Cross-calibration of eight-polar bioelectrical impedance analysis versus dual-energy X-ray absorptiometry for the assessment of total and appendicular body composition in healthy subjects aged 21-82 years

Obesity in young-adult Nigerians: variations in prevalence determined by anthropometry and bioelectrical impedance analysis, and the development of % body fat prediction equations

Background

Overweight/obesity is a growing global public health concern. The variations in the prevalence of overweight/obesity, defined by Body Mass Index (BMI), Waist Circumference (WC), Waist-to-Height Ratio (WHtR), Waist-to-Hip Ratio (WHpR) and Bioelectrical Impedance Analysis (BIA), were studied and a prediction equation for % body fat (%BF) developed.

Methods

A total of 1584 subjects (56.4% males) were recruited for the study. Data on age, gender, height, weight, hip circumference and WC were collected from the subjects using standard protocols. BMI, WHtR and WHpR were derived using standard equations. %BF was measured using a BIA device (Omron BF-400). Appropriate statistical tools were used for the data analysis.

Results

The prevalence of overweight/obesity in the population was 28.4% (36.3% for males; 22.6% for females) (BIA); 20.7% (17.5% for males; 24.8% for females) (BMI); 7.5% (1.3% for males; 16.1% for females) (WC); 2.9% (4.3% for males; 1.2% for females) (WHpR); and 15.4% (14.8% for males; 16.2% females) (WHtR). Taking BIA as the reference point, WC misclassified overweight/obesity the most for males (35%), while for the females, WHpR misclassified both disorders the most (21.4%). Correlation studies showed that only BMI correlated significantly, albeit weakly, with %BF among the males, whereas all the anthropometric measures, but WHpR correlated significantly with % body fat in females. Two prediction equations for %BF were generated, and %BF predicted with the two equations correlated significantly (P < 0.001) with that measured by BIA.

Conclusion

The prevalence of overweight/obesity in this population vary widely depending on the definition used. The developed prediction equations could be useful in resource-poor settings, but require validation.

Effects of aquatic and dry land resistance training devices on body composition and physical capacity in postmenopausal women

To determine the effects of a supervised strength training program on body composition and physical capacity of older women using three different devices: weight machines, elastic bands, and aquatic devices that increase drag forces (ADIDF). Four groups were formed: control group, weight machine group (WMG), elastic band group (EBG) and a group that used ADIDF (ADIDFG). Body composition and physical capacity were assessed before and after the intervention period. The ADIDFG showed improvements in fat mass (FM), fat-free mass of the left arm (FFM-LA) and right arm (FFM-RA), knee push-up test (KPT), squat test (ST) and crunch test (CT) (p <0.05). Individuals in the EBG and WMG also improved their FM, fat free mass (FFM), FFM-LA, FFM-RA, KPU, ST and CT. ADIDF training improves body composition and physical capacity of postmenopausal women as does performing land-based training programs.

Effectiveness of a tai-chi training and detraining on functional capacity, symptomatology and psychological outcomes in women with fibromyalgia

Background. The purpose was to analyze the effects of Tai-Chi training in women with fibromyalgia (FM). Methods. Thirty-two women with FM (mean age, 51.4 ± 6.8 years) attended to Tai-Chi intervention 3 sessions weekly for 28 weeks. The outcome measures were: tenderness, body composition, functional capacity and psychological outcomes (Fibromyalgia impact questionnaire (FIQ), Short Form Health Survey 36 (SF-36)). Results. Patients showed improvements on pain threshold, total number of tender points and algometer score (all P < 0.001). The intervention was effective on 6-min walk (P = 0.006), back scratch (P = 0.002), handgrip strength (P = 0.006), chair stand, chair sit & reach, 8 feet up & go and blind flamingo tests (all P < 0.001). Tai-Chi group improved the FIQ total score (P < 0.001) and six subscales: stiffness (P = 0.005), pain, fatigue, morning tiredness, anxiety, and depression (all P < 0.001). The intervention was also effective in six SF-36 subscales: bodily pain (P = 0.003), vitality (P = 0.018), physical functioning, physical role, general health, and mental health (all P < 0.001). Conclusions. A 28-week Tai-Chi intervention showed improvements on pain, functional capacity, symptomatology and psychological outcomes in female FM patients.

Birth-weight and resting metabolic rate in adulthood - sex-specific differences

INTRODUCTION

Low birth-weight is associated with an increased risk of cardiovascular disease, hypertension, and the metabolic syndrome (MetS) in adulthood. Resting metabolic rate (RMR) has been suggested to be associated with the development of obesity as well as MetS and might be an indirect indicator of sympathetic activity. This study's aim was to examine the association between birth-weight and adult RMR.

METHODS

A total of 896 men and women from the Helsinki Birth Cohort Study born 1934-44, for whom a detailed set of birth records were available, underwent measurement of body composition and RMR in adulthood.

RESULTS

Among women, birth-weight adjusted for age and fat-free mass (FFM) was inversely associated with RMR (r = -0.12; P < 0.01). For men, a u-shaped relationship was observed, both independently and after adjustment for age, fat mass, and FFM (P = 0.05 for final model).

DISCUSSION

The sex-specific differences for the association between birth-weight and adult RMR might partly be explained by differences in the developmental programming of the sympathetic nervous system between men and women. The higher adjusted RMR among those with the lowest birth-weights is consistent with previous evidence of higher sympathetic drive among these individuals.

Are there gender differences in quality of life and symptomatology between fibromyalgia patients?

The purpose of this study is to examine gender differences in quality of life (QoL) and symptomatology in fibromyalgia (FM) patients. A total of 20 men (48.0 ± 8.0 years) and 78 women (49.8 ± 7.2 years) with FM participated in the study (age range 31-63 years). Health-related QoL and FM impact were assessed by means of the Spanish versions of the Short-Form-36 Health Survey (SF36) and the Fibromyalgia Impact Questionnaire (FIQ), respectively. Comparisons in QoL were performed using one-way analysis of covariance adjusted by age and body mass index (BMI), and comparisons in FIQ dimensions were performed using Mann-Whitney test. Overall FM impact, as measured by FIQ-total score (p = .01) and FIQ-physical impairment (p = .02) was higher in men, whereas women presented higher values of FIQ-fatigue and FIQ-morning tiredness (p = .04) and less SF36-vitality (p = .02). Therefore, women appear to feel more fatigue, whereas men present higher FM overall impact. Due to the small number of men included in this study and the consequent small statistical power, these results should be taken as preliminary. Higher powered studies are warranted to further address gender differences in FM in order to design more successful treatments.

