Zimian Wang - Academia.edu (original) (raw)

Papers by Zimian Wang

CRC Press eBooks, Dec 9, 2003

The American Journal of Clinical Nutrition, Sep 1, 2000

The American Journal of Clinical Nutrition, May 1, 2001

The American journal of clinical nutrition, 2003

Limited research has been done to explore differences between ethnic groups, including Hispanic A... more Limited research has been done to explore differences between ethnic groups, including Hispanic Americans (HAs), in the association between percentage body fat (PBF) and body mass index (BMI; in kg/m(2)); the numbers of HAs are increasing in the US population. We investigated whether the relation between PBF and BMI in adult HAs differed from that of African Americans (AAs) and European Americans (EAs). We used a multiple regression model in which PBF measured with dual energy X-ray absorptiometry was predicted by the reciprocal of BMI (1/BMI; in m(2)/kg) in a sample of 487 men (n(EA) = 192, n(AA) = 148, and n(HA) = 147) and 933 women (n(EA) = 448, n(AA) = 304, and n(HA) = 181). For men, our results showed no significant differences between HAs and EAs, AAs and EAs, or HAs and AAs in the slope of the line relating 1/BMI to PBF. In women, there were significant differences in PBF as predicted by BMI between HAs and EAs (P < 0.002) and AAs and HAs (P = 0.020), but not between AAs a...

Human Body Composition, 2005

Handbook of Obesity, 2003

The study objective was to compare the accuracy of portable and hospital or laboratory-based body... more The study objective was to compare the accuracy of portable and hospital or laboratory-based body composition methods, as well as to evaluate reference methods that may be necessary for the development of population-specific phenotyping equations in field-study settings. Subjects were healthy adults of mixed ethnicity from the greater New York metropolitan area. Adiposity was evaluated by whole-body magnetic resonance imaging (MRI), dual energy x-ray absorptiometry (DXA), underwater weighing (UWW), air displacement plethysmography (ADP), isotope dilution (ID), bioimpedance analysis (BIA), and anthropometry (ANTH). Anthopometric measurements included height, weight, and skinfolds. MRI was selected as the reference for assessing total body adiposity. Pearson correlation coefficients with MRI-derived adipose tissue mass and fat mass measured by the other methods were: DXA (r=0.98, n=251), ADP (r=0.98, n=73), UWW (r=0.96, n=216), ID (r=0.95, n=248), ANTH (r=0.94, n=235), and BIA (r=0.92...

Journal of applied physiology (Bethesda, Md. : 1985), 1999

Although there is growing interest in studying muscle distribution, regional skeletal muscle (SM)... more Although there is growing interest in studying muscle distribution, regional skeletal muscle (SM) mass measurement methods remain limited. The aim of the present study was to develop a new dual-energy X-ray absorptiometry (DEXA) model for estimating regional adipose tissue-free skeletal muscle mass (AT-free SM). Relationships were derived from Reference Man data between tissue-system- level components (i.e., AT-free SM, AT, skeleton, and skin) and molecular-level components including fat-free soft tissue, fat, and bone mineral. The proposed DEXA-SM model was evaluated by multiscan computerized axial tomography (CT). Twenty-seven male subjects [age, 36 +/- 12 (SD) yr; body mass, 73.2 +/- 12.4 kg; 20 were healthy, and 7 had acquired immunodeficiency syndrome] completed DEXA and CT studies. Identical landmarks for DEXA and CT measurements were selected in three regions, including calves, thighs, and forearms. There was a strong correlation for AT-free SM estimates between the new DEXA ...

Journal of Applied Physiology, 2005

Aging is associated with the onset of chronic diseases that lead to pathological expansion of the... more Aging is associated with the onset of chronic diseases that lead to pathological expansion of the extracellular water (ECW) compartment. Healthy aging, in the absence of disease, is also reportedly accompanied by a relative expansion of the ECW compartment, although the studies on which this observation is based are few in number, applied different ECW measurement methods, included small ethnically homogeneous subject samples, and failed to adjust ECW for non-age-related influencing factors. The aim of the current study was to examine, in a large ( n = 1,538) ethnically diverse [African American (AA), Asian, Caucasian, Hispanic] subject group the cross-sectional relationships between ECW and age after controlling first for other potential factors that may influence fluid distribution. ECW and intracellular water (ICW) were derived from measured total body water (isotope dilution) and potassium (40K whole body counting). The cross-sectional relationships between ECW, ICW, and ECW/ICW...

