Vitamin A Status Monitoring in Women and Children in Rural Indonesia: Serum Retinol and Retinol-binding Protein and their Correlation
Idrus Jus'at *
Indonesian Nutrition Foundation for Food Fortification, Jakarta, Indonesia and Esa Unggul University, Jakarta, Indonesia.
Sandjaja Sandjaja
National Health and Development Research Institute, Ministry of Health, Jakarta, Indonesia.
Abas Basuni Jahari
National Health and Development Research Institute, Ministry of Health, Jakarta, Indonesia.
Min Kyaw Htet
Center of Community Health and Population Studies, The Research Institute, Trisakti University, Jakarta, Indonesia.
Sudikno Sudikno
National Health and Development Research Institute, Ministry of Health, Jakarta, Indonesia.
Damayanti Soekarjo
SAVICA Public Health Nutrition & Communication Consultancy, Surabaya, Indonesia.
Robert Tilden
Indonesian Nutrition Foundation for Food Fortification, Jakarta, Indonesia and University of Indonesia, School of Public Health, Jakarta, Indonesia.
Eline Korenromp
Global Alliance for Improved Nutrition, Geneva, Indonesia.
Regina Moench-Pfanner
Global Alliance for Improved Nutrition, Geneva, Indonesia.
Soekirman Soekirman
Indonesian Nutrition Foundation for Food Fortification, Jakarta, Indonesia.
*Author to whom correspondence should be addressed.
Abstract
Objectives: To assess retinol binding protein (RBP) as an indicator of vitamin A status in children and women, during a pilot program fortifying cooking oil with retinyl palmitate in West Java.
Methods: Surveys measured serum retinol using High-Performance Liquid Chromatography (as gold standard), and RBP using Enzyme-Linked Immunosorbent Sandwich Assay, among children 6-59 months (n=753) and 5-9 years (n=175), women 15-29 years not reportedly pregnant (n=170) and lactating mothers (n=303). C-reactive protein and α-1-acid glycoprotein were measured to adjust serum retinol for sub-clinical inflammation using established correction factors.
Results: At baseline, serum retinol concentrations (µg/dL, mean and standard deviation) were 33.2±14.0, 33.0±0.91, 40.9±18.7, and 44.2±18.5 for children 6-59 months, 5-9 years, women and lactating mothers. Prevalences of vitamin A deficiency (retinol <20µg/dL) were 14.9%, 10.9%, 10.0% and 5.3%. Mean RBP concentrations (mg/kg) were 1.00±0.24, 1.01±0.22, 1.24±0.35, 1.34±0.37, respectively. Serum retinol and RBP concentrations correlated positively (Pearson's correlation coefficient r=0.54, 0.50, 0.51, and 0.48 in the four groups). In the 2nd survey a year later, retinol and RBP averages were 3.2-17.4% and 3.7-13.7% increased among groups; correlation patterns were similar. Using RBP<0.80 μmol/L as cut-off (lacking a WHO recommendation), deficiency prevalence, sensitivity and specificity of RBP were 15%, 36% and 88% in children 6-59 months.
Conclusions: RBP can be an indicator of vitamin A status in child and woman populations, saving cost compared to serum retinol-based monitoring. The lesser retinol-RBP concordance compared to earlier studies suggest that precision of measurements in this study may have been less than typical.