North Korean refugee health in South Korea (NORNS) study: study design and methods

Background

Understanding the health status of North Korean refugees (NKRs), and changes in health during the resettlement process, is important from both the humanitarian standpoint and the scientific perspective. The NOrth Korean Refugee health iN South Korea (NORNS) study aims to document the health status and health determinants of North Korean refugees, to observe various health outcomes as they occur while adapting to the westernized lifestyle of South Korea, and to explain the mechanisms of how health of migrants and refugees changes in the context of new environmental risks and opportunities.

Methods

The NORNS study was composed of an initial survey and a follow-up survey 3.5 years apart. Participants were recruited voluntarily among those aged 30 or more living in Seoul. The survey consists of a health questionnaire and medical examination. The health questionnaire comprises the following six domains: 1) demographic and migration information 2) disease history, 3) mental health, 4) health-related lifestyle, 5) female reproductive health, and 6) sociocultural adaptation. The medical examination comprises anthropometric measurements, blood pressure and atherosclerosis, and various biochemical measurements. Prevalence of several diseases able to be diagnosed from the medical examination, the changes between the two surveys, and the association between the outcome and other measurements, such as length of stay and extent of adaptation in South Korea will be investigated. Furthermore, the outcome will be compared to a South Korean counterpart cohort to evaluate the relative health status of NKRs.

Discussion

The NORNS study targeting adult NKRs in South Korea is a valuable study because various scales and medical measurements are employed for the first time. The results obtained from this study are expected to be utilized for developing a health policy for NKRs and North Korean people after unification. Additionally, since NKRs are an immigrant group who are the same race and have the same genetic characteristics as South Koreans, this study has the characteristics of a unique type of migrant health study.

Higher serum testosterone is associated with increased risk of advanced hepatitis C-related liver disease in males

Males have strikingly increased risk of advanced liver disease. However, the association between testosterone and risk of hepatitis C virus (HCV)-related advanced liver disease is unknown. We performed a cross-sectional study in male veterans with chronic HCV. Blood samples were obtained to measure total serum testosterone and perform the FibroSURE-ActiTest. Other risk-factor data were obtained through systematic questionnaires (e.g., alcohol), physical measurements (e.g., body mass index), and serological tests (e.g., viral load). The association between total testosterone and risk of advanced hepatic fibrosis (F3 and F3/F4) and inflammatory activity (A3 and A2/3) measured by the FibroSURE-ActiTest was evaluated with logistic regression. A total of 308 eligible study participants were prospectively recruited (mean age: 57; 52% African-American). There were 105 cases with advanced fibrosis and 203 mild fibrosis controls as well as 88 cases with advanced inflammatory activity and 220 mild activity controls. Mean total serum testosterone was significantly higher in advanced fibrosis cases as well as advanced inflammatory activity cases, compared to mild disease controls (6.0 versus 5.3 ng/mL and 5.9 versus 5.4 ng/mL, respectively). We observed a significant 25% increase in advanced fibrosis risk and 15% increase in advanced inflammatory activity risk for each 1-ng/mL increase in total serum testosterone. Total testosterone in the upper tertile was associated with an even greater excess risk of advanced fibrosis than advanced inflammatory activity (odds ratio [OR](adjusted advanced fibrosis) = 3.74; 95% CI: 1.86-6.54 versus OR(adjusted advanced inflammatory activity) = 2.23; 95% CI: 1.07-4.93, respectively).

CONCLUSIONS

Total serum testosterone is associated with an increased risk of both advanced hepatic fibrosis and advanced hepatic inflammatory activity in HCV-infected men. Testosterone may be important in the pathogenesis of HCV-related advanced liver disease in males.

The utility of visceral fat level by bioelectrical impedance analysis in the screening of metabolic syndrome - the results of the Kyushu and Okinawa Population Study (KOPS)

AIM

A simple, non-invasive medical device, using bioelectrical impedance analysis (BIA) for the evaluation of visceral fat level (VFL) was developed recently. The aim of this study was to investigate the utility of VFL by BIA in the screening of metabolic syndrome (MetS).

METHODS

VFL was measured by the BIA device in 1,451 Japanese residents (546 men and 905 women, age range 30-69 years).

RESULTS

VFL had significant positive correlations with waist circumference (WC) and body mass index (r=0.772 and 0.849, all P < 0.0001). The overall MetS prevalence using Japanese Diagnosis Criteria was 19.8%: men 36.3% and women 9.8%. The mean VFL of the participants with MetS was significantly higher than those without MetS (men; 12.1 and 9.4, women; 13.3 and 8.7) (both P < 0.001). VFL significantly correlated with blood pressure, lipid profiles, fasting plasma glucose, and hemoglobin A1c (all P < 0.001). Receiver operating characteristic curve analysis for a diagnosis of two or more MetS risk factors excluding WC resulted in the same cutoff values for the VFL (10.0) of men and women.

CONCLUSIONS

The VFL by BIA is useful for the detection of MetS because it is correlated with all metabolic parameters and shows the same normal limit in both sexes.

Fibromyalgia's key symptoms in normal-weight, overweight, and obese female patients

Factors affecting the symptomatology of fibromyalgia (FM) are not fully understood. The aim of the present study was to analyze the relationship of weight status with pain, fatigue, and stiffness in Spanish female FM patients, with special focus on the differences between overweight and obese patients. The sample comprised 177 Spanish women with FM (51.3 ± 7.3 years old). We assessed tenderness (using pressure algometry), pain and vitality using the General Health Short-Form Survey (SF36), and pain, fatigue, morning tiredness, and stiffness using the Fibromyalgia Impact Questionnaire (FIQ). The international criteria for body mass index was used to classify the patients as normal weight, overweight, or obese. Thirty-two percent were normal-weight, 35% overweight, and 32% obese. Both overweight and obese patients had higher levels of pain than normal-weight patients, as assessed by FIQ and SF36 questionnaires and tender point count (p < .01). The same pattern was observed for algometer score, yet the differences were not significant. Both overweight and obese patients had higher levels of fatigue, and morning tiredness, and stiffness (p < .05) and less vitality than normal-weight patients. No significant differences were observed in any of the variables studied between overweight and obese patients. In conclusion, FM symptomatology in obese patients did not differ from overweight patients, whereas normal-weight patients significantly differed from overweight and obese patients in the studied symptoms. These findings suggest that keeping a healthy (normal) weight is not only associated with decreased risk for developing FM but might also be a relevant and useful way of improving FM symptomatology in women.

Pain and functional capacity in female fibromyalgia patients

OBJECTIVE

To examine the association between pain and functional capacity levels.

DESIGN

[corrected] Cross-sectional study.

SETTING

University of Granada.

SUBJECTS

One hundred twenty-three women with fibromyalgia (51.7 ± 7.2 years).

OUTCOME MEASURES

We measured weight and height, and body mass index (BMI) was calculated. We assessed tender points by pressure pain and functional capacity by means of the 30-second chair stand, handgrip strength, chair sit and reach, back scratch, blind flamingo, 8-ft up and go and 6-minute walk tests.

