Using height-for-age differences (HAD) instead of height-for-age z-scores (HAZ) for the meaningful measurement of population-level catch-up in linear growth in children less than 5 years of age

Table 2 Change in HAZ, HAD and height from baseline (children around 8 months of age) to follow-up (around 58 months of age) and expected velocity in height in the Young Lives 4 country cohort study by catch-up growth (using the z-score criterion)

			Ethiopia	India	Peru	Vietnam
All children		n	520	240	393	332
		Change from baseline to follow-up
		HAZ	-0.40	-0.61	-0.66	-0.62
		HAD (cm)	-4.1	-5.2	-6.1	-4.8
		Velocity in height^a
		Observed (cm)	34.8	35.1	32.2	34.4
		Expected (cm)	38.9	40.3	38.3	39.1
By catch-up according to z-score criterion	No	n	324	167	308	267
		Change from baseline to follow-up
		HAZ	-1.27	-1.2	-1.01	-0.92
		HAD (cm)	-6.3	-6.9	-7.3	-5.8
		Velocity in height^a
		Observed (cm)	32.6	33.7	31.1	33.7
		Expected (cm)	38.9	40.6	38.3	39.4
	Yes	n	196	73	85	65
		Change from baseline to follow-up
		HAZ	1.03	0.75	0.61	0.61
		HAD (cm)	-0.5	-1.5	-1.7	-0.5
		Velocity in height^a
		Observed (cm)	38.4	38.3	36.4	37.4
		Expected (cm)	38.9	39.8	38.1	37.9

^aThe observed velocity in height is the mean change in height between baseline and follow-up. The expected velocity is the expected change in height using the WHO 2006 growth standards

ISSN: 1471-2431