, respectively. However, when TEE was adjusted for body weight or fat-free mass, there were no age or sex differences. We conclude that in Japanese children, TEE in those aged 3–4 years was similar to the current Ministry of Health recommendations. However, TEE in children aged 5–6 years was slightly higher than the recommendations. Based on these findings, the present results obtained from a large number of participants will provide valuable reference data for Japanese children.

Relationship between Measured Aerobic Capacity and Total Energy Expenditure Obtained by the Doubly Labeled Water Method in Community-Dwelling, Healthy Adults Aged 81–94 Years

The doubly labeled water method is a gold-standard method for the measurement of total energy expenditure in daily life. We aimed to identify the relationship between measured aerobic capacity and total energy expenditure, activity energy expenditure, or physical activity level using the doubly labeled water method in adults of advanced old age. A total of 12 physically independent older adults (10 men and 2 women), aged 81–94 years, participated in this study. The aerobic capacity was evaluated according to the lactate threshold. Total energy expenditure under free-living conditions was assessed using the doubly labeled water method, and self-reported physical activity was obtained using the Japanese version of the International Physical Activity Questionnaire. The lactate threshold was significantly positively correlated with total energy expenditure, activity energy expenditure, and physical activity level after adjusting for age and sex. We found that the aerobic capacity of the lactate threshold was positively and independently correlated with total energy expenditure, activity energy expenditure, or physical activity level. The present results suggest that maintaining aerobic capacity is an important factor in preventing frailty, although further research is required.

Exercising for Insulin Sensitivity - Is There a Mechanistic Relationship With Quantitative Changes in Skeletal Muscle Mass?

Skeletal muscle (SM) tissue has been repetitively shown to play a major role in whole-body glucose homeostasis and overall metabolic health. Hence, SM hypertrophy through resistance training (RT) has been suggested to be favorable to glucose homeostasis in different populations, from young healthy to type 2 diabetic (T2D) individuals. While RT has been shown to contribute to improved metabolic health, including insulin sensitivity surrogates, in multiple studies, a universal understanding of a mechanistic explanation is currently lacking. Furthermore, exercised-improved glucose homeostasis and quantitative changes of SM mass have been hypothesized to be concurrent but not necessarily causally associated. With a straightforward focus on exercise interventions, this narrative review aims to highlight the current level of evidence of the impact of SM hypertrophy on glucose homeostasis, as well various mechanisms that are likely to explain those effects. These mechanistic insights could provide a strengthened rationale for future research assessing alternative RT strategies to the current classical modalities, such as low-load, high repetition RT or high-volume circuit-style RT, in metabolically impaired populations.

Total Energy Expenditure, Body Composition, Physical Activity, and Step Count in Japanese Preschool Children: A Study Based on Doubly Labeled Water

Adequate energy intake is essential for the healthy development of children, and the estimated energy requirement of children is determined by total daily energy expenditure (TDEE) and energy deposition for growth. A previous study in Japanese tweens indicated that TDEE could be estimated by fat-free mass (FFM) and step count. The aims of this study were to measure TDEE in Japanese preschool children and to confirm whether TDEE can be estimated by FFM and step count in preschool children. Twenty-one children aged 4-6 years old (11 girls and 10 boys; age, 5.1 (0.9) years; height, 107.2 (6.6) cm; weight, 17.5 (1.7) kg; BMI, 15.3 (1.3); mean (SD)) participated in this study. FFM and 7-day TDEE were obtained by doubly labeled water (DLW). Participants wore accelerometers during the DLW measurement period. No significant differences were observed in age-adjusted height, weight, BMI, FFM (13.0 (1.5) kg), or TDEE (1300 (174) kcal/day) between girls and boys. Girls had significantly higher percent fat and a lower daily step count than boys. Stepwise regression analysis revealed that FFM and step count were significant predictors of TDEE; TDEE (kcal/day) = 85.0 × FFM (kg) + 0.0135 × step count (steps/day). This accounted for 74% of TDEE variance. The current study confirmed that FFM and step count are major determinants of TDEE in Japanese preschool children as well as adolescents, although further research is needed to obtain precise equations.

Energy Expenditure in Older People Hospitalized for an Acute Episode

Weight loss and worsening of nutritional state is a frequent downfall of acute hospitalization in older people. It is usually accepted that acute inflammation is responsible for hypercatabolism. However, several studies suggest, on the contrary, a reduction in resting energy expenditure (REE). This study aimed to obtain a reliable measure of REE and total energy expenditure (TEE) in older patients hospitalized for an acute episode in order to better assess patients' energy requirements and help understand the mechanisms of weight loss in this situation. Nineteen hospitalized older patients (mean age 83 years) with C-reactive protein (CRP) level >20mg/L were recruited. REE and TEE were measured using gold standard methods of indirect calorimetry and doubly labeled water (DLW), respectively. REE was then compared to data from a previous study on aged volunteers from nursing homes who were free of an acute stressor event. Energy requirements measured by DLW were confirmed at 1.3 × REE. Energy intake covered the needs but did not prevent weight loss in these patients. TEE was not increased in hospitalized patients and was not influenced by inflammation, while the relationship between REE and inflammation was uncertain. Our results suggest that lean mass remains the major determinant of REE in hospitalized older people and that weight loss may not be explained solely by a state of hypercatabolism.

Validity of a triaxial accelerometer and simplified physical activity record in older adults aged 64-96 years: a doubly labeled water study

BACKGROUND

The aim was to examine the validity of a triaxial accelerometer (ACCTRI) and a simplified physical activity record (sPAR) in estimating total energy expenditure (TEE) and physical activity level (PAL) in older adults with the doubly labeled water (DLW) method.

METHODS

A total of 44 Japanese elderly individuals (64-96 years), of which 28 were community-dwelling healthy adults with or without sporting habits (S or NS group) and 16 were care home residents with frailty (F group), were included in the study. Basal metabolic rate (BMR) was measured by indirect calorimetry, TEE was obtained by the DLW method, and PAL was calculated as TEE/BMR. Daily step count was monitored by a pedometer (Lifecorder). The 24-h average metabolic equivalent was assessed by ACCTRI and sPAR.

RESULTS

The TEE_DLW in men was 2704 ± 353, 2308 ± 442, and 1795 ± 338 kcal d^-1, and that in women was 2260 ± 208, 1922 ± 285, and 1421 ± 274 kcal d^-1 for the S, NS, and F groups, respectively. ACCTRI and sPAR systematically underestimated actual TEE (- 14.2 ± 11.6 and - 15.3 ± 12.3% for ACCTRI and sPAR, respectively). After diet-induced thermogenesis was taken into account for ACCTRI and sPAR, TEE_DLW was significantly correlated with TEE_ACCTRI (R² = 0.714) and TEE_sPAR (R² = 0.668). PAL_DLW was also significantly correlated with PAL_ACCTRI (R² = 0.438) and PAL_sPAR (R² = 0.402).

