A remotely-delivered pilot and feasibility program to promote physical and food literacy in adolescents with intellectual disabilities.

BACKGROUND: Youth with intellectual disabilities experience disparities in physical activity and diet quality. Physical and food literacy are hypothesised to support adoption of healthy lifestyles; however, few such interventions have been developed for this population. METHOD: Participants with intellectual disabilities ages 12-16 years were recruited for a 12-week online sports skills and nutrition education intervention. Feasibility, acceptability, and preliminary efficacy were assessed by attendance, satisfaction, and pre-post measures of motor skills, perceived competence and motivation for physical activity, classifying foods, making healthy choices, and food consumption. RESULTS: Six teens participated in the program and attended 87.5% of the sessions. Satisfaction data suggested that the program was well-received by both teens and parents. Trends toward improvements on physical activity and nutrition outcome measures were observed. CONCLUSIONS: Preliminary data from this pilot study suggest that physical and food literacy in youth with intellectual disabilities can be improved, which in turn may contribute to the adoption of healthy lifestyles.

Nutrient adequacy, dietary patterns and diet quality among children with and without intellectual disabilities.

BACKGROUND: Children with intellectual disabilities (ID) frequently have feeding problems, but there has been limited research on nutrient intake, dietary patterns and diet quality in this population. METHOD: Nutrient intakes, dietary patterns and the Healthy Eating Index were compared between 48 children with ID and 55 typically developing (TD) children aged 3-8 years who participated in the Children's Mealtime Study. Three-day food records that included two weekdays and one weekend day were used to assess dietary intake. Food intake was entered into the Nutrition Data System for Research for analysis of nutrient intake, dietary patterns and diet quality. Height and weight were measured to determine body mass index (BMI). The relation of dietary patterns to weight status was also assessed. RESULTS: Typically developing children and children with ID met the Estimated Average Requirement/Adequate Intake (EAR/AI) for most nutrients. However, a substantial number of children in both groups did not meet the EAR for vitamins E and D and calcium and the AI for vitamin K. Only one TD child met the AI for potassium. A small percentage of children in both groups did not meet the EAR for vitamin A and vitamin C, and in the ID group, a small percentage did not meet the EAR for vitamin B12 . Children in the ID group consumed, on average, fewer servings of vegetables than TD children (0.5 vs. 1.2, P < 0.001), but there was no significant difference in servings of fruit (0.8 vs. 1.1, respectively), fruit juice (less than a half serving in both groups), sugar-sweetened beverages (less than a half serving in both groups) or snacks (1.1 vs. 1.4, respectively) after adjusting for BMI z-score, parental education and race. We found a significant correlation between snack intake and BMI z-score among children with ID but not among TD children (r = 0.48, P < 0.0001 vs. r = 0.19, P = 0.16, respectively). The Healthy Eating Index indicated, on average, poor overall diet quality in both groups (58.2 in the ID group and 59.1 in the TD group). CONCLUSIONS: This study suggests that the diets of children with ID, as in TD children, need improvement. Targeting healthy eating in children with ID would improve diet quality and overall health.

Food selectivity, mealtime behavior problems, spousal stress, and family food choices in children with and without autism spectrum disorder.

Mealtime behavior problems and family stress occur frequently among families of children with autism spectrum disorder (ASD). However, it is unknown whether food selectivity is an associated factor. The associations of high food selectivity with mealtime behavior problems, spousal stress, and influence on family members were assessed among 53 children with ASD and 58 typically developing (TD) children ages 3-11 years. Compared to TD children, children with ASD were more likely to have high food selectivity, and their parents reported more mealtime behavior problems, higher spousal stress, and influence on what other family members ate. High food selectivity was associated with mealtime behavior problems in both groups. Interventions to reduce food selectivity may lead to decreases in mealtime behavior problems.

Is body mass index a useful measure of excess body fatness in adolescents and young adults with Down syndrome?

