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M J Toth

Publications and source records attributed to M J Toth.

At least 37 records · Page 2Linked to original sources

Energy expenditure in wasting diseases: current concepts and measurement techniques.

Weight loss occurs secondary to many acute and chronic disease states. The measurement of energy balance is crucial to understanding disease-related changes in body composition. This review considers various techniques for measuring energy expenditure in wasting diseases and the current concepts regarding the effect of disease on energy expenditure.

Calorimetry, Indirect↗

Misreporting of total energy intake in older men and women.

Misreporting of total energy intake occurs frequently in dietary studies. Relatively few studies have been performed in older individuals who may be vulnerable to obesity and its associated health risks. In the present study, we examined misreporting of total energy intake by comparing self-reported food intake, measured by 3-day food diaries, to energy expenditure, measured with the doubly labeled water technique, in a relatively large sample of older men (n = 39) and women (n = 43). An additional objective was to identify potential predictors of misreporting, including body composition, fitness as assessed by peak VO2, and sociodemographic characteristics such as gender, living arrangement, education, and income. In general, men and women underreported total energy intake. The magnitude of the underreporting, as measured by percent difference between reported intake and measured total energy expenditure, was comparable between the sexes. Body mass index, waist circumference, and fat mass were significant correlates of underreporting of total energy intake, with heavier individuals underreporting more than leaner individuals. Among the demographic variables, living arrangement was a significant determinant of misreporting of total energy intake in older people. Individuals in marriage-like living arrangements underreported their total energy intake to a greater extent than married individuals. However, the magnitude of misreporting by those living alone did not differ from that of married individuals. The results of the present study highlight the need to examine misreporting of total energy intake in older individuals, who are more prone to obesity and its health risks.

Aged↗

Hormonal and physiological correlates of energy expenditure and substrate oxidation in middle-aged, premenopausal women.

An understanding of the hormonal and physiological correlates of energy expenditure and substrate oxidation in middle-aged women will increase our knowledge of factors that promote changes in energy balance and adiposity. We measured resting and postprandial energy expenditure and substrate oxidation in 59 middle-aged, premenopausal women (mean+/-sD age, 47+/-2 yr) to examine the hormonal and physiological correlates of energy and substrate metabolism. Energy expenditure and substrate oxidation were measured at rest using indirect calorimetry and urinary nitrogen excretion and for 180 min after the ingestion of a liquid meal (10 kcal/kg fat-free mass; 410+/-44 Cal). Fasting hormone levels were measured by RIA, glucose tolerance was determined by a 75-g oral glucose tolerance test, body composition was measured by dual energy x-ray absorptiometry, and peak aerobic capacity was determined by a treadmill test. Using stepwise regression analysis, we found that resting energy expenditure was predicted by fat-free mass and serum leptin concentration (r2 = 66%; P < 0.01), fat oxidation was predicted by resting energy expenditure (r2 = 17%; P < 0.01), and carbohydrate oxidation was predicted by serum leptin and appendicular skeletal muscle mass (r2 = 21%;P < 0.01). Novariables were related to postprandial energy expenditure or substrate oxidation. We conclude that in middle-aged, premenopausal women, variation in resting energy expenditure and substrate oxidation is primarily explained by fat-free mass and serum leptin levels. Thus, changes in metabolically active tissue mass or leptin concentration may partially contribute to changes in resting energy expenditure or substrate oxidation in middle-aged women.

Adult↗

Sex hormone-binding globulin levels in middle-aged premenopausal women. Associations with visceral obesity and metabolic profile.