American Journal of Human Biology, 2010

The Journal of nutrition, 2007

A whole body skeletal muscle [(SM); kg] mass estimation model, based on total body potassium [(TB... more A whole body skeletal muscle [(SM); kg] mass estimation model, based on total body potassium [(TBK); mmol] measured by whole body (40)K counting (WBC) was developed (SM = 0.0082.TBK) and validated in adults in a previous study. It is unknown whether the adult TBK SM prediction model is applicable for pediatric use. The aim of this study was to derive and validate a pediatric TBK SM prediction equation. SM measured by MRI was used as the criterion and TBK was measured by WBC. The protocol was completed in 116 healthy children, 66 males and 50 females, 11.7 +/- 3.5 y (mean +/- SD, range = 5-17 y). A strong linear correlation was observed between TBK and SM (r = 0.984; P < 0.001). The SM:TBK ratio was 0.0071 +/- 0.0008 kg/mmol in the children studied, much lower than the corresponding value of 0.0082 kg/mmol in adults. An empirical SM prediction equation was developed using TBK alone: SM = 0.0085.TBK - 2.83, r(2) = 0.97, SEE = 1.39 kg. Bland-Altman analysis did not disclose a signif...

Epidemology, Etiology, and Physiopathology, 2014

International Textbook of Obesity, 2001

ABSTRACT Traditional techniques to measure whole-body composition divide the body into five level... more ABSTRACT Traditional techniques to measure whole-body composition divide the body into five levels – atomic, molecular, cellular, tissue and organ. Adiposity within the whole body is usually estimated via the body mass index or anthropometrically by measurement of body weight, stature, skinfolds and circumference. Visceral adipose tissue is an independent predictor of obesity health-related risk. All major tissues and organs can now be measured in vivo using computerized axial tomography or magnetic resonance imaging. At the cellular level, fat cell mass cannot be quantified in vivo; it is usually estimated by combining total body adipose tissue mass with biopsy-derived adipose tissue cell mass concentration. The concentration of molecular fat, or triglyceride, in the body is measured by either body volume analysis, labelled water dilution and dual-energy X-ray absorptiometry. Studies at the atomic level assess total body potassium or total body nitrogen and carbon. The most suitable method depends on the intended use of the data and the required degree of accuracy.

The study of human body composition is a branch of human biology which focuses on the in vivo qua... more The study of human body composition is a branch of human biology which focuses on the in vivo quantification of body components, the quantitative relationships between components, and the quantitative changes in these components related to various influencing factors. Accordingly, the study of human body composition is composed of three interrelated research areas, body composition rules, body composition methodology, and body composition alterations. This thesis describes the authors recent investigations related to the first two of the three research areas. In the rules area, this thesis begins with a comprehensive five-level model of body composition. The approximate 40 body components are systematically organized into five levels with increasing complexity: 1, atomic; 11, molecular; III, cellular; IV, tissue-system; and V 1 whole-body. Although each level and its multiple components are distinct, interconnections exist such that the model is consistent and functions as a whole. ...

The American journal of clinical nutrition, 1999

The assumed "constancy" of fat-free body mass hydration is a cornerstone in the body-co... more The assumed "constancy" of fat-free body mass hydration is a cornerstone in the body-composition research field. Hydration, the observed ratio of total body water to fat-free body mass, is stable at approximately 0.73 in mammals and this constancy provides a means of estimating total body fat in vivo. This review examines both in vitro and in vivo data that support the hydration constancy hypothesis and provides a critique of applied methodology. Biological topics of interest are then examined and critical areas in need of future research are identified. These are important issues because water dilution is the only method currently available for estimating body fat in all mammals, which range in body mass by a factor of 10(4).

American journal of physiology. Endocrinology and metabolism, 2001

Potassium is an essential element of living organisms that is found almost exclusively in the int... more Potassium is an essential element of living organisms that is found almost exclusively in the intracellular fluid compartment. The assumed constant ratio of total body potassium (TBK) to fat-free mass (FFM) is a cornerstone of the TBK method of estimating total body fat. Although the TBK-to-FFM (TBK/FFM) ratio has been assumed constant, a large range of individual and group values is recognized. The purpose of the present study was to undertake a comprehensive analysis of biological factors that cause variation in the TBK/FFM ratio. A theoretical TBK/FFM model was developed on the cellular body composition level. This physiological model includes six factors that combine to produce the observed TBK/FFM ratio. The ratio magnitude and range, as well as the differences in the TBK/FFM ratio between men and women and variation with growth, were examined with the proposed model. The ratio of extracellular water to intracellular water (E/I) is the major factor leading to between-individual...