BACKGROUND: To determine the validity of body mass index (BMI) to identify excess fatness in youth with Down syndrome (DS). METHODS: Using the Centers for Disease Control and Prevention (CDC) growth reference, we defined overweight (≥ 85th percentile) and obesity (≥ 95th percentile) based on participants' age- and sex-specific BMI z-scores, calculated from measured height and weight. Percentage body fat was measured by dual-energy X-ray absorptiometry. We determined sensitivity, specificity, positive predictive value, negative predictive value and efficiency of BMI percentiles to identify excess adiposity relative to elevated percentage body fat cut-offs developed from the Pediatric Rosetta Body Composition project in 32 youth (20 boys/12 girls), ages 13-21 years with Down syndrome. RESULTS: For adolescents with Down syndrome using the cut-off points of 95th percentile for BMI (obesity), sensitivity and specificity were 71% and 96% respectively. Positive predictive value was 83% and negative predictive value was 92%. Overall efficiency was 91%. Sensitivity and specificity for BMI cut-offs above the 85th percentile (overweight) were 100% and 60% respectively. The positive predictive value was 41% and negative predictive value was 100%. Overall efficiency was 69%. CONCLUSION: On the whole, the obesity (≥ 95th percentile) cut-off performs better than the overweight cut-off (85th-94th percentile) in identifying elevated fatness in youth with DS.

Weight loss following a clinic-based weight loss program among adults with attention deficit/hyperactivity disorder symptoms.

OBJECTIVE: The purpose of the present study was to compare obese patients screening positive or negative for attention deficit/hyperactivity disorder (ADHD) on pretreatment body mass index (BMI), weight loss following a 16 week clinic-based behavioral weight loss program, weight loss attempts, dietary and physical activity habits, perceived difficulty of weight control skills, and eating self-efficacy. DESIGN: Patients who completed a behavioral weight loss program were approached to complete questionnaires on ADHD and eating habits. Medical charts were reviewed to obtain weight at pre- and post-treatment. RESULTS: Participants (N=63) were 75% female, mean age was 49 (SD=10.3), mean body mass index (BMI) was 41.4 kg/m² (SD=6.8) and 30% screened positive for ADHD on the Adult ADHD Symptom Rating Scale. Participants screening positive for ADHD did not have a higher BMI at baseline (p=0.41), but reported more previous weight loss attempts (p=0.01) and lost less weight (p=0.02) than participants who screened negative. Participants screening positive also reported consuming fast food meals more frequently (p=0.04), higher levels of emotional eating (p=0.002), greater difficulty with weight control skills (p=0.01), and lower eating self-efficacy (p=0.001). CONCLUSION: Attention-related problems appear to be common among weight treatment-seeking samples and represent a significant barrier to weight control that has not yet been addressed in the literature.

Modifiable risk factors in relation to changes in BMI and fatness: what have we learned from prospective studies of school-aged children?

Considerable interest and resources are currently being directed to primary and secondary prevention of childhood obesity among school-aged children. Intervention studies in this age group have yielded mixed results, begging the question as to whether the correct targets for intervention have been identified. To evaluate the evidence base, we reviewed prospective observational studies published in English between 1990-2007 that reported weight or fatness changes in relation to diet, physical activity, and sedentary behavior. Sugar-sweetened beverage consumption emerged as the most consistent dietary factor in association with subsequent increases in weight status or fatness. Other foods and eating patterns showed less consistent associations and when associations were present, magnitudes were generally small. This may reflect the known limitations of standard dietary methodology to assess meal patterns and dietary intake. Findings for physical activity showed more consistent inverse associations with fatness outcomes than for weight status, and as was found for dietary factors, magnitudes of association were modest. Sedentary behavior effects on weight status differ by gender in many studies, with many, but not all, showing greater positive associations among girls. The lack of consistency observed in the studies of sedentary behaviors may reflect the range of variable definitions, measurement challenges, and the changing nature of electronic media. The intrinsic interplay among eating patterns, activity and sedentary behavior adds further complexity to the interpretation of the results of these studies. More sophisticated approaches to the analysis of these complex data in future studies may maximize what is learned. Although the classic obesity risk factors seem to play a role in the development of excess weight and fatness, some more recently identified potential factors, such as sleep, warrant further investigation in prospective studies before they are ready for evaluation using more controlled study designs.

Change in leptin, body composition and other hormones around menarche--a visual representation.