CONCLUSIONS

Age, living conditions, frailty, and sporting habits contribute to TEE and PAL in the elderly population. ACCTRI and sPAR underestimated TEE and PAL, and adequate corrections are required. The corrected ACCTRI and sPAR are both useful tools to estimate TEE and PAL.

Total energy expenditure in adults aged 65 years and over measured using doubly-labelled water: international data availability and opportunities for data sharing

BACKGROUND

Increasing population lifespan necessitates a greater understanding of nutritional needs in older adults (65 year and over). A synthesis of total energy expenditure in the older population has not been undertaken and is needed to inform nutritional requirements. We aimed to establish the extent of the international evidence for total energy expenditure (TEE) using doubly-labelled water (DLW) in older adults (65 years and over), report challenges in obtaining primary data, and make recommendations for future data sharing.

METHODS

Four databases were searched to identify eligible studies; original research of any study design where participant level TEE was measured using DLW in participants aged ≥65 years. Once studies were identified for inclusion, authors were contacted where data were not publicly available.

RESULTS

Screening was undertaken of 1223 records; the review of 317 full text papers excluded 170 records. Corresponding or first authors of 147 eligible studies were contacted electronically. Participant level data were publicly available or provided by authors for 45 publications (890 participants aged ≥65 years, with 248 aged ≥80 years). Sixty-seven percent of the DLW data in this population were unavailable due to authors unable to be contacted or declining to participate, or data being irretrievable.

CONCLUSIONS

The lack of data access limits the value of the original research and its contribution to nutrition science. Openly accessible DLW data available through publications or a new international data repository would facilitate greater integration of current research with previous findings and ensure evidence is available to support the needs of the ageing population.

TRIAL REGISTRATION

The protocol was registered with the International Prospective Register of Systematic Reviews (PROSPERO), registration number CRD42016047549 .

Prior automatic posture and activity identification improves physical activity energy expenditure prediction from hip-worn triaxial accelerometry

Accelerometry is increasingly used to quantify physical activity (PA) and related energy expenditure (EE). Linear regression models designed to derive PAEE from accelerometry-counts have shown their limits, mostly due to the lack of consideration of the nature of activities performed. Here we tested whether a model coupling an automatic activity/posture recognition (AAR) algorithm with an activity-specific count-based model, developed in 61 subjects in laboratory conditions, improved PAEE and total EE (TEE) predictions from a hip-worn triaxial-accelerometer (ActigraphGT3X+) in free-living conditions. Data from two independent subject groups of varying body mass index and age were considered: 20 subjects engaged in a 3-h urban-circuit, with activity-by-activity reference PAEE from combined heart-rate and accelerometry monitoring (Actiheart); and 56 subjects involved in a 14-day trial, with PAEE and TEE measured using the doubly-labeled water method. PAEE was estimated from accelerometry using the activity-specific model coupled to the AAR algorithm (AAR model), a simple linear model (SLM), and equations provided by the companion-software of used activity-devices (Freedson and Actiheart models). AAR-model predictions were in closer agreement with selected references than those from other count-based models, both for PAEE during the urban-circuit (RMSE = 6.19 vs 7.90 for SLM and 9.62 kJ/min for Freedson) and for EE over the 14-day trial, reaching Actiheart performances in the latter (PAEE: RMSE = 0.93 vs. 1.53 for SLM, 1.43 for Freedson, 0.91 MJ/day for Actiheart; TEE: RMSE = 1.05 vs. 1.57 for SLM, 1.70 for Freedson, 0.95 MJ/day for Actiheart). Overall, the AAR model resulted in a 43% increase of daily PAEE variance explained by accelerometry predictions.

NEW & NOTEWORTHY Although triaxial accelerometry is widely used in free-living conditions to assess the impact of physical activity energy expenditure (PAEE) on health, its precision and accuracy are often debated. Here we developed and validated an activity-specific model which, coupled with an automatic activity-recognition algorithm, improved the variance explained by the predictions from accelerometry counts by 43% of daily PAEE compared with models relying on a simple relationship between accelerometry counts and EE.

Surveying predictors of late-life longitudinal change in daily activity energy expenditure

Background

Total daily energy expenditure (TEE) is composed of resting metabolic rate (RMR), post-prandial thermogenesis and activity energy expenditure (AEE). Higher AEE is strongly associated with lower mortality and physical limitations among older adults, but factors that predict changes in AEE in septu and octogenarians are not clearly understood.

Objective

To identify factors associated with late-life longitudinal change in AEE.

Design

Energy expenditure was re-assessed in 83 participants (average age at baseline, 74.4±3.2 years)—an average of 7.5±0.54 years since the baseline measure. RMR was measured using indirect calorimetry and the thermic effect of meals was estimated at 10% of TEE. AEE was calculated as: TEE(0.9)-RMR. Participants were categorized into two groups according to the estimated day-to-day precision of the doubly-labeled water technique. Those who were within 10% or increased relative to their initial AEE measurement were categorized as having preserved AEE. Participants who declined greater than 10% of their initial measurement were categorized as having reduced AEE. A variety of socio-demographic, functional and mental factors, body composition, community and personal behaviors, blood measurements and health conditions were evaluated between groups at baseline and changes during follow-up.

Results

Daily AEE declined 106.61±293.25 kcal, which equated to a 14.63±40.57 kcal/d decrease per year. Fifty-nine percent (n = 49) preserved their AEE and 41% (n = 34) declined. Those who demonstrated a decline in AEE were older, had lower walking speed at baseline and showed a higher lean mass loss during follow up. Otherwise, groups were similar for socio-demographic characteristics, body composition, mental and physical function, health conditions and community and personal behaviors at baseline and change in these factors during follow-up.

Conclusions

This study demonstrates that AEE declines through the 8^th decade of life and is associated with age, lower walking speed at baseline and lean mass loss. Additionally, there are a significant number of individuals who appear to be resilient to these declines despite having health events that are expected to have a negative impact on their physical activity.

Exercise training improves fat metabolism independent of total energy expenditure in sedentary overweight men, but does not restore lean metabolic phenotype

BACKGROUND

Obesity is a dietary fat storage disease. Although exercise prevents weight gain, effects of chronic training on dietary fat oxidation remains understudied in overweight adults.

OBJECTIVE

We tested whether 2 months of training at current guidelines increase dietary fat oxidation in sedentary overweight adults like in sedentary lean adults.

DESIGN

Sedentary lean (n=10) and overweight (n=9) men trained on a cycle ergometer at 50% VO_2peak, 1 h day^-1, four times per week, for 2 months while energy balance was clamped. Metabolic fate of [d₃₁]palmitate and [1-¹³C]oleate mixed in standard meals, total substrate use, total energy expenditure (TEE), activity energy expenditure (AEE) and key muscle proteins/enzymes were measured before and at the end of the intervention.

