Night blindness is considered as a simple and reliable population based indicator of Vitamin A Deficiency (VAD). Nonetheless, empirical evidence regarding its correlation with bio-markers of vitamin A is scarce. The purpose of the study is to assess the sensitivity and specificity of reported night blindness as an indicator of VAD during pregnancy.
The analysis was done based on secondary data collected in 2011 for assessing the prevalence of VAD among pregnant women in rural Sidama, Southern Ethiopia. Night blindness – inability to see normally after dusk or at night during pregnancy – was determined based on self reporting. Sensitivity and specificity of night blindness were determined by taking serum retinol as the gold standard measure of vitamin A status. Serum retinol was determined using high-performance liquid chromatography (HPLC).
The data of 700 pregnant women included in the analysis. About 37.9% of the women had VAD (serum retinol <0.7 µmol/l) and 39.7% reported night blindness. The mean (±SD) serum retinol among women with reported night blindness (0.77 ± 0.42 µmol/l) was significantly lower than their counterparts (0.88 ± 0.41 µmol/l) (t =3.704, p<0.000). Night blindness was significantly association with VAD (x2 =19.541, p<0.000). Nevertheless, its sensitivity and specificity to correctly classify the deficiency status were low, 50.2% and 66.7% respectively.
Reported night blindness, does not correlate strongly with serum vitamin A level.