VITAMIN-B-6 STATUS DURING CHILDHOOD - TRACKING FROM 2 MONTHS TO 11 YEARS OF AGE

To examine the development and tracking of long-term vitamin B-6 statu s from infancy to early adolescence, measurements of erythrocyte pyrid oxal 5'-phosphate concentration (EPLP), the erythrocyte aspartate tran saminase (EAST) stimulation test including measurements of basal activ ity (EAST(o)) and activation coefficient (alpha EAST), were made in a follow-up study of healthy children aged 2 (n = 139), 4 (n = 147), 6 ( n = 157), 9 (n = 159) and 12 mo (n = 188) and 5 y (n = 148). The EAST stimulation test was repeated at 11 y (n = 153). Vitamin B-6 status, h igh during infancy, reached the adult level by 5 y of age. The 10th to 90th percentile ranges for EPLP values were 61-201 nmol/L at 4 mo, 49 -101 nmol/L at 12 mo and 27-59 nmol/L at 5 y. The respective ranges fo r EAST(o) were 16-24 mu kat/L at 4 mo, 13-19 mu kat/L at 12 mo, 9-14 m u kat/L at 5 y and 25-39 mu kat/L at 11 y of age. For alpha EAST value s were 1.29-1.54 at 4 mo, 1.48-1.77 at 12 mo, 1.70-2.07 at 5 y and 2.0 0-2.57 at 11 y. Values for EPLP and the EAST stimulation test in the f irst year of life correlated with the values at 5 and 11 y. The indivi duals with values at the extreme ends of the distributions remained th ere from infancy to childhood up to 3.3 times more often than expected from random variation. Vitamin B-6 status, high in infancy, fell with age, and tracking of EPLP and EAST stimulation test values developed during the first year of life. The levels of these indices are affecte d by vitamin B-6 intake and age, but they may also be genetically infl uenced. Thus, the values for vitamin B-6 indices in infancy are predic tive of the subsequent levels later in childhood.