RESULTS

We observed an association of tender points count with the chair stand and 6-minute walk tests (r = -0.273, P = 0.004 and r = -0.183, P = 0.046, respectively). These associations became nonsignificant once the analyses were adjusted by weight or BMI. We observed an association of algometer score with the back scratch, chair stand, and 6-minute walk tests (r = 0.238, P = 0.009; r = 0.363, P < 0.001; and r = 0.186, P = 0.043, respectively), which remained after adjusting for weight or BMI, except the association between algometer score and the 6-minute walk test that became nonsignificant once the analyses were adjusted by weight. Prevalence of overweight and obesity was 39.2 and 33.3%, respectively.

CONCLUSIONS

There is an inverse association of tender points count with the chair stand and distance walked in the 6-minute walk tests, and a positive association of algometer score with the chair stand, distance walked in the 6-minute walk and back scratch tests, yet, weight status seems to play a role in these associations.

Accuracy of direct segmental multi-frequency bioimpedance analysis in the assessment of total body and segmental body composition in middle-aged adult population

BACKGROUND & AIMS

Body composition measurement is a valuable tool for assessing nutritional status and physical fitness in a variety of clinical settings. Although bioimpedance analysis (BIA) can easily assess body composition, its accuracy remains unclear. We examined the accuracy of direct segmental multi-frequency BIA technique (DSM-BIA) in assessing different body composition parameters, using dual energy X-ray absorptiometry (DEXA) as a reference standard.

METHODS

A total of 484 middle-aged participants from the Leiden Longevity Study were recruited. Agreements between DSM-BIA and DEXA for total and segmental body composition quantification were assessed using intraclass correlation coefficients and Bland-Altman plots.

RESULTS

Excellent agreements were observed between both techniques in whole body lean mass (ICC female = 0.95, ICC men = 0.96), fat mass (ICC female = 0.97, ICC male = 0.93) and percentage body fat (ICC female = 0.93, ICC male = 0.88) measurements. Similarly, Bland-Altman plots revealed narrow limits of agreements with small biases noted for the whole body lean mass quantification but relatively wider limits for fat mass and percentage body fat quantifications. In segmental lean muscle mass quantification, excellent agreements between methods were demonstrated for the upper limbs (ICC female≥0.91, ICC men≥0.87) and lower limbs (ICC female≥0.83, ICC male≥0.85), with good agreements shown for the trunk measurements (ICC female = 0.73, ICC male = 0.70).

CONCLUSIONS

DSM-BIA is a valid tool for the assessments of total body and segmental body composition in the general middle-aged population, particularly for the quantification of body lean mass.

Efficacy of Biodanza for treating women with fibromyalgia

OBJECTIVE

The objective of this study was to determine the effects of a 3-month Biodanza intervention in women with fibromyalgia (FM).

DESIGN

This was a controlled trial.

SETTING/LOCATION

The study was conducted at a university research laboratory and social center.

SUBJECTS

The study comprised 59 women with FM recruited from a local association of patients with FM. Participants were allocated to the Biodanza intervention group (n = 27) or usual-care group (n = 32).

INTERVENTION

The Biodanza intervention was carried out once a week for 3 months.

OUTCOME MEASURES

The outcome measures included the following: Pain threshold, body composition (body-mass index and estimated body fat percentage), physical fitness (30-second chair stand, handgrip strength, chair sit and reach, back scratch, blind flamingo, 8 feet up and go, and 6-minute walk test) and psychologic outcomes (Fibromyalgia Impact Questionnaire [FIQ], Short-Form Health Survey 36, Vanderbilt Pain Management Inventory, Hospital Anxiety and Depression Scale, General Self-Efficacy Scale, and Rosenberg Self-Esteem Scale).

RESULTS

We observed a significant interaction effect (group*time) for pain threshold of several tender points (left [L] and right [R] side of the anterior cervical and supraspinatus, trapezius L and lateral epicondyle R, algometer score, tender points count), body fat percentage, and FIQ total score. In the intervention group, post hoc analysis revealed a significant improvement in pain threshold of the anterior cervical R and L and supraspinatus R and L tender points (all p < 0.05), algometer score (p = 0.008), tender point count (p = 0.002), body fat percentage (p = 0.001), and FIQ total score (p = 0.003).

CONCLUSIONS

A 3-month (one session per week) Biodanza intervention shows improvements on pain, body composition, and FM impact in female patients.

Negative association between metabolic syndrome and bone mineral density in Koreans, especially in men

Cardiovascular disease and osteoporosis are thought to share common risk factors, and metabolic syndrome (MS) is composed of major risk factors for cardiovascular disease. This study was performed to investigate the relationships between specific MS components and bone mineral density (BMD). BMD was measured at the femoral neck of Korean men aged 40 years or more (n = 1,780) and postmenopausal women (n = 1,108) using dual-energy X-ray absorptiometry. We identified subjects with MS as defined by two criteria, International Diabetes Federation (IDF) and American Heart Association/National Heart, Lung, and Blood Institute (AHA/NHLBI). Body fat and lean mass were measured via bioimpedance analysis. The prevalence of MS was 19.8% and 7.7% in men and 20.8% and 11.6% in postmenopausal women according to the AHA/NHLBI definition and the IDF definition, respectively. After multivariate adjustment, femoral neck BMD was significantly lower in subjects with MS regardless of diagnostic criteria. BMD decreased as the number of MS components increased (P < 0.001 for trends in both sexes). Among MS components, waist circumference was the most important factor in this negative association. When multiple linear regression models were applied to each 5-kg weight stratum to test for a linear trend, waist circumference and fat mass were negatively associated with BMD and lean mass was positively associated with BMD in men but not in women. MS was associated with a lower BMD in Korean men and postmenopausal women, suggesting that visceral fat may lead to bone loss, especially in men.

Oxygen uptake for cycling in relation to body composition: a pilot study

The purpose of this study was to investigate the relationship between oxygen uptake (VO2) for cycle ergometry and body composition in untrained healthy young men. Fifty-six men underwent body composition measurements and ramp work rate tests at 60 revolutions/minute on a cycle ergometer. Cell mass (CM), fat mass (FM), lean body mass (LMB) and total body mass (TBM) were assessed by multifrequency and segmental bioelectric impedance analysis. Resting, unloaded, and peak VO2 were determined by a gas analyzer, and their relationships with CM, FM, LBM, and TBM were analyzed. Values of VO2/TBM were positively related to the increasing CM/TBM ratios (p < 0.05-0.01). However, VO2/CM did not change with anthropometric characteristics (p > 0.05). Resting, unloaded and peak VO2 were more strongly related to CM (p < 0.005-0.001) than to FM, LBM or TBM. Our findings revealed that FM, LBM and TBM least affected the relationship between VO2 and CM. These data suggest that CM actually provides the preferred frame of reference for estimating the VO2 for cycle ergometry at 60 revolutions/minute in untrained healthy young men.

