Association between phase angle and height-to-age index classifications of children under five years of age

The phase angle (PA) has been used as an indicator of prognosis and nutritional status because it reflects the integrity of the individuals' cellular function. In contrast to the investigations that assessed acute malnutrition (weight deficit) and PA in children, studies that evaluated the relationship of this indicator with stunting (height deficit) are still scarce and inconclusive. Thus, we aim to investigate whether there are differences in PA according to the classifications of the height-for-age (H/A) index of children under five years of age.

This is a cross-sectional study carried out in a nutritional recovery center, in households, and in a daycare center in Maceió-Alagoas, Brazil. Anthropometric data were collected, and resistance and reactance were obtained through the use of tetrapolar electrical bioimpedance, from children aged 2-5 years. The PA and the percentage of body fat were calculated. Children were divided into 3 groups: adequate H/A, at-risk of stunting and stunted. Analysis of covariance for the main outcome was performed using age, sex, and the body mass index-to-age as covariates, and the H/A classification as the exposure.

The mean children's PA in the adequate H/A group was 3.9° [95% CI 3.6-4.2], while in the group at-risk of stunting and stunted it was 4.5° [95% CI 4.3-4.7] and 4.6° [95% CI 4.4-4.8], respectively, showing statistical difference (p < 0.01).

In the present sample, stunted children have higher PA values than children with adequate H/A.