AIM: To present a visual representation of changes in body composition, leptin, insulin, estradiol and follicular stimulating hormone (FSH) levels in relation to menarche in girls. METHODS: Participants were a subset of healthy girls (n = 108) enrolled in a longitudinal study of growth and development conducted at the General Clinical Research Center at the Massachusetts Institute of Technology (MIT). Participants were seen annually from before menarche until 4 years postmenarche for measures of body composition and serum levels of leptin, insulin, estradiol and FSH. Body composition was determined by bioelectrical impedance. Standardized body composition and hormone levels were smoothed and plotted relative to menarche to visualize patterns of change. RESULTS: At menarche, the mean percentage body fat (%BF) of girls was 24.6% (SD = 4.1%) after menarche %BF was approximately 27%. Leptin levels averaged 8.4 ng/mL (SD = 4.6) at menarche and were approximately 12 ng/mL after menarche. Changes in leptin levels closely paralleled changes in %BF. Insulin, estradiol and FSH levels followed expected patterns relative to menarche. Leptin began rising closer to menarche than did insulin or the other sex hormones. CONCLUSION: We provide a visual presentation of hormonal and body composition changes occurring throughout the pubertal period in girls which may be useful in generating new hypotheses related to the timing of menarche.

Dietary pattern as a predictor of change in BMI z-score among girls.

OBJECTIVES: To describe child and adolescent dietary patterns and to determine associations between childhood dietary pattern and longitudinal change in body mass index (BMI) z-score among girls. POPULATION AND METHODS: Healthy girls (n = 101) aged 8-12 years at baseline and 11-19 years at follow-up participated in a longitudinal study of growth and development. Participants kept 7-day dietary records at two points in time. We incorporated time of day, frequency, and amount of energy consumed (defined as percentage of total energy consumed per dietary event) when characterizing dietary patterns. RESULTS: Girls ate an average of 4-5 times per day and consumed most energy in the afternoon and in the evening/night, rather than in the morning. After controlling for baseline BMI, the mean percentage of daily energy consumed in the evening/night was positively associated with change in BMI z-score (P = 0.039). Eating between 4.0 and 5.9 times per day overall and no more than 1.9 times in the evening/night daily were negatively associated with change in BMI z-score (P = 0.002 and 0.047, respectively), after controlling for baseline BMI z-score. DISCUSSION: Recommendations to decrease the percentage of energy coming from the evening/night meal and the number of dietary events to no more than six times per day and two times in the evening/night should be evaluated in future longitudinal investigations.

Child temperament does not predict adolescent body composition in girls.

OBJECTIVES: Our previous cross-sectional analysis of MIT Growth and Development (MIT) Study girls showed that activity temperament, as assessed by a nine-item temperament questionnaire, was related to body composition and nonresting energy expenditure (NREE). In girls with lower levels of physical activity, having a high activity temperament was associated with a higher NREE. Percentage body fat was lower in girls with high vs low activity temperament. Based on these results, we hypothesized that, especially in girls with declining levels of physical activity over adolescence, high activity temperament in childhood would be protective against increased adiposity during adolescence. We tested this hypothesis with longitudinal data from the MIT study. DESIGN, SETTING, AND PARTICIPANTS: A total of 196 nonobese premenarcheal girls 8-12 y old were enrolled between 1990 and 1993. Girls were followed until 4 y postmenarche; average duration of follow-up was 7 y. MEASURES: Activity temperament was assessed at baseline by the girls' mothers with questions modified from those developed by Thomas and Chess that tapped predilection for movement. Temperament, the stylistic component of behavior, is considered relatively stable within an individual. Body composition was assessed by total body water at baseline and study completion (4 y postmenarche), and by bioelectrical impedance (BIA) annually. Physical activity was assessed annually by questionnaire, and by activity diary at baseline only. RESULTS: Child activity temperament was not associated with percentage body fat at 4 y postmenarche in multivariate regression models controlling for baseline percentage body fat, physical activity, parental obesity status, age at menarche, age at baseline, and race-ethnicity. Body composition of girls with low and high activity temperaments who reported declining levels of physical activity over adolescence was not statistically significantly different at study completion. In longitudinal models of percentage body fat by BIA, high activity temperament was not associated with lower adiposity. CONCLUSION: Although high activity temperament was associated cross-sectionally with lower percentage body fat and higher NREE, we did not find evidence to support our hypothesis that high child activity temperament would be protective for increased adiposity prospectively in our cohort of girls followed over the adolescent period.