OBJECTIVE: Low sex hormone-binding globulin (SHBG) levels in women are associated not only with hyperinsulinemia, increased risk for cardiovascular disease, and type 2 diabetes but also with excess body fatness and abdominal obesity. We tested the hypothesis that an elevated total or intra-abdominal adipose tissue accumulation mediates the relationship between low SHBG levels and an altered metabolic profile. RESEARCH DESIGN AND METHODS: We measured body composition (dual-energy X-ray absorptiometry [DEXA]) and body fat distribution (computed tomography) in 52 middle-aged (46.7 +/- 0.4, mean +/- SEM) premenopausal women. Insulin and glucose responses to a 75-g oral glucose load and plasma lipid-lipoprotein levels were also measured. RESULTS: Low plasma SHBG concentrations were associated with increased total body fat mass (r = -0.41, P < 0.005) and subcutaneous abdominal (r = -0.39, P < 0.005) and intra-abdominal (r = -0.37, P < 0.008) adipose tissue area. Low SHBG was also associated with a greater insulin response to oral glucose (r = -0.40, P < 0.005), higher triglyceride levels (r = -0.29, P < 0.05), higher cholesterol/HDL cholesterol ratio (r = -0.51, P < 0.005), but lower HDL cholesterol concentrations (r = 0.65, P < 0.005). When matched for intra-abdominal fat or total fat mass, subjects with either low or high SHBG showed no difference in the insulin response to an oral glucose challenge. Statistical adjustment for differences in intra-abdominal adipose tissue accumulation or total body fat mass also eliminated the associations between SHBG levels and metabolic variables, with the exception of the association between SHBG and HDL cholesterol levels (r = 0.52, P < 0.005). CONCLUSIONS: Our results suggest that the previously reported relationship between low SHBG levels and increased metabolic disease risk in women is mediated, to a large extent, by concomitant variation in body fatness and intra-abdominal adipose tissue accumulation.

Adipose Tissue↗

Assessment of research-based body composition techniques in healthy elderly men and women using the 4-compartment model as a criterion method.

OBJECTIVE: To examine the accuracy, precision and bias of body fat estimates using traditional research based techniques, relative to those derived from a 4-compartment model in healthy, older men and women. DESIGN AND SUBJECTS: Cross-sectional comparison of various body composition techniques in 41 healthy women (68.2 +/- 6.6 y) and 41 healthy men (70.2 +/- 7.0 y) with an age range of 57-90 y. METHODS: Fat mass (FM) by the 4-compartment (4C) model was compared to that derived by dual energy X-ray absorptiometry (DXA), underwater weight (UWW) and total body water (TBW). RESULTS: On a group mean basis, FM by the 4C model (24.4 +/- 7.4 kg in women, 18.2 +/- 7.6 kg in men) was similar to other techniques. The regression between FM by 4C and DXA significantly deviated from the line of identity (FM by 4C = 0.76*FM by DXA + 5.9 kg for women; 0.81*FM by DXA + 3.4 kg for men). FM by UWW was similar to FM by 4C model in men but not women (FM by 4C = 0.87*FM by UWW + 4.3 kg). FM by TBW was similar to FM by 4C model in women, but not men (FM by 4C = 0.80*FM by TBW + 4.7 kg). For DXA, there was no significant bias in estimates of FM in men or women. For UWW, there was significant bias in men with an over-estimate of FM among leaner subjects and under-estimates in fatter subjects. For TBW data, there was a significant bias in men with an under-estimate of FM among leaner subjects and over-estimate in fatter subjects. CONCLUSIONS: Individual estimates of FM by DXA can be improved by correction factors that calibrate experimental data to standards such as the 4-C model. The assumptions of the Siri 2 compartment model are appropriate in healthy elderly men but not women, where a new equation is suggested. Inaccuracies in FM from TBW data are likely to be explained by age-related changes in the hydration of fat free mass (FFM).

Absorptiometry, Photon↗

Fat distribution and plasma lipid-lipoprotein concentrations in pre- and postmenopausal women.