RESULTS

Conversely to lean subjects, TEE and AEE did not increase in overweight participants due to a spontaneous decrease in non-training AEE. Despite this compensatory behavior, aerobic fitness, insulin sensitivity and fat oxidation were improved by exercise training. The latter was not explained by changes in dietary fat trafficking but more likely by a coordinated response at the muscle level enhancing fat uptake, acylation and oxidation (FABPpm, CD36, FATP1, ACSL1, CPT1, mtGPAT). ACSL1 fold change positively correlated with total fasting (R²=0.59, P<0.0001) and post-prandial (R²=0.49, P=0.0006) fat oxidation whereas mtGPAT fold change negatively correlated with dietary palmitate oxidation (R²=0.40, P=0.009), suggesting modified fat trafficking between oxidation and storage within the muscle. However, for most of the measured parameters the post-training values observed in overweight adults remained lower than the pre-training values observed in the lean subjects.

CONCLUSION

Independent of energy balance and TEE, exercise training at current recommendations improved fitness and fat oxidation in overweight adults. However the improved metabolic phenotype of overweight adults was not as healthy as the one of their lean counterparts before the 2-month training, likely due to the spontaneous reduction in non-training AEE.

Considerations When Using Predictive Equations to Estimate Energy Needs Among Older, Hospitalized Patients: A Narrative Review

The aim of this narrative review was to summarize the accuracy of predictive equations used to estimate energy expenditure in older, hospitalized adults. More than 50% of patients admitted to intensive care units are older adults. Currently accepted prediction equations used to determine energy intake in the older, hospitalized patient were not specifically developed for the aging population. Rates of multimorbidity, polypharmacy and malnutrition, conditions that influence energy expenditure, are higher in older adults compared to younger adults. For these reasons, current equations may not accurately assess energy needs in this population. As the evidence demonstrating the importance of nutritional supplementation in older, hospitalized adults grows, more accurate energy assessment methods that account for age-related conditions are needed to predict nutritional requirements.

Energetics of Aging and Frailty: The FRADEA Study

BACKGROUND

Resting metabolic rate (RMR) and total daily energy expenditure (TDEE) decrease with aging, but it is not known whether frailty modulates this association. We hypothesize that RMR and TDEE values are similar between younger and older nonfrail older adults, whereas they are lower in older prefrail and frail compared with younger adults.

METHODS

A cross-sectional analysis of the FRADEA study, Albacete (Spain), including 402 participants (213 women) older than 70 years (mean age 76 years; range 70-91), was conducted. Estimated RMR (eRMR), oxygen consumption (VO2), expired volume (Ve), and respiratory frequency (RF) were determined using indirect calorimetry; TDEE was determined with the Calcumed instrument; and fat-free mass was determined by bioimpedanciometry. General linear models were used for analysis.

RESULTS

Mean TDEE was 1,889 (SD 470) kcal and eRMR was 1,071 (SD 323) kcal. Both TDEE (B = -24 kcal/day; 95% confidence interval: -35.4 to -14.2; p < .001) and eRMR (B= -15.8 kcal/day; 95% confidence interval: -23.1 to -8.5; p < .001) diminished linearly with age, with lower values in frail and prefrail participants. There was a strong trend between frailty and lower eRMR (F = 2.9; p = .058), with a modifying effect between age and frailty (F = 3.6; p = .002). eRMR in prefrail and frail participants were on average 160 and 114 kcal/day less than that in the nonfrail participants, respectively, and taken together, 154 kcal/day less (F = 5.4; p = .020). Frail and prefrail participants also presented lower Ve and VO2 values that were partially compensated by an RF increase.

CONCLUSION

Frailty status modulates the energy requirements of aging. Frail and prefrail older adults present lower eRMR than nonfrail adults.

Best-fitting prediction equations for basal metabolic rate: informing obesity interventions in diverse populations

Basal metabolic rate (BMR) represents the largest component of total energy expenditure and is a major contributor to energy balance. Therefore, accurately estimating BMR is critical for developing rigorous obesity prevention and control strategies. Over the past several decades, numerous BMR formulas have been developed targeted to different population groups. A comprehensive literature search revealed 248 BMR estimation equations developed using diverse ranges of age, gender, race, fat-free mass, fat mass, height, waist-to-hip ratio, body mass index and weight. A subset of 47 studies included enough detail to allow for development of meta-regression equations. Utilizing these studies, meta-equations were developed targeted to 20 specific population groups. This review provides a comprehensive summary of available BMR equations and an estimate of their accuracy. An accompanying online BMR prediction tool (available at http://www.sdl.ise.vt.edu/tutorials.html) was developed to automatically estimate BMR based on the most appropriate equation after user-entry of individual age, race, gender and weight.

Long-term calorie restriction decreases metabolic cost of movement and prevents decrease of physical activity during aging in rhesus monkeys

BACKGROUND

Short-term (<1 year) calorie restriction (CR) has been reported to decrease physical activity and metabolic rate in humans and non-human primate models; however, studies examining the very long-term (>10 year) effect of CR on these parameters are lacking.

OBJECTIVE

The objective of this study was to examine metabolic and behavioral adaptations to long-term CR longitudinally in rhesus macaques.

DESIGN

Eighteen (10 male, 8 female) control (C) and 24 (14 male, 10 female) age matched CR rhesus monkeys between 19.6 and 31.9 years old were examined after 13 and 18 years of moderate adult-onset CR. Energy expenditure (EE) was examined by doubly labeled water (DLW; TEE) and respiratory chamber (24 h EE). Physical activity was assessed both by metabolic equivalent (MET) in a respiratory chamber and by an accelerometer. Metabolic cost of movements during 24 h was also calculated. Age and fat-free mass were included as covariates.

RESULTS

Adjusted total and 24 h EE were not different between C and CR. Sleeping metabolic rate was significantly lower, and physical activity level was higher in CR than in C independent from the CR-induced changes in body composition. The duration of physical activity above 1.6 METs was significantly higher in CR than in C, and CR had significantly higher accelerometer activity counts than C. Metabolic cost of movements during 24 h was significantly lower in CR than in C. The accelerometer activity counts were significantly decreased after seven years in C animals, but not in CR animals.

CONCLUSIONS

The results suggest that long-term CR decreases basal metabolic rate, but maintains higher physical activity with lower metabolic cost of movements compared with C.

Association between lifestyle and physical activity level in the elderly: a study using doubly labeled water and simplified physical activity record

PURPOSE

Physical activity level (PAL) is associated with all-cause mortality in the elderly. However, few studies have attempted to clarify the relationship between lifestyle and PAL in the elderly. This study aimed to examine the determinants of PAL in the elderly in terms of behavioral patterns and exercise intensity, and to validate the simplified physical activity record (sPAR).

METHODS

Thirty healthy, elderly individuals, aged 64-87 years, participated in the study. Total energy expenditure (TEEDLW), physical activity energy expenditure (PAEEDLW), and PAL (PALDLW) were calculated based on doubly labeled water (DLW) and measured basal metabolic rate. Physical activity was recorded using the sPAR.