Journal of Parenteral and Enteral Nutrition

The American Journal of Clinical Nutrition, May 1, 2001

CRC Press eBooks, Dec 9, 2003

The American Journal of Clinical Nutrition, Sep 1, 2000

The American Journal of Clinical Nutrition, May 1, 2001

The American journal of clinical nutrition, 2003

Limited research has been done to explore differences between ethnic groups, including Hispanic A... more Limited research has been done to explore differences between ethnic groups, including Hispanic Americans (HAs), in the association between percentage body fat (PBF) and body mass index (BMI; in kg/m(2)); the numbers of HAs are increasing in the US population. We investigated whether the relation between PBF and BMI in adult HAs differed from that of African Americans (AAs) and European Americans (EAs). We used a multiple regression model in which PBF measured with dual energy X-ray absorptiometry was predicted by the reciprocal of BMI (1/BMI; in m(2)/kg) in a sample of 487 men (n(EA) = 192, n(AA) = 148, and n(HA) = 147) and 933 women (n(EA) = 448, n(AA) = 304, and n(HA) = 181). For men, our results showed no significant differences between HAs and EAs, AAs and EAs, or HAs and AAs in the slope of the line relating 1/BMI to PBF. In women, there were significant differences in PBF as predicted by BMI between HAs and EAs (P < 0.002) and AAs and HAs (P = 0.020), but not between AAs a...

Human Body Composition, 2005

Handbook of Obesity, 2003

The study objective was to compare the accuracy of portable and hospital or laboratory-based body... more The study objective was to compare the accuracy of portable and hospital or laboratory-based body composition methods, as well as to evaluate reference methods that may be necessary for the development of population-specific phenotyping equations in field-study settings. Subjects were healthy adults of mixed ethnicity from the greater New York metropolitan area. Adiposity was evaluated by whole-body magnetic resonance imaging (MRI), dual energy x-ray absorptiometry (DXA), underwater weighing (UWW), air displacement plethysmography (ADP), isotope dilution (ID), bioimpedance analysis (BIA), and anthropometry (ANTH). Anthopometric measurements included height, weight, and skinfolds. MRI was selected as the reference for assessing total body adiposity. Pearson correlation coefficients with MRI-derived adipose tissue mass and fat mass measured by the other methods were: DXA (r=0.98, n=251), ADP (r=0.98, n=73), UWW (r=0.96, n=216), ID (r=0.95, n=248), ANTH (r=0.94, n=235), and BIA (r=0.92...

Journal of applied physiology (Bethesda, Md. : 1985), 1999

Although there is growing interest in studying muscle distribution, regional skeletal muscle (SM)... more Although there is growing interest in studying muscle distribution, regional skeletal muscle (SM) mass measurement methods remain limited. The aim of the present study was to develop a new dual-energy X-ray absorptiometry (DEXA) model for estimating regional adipose tissue-free skeletal muscle mass (AT-free SM). Relationships were derived from Reference Man data between tissue-system- level components (i.e., AT-free SM, AT, skeleton, and skin) and molecular-level components including fat-free soft tissue, fat, and bone mineral. The proposed DEXA-SM model was evaluated by multiscan computerized axial tomography (CT). Twenty-seven male subjects [age, 36 +/- 12 (SD) yr; body mass, 73.2 +/- 12.4 kg; 20 were healthy, and 7 had acquired immunodeficiency syndrome] completed DEXA and CT studies. Identical landmarks for DEXA and CT measurements were selected in three regions, including calves, thighs, and forearms. There was a strong correlation for AT-free SM estimates between the new DEXA ...

Journal of Applied Physiology, 2005

Aging is associated with the onset of chronic diseases that lead to pathological expansion of the... more Aging is associated with the onset of chronic diseases that lead to pathological expansion of the extracellular water (ECW) compartment. Healthy aging, in the absence of disease, is also reportedly accompanied by a relative expansion of the ECW compartment, although the studies on which this observation is based are few in number, applied different ECW measurement methods, included small ethnically homogeneous subject samples, and failed to adjust ECW for non-age-related influencing factors. The aim of the current study was to examine, in a large ( n = 1,538) ethnically diverse [African American (AA), Asian, Caucasian, Hispanic] subject group the cross-sectional relationships between ECW and age after controlling first for other potential factors that may influence fluid distribution. ECW and intracellular water (ICW) were derived from measured total body water (isotope dilution) and potassium (40K whole body counting). The cross-sectional relationships between ECW, ICW, and ECW/ICW...

