HFA: HFA z‐score measures linear growth. A child who is < –2 SD from the median of the WHO Child Growth Standards in terms of HFA is considered short for his/her age, or stunted. This condition reflects the cumulative effect of chronic malnutrition. If a child is < –3 SD from the median of the WHO Child Growth Standards, then he/she is considered to be severely stunted. Stunting often reflects a failure to receive adequate nutrition over a long period of time and is worsened by recurrent and chronic illness. Therefore, HFA reflects the long‐term effects of malnutrition in a population and does not vary appreciably according to recent dietary intake. |
Birth weight or LBW: birth weight is the body mass of a baby at its birth. It represents the growth of all tissues of the body and is the most commonly used indicator of the adequacy of antenatal growth. Inadequate birth weight may be caused by deficiencies or excess of some nutrients, infections, congenital anomalies, adverse maternal behaviour (e.g. smoking, drug use, heavy physical labour), and by variation in gestation length. LBW is defined as a weight < 2500 g at birth for a pregnancy of 37–42 weeks' gestation. Some studies reported differences in mean birth weight between control and intervention groups. Other studies presented LBW as a dichotomous variable (yes/no). |
WFH: WFH z‐score describes current nutritional status. A child who is < –2 SD from the median of the WHO Child Growth Standards for WFH is considered to be too thin for his/her height, or wasted. This condition reflects acute or recent nutritional deficit. As with stunting, wasting is considered severe if the child is < –3 SD below the reference median or by an MUAC < 115 mm with or without nutritional oedema. In the presence of bilateral pitting oedema, the term kwashiorkor is used. Severe wasting is closely linked to mortality risk. |
WFA: WFA z‐score is a composite index of WFH and HFA. Thus, it does not distinguish between acute malnutrition (wasting) and chronic malnutrition (stunting). A child can be underweight for age because he/she is stunted, because he/she is wasted, or both. Children whose WFA is < –2 SD from the median of the WHO Child Growth Standards are classified as underweight. Children whose WFA is < –3 SD from the median of the WHO Child Growth Standards are considered severely underweight. WFA is a good overall indicator of a population's nutritional health. |
MUAC: measures the muscle mass of the upper arm. A flexible measuring tape is wrapped around the mid‐upper arm (between the shoulder and elbow) to measure its circumference. MUAC should be measured to the nearest 0.1 cm. MUAC is a rapid and effective predictor of risk of death in children aged 6–59 months and is increasingly being used to assess adult nutritional status. The cutoffs are: well nourished ≥ 135 mm, at risk of malnutrition 125–134 mm, moderate acute malnutrition 115–124 mm, and severe acute malnutrition < 115 mm. |
Triceps skinfold thickness: is used to estimate body fat, measured on the right arm halfway between the olecranon process of the elbow and the acromial process of the scapula. Reference values have been published for school children from the US or Europe but not specifically for LMIC. |
HFA: height‐for‐age; LBW: low birth weight; MUAC: mid‐upper‐arm circumference; SD: standard deviation; WFA: weight‐for‐age; WFH: weight‐for‐height; WHO: World Health Organization. |