OBJECTIVE: In the postmenopausal years, women develop a central pattern of fat distribution and an increased risk of developing cardiovascular disease (CVD). The possibility that these events are related has not been extensively investigated. The object of the present study was to test the hypotheses that, 1) menopause-related differences in lipids are associated with greater estimated intra-abdominal adiposity, and 2) the relationship between individual adipose depots and plasma lipids differs with menopausal status. DESIGN: Cross-sectional. SUBJECTS: 141 healthy pre- and postmenopausal women aged 35-65 y. MEASUREMENTS: Total body fat by hydrodensitometry was used as an index of whole-body adiposity, the sum of five central skinfold measurements as an index of subcutaneous upper-body adiposity, and estimated intra-abdominal adipose tissue (IAF) as an index of visceral adiposity. Fasting plasma concentrations of total cholesterol (total-C), high- and low-density-lipoprotein cholesterol (HDL-C, LDL-C), and triglycerides were used as indices of CVD risk. RESULTS: Postmenopausal women had greater total body fat (P < 0.001), summed central skinfolds (P < 0.01), estimated IAF (P < 0.001), higher plasma concentrations of total-C (P < 0.001), LDL-C (P < 0.001) and triglycerides (P < 0.001), than premenopausal women. The relationship between central skinfolds and LDL-C differed with menopausal status, being significant in pre- but not postmenopausal women. Adjustment for estimated IAF with analysis of covariance decreased menopause-related differences in levels of total-C, LDL-C and triglycerides by approx 40-70%. CONCLUSION: These observations suggest that, 1) menopause-related changes in IAF may adversely affect the plasma lipid profile, and 2) menopausal status affects the relationship between central subcutaneous fat and LDL-C. Studies with measured IAF are needed to confirm present results.

Adipose Tissue↗

Total daily energy expenditure in free-living older African-Americans and Caucasians.

Low rates of daily energy expenditure, increased energy intake, or a combination of both contribute to obesity in African-Americans. We examined whether African-Americans have lower rates of free-living daily energy expenditure than Caucasians. One hundred sixty-four (> 55 yr) volunteers (37 African-American women, 52 Caucasian women, 28 African-American men, and 47 Caucasian men) were characterized for total daily energy expenditure, resting metabolic rate, and physical activity energy expenditure from the doubly labeled water method and indirect calorimetry. Absolute total daily energy expenditure was lower in women than men but was not different between African-Americans and Caucasians. However, we found race and gender differences in total daily energy expenditure after controlling for differences in fat-free mass. Total daily energy expenditure was 10% lower (P < 0.01) in African-Americans compared with Caucasians due to a 5% lower resting metabolic rate (P < 0.01) and 19% lower physical activity energy expenditure (P = 0.08). Moreover, total daily energy expenditure was 16% lower (P < 0.01) in women compared with men due to a 6% lower resting metabolic rate (P = 0.09) and a 37% lower physical activity energy expenditure (P = 0.06). Low rates of energy expenditure may be a predisposing factor for obesity, particularly in African-American women.

Aged↗

Energy requirements and physical activity in free-living older women and men: a doubly labeled water study.

Determinants of daily energy needs and physical activity are unknown in free-living elderly. This study examined determinants of daily total energy expenditure (TEE) and free-living physical activity in older women (n = 51; age = 67 +/- 6 yr) and men (n = 48; age = 70 +/- 7 yr) by using doubly labeled water and indirect calorimetry. Using multiple-regression analyses, we predicted TEE by using anthropometric, physiological, and physical activity indexes. Data were collected on resting metabolic rate (RMR), body composition, peak oxygen consumption (VO2 peak), leisure time activity, and plasma thyroid hormone. Data adjusted for body composition were not different between older women and men, respectively (in kcal/day): TEE, 2,306 +/- 647 vs. 2,456 +/- 666; RMR, 1,463 +/- 244 vs. 1,378 +/- 249; and physical activity energy expenditure, 612 +/- 570 vs. 832 +/- 581. In a subgroup of 70 women and men, RMR and VO2 peak explained approximately two-thirds of the variance in TEE (R2 = 0.62; standard error of the estimate = +/-348 kcal/day). Crossvalidation of this equation in the remaining 29 women and men was successful, with no difference between predicted and measured TEE (2,364 +/- 398 and 2,406 +/- 571 kcal/day, respectively). The strongest predictors of physical activity energy expenditure (P < 0.05) for women and men were VO2 peak (r = 0.43), fat-free mass (r = 0.39), and body mass (r = 0.34). In summary, RMR and VO2 peak are important independent predictors of energy requirements in the elderly. Furthermore, cardiovascular fitness and fat-free mass are moderate predictors of physical activity in free-living elderly.

