Use of breast milk vitamin A concentration as an indicator of population vitamin A status in a national survey in Cameroon

Abstract

Breast milk vitamin A (BMVA) has been proposed as an indicator of population VA status but has rarely been applied in large surveys or compared with conventional VA biomarkers. We assessed the prevalence of, and risk factors for, low BMVA and its relationships with VA intake, plasma retinol‐binding protein (pRBP) and markers of inflammation in a national survey in Cameroon. We randomly selected 30 clusters in each of 3 strata (South, North, and Cities). Casual milk samples were collected from 5 women per cluster (n = 437 total). pRBP, C‐reactive protein (CRP), α1‐acid glycoprotein (AGP), and VA intake were assessed in a subset (n = 269). Mean BMVA was 3.80 (95% CI: 3.54 – 4.06) μmol/L and 23.4 (22.0 – 24.8) μg/g fat. Low BMVA was infrequent: 7.3% (4.7 – 9.9) of values were < 1.05 μmol/L and 9.4% (5.9 – 12.9) were < 8 μg/g fat, consistent with the low prevalence of pRBP < 0.78 μmol/L (< 5%). Risk factors for both low BMVA and pRBP included living in the North and low maternal education. BMVA was positively associated with inflammation‐adjusted pRBP among women in the lowest VA intake tertile (< 114 μg RAE/d, P < 0.01), but not in the highest tertile (>; 462 μg RAE/d, P >; 0.6). Controlling for milk fat, BMVA was negatively associated with CRP (P = 0.011) but not AGP (P = 0.53). BMVA and pRBP provide similar estimates of VA deficiency prevalence and identify the same risk groups among women in Cameroon. Data from populations with lower VA status are needed.Grant Funding Source: Michael and Susan Dell Foundation; Sight & Life