Food purchased away from home as a predictor of change in BMI z-score among girls.

OBJECTIVES: To assess the relationship between eating food purchased away from home (FAH) and longitudinal change in body mass index (BMI) z-score among girls, and to assess the longitudinal tracking of eating FAH from childhood through adolescence. DESIGN: Participants kept 7-day dietary records at two points in time. The records included the place and time for all foods consumed. We recorded how often participants ate FAH, calculated the percent of total energy derived from FAH, and classified foods as quick-service food, coffee-shop food, or restaurant food. PARTICIPANTS: Healthy girls (n=101) between the ages of 8 and 12 y at baseline and 11 and 19 y at follow-up participated in a longitudinal study of growth and development at the Massachusetts Institute of Technology. STATISTICAL ANALYSES: Analysis of variance was used to assess the relationship between change in BMI z-score and both the frequency of eating FAH and energy derived from eating FAH. The participants' baseline BMI z-score was a significant covariate and was controlled for in both models. We used the kappa coefficient to assess FAH tracking from childhood through adolescence. RESULTS: The frequency of eating quick-service food at baseline was positively associated with change in BMI z-score (F=6.49, P<0.01). Participants who ate quick-service food twice a week or more at baseline had the greatest mean increase in BMI z-score compared to those who ate quick-service food once a week or not at all. Quick-service food eating tracked slightly from childhood through adolescence (k=0.17, P<0.05). DISCUSSION: Adolescent girls who eat quick-service food twice a week or more are likely to increase their relative BMI over time.

Relationship between temperament, nonresting energy expenditure, body composition, and physical activity in girls.

OBJECTIVES: To assess the extent that predilection for movement, as measured by a temperament questionnaire (activity temperament), contributes to nonresting energy expenditure and body composition in girls. DESIGN, SETTING, AND PARTICIPANTS: Baseline data for 196 premenarcheal non-obese girls aged 8-12 y were obtained from a longitudinal study of growth and development. The association of activity temperament with nonresting energy expenditure in girls with low and high levels of physical activity was evaluated, as was the association of activity temperament with body composition. MEASURES: Maternal reports of child activity temperament were obtained by questionnaire. Nonresting energy expenditure was calculated as total energy expenditure (measured by doubly labeled water) minus resting energy expenditure (obtained by indirect calorimetry). Body composition was estimated by total body water. Questionnaires and activity diaries were used to assess physical activity and sedentary behavior. RESULTS: Higher activity temperament was associated with higher nonresting energy expenditure after multivariate control for weight, vigorous activity, walking and light activity, and television viewing, although activity temperament did not account for a large percentage of the variability in nonresting energy expenditure (partial squared correlation coefficient=0.03). In girls with physical activity levels below the median, high activity temperament was associated with a mean+/-s.d., nonresting energy expenditure of 310+/-138 kJ (74+/-33 kcal) above that of girls with a low activity temperament. Girls with a high activity temperament had less body fat than did girls with a low activity temperament (21.6 vs 24.5%, a difference of 2.9 percentage points; 95% confidence interval, 1.3-4.4 percentage points). CONCLUSION: Predilection for movement, as measured by a temperament questionnaire, contributes to nonresting energy expenditure and may be useful in capturing an aspect of energy expenditure in population studies. The cross-sectional observation that girls with a high activity temperament were leaner than girls with a low activity temperament suggests that a constitutional predilection for movement may play a role in the development of obesity.

Energy cost of physical activities in 12-y-old girls: MET values and the influence of body weight.