Adolescent↗

Energy requirements and physical activity of older free-living African-Americans: a doubly labeled water study.

We examined daily energy requirements and determinants of physical activity in older, free-living African-American women (n = 37; age, 64 +/- 8 yr) and men (n = 28; age, 64 +/- 7 yr). Total daily energy expenditure and its components [i.e. resting metabolic rate (RMR) and physical activity energy expenditure] were determined using doubly labeled water and indirect calorimetry. Body composition from dual energy x-ray absorptiometry, maximal oxygen consumption from a graded treadmill test, and leisure time physical activity from a structured interview were determined. Total daily energy expenditure adjusted for body composition was lower (P < 0.05) for women (2198 +/- 621 kcal/d) than for men (2633 +/- 669 kcal/d) due to a lower RMR (1431 +/- 240 vs. 1576 +/- 259 kcal/d; P = 0.07) and physical activity energy expenditure (548 +/- 559 vs. 794 +/- 603 kcal/d; P = 0.19), respectively. The physical activity level ratio (i.e. total daily energy expenditure/RMR) was not different from Food and Agriculture Organization/World Health Organization/United Nations University recommendations (i.e. 1.51) for women (1.51 +/- 0.25), but was higher for men (1.71 +/- 0.32). The strongest correlates with physical activity energy expenditure were age for women (r = -0.44; P < 0.01) and maximal oxygen consumption for men (r = 0.39; P < 0.05). These data show that daily energy requirements are significantly lower in African-American women compared to men, primarily due to lower levels of physical activity energy expenditure. Furthermore, lower levels of cardiovascular fitness in men and advancing age in women are associated with lower physical activity energy expenditure.

Aged↗

Gender differences in fat oxidation and sympathetic nervous system activity at rest and during submaximal exercise in older individuals.

1. Gender differences in fat oxidation at rest and during exercise may contribute to higher body fat in women. We examined gender differences in fat oxidation at rest and during submaximal exercise and their relationship to sympathetic nervous system activity, free fatty acid availability, body composition and aerobic capacity in older volunteers. 2. We measured free fatty acid kinetics using [14C]palmitate, absolute (micromol/min) and relative (respiratory quotient) rates of fat oxidation by indirect calorimetry and sympathetic nervous system activity from noradrenaline kinetics using [3H]noradrenaline in 12 older men (70+/-4 years) and 12 older women (66+/-4 years) at rest and during 30 min of submaximal exercise (45% of peak oxygen consumption). 3. At rest, men oxidized more fat than women on both an absolute (88+/-19 versus 51+/-15 micromol/min; P<0.01) and relative (respiratory quotient: 0.80+/-0. 04 versus 0.85+/-0.04; P<0.01) basis. These differences were not related to noradrenaline appearance rate, free fatty acid concentration, body composition or aerobic capacity. During exercise, fat oxidation was higher (P<0.05 to P<0.01) in men on an absolute level, but respiratory quotient did not differ. Higher absolute fat oxidation in men during exercise was explained by their higher absolute workload. Plasma free fatty acids and free fatty acid rate of appearance did not differ between men and women during exercise despite higher (P<0.05 to P<0.01) plasma noradrenaline concentrations in men. 4. We conclude that: (i) resting fat oxidation is higher in older men compared with older women independent of differences in noradrenaline appearance rate, free fatty acid availability, body composition or aerobic capacity, and (ii) despite higher plasma noradrenaline concentrations during submaximal exercise, no gender differences in free fatty acid appearance rate or fat oxidation were found. These results suggest a sex dimorphism in post-absorptive fat metabolism in the elderly.

Aged↗

Skeletal muscle atrophy and peak oxygen consumption in heart failure.

We measured skeletal muscle mass and peak oxygen consumption (VO2) in 13 cachectic heart failure patients, 14 noncachectic patients, and in 52 healthy controls to examine skeletal muscle atrophy and its relation to low peak VO2 in heart failure patients. Our results show that skeletal muscle atrophy is associated with prior weight loss and is related to low peak VO2 in heart failure patients.

