Elevated urinary Na/K ratio among Lebanese elementary school children is attributable to low K intake.

PURPOSE: To estimate total sodium (Na) and potassium (K) intake using non-fasting morning urine specimens among Lebanese elementary (6-10 year old) schoolchildren. METHOD: A national cross-sectional study was conducted. A multistage cluster sampling procedure was used to select a representative sample of 1403 healthy children from the eight districts of Lebanon. Age, anthropometric measurements, and urine samples were collected and analyzed for Na, K, and creatinine (Cr). RESULTS: The ratios of Na and K to Cr were 23.93 ± 15.54 mM/mM (4.86 ± 3.16 mg/mg) and 11.48 ± 5.82 mM/mM (3.97 ± 2.01 mg/mg), respectively, and showed differences (P value <0.001) between age groups. No differences were found between boys and girls in all the measured Na and K parameters. The estimated mean Na intake was 96.57 ± 61.67 mM/day (2.220 ± 1.418 g/day or 5.69 ± 3.64 g NaCl/day) and exceeded the upper limit of intake in half the children. Estimated K intake was 46.6 ± 23.02 mM/day (1.822 ± 0.900 g/day), and almost all children failed to meet the recommended daily K intake. The high Na/K ratio (2.361 ± 1.67 mM/mM or 1.39 ± 0.98 mg/mg) resulted from a combination of high Na and low K intake but was mostly affected by K intake. CONCLUSIONS: About 50 % of children exceeded the recommended daily upper intake for Na, while the majority was below K adequate intake. This unfavorable Na/K ratio is indicative of potentially negative health effects at later stages in life. Interventions aimed at reducing salt intake and increasing consumption of fruits and vegetables are warranted.

Lebanese children are iodine deficient and urinary sodium and fluoride excretion are weak positive predictors of urinary iodine.

PURPOSE: To assess iodine and fluoride status among Lebanese children. METHODS: A nationally representative cross-sectional study of 6- to 10-year-old schoolchildren was conducted using multistage cluster sampling. Spot urine samples were collected from 1403 children, and urinary iodine, fluoride, creatinine and sodium levels were measured. Salt samples from markets (n = 30) were tested for iodine concentration by titration. RESULTS: Median urinary iodine concentration was 66.0 µg/l, indicating mild deficiency, and almost 75 % of Lebanese children had a urinary iodine concentration (UIC) <100 µg/l. UIC was higher among children from private schools and in areas of higher socioeconomic status. Most salt samples were fortified at levels far below the legislated requirement, and 56 % of samples contained less than 15 ppm iodine. Fluoride-to-creatinine ratio (F/Cr) was 0.250 (0.159-0.448) mg/g. There were weak positive correlations between UIC and urinary sodium (r 2 = 0.039, P value <0.001) and UIC and urinary fluoride (r 2 = 0.009, P value <0.001). CONCLUSIONS: Lebanese elementary school children are iodine deficient due to inadequately iodized salt. The weak correlation between UIC and urinary sodium suggests most dietary iodine does not come from iodized salt. The poor correlation between UIC and urinary fluoride suggests that fluoride intake is not affecting iodine metabolism. Efforts are needed in Lebanon to improve industry compliance with salt fortification through improved monitoring and enforcement of legislation.

Urinary Magnesium, Calcium, and Phosphorus to Creatinine Ratios of Healthy Elementary School Lebanese Children.

Urinary magnesium (Mg), calcium (Ca), and phosphorus (P) excretions are known to vary greatly between populations due to dietary habits, physical activity, mineral content of water, climate, genetics, and race. Thus, it is essential to determine the normal values in each population in order to assess the status as well as to diagnose any possible abnormality of metabolisms especially hypercalciuria. A study was conducted to determine urinary Mg/creatinine (Cr), Ca/Cr, and P/Cr ratios of healthy Lebanese elementary schoolchildren. Using a multi-stage cluster sampling at district, school, and class levels, a sample of 1403 children (781 boys and 622 girls), from 26 different schools, was selected. Non-fasting morning urine samples and anthropometric data were collected and analyzed. The mean Mg/Cr, Ca/Cr, and P/Cr ratios were 0.122 ± 0.075 mg/mg (0.568 ± 0.348 mM/mM), 0.084 ± 0.101 mg/mg (0.237 ± 0.286 mM/mM), and 0.692 ± 0.417 mg/mg (2.527 ± 1.524 mM/mM), respectively, with no significant difference between boys and girls (P = 0.706, 0.161, and 0.604; respectively). The 95th percentile of Mg/Cr, Ca/Cr, and P/Cr ratios fluctuated with age, showing a sharp decrease in Ca/Cr and P/Cr at the age of 10. The mean Mg/Cr, Ca/Cr, and P/Cr ratios were comparable to those of similar age groups in other populations. The 95th percentiles of Mg/Cr, Ca/Cr, and P/Cr ratios were 0.26 mg/mg (1.23 mM/mM), 0.27 mg/mg (0.76 mM/mM), and 1.48 mg/mg (5.40 mM/mM), respectively. These values can be used as cutoffs to detect abnormalities in these three minerals' metabolisms among healthy Lebanese children.