BACKGROUND: Few data exist on the energy cost of specific activities in children. The influence of body weight on the energy cost of activity when expressed as metabolic equivalents (METs) has not been vigorously explored. OBJECTIVE: To provide MET data on five specific activities in 12-y-old girls and to test the hypothesis that measured MET values are independent of body weight. SUBJECTS AND METHODS: In 17 12-y-old girls, resting metabolic rate (RMR) and the energy expended while sitting, standing, walking on a flat treadmill at 3.2 and at 4.8 km/h, and walking on a treadmill at a 10% incline at 4.8 km/h were measured using indirect calorimetry. MET values were calculated by dividing the energy expenditure of an activity by the subject's RMR. The influence of body weight was assessed using simple linear regression. RESULTS: The observed METs were more consistent with published values for similar activities in adults than those offered for children. Body weight was a statistically significant predictor of the MET of all three walking activities, but not the MET of sitting or standing. Body weight explained 25% of the variance in the MET value for walking at 3.2 km/h, 39% for walking at 4.8 km/h, and 63% for walking at a 10% incline at 4.8 km/h. CONCLUSION: METs for the three walking activities were not independent of body weight. The use of average MET values to estimate the energy cost of these three activities would result in an underestimation of their energy cost in heavier girls and an overestimation in lighter girls. These results suggest that the estimation of total energy expenditure from activity diary, recall, and direct observation data using average MET values may be biased by body weight.

Dairy food consumption and body weight and fatness studied longitudinally over the adolescent period.

OBJECTIVE: Although research suggests that adolescents, particularly girls, may avoid dairy products due to concerns that these foods are 'fattening,' the longitudinal relation between consumption of dairy foods and relative weight status during adolescence has not been explored. Using data from the MIT Growth and Development Study, a longitudinal study designed to assess the metabolic, dietary, and behavioral factors that predict changes in body composition with growth and development in girls during the adolescent period, the current analysis was undertaken to examine the relation of dairy food intake with relative weight status and percentage body fat (%BF). SUBJECTS: A total of 196 nonobese premenarcheal girls 8-12 y old were enrolled between 1990 and 1993. Girls were followed until 4 y postmenarche. MEASUREMENTS: At each annual follow-up visit, data were collected on %BF by BIA, body mass index (BMI) z-score, and dietary intake (assessed by FFQ). The present analysis is limited to the 178 girls who have at least three annual visits and who have valid anthropometric and food frequency data. In all, 1198 individual measurements were analyzed. RESULTS: At study entry, participants had a mean (s.d.) BMI z-score of -0.27 (0.89), a mean (s.d.) %BF of 23.4 (4.7), and obtained 19.9% (9.2) of daily calories from dairy foods. Linear mixed effects modeling indicated no relationship between BMI z-score or %BF and measures of dairy food or calcium consumption. CONCLUSION: Avoidance of dairy foods due to a possible association with relative body weight is not supported by these findings. We find no evidence that dairy food consumption is associated with BMI z-score or %BF during adolescence, but further research specifically designed to address this question is needed.

Comparison of high-calorie, low-nutrient-dense food consumption among obese and non-obese adolescents.

OBJECTIVE: The purpose of this study was to determine whether obese adolescents eat more high-calorie low-nutrient-dense foods than non-obese adolescents. RESEARCH METHODS AND PROCEDURES: Using a cross-sectional design, 22 non-obese and 21 obese adolescents kept 14-day food records. Records provided estimates of total daily energy intake and caloric intake from five categories of high-calorie, low-nutrient-dense (HC) foods: candy, chips, soda, baked goods, and ice cream. Body composition was determined by 18O dilution and daily energy expenditure by doubly labeled water. Percentage of energy intake reported (%report) was calculated as the ratio of reported energy intake to measured energy expenditure (x 100%). RESULTS: Both groups underreported energy intake, but the percentage reported was significantly greater in the non-obese group (78.2+/-20.5% non-obese vs. 55.5+/-21.8% obese, p<0.001). Consumption of calories from chips and soda was similar among non-obese and obese adolescents. However, total energy intake from all HC foods was higher in the non-obese group than among the obese (617+/-356 kcal/day vs. 362+/-223 kcal/day; p<0.01) and represented 27.2+/-10.5% and 19.9+/-9.6% of reported energy intake in the non-obese and obese groups, respectively. After adjustment for under-reporting, the percentage of calories provided by each of the HC foods was similar in the obese and non-obese groups except for ice cream, which remained significantly greater in the non-obese group (p<0.05). DISCUSSION: Our findings suggest that both non-obese and obese adolescents consume a substantial portion of reported calories from HC foods and that obese adolescents do not consume more calories from these foods than non-obese adolescents. These data offer no evidence to support the widespread notion that obese adolescents eat more "junk food" than non-obese adolescents. Health professionals who treat obese adolescents must be aware that the excess calories in their diets may come from a variety of food sources and not solely from high-calorie snack foods.