RESULTS

PALDLW was significantly correlated with PAL estimated by sPAR (r = 0.588, P < 0.001). Good agreement was observed between TEEDLW (1,860 ± 373 kcal/day) and TEE estimated by sPAR (1,854 ± 377 kcal/day) (r = 0.825, P < 0.001). Good agreement was also observed between PAEEDLW (552 ± 242 kcal/day) and PAEE estimated by sPAR (562 ± 240 kcal/day) (r = 0.666, P < 0.001). The high PALDLW group had significantly shorter durations of 'sleeping time and rest periods' and 'daily life sedentary activities', and significantly longer durations of 'bicycling with moderate speed', 'housekeeping with standing', 'gymnastics, tai chi, stretching' and "swimming, hill climbing, fast jogging" than the low PAL group (P < 0.05).

CONCLUSIONS

The sPAR provides valid estimates of TEE and PAEE in the healthy elderly. The results suggest that engaging in housekeeping or sports activities for longer and being less sedentary may increase PALDLW in healthy elderly individuals.

Longitudinal change in energy expenditure and effects on energy requirements of the elderly

Background

Very little is known about the longitudinal changes in energy requirements in late life. The purposes of this study were to: (1) determine the energy requirements in late life and how they changed during a 7 year time-span, (2) determine whether changes in fat free mass (FFM) were related to changes in resting metabolic rate (RMR), and (3) determine the accuracy of predicted total energy expenditure (TEE) to measured TEE.

Methods

TEE was assessed via doubly labeled water (DLW) technique in older adults in both 1999 (n = 302; age: 74 ± 2.9 yrs) and again in 2006 (n = 87 age: 82 ± 3.1 yrs). RMR was measured with indirect calorimetry, and body composition was assessed with dual-energy x-ray absorptiometry.

Results

The energy requirements in the 9th decade of life were 2208 ± 376 kcal/d for men and 1814 ± 337 kcal/d for women. This was a significant decrease from the energy requirements in the 8th decade of life in men (2482 ± 476 kcal/d vs. 2208 ± 376 kcal/d) but not in women (1892 ± 271 kcal/d vs. 1814 ± 337 kcal/d). In addition to TEE, RMR, and activity EE (AEE) also decreased in men, but not women, while FFM decreased in both men and women. The changes in FFM were correlated with changes in RMR for men (r = 0.49, p < 0.05) but not for women (r = −0.08, ns). Measured TEE was similar to Dietary Reference Intake (DRI) predicted TEE for men (2208 ± 56 vs. 2305 ± 35 kcal/d) and women (1814 ± 42 vs. 1781 ± 20 kcal/d). However, measured TEE was different than the World Health Organization (WHO) predicted TEE in men (2208 ± 56 vs. 2915 ± 31 kcal/d (p < 0.05)) and women (1814 ± 42 vs. 2315 ± 21 kcal/d (p < 0.05)).

Conclusions

TEE, RMR and AEE decreased in men, but not women, from the 8th to 9th decade of life. The DRI equation to predict TEE was comparable to measured TEE, while the WHO equation over-predicted TEE in our elderly population.

High energy expenditure masks low physical activity in obesity

OBJECTIVE

To investigate energy expenditure in lean and obese individuals, focusing particularly on physical activity and severely obese individuals.

DESIGN

Total daily energy expenditure (TDEE) was assessed using doubly labeled water, resting metabolic rate (RMR) by indirect calorimetry, activity energy expenditure (AEE) by difference and time spent in physical activity by multisensor activity monitors.

SUBJECTS

In all, 177 lean, Class I and severely obese individuals (age 31-56 years, body mass index 20-64 kg m(-2)) were analyzed.

RESULTS

All components of energy expenditure were elevated in obese individuals. For example, TDEE was 2404±95 kcal per day in lean and 3244±48 kcal per day in Class III obese individuals. After appropriate adjustment, RMR was similar in all groups. Analysis of AEE by body weight and obesity class indicated a lower AEE in obese individuals. Confirming lower physical activity, obese individuals spent less time engaged in moderate-to-vigorous physical activity (2.7±1.3, 1.8±0.6, 2.0±1.4 and 1.2±1.0 h per day in lean, Class I, Class II and Class III individuals) and more time in sedentary behaviors.

CONCLUSIONS

There was no indication of metabolic efficiency in even the severely obese, as adjusted RMR was similar across all groups. The higher AEE observed in the obese is consistent with a higher cost of activities due to higher body weight. However, the magnitude of the higher AEE (20-25% higher in obese individuals) is lower than expected (weight approximately 100% higher in Class III individuals). Confirming a lower volume of physical activity in the obese, the total time spent in moderate-to-vigorous physical activity and average daily metabolic equivalent of task level were lower with increasing obesity. These findings demonstrate that high body weight in obese individuals leads to a high TDEE and AEE, which masks the fact that they are less physically active, which can be influenced by duration or intensity of activity, than in lean individuals.

Validity of combining heart rate and uniaxial acceleration to measure free-living physical activity energy expenditure in young men

Combining accelerometry (ACC) with heart rate (HR) monitoring is thought to improve activity energy expenditure (AEE) estimations compared with ACC alone to evaluate the validity of ACC and HR used alone or combined. The purpose of this study was to estimate AEE in free-living conditions compared with doubly labeled water (DLW). Ten-day free-living AEE was measured by a DLW protocol in 35 18- to 55-yr-old men (11 lean active; 12 lean sedentary; 12 overweight sedentary) wearing an Actiheart (combining ACC and HR) and a RT3 accelerometer. AEE was estimated using group or individual calibration of the HR/AEE relationship, based on an exercise-tolerance test. In a subset (n = 21), AEE changes (ΔAEE) were measured after 1 mo of detraining (active subjects) or an 8-wk training (sedentary subjects). Actiheart-combined ACC/HR estimates were more accurate than estimates from HR or ACC alone. Accuracy of the Actiheart group-calibrated ACC/HR estimates was modest [intraclass correlation coefficient (ICC) = 0.62], with no bias but high root mean square error (RMSE) and limits of agreement (LOA). The mean bias of the estimates was reduced by one-third, like RMSE and LOA, by individual calibration (ICC = 0.81). Contrasting with group-calibrated estimates, the Actiheart individual-calibrated ACC/HR estimates explained 40% of the variance of the DLW-ΔAEE (ICC = 0.63). This study supports a good level of agreement between the Actiheart ACC/HR estimates and DLW-measured AEE in lean and overweight men with varying fitness levels. Individual calibration of the HR/AEE relationship is necessary for AEE estimations at an individual level rather than at group scale and for ΔAEE evaluation.