Aged↗

Structural definition of the C5a C terminus by two-dimensional nuclear magnetic resonance spectroscopy.

The serum glycoprotein C5a, which is derived from the proteolytic cleavage of complement protein C5, has been implicated in the pathogenesis of a number of inflammatory and allergic conditions. Because C5a induces an inflammatory response upon binding to a specific receptor, structural and mutagenesis studies were carried out to gain a better understanding of this binding interaction. These studies led to the first structural definition of the C terminus of recombinant human (rh)-C5a, determined by two-dimensional nuclear magnetic resonance (NMR) spectroscopy. Our results show that the C terminus adopts an alpha-helical conformation spanning residues 69 to 74, while the core domain exists as an antiparallel alpha-helical bundle. This C-terminal helix is connected to the core by a short loop that orients Arg 74 adjacent to Arg 62. Point mutation analysis had already revealed that residues 62 and 74 significantly contribute to agonist activity and receptor binding. Correlation of the C5a tertiary structure with mutational analyses clarifies the significance of the functional and binding properties of Arg 62 and suggests that both Arg 62 and Arg 74 interact at the same binding site on the receptor.

Amino Acid Sequence↗

Plasma leptin concentrations and energy expenditure in heart failure patients.

Leptin, the protein encoded by the obese gene, is a newly described hormone implicated in the regulation of energy balance. To examine the possible role of leptin in the energy dysregulation that frequently accompanies chronic heart failure, we examined plasma leptin concentrations and energy expenditure in 18 heart failure patients (aged 71 +/- 6 years) and 46 healthy elderly controls (66 +/- 6 years). Plasma leptin concentrations were measured by radioimmunoassay, daily energy expenditure by doubly labeled water, and body composition by dual-energy x-ray absorptiometry. Fat mass was lower (P < .01) in heart failure patients compared with healthy controls, whereas fat-free mass did not differ between groups. Plasma leptin concentrations were not different between heart failure patients and healthy controls (5.1 +/- 4.2 v 6.8 +/- 4.4 pg/mL) and remained similar after statistical control for fat mass (6.0 +/- 3.1 v 7.1 +/- 3.2 pg/mL). Plasma leptin was related to fat mass in heart failure patients (r = .92, P < .01) and healthy controls (r = .69, P < .01). Free-living daily and physical-activity energy expenditures were lower (P < .01) in heart failure patients compared with healthy controls. Plasma leptin concentrations were related to both daily (r = .67, P < .01) and resting (r = .67, P < .01) energy expenditure in heart failure patients, but not in healthy controls (r = .09 and r = .33, respectively). In conclusion, we found an association between plasma leptin concentrations and energy expenditure in heart failure patients, but not in healthy controls. Thus, leptin may participate in the regulation of energy expenditure and body energy stores in heart failure patients.

Aged↗

Daily energy requirements in heart failure patients.

Diminished body cell mass in heart failure patients contributes to poor prognosis and decreased quality of life. The level of daily energy intake needed to maintain body cell mass and optimal physiological function in heart failure patients is unknown. Thus, we examined daily energy expenditure in free-living heart failure patients to estimate daily energy requirements. Daily energy expenditure (doubly labeled water) and its components (resting and physical activity energy expenditures) were measured in 26 heart failure patients (25 men and one woman aged 69 +/- 7 years) and 50 healthy controls (48 men and two women aged 69 +/- 6 years). Resting energy expenditure was measured by indirect calorimetry; physical activity energy expenditure from the difference between daily and resting energy expenditure; body composition by dual-energy x-ray absorptiometry; leisure time physical activity from a questionnaire; and peak oxygen consumption ([peak VO2] n = 16 heart failure patients) from a treadmill test to exhaustion. Plasma markers of nutritional status were also considered. Daily energy expenditure was 17% lower (2,110 +/- 500 v 2,543 +/- 449 kcal/d) and physical activity energy expenditure 54% lower (333 +/- 345 v 728 +/- 374 kcal/d) in heart failure patients compared with healthy controls. Daily energy expenditure was related to physical activity energy expenditure (r = .79, P < .01), resting energy expenditure (r = .63, P < .01), leisure time physical activity (r = .63, P < .01), and peak VO2 (r = .58, P < .01) in heart failure patients. Stepwise regression analysis showed that daily energy requirements in heart failure patients were best estimated by a combination of resting energy expenditure and reported leisure time physical activity (total R2 = 61%; standard error of the estimate, +/- 333 kcal/d). Daily energy requirements predicted from equations derived in healthy elderly were inaccurate when applied to heart failure patients, deviating -10% to +30% from measured daily energy expenditure. We conclude that despite low levels of activity, markers of physical activity predicted daily energy needs in heart failure patients. We provide a new equation to estimate energy needs in free-living heart failure patients based on measurements of daily energy expenditure.