New method of predicting dry weight using bioelectrical impedance analysis in haemodialysis patients

AIM

There were significant differences in the slopes of the ultrafiltration (UF) amount removed during haemodialysis (HD) sessions versus the percentage change in the extracellular fluid/total body water ratio for the right lower extremity (ECF/TBW(right leg)) plot in normohydrated (NH) and overhydrated states. The purpose of this study was to develop and validate a method for predicting dry weight (DW) using these results.

METHODS

It was hypothesized that for patients to become NH, the slope of the UF amount versus the percentage changes in ECF/TBW(right leg) plot should be same as that of NH patients and a method for predicting DW was developed. To validate the accuracy of this method, the ECF/TBW(right leg) was measured by eight-point tactile-electrode bioelectrical impedance analysis before and after HD in 17 newly enrolled NH patients. Using the current DW (cDW) of subjects as a reference, we compared the accuracies of pDW1 (our devised method) and pDW2 (the normovolaemia/hypervolaemia slope method).

RESULTS

The mean cDW, pDW1 and pDW2 values were 56.8 +/- 7.9, 56.4 +/- 7.7 and 56.3 +/- 8.0 kg, respectively. No significant differences existed between cDW, pDW1 and pDW2. pDW1 had a lower root mean square error than pDW2 (1.12 vs 1.69). On the Bland-Altman plot, differences between pDW1 and cDW were closer to zero than between pDW2 and cDW.

CONCLUSION

A new method was developed of predicting the DW using the relationship between the UF amount and the percentage change in the ECF/TBW ratio of the lower extremities after HD. The devised method appears to be as accurate as the normovolaemia/hypervolaemia slope method.

Physical activity and body composition changes during military service

PURPOSE

To examine how body composition changes in different body mass index (BMI) categories among young Finnish men during military service, which is associated with marked changes in diet and physical activity. In addition, this study examined how reported previous physical activity affected the body composition changes.

METHODS

Altogether 1003 men (19 yr) were followed throughout their military service (6-12 months). Height, weight, BMI, waist circumference, and waist-to-hip ratio (WHR) were recorded. Previous physical activity was assessed at the beginning of the service by a questionnaire. Body composition was measured by bioelectrical impedance assessments (BIA) at the beginning and at the end of the service. The measured parameters were fat mass (FM), fat percentage (fat %), fat-free mass (FFM), visceral fat area (VFA), lean body mass (LBM), and skeletal muscle mass (SMM).

RESULTS

On average, military training decreased weight by 0.7%, FM by 9.7%, fat % by 6.6%, and VFA by 43.4%. FFM increased by 1.3%, LBM by 1.2%, and SMM by 1.7%. The group of underweight and normal-weight men gained weight, FM, and FFM, whereas overweight and obese men lost weight and FM and gained FFM. FM was most reduced in the groups of overweight (20.8%) and obese (24.9%) men. The amount of VFA was reduced in all BMI groups (38%-44%). Among overweight men who reported being inactive previous to the military service, more beneficial changes in body composition were observed compared with those who reported being physically active.

CONCLUSIONS

The lifestyle changes associated with military service markedly reduce fat tissue and increase the amount of lean tissue. These beneficial changes are prominent among previously inactive subjects with high BMI.

Body composition at high altitude: a randomized placebo-controlled trial of dietary carbohydrate supplementation

BACKGROUND

Body mass loss is inevitable with chronic hypoxic exposure. However, the exact body-composition changes, their causes, and possible treatments remain unknown.

OBJECTIVE

The objective was to investigate body composition during a high-altitude expedition by using non-empirically derived methods, experimentally manipulating energy intake, and investigating the influence of initial body composition.

DESIGN

Forty-one participants completed a 21-d expedition in the Himalayas. Energy intake was manipulated with a double-blind, placebo-controlled, randomized trial of carbohydrate energy supplementation. Body composition was assessed before and after the expedition by using a 4-component model including fat mass, total body water, bone mineral mass, and residual mass (principally protein and glycogen). Data were analyzed by repeated-measures analysis of variance.

RESULTS

Participants allocated to receive carbohydrate were given an additional 15,058 +/- 6211 kcal over the 21-d expedition (>6 kcal x kg(-1) x d(-1)). Nevertheless, the functionally important residual mass decreased in both groups by 6% (main effect of time: P = 0.021), with no effect of allocation (interaction effect: P = 0.116). Similar decreases were observed for fat mass (11%) and total body water (3%), which were also unabated by allocation. Furthermore, high initial fat mass (by median split) did not preserve residual mass (high-fat compared with low-fat participants: residual loss = 5% compared with 8%; P = 0.990).

CONCLUSIONS

High-altitude exposure decreased body mass, including the functionally important residual component. These losses were not abated by increasing energy intake or an initially high fat mass. Factors other than negative energy balance must contribute to body-composition changes with chronic hypoxia. This trial was registered at clinicaltrials.gov as NCT00731510.

Body composition in psychotic disorders: a general population survey

BACKGROUND

The literature suggests an association between obesity and schizophrenia but fat mass and fat-free mass, which have been shown to be more predictive of all-cause mortality than only waist circumference and obesity [body mass index (BMI) 30 kg/m2], have not been reported in psychotic disorders. We examined the detailed body composition of people with different psychotic disorders in a large population-based sample.

METHOD

We used a nationally representative sample of 8082 adult Finns aged 30 years with measured anthropometrics (height, weight, waist circumference, fat percentage, fat-free mass and segmental muscle mass). Psychiatric diagnoses were based on a consensus procedure utilizing the Structured Clinical Interview for DSM-IV (SCID)-interview, case-notes and comprehensive register data.

RESULTS

Schizophrenia (including schizo-affective disorder) was associated with obesity [odds ratio (OR) 2.3, 95% confidence interval (CI) 1.5-3.6], abdominal obesity (waist circumference 88 cm for women, 102 cm for men) (OR 2.2, 95% CI 1.3-3.6) and with higher fat percentage (mean difference 3.8%, 95% CI 2.0-5.7%), adjusted for age and gender, than in the remaining sample. The associations between schizophrenia and low fat-free mass and decreased muscle mass on trunk and upper limbs became statistically significant after adjusting for BMI. After further adjusting for current antipsychotic medication, education, diet and smoking, schizophrenia remained associated with obesity (OR 1.9, 95% CI 1.1-3.6) and abdominal obesity (OR 3.8, 95% CI 1.5-9.4). Participants with affective psychoses did not differ from the general population.

CONCLUSIONS

Individuals with schizophrenia have metabolically unfavorable body composition, comprising abdominal obesity, high fat percentage and low muscle mass. This leads to increased risk of metabolic and cardiovascular diseases.