Mitochondrial DNA sequence variation is associated with free-living activity energy expenditure in the elderly

The decline in activity energy expenditure underlies a range of age-associated pathological conditions, neuromuscular and neurological impairments, disability, and mortality. The majority (90%) of the energy needs of the human body are met by mitochondrial oxidative phosphorylation (OXPHOS). OXPHOS is dependent on the coordinated expression and interaction of genes encoded in the nuclear and mitochondrial genomes. We examined the role of mitochondrial genomic variation in free-living activity energy expenditure (AEE) and physical activity levels (PAL) by sequencing the entire (~16.5 kilobases) mtDNA from 138 Health, Aging, and Body Composition Study participants. Among the common mtDNA variants, the hypervariable region 2 m.185G>A variant was significantly associated with AEE (p=0.001) and PAL (p=0.0005) after adjustment for multiple comparisons. Several unique nonsynonymous variants were identified in the extremes of AEE with some occurring at highly conserved sites predicted to affect protein structure and function. Of interest is the p.T194M, CytB substitution in the lower extreme of AEE occurring at a residue in the Qi site of complex III. Among participants with low activity levels, the burden of singleton variants was 30% higher across the entire mtDNA and OXPHOS complex I when compared to those having moderate to high activity levels. A significant pooled variant association across the hypervariable 2 region was observed for AEE and PAL. These results suggest that mtDNA variation is associated with free-living AEE in older persons and may generate new hypotheses by which specific mtDNA complexes, genes, and variants may contribute to the maintenance of activity levels in late life.

Omega 3 fatty acids in the elderly

Population ageing affects the entire world population. Also at world level one can observe a sharp increase in the proportion of older people. The challenge posed by population ageing translates into ensuring that the extra years of life will be as good as possible, free from high-cost dependency. Omega-3 fatty acids are now generally recognized as potential key nutrients to prevent the pathological conditions associated to the aging process. Ageing physiological process, its association with quality of life and the impact of omega-3 fatty acids intake and/or status is the focus of the present review. This report deals with the effects of omega-3 fatty acids on normal aging of older adults ( ≥  65 years) mainly on the effects such as nutritional status itself, cognition, bone health, muscle tonus, and general health status. The preliminary broad search of the literature on the effects of omega-3 fatty acids on normal aging yielded 685 citations. Forty two full text papers were checked for inclusion and thirty six studies were finally included in this review. It may be concluded that paradoxically even though the elderly population is the largest one, the number of studies and the methodology employed clearly lacks of sufficient evidence to establish definite conclusions on the effects of omega-3 fatty acids on aging metabolism without pathological conditions and on quality of life.

Urinary C-peptide is not an accurate bioindicator of energy balance in humans

The apprehension of the factors that affect long term regulation of energy balance is indispensable to understand the rise in obesity prevalence as well as to delineate levers to prevent it. Accurate measurements of energy balance are however challenging during free-living conditions. Recent studies proposed urinary C-peptide, a metabolic byproduct of insulin synthesis, as reliable noninvasive assessment of energy balance. These studies were in fact essentially based on correlations between urinary C-peptide and energy intake and only focused on nonhuman primates. During a bed-rest study conducted in 16 healthy women in a controlled environment, we tested the existence of a relationship between 24 h-urinary C-peptide and energy balance in humans. Daily energy intake and body mass, body composition (dual-energy X-ray absorptiometry (DXA)) and total energy expenditure (doubly labeled water (DLW) method) was measured and energy balance was calculated as the difference between energy intake and expenditure. Urinary C-peptide was positively correlated with bed-rest-induced changes in fat mass (r(2) = 0.285; P = 0.03) and energy balance assessed at the end of the bed-rest (r(2) = 0.302; P = 0.027). However, in this tightly controlled environment, urinary C-peptide only accounted for 30% of variations in energy balance. No relationship was noted between urinary C-peptide and body or fat mass both at baseline and at the end of the bed-rest. These results indicate that urinary C-peptide cannot be used as an accurate biomarker of energy balance in the general human population in free-living conditions.

Mitochondrial DNA variation in human metabolic rate and energy expenditure

The role of climate in driving selection of mtDNA as Homo sapiens migrated out of Africa into Eurasia remains controversial. We evaluated the role of mtDNA variation in resting metabolic rate (RMR) and total energy expenditure (TEE) among 294 older, community-dwelling African and European American adults from the Health, Aging and Body Composition Study. Common African haplogroups L0, L2 and L3 had significantly lower RMRs than European haplogroups H, JT and UK with haplogroup L1 RMR being intermediate to these groups. This study links mitochondrial haplogroups with ancestry-associated differences in metabolic rate and energy expenditure.

Activity energy expenditure and incident cognitive impairment in older adults

BACKGROUND

Studies suggest that physically active people have reduced risk of incident cognitive impairment in late life. However, these studies are limited by reliance on self-reports of physical activity, which only moderately correlate with objective measures and often exclude activity not readily quantifiable by frequency and duration. The objective of this study was to investigate the relationship between activity energy expenditure (AEE), an objective measure of total activity, and incidence of cognitive impairment.

METHODS

We calculated AEE as 90% of total energy expenditure (assessed during 2 weeks using doubly labeled water) minus resting metabolic rate (measured using indirect calorimetry) in 197 men and women (mean age, 74.8 years) who were free of mobility and cognitive impairments at study baseline (1998-1999). Cognitive function was assessed at baseline and 2 or 5 years later using the Modified Mini-Mental State Examination. Cognitive impairment was defined as a decline of at least 1.0 SD (9 points) between baseline and follow-up evaluations.

RESULTS

After adjustment for baseline Modified Mini-Mental State Examination scores, demographics, fat-free mass, sleep duration, self-reported health, and diabetes mellitus, older adults in the highest sex-specific tertile of AEE had lower odds of incident cognitive impairment than those in the lowest tertile (odds ratio, 0.09; 95% confidence interval, 0.01-0.79). There was also a significant dose response between AEE and incidence of cognitive impairment (P = .05 for trend over tertiles).

CONCLUSIONS

These findings indicate that greater AEE may be protective against cognitive impairment in a dose-response manner. The significance of overall activity in contrast to vigorous or light activity should be determined.

Validation of an armband to measure daily energy expenditure in older adults

BACKGROUND

Objective methods to measure daily energy expenditure in studies of aging are needed. We sought to determine the accuracy of total energy expenditure (TEE) and activity energy expenditure (AEE) estimates from the SenseWear Pro armband (SWA) using software versions 6.1 (SWA 6.1) and 5.1 (SWA 5.1) relative to criterion methods in free-living older adults.

METHODS

Participants (n = 19, mean age 82.0 years) wore a SWA for a mean ± SD 12.5 ± 1.1 days, including while sleeping. During this same period, criterion values for TEE were assessed with doubly labeled water and for resting metabolic rate (RMR) with indirect calorimetry. AEE was calculated as 0.9 TEE - RMR.

