School
School of Public Health
Document Type
Dissertation
Department (new version)
Public Health
Date of Award
1997
Degree Name by School
Doctor of Public Health (DrPH) School of Public Health
Abstract
Urinary retinol excretion was measured in 206 children aged 5 mo to 5 y with various illnesses. The mechanism of retinol excretion was examined in patients who had Shigella infection (n = 66). Serum retinol concentrations in patients with shigellosis were very low at admission, and increased significantly by discharge (0.36 $\pm$ 0.22 vs. 1.15 $\pm$ 0.50 $\mu$mol/L, $p < 0.001),$ although no vitamin A supplements were given. Poor nutritional status (wt/age z-score), and S. dysenteriae infection significantly predicted admission serum retinol, after controlling for possible confounding variables. Retinol loss in the urine was significantly higher among children with sepsis (0.154 $\pm$ 0.148 $\mu$mol/d) than among the other groups. Among those with shigellosis, infection due to S. dysenteriae was associated with a significantly higher amount of urinary retinol excretion compared to other Shigella (0.048 $\pm$ 0.127 vs. 0.002 $\pm$ 0.005 $\mu$mol/d, p = 0.015). The threshold of excreting $>$0.1 $\mu$mol/d increases substantially when body temperature is ${\ge}40\sp\circ$C and acute phase proteins (CRP and AGP) reach high serum concentrations, indicating a severely sick patient who is excreting a greater amount of urinary retinol. Proximal tubular function was compromized in children with severe disease and malnutrition. Urinary retinol excretion was significantly higher in patients with abnormal tubular reabsorption of RBP ($p < 0.0001)$ and $\beta$2M ($p < 0.0001)$ compared with their counterparts with normal values of these low-molecular-weight proteins. In a multiple stepwise regression, tubular reabsorption of $\beta$2M ($\beta = {-}0.016,\ p < 0.0001)$ was the significant predictor of urinary retinol excretion on day 1 when all the kidney function tests, age, and Shigella type were in the model. In conclusion, this study demonstrates that, in patients with shigellosis, (1) decreased serum retinol is associated with poor nutritional status, increased acute phase reactants, and severe illness due to S. dysenteriae; (2) a significantly higher amount of retinol is excreted in the urine by children with severe illness and malnutrition; and (3) the excretion of retinol is associated with decreased proximal tubular reabsorption of low-molecular-weight proteins (RBP and $\beta$2M). The results of this study provide greater understanding of the mechanisms by which retinol is excreted in the urine during infection. Enhancing our understanding of these mechanisms will help combat vitamin A deficiency, a major public health problem among children in developing countries.
ProQuest Publication Number
ProQuest ID
9804943
ISBN
978-0-591-56519-5
Recommended Citation
Mitra, Amal Krishna, "Effect of shigellosis on serum concentration and urinary excretion of retinol" (1997). All ETDs from UAB. 7196.
https://digitalcommons.library.uab.edu/etd-collection/7196
Comments
DrPH