Cross-calibration of multi-frequency bioelectrical impedance analysis with eight-point tactile electrodes and dual-energy X-ray absorptiometry for assessment of body composition in healthy children aged 6-18 years

BACKGROUND

In diagnosis and treatment of obesity, body composition analysis including percent body fat (%BF) is useful in the clinical setting. Because bioelectrical impedance analysis (BIA) could be used quickly, easily and was non-invasive in clinical setting, the purpose of the present study was to evaluate the usefulness of multi-frequency BIA with eight-point tactile electrodes (MF-BIA8; InBody 720, Biospace) compared with dual-energy X-ray absorptiometry (DXA) in healthy children and adolescents.

METHODS

A total of 166 children and adolescents under 18 (male, n = 86; female, n = 80) were recruited. Height, weight, body mass index (BMI) and Tanner stage were measured for each subject. The body composition such as fat-free mass (FFM), fat mass (FM), and %BF was measured on BIA and DXA and compared.

RESULTS

On linear regression analysis, DXA FFM = 1.006(BIA FFM) + 0.554, R(2) = 0.99 and the standard error of the estimate (SEE) was 1.16 kg; DXA FM = 0.971(BIA FM) - 0.596, R(2) = 0.93; SEE, 1.34 kg; and DXA %BF = 0.940(BIA %BF) - 1.026, R(2) = 0.858; SEE, 3.03%. Limit of agreement in FFM, FM, and %BF was 0.7 +/- 2.3 kg, -0.9 +/- 2.9 kg and -2.2 +/- 6.1%, respectively.

CONCLUSIONS

Although the %BF was not interchangeable with DXA, MF-BIA8 (InBody 720; Biospace) could be used to measure body composition of children and adolescents in the clinical field because of its high precision.

Study design and methods of the Ansan Geriatric Study (AGE study)

Background

The overall objective of the Ansan Geriatric Study (AGE study) was to describe the prevalence, incidence, and related risk factors for geriatric diseases in elderly Koreans.

Methods/Design

The AGE study was designed as a population-based prospective cohort study on health, aging, and common geriatric diseases of elderly Koreans aged 60 to 84 years. The inception cohort was recruited in May 2002. The first-wave and second-wave studies were performed using uniform and structured procedures. At the screening study, 2,767 participants were enrolled. Participants (1391 in the first wave study and 841 in the second wave study) were recruited and completed the evaluation. The prevalence of geriatric disease and related factors in elderly Koreans were estimated.

Discussion

Here, we report the design and sampling participants, measurement tools, and characteristics of the AGE study. This cohort study will allow a detailed study of the longitudinal comprehensive data on health information of elderly Koreans, thereby contributing to policy formulation and planning of health, welfare management, and other social services in Korea.

Effects of aquatic resistance training on health and fitness in postmenopausal women

To investigate effects of 24 weeks of resistance training with aquatic resistance devices or elastic bands (EB) on markers of cardiovascular health and physical capacity. Forty-six healthy, sedentary postmenopausal women participated. The groups were aquatic exercise (AE; n = 15), EB (n = 21), and control (n = 10). Venous blood chemistry included cholesterol, triglycerides, glucose, and apolipoprotein B. Physical capacity was assessed by the sit-and-reach, knee push-up, 60-s squat, and abdominal crunch tests. Both AE and EB, respectively, showed a significant (P <or= 0.05) decrease in body fat (14.56, 11.97%) and diastolic blood pressure (8.03, 5.88%), and a significant increase in fat-free mass (2.88, 1.22%), sit-and-reach (27.94, 44.2%), knee push-ups (84.74, 51.59%), and 60-s squats (65.76, 46.04%). AE also showed a significant increase in abdominal crunches (28.11%). Aquatic resistance training can offer significant physiological benefits in health and performance that are comparable to those obtained from EB in this population.

Validity and reliability of body composition analysers in children and adults

We tested the validity and reliability of the BioSpace InBody 320, Omron and Bod-eComm body composition devices in men and women (n 254; 21–80 years) and boys and girls (n 117; 10–17 years). We analysed percentage body fat (%BF) and compared the results with dual-energy X-ray absorptiometry (DEXA) in adults and compared the results of the InBody with underwater weighing (UW) in children. All body composition devices were correlated (r 0·54–0·97; P ≤ 0·010) to DEXA except the Bod-eComm in women aged 71–80 years (r 0·54; P = 0·106). In girls, the InBody %BF was correlated with UW (r 0·79; P ≤ 0·010); however, a more moderate correlation (r 0·69; P ≤ 0·010) existed in boys. Bland–Altman plots indicated that all body composition devices underestimated %BF in adults (1·0–4·8 %) and overestimated %BF in children (0·3–2·3 %). Lastly, independent t tests revealed that the mean %BF assessed by the Bod-eComm in women (aged 51–60 and 71–80 years) and in the Omron (age 18–35 years) were significantly different compared with DEXA (P ≤ 0·010). In men, the Omron (aged 18–35 years), and the InBody (aged 36–50 years) were significantly different compared with DEXA (P = 0·025; P = 0·040 respectively). In addition, independent t tests indicated that the InBody mean %BF in girls aged 10–17 years was significantly different from UW (P = 0·001). Pearson's correlation analyses demonstrated that the Bod-eComm (men and women) and Omron (women) had significant mean differences compared with the reference criterion; therefore, the %BF output from these two devices should be interpreted with caution. The repeatability of each body composition device was supported by small CV ( < 3·0 %).

Body composition and fitness during strength and/or endurance training in older men

PURPOSE

This study examined adaptations in body composition and physical fitness during a 21-wk strength and/or endurance training period in 40- to 65-yr-old men. We also compared the usefulness of different methods for the analysis of body composition to detect training-induced adaptations.

METHODS

Fifty-three men were randomized into the endurance training (E: N = 14), strength training (S: N = 13), combined strength and endurance training (SE: N = 15), or control (C: N = 11) groups. S and E trained 2 and SE 2 x 2 times a week for strength and endurance.

RESULTS

Percentage of fat (fat%) decreased (5-8%) similarly in all training groups. Fat% measured by DXA at baseline and its change correlated with those recorded by bioimpedance (r = 0.90 and 0.66), skinfolds (r = 0.80 and 0.78), and waistline (r = 0.84 and 0.74). Lean mass in legs (DXA) increased only in S (2.0 +/- 1.5%, P < 0.001), but the thickness of vastus lateralis and intermedius measured by ultrasound increased (7-11%) in all training groups, and that of triceps brachii increased in S (22%) and SE (20%). Maximal concentric force increased significantly in S, SE, and E (by 22, 23, and 7%), and maximal oxygen uptake increased in both E (11%) and SE (11%).

