Wasting
Overview
- Wasting is also useless spending.
In medical circles, wasting refers to the process by which a debilitating disease causes muscle and fat tissue to "waste" away. Wasting is sometimes referred to as "acute malnutrition" because it is believed that episodes of wasting have a short duration, in contrast to stunting, which is regarded as chronic malnutrition.
Causes
Wasting can be caused by an extremely low energy intake (e.g., caused by famine), nutrient losses due to infection, or a combination of low intake and high loss. Infections associated with wasting include tuberculosis, chronic diarrhea, and AIDS. The mechanism may involve cachectin - also called tumor necrosis factor, a macrophage-secreted cytokine. Caretakers and health providers sometimes contribute to wasting by putting the patient on a very restrictive diet. Voluntary weight loss and eating disorders are excluded as causes of wasting.
Classification
- Children: Weight-for-height (WFH). In infants under 24 months, recumbent (supine) length is used. WFH as % of median reference value is calculated this way:
- <math>\mathrm{WFH} = \frac{\mbox{weight of a given child}}{\mbox{median weight for a given child of that height}} \times 100</math>
Cutoff points may vary, but <80% (close to -2 Z-score) is often used.
- Adults:
- Body Mass Index (BMI) is the quotient between weight and height squared (kg/m2). An individual with a BMI < 18.5 is regarded as a case of wasting.
- Percent of body weight lost (At Tufts, an unintentional loss of 6% or more in 6 months is regarded as wasting)