RESULTS

For TEE, there was no difference in mean ± SD values from doubly labeled water (2,040 ± 472 kcal/day) versus SWA 6.1 (2,012 ± 497 kcal/day, p = .593) or SWA 5.1 (2,066 ± 474 kcal/day, p = .606); individual values were highly correlated between methods (SWA 6.1 r = .893, p < .001; SWA 5.1 r = .901, p < .001) and demonstrated strong agreement (SWA 6.1 intraclass correlation coefficient = .896; SWA 5.1 intraclass correlation coefficient = .904). For AEE, mean values from SWA 6.1 (427 ± 304 kcal/day) were lower by 26.8% than criterion values (583 ± 242 kcal/day, p = .003), and mean values from SWA 5.1 (475 ± 299 kcal/day) were lower by 18.5% than criterion values (p = .021); however, individual values were highly correlated between methods (SWA 6.1 r = .760, p < .001; SWA 5.1 r = .786, p < .001) and demonstrated moderate agreement (SWA 6.1 intraclass correlation coefficient = .645; SWA 5.1 intraclass correlation coefficient = .720). Bland-Altman plots identified no systematic bias for TEE or AEE.

CONCLUSIONS

Acceptable levels of agreement were observed between SWA and criterion measurements of TEE and AEE in older adults.

European ancestry and resting metabolic rate in older African Americans

BACKGROUND/OBJECTIVES

Resting metabolic rate (RMR) contributes 60-80% of total energy expenditure and is consistently lower in populations of African descent compared with populations of European populations. Determination of European ancestry (EA) through single nucleotide polymorphism (SNP) analysis would provide an initial step for identifying genetic associations that contribute to low RMR. We sought to evaluate the association between RMR and EA in African Americans.

SUBJECTS/METHODS

RMR was measured by indirect calorimetry in 141 African American men and women (aged 74.7±3.0 years) enrolled in a substudy of the Health, Aging and Body Composition Study. Ancestry informative markers were used to estimate individual percent EA. Multivariate regression was used to assess the association between RMR and EA after adjustments for soft tissue fat-free mass (STFFM), fat mass, age, study site, physical activity level and sex.

RESULTS

Mean EA was 23.8±16% (range: 0.1-70.7%) and there were no differences by sex. Following adjustments, each percent EA was associated with a 1.6 kcal/day (95% Confidence interval: 0.42, 2.7 kcal/day) higher RMR (P=0.008). This equates to a 160 kcal/day lower RMR in a population of completely African ancestry, with one of completely European ancestry. Additional adjustment for trunk STFFM that partially accounts for high-metabolic rate organs did not affect this association.

CONCLUSIONS

EA in African Americans is strongly associated with higher RMR. The data suggest that population differences in RMR may be due to genetic variants.

Energy expenditure in adults living in developing compared with industrialized countries: a meta-analysis of doubly labeled water studies

BACKGROUND

There is an assumption that people in developing countries have a higher total energy expenditure (TEE) and physical activity level (PAL) than do people in developed nations, but few objective data for this assertion exist.

OBJECTIVE

We conducted a meta-analysis of TEE and PAL by using data from countries that have a low or middle human development index (HDI) compared with those with a high HDI to better understand how energy-expenditure variables are associated with development status and population differences in body size.

DESIGN

We performed a literature search for studies in which energy expenditure was measured by using doubly labeled water. Mean data on age, weight, body mass index (BMI; in kg/m(2)), TEE, and PAL were extracted, and HDI status was assessed. Pooled estimates of the mean effect by sex were obtained, and the extent to which age, weight, HDI status, and year of publication explained heterogeneity was assessed.

RESULTS

A total of 98 studies (14 studies from low- or middle-HDI countries) that represented 183 cohorts and 4972 individuals were included. Mean (±SE) BMI was lower in countries with a low or middle HDI than in those with a high HDI for both men and women (22.7 ± 1.0 compared with 26.0 ± 0.7, respectively, in men and 24.3 ± 0.7 compared with 26.6 ± 0.4, respectively, in women). In meta-regression models, there was an inverse association of age (P < 0.001) and a positive association of weight (P < 0.001) with TEE for both sexes; there was an association of age only in men with PAL (P < 0.001). There was no association of HDI status with either TEE or PAL.

CONCLUSION

TEE adjusted for weight and age or PAL did not differ significantly between developing and industrialized countries, which calls into question the role of energy expenditure in the cause of obesity at the population level.

Misreporting of energy intake in the elderly using doubly labeled water to measure total energy expenditure and weight change

BACKGROUND

One of the major problems in dietary assessment is inaccuracy in reporting diet.

OBJECTIVE

To examine the association between self-reported energy intake (EI) by food frequency questionnaire (FFQ) and energy expenditure (EE), measured by doubly labeled water (DLW), among older persons.

DESIGN

EE was assessed in 298 high-functioning, community-dwelling older adults (70-79 years of age) over a 2-week period using DLW. Dietary intake was assessed using a Block FFQ. The ratio between reported EI and total energy expenditure (TEE) was calculated. Misreporting was defined as follows: participants with an EI/TEE ratio of <0.77 were categorized as low energy reporters, while participants with an EI/TEE ratio >1.28 were categorized as high energy reporters. Participants with an EI/TEE ratio of 0.77-1.28 were categorized as "true" energy reporters. One-year percent weight change prior to EE visit was used as another validation indicator. Participants who were low energy reporters but lost >2% of their body weight were categorized as undereaters.

RESULTS

Two hundred ninety-six participants provided both FFQ and DLW measurements. Forty-three percent of participants were low energy reporters; among them, almost 30% lost weight and, therefore, were categorized as undereaters. The undereaters consumed significantly fewer calories. No difference in the frequency of low energy reporting was detected between genders or racial groups. Underreporters had significantly higher body weight than "true" or high reporters. Undereaters tended to have higher body mass index than the underreporters.

CONCLUSIONS

Undereating is prevalent in the elderly and may be falsely perceived as underreporting. It should be further addressed and characterized in future studies.

Associations between energy demands, physical activity, and body composition in adult humans between 18 and 96 y of age

BACKGROUND

Associations between body composition and the energy expended on basal metabolism and activity are complex and age dependent.

OBJECTIVE

The objective was to examine associations between body composition and daily (DEE), basal (BEE), and activity energy expenditure (AEE) throughout the adult life span.

DESIGN

A cross-sectional study was conducted in 529 adults aged 18-96 y. DEE was measured by using doubly labeled water, BEE by using respirometry, and body composition by isotope dilution. AEE was calculated as DEE - BEE, and physical activity level (PAL) was calculated as DEE/BEE.

RESULTS

Up to age 52 y, fat-free mass (FFM) and fat mass (FM) were positively associated with age in men, but no significant effect was observed in women. No effects of age on DEE and AEE were observed. The average DEE in men (14.1 MJ/d) was 27% greater than that in women (10.7 MJ/d). PAL averaged 1.84 in men and 1.75 in women. Above and including the age of 52 y, FFM, FM, DEE, BEE, and AEE were all negatively associated with greater age. The effect of age on AEE was greater than on BEE; consequently, PAL by the age of 95 y was only 1.36. PAL and AEE were both unrelated to FFM (both age adjusted).