CONCLUSIONS

Waist circumference and skinfold thickness seem to reasonably assess changes in percent body fat during training. However, only DXA was capable to separate small differences between the groups in training-induced changes in lean body mass. Combined strength and endurance training is of greater value than either alone in optimizing body composition or improving physical fitness in older men.

Japanese study to organize proper lifestyle modifications for metabolic syndrome (J-STOP-MetS): design and method

Prevalence of the metabolic syndrome is now a very serious health problem in Japan and a public preventive strategy is essential to reduce morbidity. A systematic interventional strategy for the metabolic syndrome remains to be established. In order to address this issue, a multi-center study; Japanese Study to Organize Proper lifestyle modification for the metabolic syndrome (J-STOP-MetS), has been established by nine preventive medical centers among Rosai hospital groups. This study comprises a cross-sectional study (J-STOP-MetS 1) and a prospective randomized control study (J-STOP-MetS 2). J-STOP-MetS 1 examines the causes of the metabolic syndrome by means of a questionnaire in a large cohort of patients with the metabolic syndrome and control subjects matched for age and sex. J-STOP-MetS 2 examines the hypothesis that guidance on lifestyle modifications will help at risk patients to reduce abdominal fat and cardiovascular risk factors. The metabolic syndrome patients are randomly assigned either to a single visit to a guidance group or multiple visits every two months. The individualized guidance is provided by the coordination of physician, trained nurse, dietician and exercise trainer. Several parameters are measured before and six months after the first guidance session, including, body weight, waist circumference, blood pressure, several blood markers and arterial stiffness. The J-STOP-MetS is the first large-scale clinical study of the metabolic syndrome in Japan and should provide important evidence for the practical management of the metabolic syndrome.

Body mass index during childhood and adult body composition in men and women aged 56-70 y

BACKGROUND

The relation between the change in body mass index (BMI) through childhood and body composition in adult life is important because body composition is known to affect adult health.

OBJECTIVE

The objective was to examine how the change in BMI throughout childhood is related to adult lean and fat mass.

DESIGN

We examined how the change in BMI in childhood was related to adult body composition in 885 men and 1032 women born during 1934-1944, whose weights and heights during childhood were recorded serially. Adult lean and fat mass were measured by bioelectrical impedance with an 8-polar tactile electrode system.

RESULTS

In these 56-70-y-old men and women, adult lean body mass index (lean mass/height(2); in kg/m(2)) was positively associated with BMI at birth (0.24 and 0.20 higher for each 1-SD increase in BMI at birth, respectively) and with more rapid gain in BMI from birth to 1 y (0.17 and 0.22), 1-2 y (0.21 and 0.20), 2-7 y (0.44 and 0.46), and 7-11 y (0.32 and 0.26) of age. Fat mass index (fat mass/height(2)) was positively associated with more rapid increases in BMI between 2 and 11 y of age.

CONCLUSIONS

Rapid gain in BMI before the age of 2 y increased adult lean body mass without excess fat accumulation, whereas rapid gain in BMI in later childhood, despite the concurrent rise in lean mass, resulted in relatively larger increases in fat mass.

Agreements between indirect calorimetry and prediction equations of resting energy expenditure in end-stage renal disease patients on continuous ambulatory peritoneal dialysis

PURPOSE

Equations are frequently used to estimate resting energy expenditure (REE) in a clinical setting. However, few studies have examined their accuracy in end-stage renal disease (ESRD) patients.

PATIENTS AND METHODS

To investigate agreement between indirect calorimetry and several REE estimating equations in 38 ESRD patients on peritoneal dialysis, we performed indirect calorimetry and compared the results with REEs estimated using 5 equations [Harris-Benedict (HBE), Mifflin, WHO, Schofield, and Cunningham].

RESULTS

Measured REE was 1393.2+/-238.7 kcal/day. There were no significant differences between measured and estimated REEs except Mifflin (1264.9+/-224.8 kcal/day). Root mean square errors were smallest for HBE, followed by Schofield, Cunningham, and WHO, and largest for Mifflin (171.3, 171.9, 174.6, 175.3, and 224.6, respectively). In Bland-Altman plot, correlation coefficients between mean values and differences were significant for HBE (r=0.412, p=0.012) and tended to be significant for Cunningham (r=0.283, p=0.086). In DM patients and patients with overhydration, HBE showed significant underestimation when REE increased.

CONCLUSION

In ESRD patients on continuous ambulatory peritoneal dialysis (CAPD), REE-estimating equations have no significant differences from indirect calorimetry, except Mifflin. However, HBE showed greater bias than others when REE was high.

Cross-validation of bioelectrical impedance analysis for the assessment of body composition in a representative sample of 6- to 13-year-old children

BACKGROUND/OBJECTIVES

(1) To cross-validate tetra- (4-BIA) and octopolar (8-BIA) bioelectrical impedance analysis vs dual-energy X-ray absorptiometry (DXA) for the assessment of total and appendicular body composition and (2) to evaluate the accuracy of external 4-BIA algorithms for the prediction of total body composition, in a representative sample of Swiss children.

SUBJECTS/METHODS

A representative sample of 333 Swiss children aged 6-13 years from the Kinder-Sportstudie (KISS) (ISRCTN15360785). Whole-body fat-free mass (FFM) and appendicular lean tissue mass were measured with DXA. Body resistance (R) was measured at 50 kHz with 4-BIA and segmental body resistance at 5, 50, 250 and 500 kHz with 8-BIA. The resistance index (RI) was calculated as height(2)/R. Selection of predictors (gender, age, weight, RI4 and RI8) for BIA algorithms was performed using bootstrapped stepwise linear regression on 1000 samples. We calculated 95% confidence intervals (CI) of regression coefficients and measures of model fit using bootstrap analysis. Limits of agreement were used as measures of interchangeability of BIA with DXA.

RESULTS

8-BIA was more accurate than 4-BIA for the assessment of FFM (root mean square error (RMSE)=0.90 (95% CI 0.82-0.98) vs 1.12 kg (1.01-1.24); limits of agreement 1.80 to -1.80 kg vs 2.24 to -2.24 kg). 8-BIA also gave accurate estimates of appendicular body composition, with RMSE < or = 0.10 kg for arms and < or = 0.24 kg for legs. All external 4-BIA algorithms performed poorly with substantial negative proportional bias (r> or = 0.48, P<0.001).

CONCLUSIONS

In a representative sample of young Swiss children (1) 8-BIA was superior to 4-BIA for the prediction of FFM, (2) external 4-BIA algorithms gave biased predictions of FFM and (3) 8-BIA was an accurate predictor of segmental body composition.

Ability of new octapolar bioimpedance spectroscopy analyzers to predict 4-component-model percentage body fat in Hispanic, black, and white adults

BACKGROUND

New, vertical, 8-electrode bioimpedance spectroscopy (BIS) analyzers provide detailed body-composition and nutritional information within 2 min. This is the first report on BIS's accuracy in predicting relative fatness [percentage body fat (%BF)] in a heterogeneous sample according to a multicomponent model criterion.