Absorptiometry, Photon↗

Prediction of resting energy needs in older men with heart failure.

OBJECTIVES: Patients with congestive heart failure are often undernourished. The measurement of resting energy expenditure has served as the basis upon which estimates of daily caloric needs have been developed. Resting energy needs, however, in heart failure patients are unknown. We have developed a new equation to predict resting energy needs in heart failure patients that takes into account easily measured clinical variables and symptom severity. DESIGN: Observational. SETTING: Baltimore VA Medical Center. SUBJECTS: Forty male patients with heart failure aged, 57-85 y; (27 Class II; 13 Class IV). MEASUREMENTS: Resting metabolic rate was measured by indirect calorimetry, fat-free mass and fat mass by dual energy X-ray absorptiometry, peak VO2 by a treadmill test. Symptom severity was measured by the New York Heart Association classification. Ejection fraction, plasma albumin and plasma glucose were also assessed. RESULTS: Stepwise regression analysis showed that body weight, fasting glucose, plasma albumin and New York Heart Association classification accounted for 83% of the variation in resting energy needs. The regression equation had a root mean square error of 130 kcal (544 kJ) per day. The equation is: RMR (kcal/d) = 12.2 (wt, kg) + 1.6 (glucose, gm/dl) + 103 (NYHA; III, IV)-144 (albumin, mg/dl) + 755. Moreover, prediction equations based on observations in healthy individuals significantly underestimated resting energy needs in heart failure patients. CONCLUSION: We offer a new equation to predict resting energy needs in heart failure patients based upon readily available clinical measurements. Further studies are needed to cross-validate our equation.

Absorptiometry, Photon↗

Gender differences in resting metabolic rate and noradrenaline kinetics in older individuals.

The physiological factors mediating gender differences in resting metabolic rate (RMR) in older individuals are presently unclear. We examined the contribution of sympathetic nervous system activity to gender differences in resting metabolic rate in older men and women and its relation to body fat distribution. We performed measurements of noradrenaline (NA) kinetics from infusions of [3H]-NA, RMR, body fat distribution, body composition, peak Vo2 and dietary intake in 29 older men (69 +/- 6 years) and 26 older women (65 +/- 5 years). Older men weighed more (P < 0.01) and had a greater fat-free mass (P < 0.01) and a larger waist circumference (P < 0.01) than older women. Older men had a higher RMR (P < 0.05) than older women, which persisted after controlling for differences in fat-free mass and fat mass. Older men also showed a greater NA appearance rate (P < 0.01) at rest than older women. The higher NA appearance rate in older men was partly related to their greater waist circumference (r = 0.50, P < 0.01). We explored the sympathetic contribution to gender differences in RMR by statistically controlling for differences in body composition and NA appearance rate. After this procedure, we found no gender differences in adjusted RMR between older men (4.3 +/- 0.5 kJ min(-1)) and older women (4.3 +/- 0.4 kJ min(-1)). Our results suggest that: (a) older men have a higher RMR than older women independent of differences in body composition; (b) the higher RMR in older men may be partly due to higher levels of sympathetic nervous system activity; (c) the higher sympathetic nervous system activity in older men is partly related to their greater waist circumference, a proxy measure of central body fatness.

