Zinc status and functional correlates in preschool and school-aged children in Egypt.

Abstract

Zinc status of Egyptian children 18-30 months and 6-10 years of age was characterized in relation to morbidity, growth, and socioeconomic variables. In a pilot study of children whose general nutrition ranged from adequately nourished to moderately malnourished, mean hair zinc was 135 ug/g (63-230 ug/g), with suboptimal zinc status suggested for 44%. Predictors of hair and serum zinc levels were explored for 23 school-aged and 40 preschool children. Included in models were weaning age for preschool children, body size (length- or height- and weight-for-age Z scores), current growth over 6 months or longer, illness experience over 10 to 12 months, demographic variables affecting food availability and distribution, sex, and season. Data were collected by Egyptian workers as part of a larger field project. Hair and serum samples were analyzed for zinc content by atomic absorption spectrophotometry. Results showed no difference in hair zinc levels by color, presence or absence of louse egg fragments and mucilage, or presence or absence of henna dye. In multiple regression models, the best predictor of hair zinc in preschool children was season of year, with zinc lower in summer. Season, negative effect of percent of weeks ill with diarrhea, and positive effects of socioeconomic status (SES) based on father's education/literacy and economic subsistence base excluding agriculture (ESB-A) predicted 23% of total hair zinc variation in preschool children. In preschool children serum zinc was lower in summer. Season, positive effect of rate of weight increase, and negative effects of rate of height increase, SES based on father's occupation(s) (SES2), and ESB-A predicted 53% of total serum zinc variation in preschool children. Serum zinc was higher in summer in school-aged children. Season, negative effect of SES2 and ESB-A, and positive effects of percent weeks ill with diarrhea and height for age Z scores predicted 60% of total serum zinc variation in school-age children. Negative effects of percent weeks ill with diarrhea and parents' age and child:adult ratio predicted 29% of hair zinc in school-aged children.