OBJECTIVE

We compared %BF measurements from 2 BIS devices with those from a multicomponent model in a sample of Hispanic, black, and white adults.

DESIGN

Equal numbers of apparently healthy men and women (n = 75 of each) from each racial-ethnic group, diverse in body mass index and age, volunteered. Reference %BF (%BF(4C)) was computed by using a 4-component (4C) model with total bone mineral content obtained from dual-energy X-ray absorptiometry, body density from underwater weighing with measured residual lung volume, and total body water from traditional BIS. Estimations from InBody 720 (%BF(720)) and InBody 320 (%BF(320)) BIS analyzers were validated against %BF(4C).

RESULTS

The %BF(720) (r = 0.85, SEE = 5.19%BF) and %BF(320) (r = 0.84, SEE = 5.17%BF) correlations were significant (P < 0.05) in the men; main effects were nonsignificant. Correlations for %BF(720) (r = 0.88, SEE = 4.85%BF) and %BF(320) (r = 0.89, SEE = 4.82%BF) also were significant in the women (P < 0.05); there was a main effect for method but not race-ethnicity. There were no sex-specific overestimations or underestimations at the extremes of the distributions.

CONCLUSIONS

BIS estimates of %BF(4C) were well correlated in men and women. There were no significant methodologic differences in the men. The %BF(4C) was significantly underestimated by %BF(720) and %BF(320) in the women.

The mediating role of C-reactive protein and handgrip strength between obesity and walking limitation

OBJECTIVES

To study the association between different obesity indicators and walking limitation and to examine the role of C-reactive protein (CRP) and handgrip strength in that association.

DESIGN

A cross-sectional, population-based study.

SETTING

The Health 2000 Survey with a representative sample of the Finnish population.

PARTICIPANTS

Subjects aged 55 and older with complete data on body composition, CRP, handgrip strength, and walking limitation (N=2,208).

MEASUREMENTS

Body composition, anthropometrics, CRP, medical conditions, handgrip strength, and maximal walking speed were measured in the health examination. Walking limitation was defined as maximal walking speed less than 1.2 m/s or difficulty walking half a kilometer.

RESULTS

The two highest quartiles of body fat percentage and CRP and the two lowest quartiles of handgrip strength were all significantly associated with greater risk of walking limitation when chronic diseases and other covariates were taken into account. In addition, high CRP and low handgrip strength partially explained the association between high body fat percentage and walking limitation, but the risk of walking limitation remained significantly greater in persons in the two highest quartiles than in those in the lowest quartile of body fat percentage (odds ratio (OR)=1.75, 95% confidence interval (CI)=1.19-2.57 and OR=2.80, 95% CI 1.89-4.16). The prevalence of walking limitation was much higher in persons who simultaneously had high body fat percentage and low handgrip strength (61%) than in those with a combination of low body fat percentage and high handgrip strength (7%). Using body mass index and waist circumference as indicators of obesity yielded similar results as body fat percentage.

CONCLUSION

Low-grade inflammation and muscle strength may partially mediate the association between obesity and walking limitation. Longitudinal studies and intervention trials are needed to verify this pathway.

Body fat distribution and insulin resistance: beyond obesity in nonalcoholic fatty liver disease among overweight men

OBJECTIVE

The aim of this study was to characterize the relationship between nonalcoholic fatty liver disease (NAFLD) and body fat distribution and insulin resistance in a sample of non-diabetic overweight men.

SUBJECTS AND METHODS

We conducted a cross-sectional survey of 117 overweight men with NAFLD, as well as 117 controls, who were matched with regard to age and body mass index. None of the study subjects exhibited signs of alcohol abuse, hepatitis B or C, diabetes or fasting hyperglycemia, or hypertension. The diagnosis of NAFLD was based on dual findings of elevated alanine aminotransferase levels and sonographically-determined fatty liver. Body fat distribution was assessed via bioelectrical impedance. Insulin resistance was evaluated via homeostasis model assessment (HOMA-IR).

RESULTS

The risk of developing NAFLD was found to be profoundly associated with elevated measurements of waist circumference, fat mass, percentage of body fat and abdominal fat, iron, triglycerides, apolipoprotein B, and results of HOMA-IR. Multivariate analysis revealed that NAFLD was significantly associated with elevated measurements of waist circumference, iron, apolipoprotein B, and HOMA-IR.

CONCLUSIONS

Our study provides evidence for a profound and dose-dependent association of NAFLD with central adiposity, insulin resistance in overweight men lacking complications of metabolic syndrome. Overweight subjects with insulin resistance or central adiposity were at more risk of NAFLD than were those subjects with less insulin resistance or central adiposity, even those with a similar degree of obesity.

Evaluation of air-displacement plethysmography and bioelectrical impedance analysis vs dual-energy X-ray absorptiometry for the assessment of fat-free mass in elderly subjects

OBJECTIVE

To evaluate air-displacement plethysmography (ADP) and bioelectrical impedance analysis (BIA) vs dual-energy X-ray absorptiometry (DXA) for the assessment of fat-free mass (FFM) in healthy elderly subjects.

SUBJECTS

Forty-two women and twenty-six men aged 60-84 years.

METHODS

FFM was measured by DXA and ADP. Body impedance (Z) was measured by four-polar BIA and the impedance index (ZI) was calculated as stature(2)/Z. Selection of predictors (gender, age, weight and ZI at 5, 50 and 100 kHz) for BIA algorithms was carried out using bootstrapped stepwise linear regression on 1000 samples of 68 subjects. Limits of agreement were used as measures of interchangeability of ADP and BIA with DXA.

RESULTS

The limits of agreement of ADP vs DXA were -11.0 to 2.4 kg in males and -4.8 to 2.2 kg in females. Gender, weight and ZI(100) were selected as predictors of FFM by bootstrapped stepwise linear regression. In males, ZI(100) (-12.2 to 12.2 kg) was much less accurate than weight (-6.0 to 6.0 kg) at predicting FFM and their combination did not improve the estimate (-6.0 to 6.0 kg). In females, ZI(100) (-6.8 to 6.8 kg) was less accurate than weight (-5.6 to 5.6 kg) at predicting FFM and their combination improved the estimate only slightly (-5.0 to 5.0 kg).

CONCLUSIONS

In healthy elderly subjects, (1) ADP and DXA are not interchangeable for the assessment of FFM, especially in males; and (2) ZI(100) is not superior to weight for the prediction of FFM and their combination is of little advantage and only in females.

Birth size, adult body composition and muscle strength in later life

OBJECTIVE

Low birth weight has been linked to lower lean body mass and abdominal obesity later in life, whereas high birth weight has been suggested to predict later obesity as indicated by high body mass index (BMI). We examined how birth weight was related to adult body size, body composition and grip strength.