Aged↗

Menopause-associated changes in plasma lipids, insulin-like growth factor I and blood pressure: a longitudinal study.

We examined the effects of the menopause transition on plasma lipids, insulin-like growth factor I (IGF-I) and blood pressure. An initial cohort of 38, non-smoking, healthy premenopausal women (44-48 years) were examined at baseline and after a 6-year follow-up period. At follow-up, 18 women had spontaneously stopped menstruating, whereas 17 women remained premenopausal. Women who experienced natural menopause showed a greater decline in high-density lipoproteins (-5 +/- 4 mg dL-1 vs. -1 +/- 3 mg dL-1; P < 0.01) and a greater increase in low-density lipoproteins (13 +/- 12 vs. 5 +/- 10 mg dL-1; P < 0.05) and fasting triglycerides (14 +/- 15 vs. 5 +/- 11 mg dL-1; P < 0.05) than women who remained premenopausal. No menopause effect was noted for total cholesterol. We noted a greater decline in IGF-I levels in women who experienced a natural menopause (-21 +/- 11 ng mL-1) than women who remained postmenopausal (-4 +/- 10 ng mL-1). Systolic blood pressure increased in postmenopausal (13 +/- 10 mmHg) compared with premenopausal women (5 +/- 4 mmHg: P < 0.01), whereas no menopause effect was noted for diastolic blood pressure. The increase in the waist-to-hip ratio was related to a decrease in high-density lipoprotein (r = -0.49; P < 0.05) and increase in low-density lipoprotein (r = 0.48; P < 0.05). The decline in IGF-I was related to the decline in reported leisure time physical activity (0.44: P < 0.05). We conclude that the natural menopause transition is associated with a worsening of the lipid profile and decline in IGF-I, which might be mitigated by deleterious changes in body fat distribution and physical activity.

Adult↗

Cross-validation of anthropometric and bioelectrical resistance prediction equations for body composition in older people using the 4-compartment model as a criterion method.

OBJECTIVE: To cross-validate existing equations in the literature for their accuracy and precision for estimating body fat in older people from anthropometric measures and height2/resistance, using the 4-compartment model as a criteria method, and to propose new practical equations with improved accuracy and precision. DESIGN: Measurement of body composition in a cross-sectional cohort of healthy men and women and comparison by cross-validation techniques against existing prediction equations. SETTING: The study was performed on subjects admitted to a General Clinical Research Center. PARTICIPANTS: The subjects were 41 healthy women (68.2 +/- 6.6 years; 64.1 +/- 10.2 kg) and 41 healthy men (70.2 +/- 7.0 years; 74.9 +/- 11.0 kg). MEASUREMENTS: The criteria method for total body composition was the 4-compartment model based on measurement of total body density by underwater weight, total body water by isotope dilution, and total bone mineral from dual energy X-ray absorptiometry. The other techniques examined for accuracy and validity were body fat estimates derived by skinfolds using the Durnin and Womersley Equations; waist circumference and age using the Lean Equations; and bio-electrical resistance using five published equations, including two derived in the older population. RESULTS: When compared with data derived from the 4-compartment model, the skinfold equation of Durnin and Womersley was cross-validated successfully in women but not in men. The Baumgartner equation was the only bioelectrical resistance equation that met the criteria for successful cross-validation in men and women, although in women the intercept (4.0 +/- 2.1 kg) was close to significantly different from zero (P = .06). Error in the estimates of body fat using the Durnin and Womersley and the Baumgartner equations was significantly and inversely related to fat mass (r = -.39 to r = -.56). In our data, the significant predictors of fat mass were hip circumference, calf skinfold, gender, body weight, height2/resistance, and biceps skinfold, explaining 84% of the variance. CONCLUSIONS: The Durnin and Womersley equation is accurate for women and the Baumgartner equation is accurate for both men and women if a correction of +4 kg is made in women; however, for both equations the error in the estimate is inversely related to fat mass. We suggest new anthropometric equations for estimating body fat in older people, which may improve accuracy and precision. The new equations will need to be tested in independent cross-validation studies.

Adipose Tissue↗