TY - JOUR
T1 - Pupillary threshold as an index of population vitamin A status among children in India
AU - Sanchez, Ana M.
AU - Congdon, Nathan G.
AU - Sommer, Alfred
AU - Rahmathullah, L.
AU - Venkataswamy, P. G.
AU - Chandravathi, P. S.
AU - Clement, Lily
PY - 1997
Y1 - 1997
N2 - Two hundred seven vitamin A-deficient southern Indian children aged 1-7 y (mean age: 56.9 mo) underwent testing of dark-adapted visual and pupillary thresholds in their village setting according to a previously reported protocol. One hundred thirty (62.8%) of the children also underwent serum retinol testing, and 178 (86.0%) participated in a randomized, placebo- controlled vitamin A dosing trial with pre- and postdose testing of dark- adaptation threshold. Most subjects (184 of 207, 88.9%) were able to complete pupillary testing, an objective sign requiring minimal cooperation, including a high proportion of the youngest children (72.2% of subjects aged 2 y). The proportion of children completing visual threshold testing, which requires greater understanding and cooperation, was significantly smaller than that able to complete pupillary testing (131 of 207, 63.3%; P < 0.0001, chi square). At baseline (predosing), the mean serum retinol concentration declined in linear fashion with a higher pupillary threshold (0.73 μmol/L with a score ≤ 4; 0.47 μmol/L with a score ≤ 8; P < 0.01). The mean pupillary threshold for these highly vitamin A-deficient Indian children (- 0.622 log cd/m2) was significantly higher than that for 136 more moderately deficient Indonesian children (-0.985 log cd/m2; P < 0.001, two-sample t test) and 56 normal American children (-1.335 log cd/m2; P < 0.0001, two- sample t test). The improvement in pupillary dark-adaptation testing was not significant for children receiving vitamin A or placebo, though there was a nonsignificant trend toward greater improvement in children receiving vitamin A (P = 0.2, two-sample t test). Pupillary threshold testing represents a new, noninvasive, practical, and seemingly valid approach to assessing the vitamin A status of a moderately to severely deficient preschool population.
AB - Two hundred seven vitamin A-deficient southern Indian children aged 1-7 y (mean age: 56.9 mo) underwent testing of dark-adapted visual and pupillary thresholds in their village setting according to a previously reported protocol. One hundred thirty (62.8%) of the children also underwent serum retinol testing, and 178 (86.0%) participated in a randomized, placebo- controlled vitamin A dosing trial with pre- and postdose testing of dark- adaptation threshold. Most subjects (184 of 207, 88.9%) were able to complete pupillary testing, an objective sign requiring minimal cooperation, including a high proportion of the youngest children (72.2% of subjects aged 2 y). The proportion of children completing visual threshold testing, which requires greater understanding and cooperation, was significantly smaller than that able to complete pupillary testing (131 of 207, 63.3%; P < 0.0001, chi square). At baseline (predosing), the mean serum retinol concentration declined in linear fashion with a higher pupillary threshold (0.73 μmol/L with a score ≤ 4; 0.47 μmol/L with a score ≤ 8; P < 0.01). The mean pupillary threshold for these highly vitamin A-deficient Indian children (- 0.622 log cd/m2) was significantly higher than that for 136 more moderately deficient Indonesian children (-0.985 log cd/m2; P < 0.001, two-sample t test) and 56 normal American children (-1.335 log cd/m2; P < 0.0001, two- sample t test). The improvement in pupillary dark-adaptation testing was not significant for children receiving vitamin A or placebo, though there was a nonsignificant trend toward greater improvement in children receiving vitamin A (P = 0.2, two-sample t test). Pupillary threshold testing represents a new, noninvasive, practical, and seemingly valid approach to assessing the vitamin A status of a moderately to severely deficient preschool population.
KW - Vitamin A
KW - children
KW - dark adaptation
KW - night vision
KW - pupil
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U2 - 10.1093/ajcn/65.1.61
DO - 10.1093/ajcn/65.1.61
M3 - Article
C2 - 8988914
AN - SCOPUS:0031036173
SN - 0002-9165
VL - 65
SP - 61
EP - 66
JO - American Journal of Clinical Nutrition
JF - American Journal of Clinical Nutrition
IS - 1
ER -