American Journal of Human Biology, 2010

The Journal of nutrition, 2007

A whole body skeletal muscle [(SM); kg] mass estimation model, based on total body potassium [(TB... more A whole body skeletal muscle [(SM); kg] mass estimation model, based on total body potassium [(TBK); mmol] measured by whole body (40)K counting (WBC) was developed (SM = 0.0082.TBK) and validated in adults in a previous study. It is unknown whether the adult TBK SM prediction model is applicable for pediatric use. The aim of this study was to derive and validate a pediatric TBK SM prediction equation. SM measured by MRI was used as the criterion and TBK was measured by WBC. The protocol was completed in 116 healthy children, 66 males and 50 females, 11.7 +/- 3.5 y (mean +/- SD, range = 5-17 y). A strong linear correlation was observed between TBK and SM (r = 0.984; P < 0.001). The SM:TBK ratio was 0.0071 +/- 0.0008 kg/mmol in the children studied, much lower than the corresponding value of 0.0082 kg/mmol in adults. An empirical SM prediction equation was developed using TBK alone: SM = 0.0085.TBK - 2.83, r(2) = 0.97, SEE = 1.39 kg. Bland-Altman analysis did not disclose a signif...

Epidemology, Etiology, and Physiopathology, 2014

International Textbook of Obesity, 2001

ABSTRACT Traditional techniques to measure whole-body composition divide the body into five level... more ABSTRACT Traditional techniques to measure whole-body composition divide the body into five levels – atomic, molecular, cellular, tissue and organ. Adiposity within the whole body is usually estimated via the body mass index or anthropometrically by measurement of body weight, stature, skinfolds and circumference. Visceral adipose tissue is an independent predictor of obesity health-related risk. All major tissues and organs can now be measured in vivo using computerized axial tomography or magnetic resonance imaging. At the cellular level, fat cell mass cannot be quantified in vivo; it is usually estimated by combining total body adipose tissue mass with biopsy-derived adipose tissue cell mass concentration. The concentration of molecular fat, or triglyceride, in the body is measured by either body volume analysis, labelled water dilution and dual-energy X-ray absorptiometry. Studies at the atomic level assess total body potassium or total body nitrogen and carbon. The most suitable method depends on the intended use of the data and the required degree of accuracy.

The study of human body composition is a branch of human biology which focuses on the in vivo qua... more The study of human body composition is a branch of human biology which focuses on the in vivo quantification of body components, the quantitative relationships between components, and the quantitative changes in these components related to various influencing factors. Accordingly, the study of human body composition is composed of three interrelated research areas, body composition rules, body composition methodology, and body composition alterations. This thesis describes the authors recent investigations related to the first two of the three research areas. In the rules area, this thesis begins with a comprehensive five-level model of body composition. The approximate 40 body components are systematically organized into five levels with increasing complexity: 1, atomic; 11, molecular; III, cellular; IV, tissue-system; and V 1 whole-body. Although each level and its multiple components are distinct, interconnections exist such that the model is consistent and functions as a whole. ...

The American journal of clinical nutrition, 1999

The assumed "constancy" of fat-free body mass hydration is a cornerstone in the body-co... more The assumed "constancy" of fat-free body mass hydration is a cornerstone in the body-composition research field. Hydration, the observed ratio of total body water to fat-free body mass, is stable at approximately 0.73 in mammals and this constancy provides a means of estimating total body fat in vivo. This review examines both in vitro and in vivo data that support the hydration constancy hypothesis and provides a critique of applied methodology. Biological topics of interest are then examined and critical areas in need of future research are identified. These are important issues because water dilution is the only method currently available for estimating body fat in all mammals, which range in body mass by a factor of 10(4).

American journal of physiology. Endocrinology and metabolism, 2001

Potassium is an essential element of living organisms that is found almost exclusively in the int... more Potassium is an essential element of living organisms that is found almost exclusively in the intracellular fluid compartment. The assumed constant ratio of total body potassium (TBK) to fat-free mass (FFM) is a cornerstone of the TBK method of estimating total body fat. Although the TBK-to-FFM (TBK/FFM) ratio has been assumed constant, a large range of individual and group values is recognized. The purpose of the present study was to undertake a comprehensive analysis of biological factors that cause variation in the TBK/FFM ratio. A theoretical TBK/FFM model was developed on the cellular body composition level. This physiological model includes six factors that combine to produce the observed TBK/FFM ratio. The ratio magnitude and range, as well as the differences in the TBK/FFM ratio between men and women and variation with growth, were examined with the proposed model. The ratio of extracellular water to intracellular water (E/I) is the major factor leading to between-individual...

Journal of Parenteral and Enteral Nutrition

The American Journal of Clinical Nutrition, May 1, 2001