Table 1.
BCA in clinical practice. Some examples show that going beyond the BMI is related to a question of interest; FBC takes into account masses and their interrelations in the context of their metabolic and physical functions
| Question | To be measured | Method of choice | FBC Body component – function relationships |
|---|---|---|---|
| Energy balance? e.g., ‘healthy' weight loss (i.e., loss in FFM should not exceed 15% of weight loss), weight re-gain after weight loss (FM » FFM?), adherence to diet, effect of exercise, weight gain as a side effect of drugs (e.g., insulin, incretin mimetics, antidepressants) | FM, FFM | ADP, HD, MRI, QMR, DXA | FM – plasma leptin; FFM – resting energy expenditure |
|
| |||
| Metabolic risk? e.g., insulin resistance, lipodystrophy, metabolically healthy obese patient | liver (ectopic) fat, VAT, (SAT) | MRI, MRS, CT, (DXA) | liver fat – plasma insulin/insulin resistance |
|
| |||
| Malnutrition? e.g., sarcopenic obese patient | muscle mass, (BIVA?) | DXA, MRI, NA, TBP, BIA | muscle mass – plasma insulin; muscle mass – muscle strength – insulin resistance |
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| |||
| Osteoporosis? e.g., osteosarcopenic obese patient | bone minerals | DXA, CT, NA | bone-density – fractural risk – insulin resistance |
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| |||
| Hydration? e.g., obesity-associated co-morbidities, edema, heart and kidney failure | TBW/ECW, BIVA | D2O, NaBr dilution, BIA | TBW/ECW – blood pressure – insulin resistance – RAAS |
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| |||
| Prognosis? e.g., obese cancer patient | phase angle, attenuation | BIA, CT | phase angle, muscle attenuation – insulin resistance, inflammation, hypermetabolism |
FM = Fat mass; FFM = fat-free mass; VAT = visceral adipose tissue; SAT = subcutaneous adipose tissue; BIVA = bioelectrical impedance vector analysis; TBW = total body water; ECW = extracellular water; ADP = air displacement plethysmography; HD = hydrodensitometry; MRI = magnetic resonance imaging; QMR = quantitative (non-imaging) magnetic resonance; MRS = magnetic resonance spectroscopy; CT = computer tomography; DXA = dual energy X ray absorptiometry; NA = neutron activation; TBP = total body potassium; D2O2 = deuterium oxide; NaBr = sodium bromide; BIA = bioelectrical impedance analysis; RAAS = renin-angiotensin-aldosterone system.