CONCLUSIONS

PAL and AEE were not associated with age in subjects aged <52 y. AEE, BEE, and PAL were all negatively associated with age in subjects aged ≥52 y. An absence of a relation between age-adjusted PAL and FFM suggested that greater physical activity was not associated with higher FFM in the elderly.

Regulation of energy balance during long-term physical inactivity induced by bed rest with and without exercise training

BACKGROUND

Short-term physical inactivity affects energy balance and is considered conducive to weigh gain. Long-term effects are unknown.

OBJECTIVE

The objective of the study was to use a bed-rest model to determine the long-term effects of physical inactivity on energy balance regulation and test the effect of exercise training on energy balance adjustment to physical inactivity.

DESIGN

Sixteen lean women were divided into two groups (n = 8 each): a control group subjected to a strict 60-d bed rest and an exercise group subjected to a combined aerobic/resistive exercise training concomitantly to bed rest. Body composition, spontaneous energy intake, hunger, total energy expenditure (TEE), and fasting gut hormones were measured.

RESULTS

Based on bed-rest-induced body composition changes, the control group were in slight negative energy balance (-0.4 +/- 0.4 MJ/d; P = 0.01 vs. zero), essentially due to muscle atrophy (P < 0.001 vs. zero). The stable fat mass (P = 0.19 vs. zero), and the matching between spontaneous energy intake and TEE indicated, however, a stable energy balance. Hunger and gut hormones remained unchanged during the bed rest. In the exercise group, TEE was 24% higher than in the control group (P = 0.004). Unexpectedly, desire to consume food (P = 0.025) decreased and spontaneous energy intake (P = NS) was not stimulated, promoting a negative energy balance (-1.1 +/- 0.5 MJ/d, P = 0.0003 vs. zero).

CONCLUSIONS

Energy balance is regulated during 2 months of physical inactivity, contrasting with short-term experiments. Conversely, exercise-induced energy expenditure in bed-resting subjects who have no spontaneous physical activity did not induce hunger and promoted a negative energy balance, suggesting a potential role of nonexercise physical activities in energy balance regulation.

Activity energy expenditure and change in body composition in late life

BACKGROUND

Change in body composition, specifically loss of fat-free mass and gain in fat mass, in older adults is a major pathway leading to the onset of functional decline and physical disability.

OBJECTIVE

The objective was to determine the association of activity-related energy expenditure with change in body mass and composition among older men and women.

DESIGN

Total energy expenditure (TEE) was assessed over 2 wk by using the doubly labeled water method in 302 community-dwelling older adults aged 70-82 y. Resting metabolic rate (RMR) was measured by using indirect calorimetry, and the thermic effect of meals was estimated at 10% of TEE. Activity energy expenditure (AEE) was calculated as [TEE(0.9) - RMR]. Total body mass, fat-free mass (FFM), and fat mass (FM) were assessed by dual-energy X-ray absorptiometry annually over a mean (+/-SD) of 4.9 +/- 1.3 y.

RESULTS

In multivariate models adjusted for baseline age, smoking status, and race, men and women had a decline (in kg/y) in body mass (men: -0.34, 95% CI: -0.71, 0.02; women: -0.45, 95% CI: -0.71, -0.19) and FFM (men: -0.48, 95% CI: -0.67, -0.29; women: -0.14, 95% CI: -0.026, -0.03). No changes (in kg/y) were observed in FM (men: 0.14, 95% CI: -0.10, 0.38; women: -0.28, 95% CI: -0.49, -0.07). In men and women, higher AEE at baseline was associated with greater FFM. The average change in these outcomes (ie, slope), however, was similar across tertiles of AEE.

CONCLUSIONS

These data suggest that accumulated energy expenditure from all physical activities is associated with greater FFM, but the effect does not alter the trajectory of FFM change in late life.

Activity energy expenditure and mobility limitation in older adults: differential associations by sex

In this study, the authors aimed to determine whether higher activity energy expenditure, assessed by using doubly labeled water, was associated with a reduced decline in mobility limitation among 248 older community-dwelling US adults aged 70-82 years enrolled in 1998-1999. Activity energy expenditure was calculated as total energy expenditure (assessed over 2 weeks by using doubly labeled water) minus resting metabolic rate (measured with indirect calorimetry), with adjustment for the thermic effect of food. Across sex-specific tertiles of activity energy expenditure, men in the lowest activity group experienced twice the rate of mobility limitation as men in the highest activity group (41% (n = 18) vs. 18% (n = 8)). Conversely, women in the lowest and highest activity groups exhibited similarly high rates of mobility limitation (40% (n = 16) vs. 38% (n = 15)). After adjustment for potential confounders, men with higher activity energy expenditure levels continued to show reduced risk of mobility limitation (per standard deviation (284 kcal/day): hazard ratio = 0.61, 95% confidence interval: 0.41, 0.92). Women showed no association (per standard deviation (226 kcal/day): hazard ratio = 1.34, 95% confidence interval: 0.98, 1.85). Greater energy expenditure from any and all physical activity was significantly associated with reduced risk of developing mobility limitation among men, but not among women.

Dietary factors in relation to daily activity energy expenditure and mortality among older adults

OBJECTIVES

To examine the association between dietary factors to daily activity energy expenditure (DAEE) and mortality among older adults.

DESIGN AND SETTING

A sub-study of Health, Aging, and Body Composition study.

PARTICIPANTS

298 older participants (aged 70-82 years) in the Health, Aging, and Body Composition Energy Expenditure sub-study.

MEASUREMENTS

Dietary factors, DAEE, and all-cause mortality were measured in 298 older participants. Dietary factors include dietary intake assessed by the Block Food Frequency Questionnaire (FFQ), Healthy Eating Index (HEI), and self-reported appetite and enjoyment of eating. DAEE was assessed using doubly labeled water. All-cause mortality was evaluated over a 9 year period.

RESULTS

Participants in the highest tertile of DAEE were more likely to be men and to report having a 'good' appetite; BMI among men, proportion married, IL-6 and CRP levels and energy intake were also higher. Fewer black participants were in the 'good' HEI category. Participants in the 'good' HEI category had higher cognitive scores and a higher education level. Participants who reported improvement in their appetite as well as participants who reported a 'good' appetite were at lower risk for mortality (HR (95% CI): 0.42 (0.24-0.74) and 0.50 (0.26-0.88), respectively) even after adjusting for DAEE, demographic, nutritional and health indices.

CONCLUSIONS

We showed an association between DAEE and appetite and mortality among well-functioning, community-dwelling older adults. These findings may have some practical use for the health providers. Inclusion of a question regarding appetite of an elderly patient may provide important information regarding risk for health deterioration and mortality.

