title: Use of biomarkers of sub-clinical infection, nutrition and neonatal maturity to interpret plasma retinol in Nigerian neonates.
abstract: Using the World Health Organization criterion, the prevalence of sub-clinical vitamin A deficiency can be assessed using plasma retinol concentrations <0.7 micromol/l. However, plasma retinol can be depressed by infection; thus, the use of this criterion alone may overestimate deficiency. In the present study, we investigated the usefulness of the acute-phase proteins (APP) alpha1-antichymotrypsin (ACT) and alpha1-acid glycoprotein (AGP), plasma carotenoids and anthropometric and gestational indices to interpret plasma retinol in the blood of 192 apparently healthy Nigerian neonates collected randomly during days 1-20 postpartum. The mean weight (2.64 kg) and length (0.458 m) of the neonates and plasma concentrations (geometric mean, micromol/l) of retinol (0.54), alpha-carotene (0.072), ss-carotene (0.076) and lutein (0.080) were low. The prevalence of vitamin A deficiency was 72 %, indicating a severe public health problem. Babies who were of low birth weight (P<0.003) or premature and low birth weight (P<0.023) had significantly lower retinol concentrations than full-term normal weight babies. Thirty-two neonates had abnormal ACT and forty-four abnormal AGP concentrations. Positive correlations between retinol and ACT (r 0.186, P=0.05) and AGP (r 0.31, P=0.0001) during days 1-5 may be due to the increasing plasma retinol from maternal milk and a coincidental increasing capacity to synthesise APP. Subsequently, negative correlations between retinol and ACT (r -0.28, P=0.02) and AGP (r -0.29, P=0.018) from day 6 onwards reflected the continuing increase in plasma retinol, but no further increase in the APP. Overall, weight, ACT, lutein and age explained 30 % of the variance in retinol, but lutein was the most significant (r(2) 0.18, P<0.0001). Hence, the distribution of plasma retinol concentrations in this group of neonates was more strongly linked with nutrition (via the surrogate marker lutein) than infection.
authors.affiliation: Department of Community Health, Obafemi Awolowo, University Ile-Ife, Nigeria.
authors.forename: Delana A
authors.initials: DA
authors.lastname: Adelekan
authors.forename: Christine A
authors.initials: CA
authors.lastname: Northrop-Clewes
authors.forename: Joshua A
authors.initials: JA
authors.lastname: Owa
authors.forename: Adesola O
authors.initials: AO
authors.lastname: Oyedeji
authors.forename: Adedayo A
authors.initials: AA
authors.lastname: Owoeye
authors.forename: David I
authors.initials: DI
authors.lastname: Thurnham
mesh_terms: D015415:Biomarkers / Q000097:blood; D001724:Birth Weight; D001835:Body Weight; D002338:Carotenoids / Q000097:blood; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D007239:Infections / Q000097:blood; D014975:Lutein / Q000097:blood; D009752:Nutritional Status / Q000502:physiology*; D009961:Orosomucoid / Q000032:analysis*; D014801:Vitamin A / Q000097:blood*; D014802:Vitamin A Deficiency / Q000097:blood / Q000175:diagnosis; D000514:alpha 1-Antichymotrypsin / Q000097:blood*; D024502:alpha-Tocopherol / Q000097:blood
chemical_list: D015415:Biomarkers; D009961:Orosomucoid; D000514:alpha 1-Antichymotrypsin; D014801:Vitamin A; D002338:Carotenoids; D024502:alpha-Tocopherol; D014975:Lutein