Body fatness and bioelectrical impedance in non-obese pre-menarcheal girls: comparison to anthropometry and evaluation of predictive equations.

OBJECTIVES: To determine in non-obese pre-menarcheal girls if bioelectrical impedance (BIA) is a better predictor of body fatness than triceps skinfold (TSF) or body mass index (BMI) and to cross-validate published equations for determination of fat-free mass (FFM) from BIA in pre-menarcheal girls. DESIGN: Cross-sectional analysis of data from 132 non-obese pre-menarcheal girls. The relationship of percent body fat (%BF), derived from isotopic dilution of H2 18O to TSF, BMI, and %BF by BIA, calculated from measures of height, weight and resistance was examined by correlation analysis. SETTING: Massachusetts Institute of Technology (MIT) Clinical Research Center in Cambridge, MA, USA. SUBJECTS: Pre-menarcheal girls aged 8-12 y were recruited from local schools, MIT summer day camp and by word of mouth. RESULTS: TSF accounted for 68% of the explained variance (R2) in the prediction of %BF measured by H2 18O, compared to 38% for BMI and 70% for BIA. Prediction of FFM by comparison of published equations was evaluated in this population. The predictive ability differed by Tanner stage. Kushner's equation (Kushner et al, 1992), based solely on height2/resistance was the only equation that provided estimates that did not differ significantly from measured values among all Tanner stages. CONCLUSIONS: BIA appears to be a valid and reliable measure of FFM but is no better than TSF in predictions of body fat.

Validity of reported energy intake in preadolescent girls.

Energy intake and energy expenditure were assessed in 109 girls aged 8-12 y. Intake was estimated from a 7-d dietary record based on household measures. Expenditure was measured with the doubly labeled water technique during 2-wk period. Overall, the mean (+/-SD) energy intake was 7.0 +/- 1.67 MJ/d and the mean energy expenditure was 8.03 +/- 1.28 MJ/d. The mean difference between intake and expenditure was 1.03 +/- 1.77 MJ/d (P < 0.0001). The mean proportion of actual intake reported was 88.3 +/- 21.0%. Multivariate-regression analysis showed that age and total daily energy expenditure were significantly and independently related to the reporting error. Coefficients for age and total daily energy expenditure were both positive, indicating that as age and daily energy expenditure increased, the magnitude of the error of reporting increased. Income, ethnicity, parental obesity, and body fat were not significantly related to accuracy of reporting. The use of food records to determine energy intake appears to provide more accurate results in younger than in older girls, and the accuracy of the method apparently decreases as energy expenditure increases.

The impact of physical activity on lipids, lipoproteins, and blood pressure in preadolescent girls.

OBJECTIVE: Inconsistent findings reported for the effect of physical activity on lipids, lipoproteins, and blood pressure in children may be due to errors inherent in the methods used to measure physical activity, lack of control for other cardiovascular risk factors, or both. The purpose of this study was to evaluate the association between physical activity assessed using direct measures of energy expenditure and cardiovascular risk factors, controlling for dietary intake and percent body fat. METHODS: Nonresting energy expenditure was determined in 49 8- to 11-year-old girls from measurements of daily energy expenditure (using doubly-labeled water, 2H2(18)O) and resting metabolic rate (using indirect calorimetry). Self-reported recall of the hours of participation in physical activities of at least moderate intensity (energy expenditure at least four times the resting metabolic rate, METS > or = 4) during the previous year was also obtained. Percent body fat was estimated from the measurement of total body water with H2(18)O. Concentrations of total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol (LDL-C), apolipoprotein B (apo B), apo A-I, lipoprotein (a), insulin, and estradiol, as well as the waist-to-hip ratio, systolic blood pressure, diastolic blood pressure, and dietary intake from 7-day food records were measured. Data were analyzed using Pearson product-moment correlation and stepwise multiple regression. RESULTS: Self-reported hours of participation in activities with METS (metabolic equivalents) of 4 or greater significantly predicted LDL-C and apo B concentrations, even after adjustment for percent body fat and percentage of dietary energy from saturated fat. Nonresting energy expenditure adjusted for weight, a measure of the energy spent on physical activity, did not predict LDL-C or high-density lipoprotein cholesterol concentrations. Body mass index and insulin concentration predicted systolic and diastolic blood pressure, respectively. CONCLUSIONS: These findings suggest that the intensity of physical activity may be a more important determinant of LDL-C in children than the energy spent on physical activity.