DESIGN/SUBJECTS

Cross-sectional study on 928 men and 1075 women born in 1934-1944, with measurements at birth recorded.

MEASUREMENTS

Height, weight, waist and hip circumference and isometric grip strength were measured. Lean and fat body mass were estimated by bioelectrical impedance with an eight-polar tactile electrode system.

RESULTS

A 1 kg increase in birth weight corresponded in men to a 4.1 kg (95% CI: 3.1, 5.1) and in women to a 2.9 kg (2.1, 3.6) increase in adult lean mass. This association remained significant after adjustment for age, adult body size, physical activity, smoking status, social class and maternal size. Grip strength was positively related to birth weight through its association with lean mass. The positive association of birth weight with adult BMI was explained by its association with lean mass. Low birth weight was related to higher body fat percentage only after adjustment for adult BMI. Abdominal obesity was not predicted by low birth weight.

CONCLUSIONS

Low birth weight is associated with lower lean mass in adult life and thus contributes to the risk of relative sarcopenia and the related functional inability at the other end of the lifespan. At a given level of adult BMI, low birth weight predicts higher body fat percentage.

Quantification of spinning® bike performance during a standard 50-minute class

Spinning is a type of indoor fitness activity performed on stationary bikes by participants who pedal together to the rhythm of music and the motivating words of an instructor. Despite worldwide popularity of this type of recreational activity, to date there have been few, mainly non-scientific, studies of the impact of spinning on metabolic, respiratory, and cardiovascular functions. The main aim of this study was to evaluate a number of metabolic and cardiovascular variables during a standard 50-min class performed by Spinning instructors of both sexes: six males (age 30 +/- 4.8 years, body mass index 24 +/- 2.5 kg x m(-2); mean +/- s) and six females (age 34 +/- 6.3 years, body mass index 21 +/- 1.9 kg x m(-2)). The mean power output, heart rate, and oxygen uptake during the performance were 120 +/- 4 W, 136 +/- 13 beats x min(-1), and 32.8 +/- 5.4 ml x kg(-1) x min(-1) respectively for males, and 73 +/- 43 W, 143 +/- 25 beats x min(-1), and 30 +/- 9.9 ml x kg(-1) x min(-1) respectively for females. Analysis of individual performances showed that they were compatible with physical exercise that ranged from moderate-to-heavy to very heavy, the latter conditions prevailing. The results show that this type of fitness activity has a high impact on cardiovascular function and suggest that it is not suitable for unfit or sedentary individuals, especially the middle aged or elderly, who are willing to begin a recreational physical activity programme.

Relative contribution of body composition to bone mineral density at different sites in men and women of South Korea

We examined the relative contribution of body composition to bone mineral density (BMD) at various sites in 1406 Korean rural men and women, aged 19-80 years, from July to August 2004. The BMD was measured at peripheral (distal forearm and calcaneus) and central (lumbar spine at L1-L4, femoral neck, trochanter, and Ward's triangle) using dual-energy X-ray absorptiometry. In multivariate analyses, the linear regression models were adjusted for relevant covariates. In premenopausal women, only lean mass had a significant positive correlation with BMD at all sites. In postmenopausal women, fat mass was significantly positively correlated with BMD at all sites, except the Ward's triangle; fat mass was the only determinant of BMD at the lumbar, distal forearm, and calcaneus sites, whereas both lean and fat mass contributed to BMD at the hip, with the effect of lean mass being slightly greater than that of fat mass. In younger men, lean mass had a significant positive contribution to BMD at all sites, whereas fat mass appeared to contribute negatively to BMD at all sites, except the calcaneus. In older men, lean mass made a significant positive contribution to the BMD at all sites; fat mass also made a significant positive contribution to the BMD at the forearm and calcaneus. These data indicate that in the Korean rural population, lean mass may be an important determinant of the BMD, whereas fat mass may contribute positively to BMD only in postmenopausal women and older men.

Within-day variability of whole-body and segmental bioelectrical impedance in a standing position

OBJECTIVE

To assess the variation in whole-body and segmental bioelectrical impedance measured in the standing position over the course of a day.

SUBJECTS

Sixteen healthy men aged 29.6 +/- 3.1 years participated in this study.

MEASUREMENT

Impedance between the hands (Z H-H), the feet (Z F-F), and the both hands and feet (Z H-F) was measured using a bioelectrical impedance analysis (BIA) data acquisition system at 500 microA and 50 kHz. Body weight, Z H-H, Z F-F and Z H-F were measured every 3 h from 0900 to 1800.

RESULTS

Body weight was slightly, but significantly, changed at 1200 (-0.4 +/- 0.4 kg, P < 0.05), 1500 (+0.4 +/- 0.3 kg, P < 0.05) and 1800 (-0.2 +/- 0.2 kg, P < 0.05) compared to their respective previous measurement values. Z H-H significantly increased (P < 0.05) and Z F-F significantly decreased (P < 0.05) over the course of a day. The mean changes in impedance from 0900 to 1800 were +27.2 Omega (Z H-H) and -31.8 Omega (Z F-F), respectively. There were no changes in Z H-H at 1500 and in Z F-F at 1800 compared to their respective previous measurement values. The Z H-F value did not change significantly between 0900 and 1800.

CONCLUSION

Although changes in standing whole-body impedance during the day are small, arm and leg segmental impedance measurements change significantly. Therefore, it is necessary to measure the impedance at regularly scheduled times when evaluating whole-body %fat or body water content using the segmental BIA method.

A white blood cell count in the normal concentration range is independently related to cardiorespiratory fitness in apparently healthy Korean men

Despite the documented health benefits of physical activity, the mechanism whereby physical activity prevents cardiovascular disease is incompletely understood. In the present study, we investigated the relationship between white blood cell (WBC) count and cardiorespiratory fitness (V o(2)max) after adjusting for several well-known cardiovascular risk factors. Subjects who visited our health promotion center for a medical checkup and treadmill test (n=8241; age: median, 48 years; range, 16-79 years) were classified into 3 groups based on their WBC counts (group 1, 2200-5300 microL, n=2823; group 2, 5301-6500 microL, n=2709; group 3, 6501-10000 microL, n=2709). After adjusting for age, body mass index, body fat percentage, smoking history, systolic blood pressure, diastolic blood pressure, serum lipid profile, and fasting plasma glucose, V o(2)max still showed a significant association with WBC count (partial r=-0.11, P<.001). In logistic regression analyses, subjects in the highest WBC tertile showed lower V o(2)max compared with those in the lowest WBC tertile after adjusting for age and cardiovascular risk factors (odds ratio, 0.42; 95% confidence interval, 0.36-0.49 for the highest V o(2)max tertile). These results suggest that a WBC count in the normal concentration range is independently related to cardiorespiratory fitness in Korean men.