Assessing validity and reliability of resting metabolic rate in six gas analysis systems

The Deltatrac Metabolic Monitor (DTC) (VIASYS Healthcare Inc, SensorMedics, Yorba Linda, CA), one of the most popular indirect calorimetry systems for measuring resting metabolic rate (RMR) in human subjects, is no longer being manufactured. This study compared five different gas analysis systems to the DTC. RMR was measured by the DTC and at least one other instrument at three study sites for a total of 38 participants. The five indirect calorimetry systems included the MedGraphics CPX Ultima (Medical Graphics Corp, St Paul, MN), the MedGem (Microlife USA, Golden, CO), Vmax Encore 29 System (VIASYS Healthcare Inc, Yorba Linda, CA), the TrueOne 2400 (Parvo Medics, Sandy, UT), and the Korr ReeVue (Korr Medical Technologies, Salt Lake City, UT). Validity was assessed using paired t tests to compare means; reliability was assessed by using both paired t tests and root mean square calculations with F tests for significance. Within-subject comparisons for validity of RMR revealed a significant difference between the DTC and the Ultima system. Bland-Altman plot analysis showed significant bias with increasing RMR values for the Korr and MedGem systems. Respiratory exchange ratio (RER) analysis showed a significant difference between the DTC and the Ultima system and a trend for a difference with the Vmax system (P=0.09). Reliability assessment for RMR revealed that all instruments had a significantly larger coefficient of variation (CV) (ranging from 4.8% to 10.9%) for RMR compared to the 3.0% CV for the DTC. Reliability assessment for RER data showed none of the instrument CVs was significantly larger than the DTC CV. The results were quite disappointing because none of the instruments equaled the within-person reliability of the DTC. The TrueOne and Vmax systems were the most valid instruments in comparison with the DTC for both RMR and RER assessment. Further testing is needed to identify an instrument with the reliability and validity of the DTC.

Physical activity in aging: comparison among young, aged, and nonagenarian individuals

Physical activity (PA) is known to decline with age; however, there is a paucity of data on activity in persons who are in their nineties and beyond. We used objective and reliable methods to measure PA in nonagenarians (>or=90 yr; n=98) and hypothesized that activity would be similar to that of aged (60-74 yr; n=58) subjects but less than in young (20-34 yr; n=53) volunteers. Total energy expenditure (TEE) was measured by doubly labeled water over 14 days and resting metabolic rate (RMR) by indirect calorimetry. Measures of PA included activity energy expenditure adjusted for body composition, TEE adjusted for RMR, physical activity level (PAL), and activity over 14 days by accelerometry expressed as average daily durations of light and moderate activity. RMR and TEE were lower with increasing age group (P<0.01); however, RMR was not different between aged and nonagenarian subjects after adjusting for fat-free mass, fat mass, and sex. Nonagenarians had a lower PAL and were more sedentary than the aged and young groups (P<0.01); however, the nonagenarians who were more active on a daily basis walked further during a timed test, indicating higher physical functionality. For all measures of activity, no differences were found between young and aged volunteers. PA was markedly lower in nonagenarians compared with young and aged adults. Interestingly, PA was similar between young volunteers and those who were in their 60s and 70s, likely due to the sedentary nature of our society, particularly in young adults.

Modified MyPyramid for Older Adults

In 1999 we proposed a Modified Food Guide Pyramid for adults aged 70+ y. It has been extensively used in a variety of settings and formats to highlight the unique dietary challenges of older adults. We now propose a Modified MyPyramid for Older Adults in a format consistent with the MyPyramid graphic. It is not intended to substitute for MyPyramid, which is a multifunctional Internet-based program allowing for the calculation of individualized food-based dietary guidance and providing supplemental information on food choices and preparation. Pedagogic issues related to computer availability, Web access, and Internet literacy of older adults suggests a graphic version of MyPyramid is needed. Emphasized are whole grains and variety within the grains group; variety and nutrient density, with specific emphasis on different forms particularly suited to older adults' needs (e.g. frozen) in the vegetables and fruits groups; low-fat and non-fat forms of dairy products including reduced lactose alternatives in the milk group; low saturated fat and trans fat choices in the oils group; and low saturated fat and vegetable choices in the meat and beans group. Underlying themes stress nutrient- and fiber-rich foods within each group and food sources of nutrients rather than supplements. Fluid and physical activity icons serve as the foundation of MyPyramid for Older Adults. A flag to maintain an awareness of the potential need to consider supplemental forms of calcium, and vitamins D and B-12 is placed at the top of the pyramid. Discussed are newer concerns about potential overnutrition in the current food landscape available to older adults.

Total daily energy expenditure among middle-aged men and women: the OPEN Study

BACKGROUND

Few large doubly labeled water (DLW) studies have provided an objective measure of total energy expenditure (TEE) in free-living men and women. The committee that developed the 2002 Dietary Reference Intake (DRI) estimated energy requirements (EER) noted that DLW studies in adults aged 40 to 60 y were limited.

OBJECTIVE

We aimed to describe TEE and physical activity energy expenditure in middle-aged men and women by sex, age, menopausal status, and level of obesity, and to compare TEE to the DRI EER.

DESIGN

TEE was measured by the DLW method in 450 men and women aged 40-69 y from the Observing Protein and Energy Nutrition Study. Resting metabolic rate was estimated by use of the Mifflin equation.

RESULTS

Unadjusted TEE was lower in women than in men (591 kcal/d); however, when the analysis was adjusted for fat-free mass, women had significantly higher TEE than did men (182 kcal/d). This difference appeared to be due to higher physical activity levels in women (physical activity energy expenditure adjusted for FFM was 188 kcal/d greater in women than in men). Mean TEE was lowest in the seventh decade. TEE from DLW was highly correlated (r = 0.93) with EER from the DRI equations.

CONCLUSION

In this population, TEE was higher in women than in men when adjusted for FFM, apparently because of higher physical activity levels in women. There were no significant differences in TEE, FFM, or physical activity levels in women by menopausal status. TEE was inversely associated with age and increased linearly with body mass index. This study corroborates the use of the DRI equations for EER.

Energy requirements in frail elderly people: A review of the literature

This review collates studies of healthy, sick, underweight (BMI < or = 21 kg/m2) and very elderly people (> or = 90 yr), in whom resting energy expenditure (REE) was measured using indirect calorimetry. We have observed the following: (1) REE, when adjusted for differences in both body weight and fat-free mass (FFM), is similar in healthy and in sick elderly people being 20 and 28 kcal/kg of FFM per day, respectively, (2) their nutritional status influences their energy requirements given that weight-adjusted REE increases in line with a decrease in BMI, (3) total energy expenditure is lower in sick elderly people given that their physical activity level, i.e. the ratio of total energy expenditure to REE, is reduced during disease averaging at 1.36, (4) energy intake (EI) being only 1.23 x REE is insufficient to cover energy requirements in sick elderly patients, whereas the EI of healthy elderly people appears sufficient to cover requirements, and finally, (5) gender ceases to be a determinant of REE in people aged 60 yr or over, with the Harris & Benedict equation capable of accurately predicting mean REE in this population, whether healthy or sick.