Effect of age on body water and resting metabolic rate.

BACKGROUND: We previously reported that differences in fat-free mass (FFM) estimated by isotope dilution of 18O-labeled water could not fully account for lower resting metabolic rates (RMR) in old men and women compared to RMR in young men. METHODS: Since age-related changes in the distribution of water between extracellular and intracellular spaces could lead to overestimation of FFM in the old, we reanalyzed our data using estimates for total body and intracellular water (TBW and ICW, respectively) derived from published equations and included data from adolescent boys and girls studied under similar conditions. RESULTS: In both sexes, the age-related reduction in RMR remained significant after adjustment for estimated body water compartments (p < .05). While adjusted RMR differed in boys and girls (p < .0001), it did not in old men and women (p = .15). CONCLUSION: We conclude that aging per se reduces RMR in lean tissue, a difference which cannot be fully explained by changes in body water or its distribution. Investigators should be cautious when selecting models and equations to estimate body water compartments.

Accuracy of standardized equations for predicting metabolic rate in premenarcheal girls.

Several different equations based on height, weight, sex, and age are available to predict metabolic rate in children and adolescents. The purpose of this study was to determine which of the published standardized equations most accurately predicts metabolic rate in premenarcheal girls. Resting metabolic rate (RMR) was measured in 186 premenarcheal girls by using open-circuit indirect calorimetry with a ventilated hood. Measured RMR was compared with equations provided by the FAO/WHO/UNU, the Mayo Clinic, and Robertson and Reid for girls of the same age. The accuracy of each equation differed for each Tanner stage. The Mayo Clinic standards significantly differed from measured RMR among girls in Tanner stages 1 and 2. The Robertson and Reid standards differed from measured RMR for girls in Tanner stage 1. Only the FAO/WHO/UNU equation predictions did not differ from measured RMR for all Tanner stages studied. These results indicate that the FAO/WHO/UNU equation is the best predictor of RMR in premenarcheal girls at different stages of development. Furthermore, because RMR measured under inpatient and outpatient conditions did not differ significantly, an overnight measurement is not necessary for a reliable determination of RMR.

Estimation of energy requirements in persons with severe central nervous system impairment.

We measured resting metabolic rate (RMR) in 12 persons (aged 10 to 30 years) with severe impairment of the central nervous system requiring gastrostomy feedings, and compared our findings with the RMR predicted from standardized equations. The RMR was 70.6% +/- 15.7% of that predicted from the Mayo Clinic nomogram, 63.7% +/- 18% of that predicted from the Food and Agriculture Organization/World Health Organization/United Nations University equation, and 75.4% +/- 17.3% of that predicted from the Robertson and Reid equation. Energy intake was 756 +/- 225 kcal/day and RMR was 708 +/- 231 kcal/day; RMR adjusted for changes in body energy stores was 729 +/- 231 kcal/day. No significant differences were found between energy intake and RMR, or between energy intake and the sum of RMR and changes in body energy stores. These findings demonstrate that standardized equations overestimate energy needs of individuals with severe CNS impairment. Measures of energy intake adjusted for weight changes represent a valid method to determine energy requirements in a group of individuals with severe CNS impairment. Length was found to be significantly correlated with RMR (r = 0.79; p < 0.01). When the regression equation was tested on another group of subjects from the same residential facility, the equation predicted energy needs reasonably well for those individuals with similar energy intakes but not for all patients with CNS disorders.