RESUMO
This study aimed to develop and validate a food frequency questionnaire [FFQ] for measuring calcium intake in 9-13 years old children in Tehran, Iran. A 56-item FFQ containing main contributors of calcium in Iranian diet was designed. Criterion validity of the calcium specific FFQ was evaluated through comparing its result with five 24-h recalls as the reference method. Reproducibility was measured by twice administration of FFQ, one month apart. The study was performed in the selected primary and middle schools of Tehran city. Subjects included 184 children aged 9-13 years [90 girls and 94 boys], who were recruited through two-stage systematic cluster sampling from 20 primary and middle schools. Mean calcium intake was 922.8 +/- 322.3 and 876.0 +/- 491.8 mg/d for the 24-h recalls and FFQ, respectively, indicating a mean difference of 46.7 +/- 458.7 mg/d [P<0.001]. Corrected Pearson's correlation was 0.57. Cross-classification analysis of the FFQ and 24-h recalls classified 80% of the subjects in the same or adjacent category, and 6% in the extreme quartiles. The FFQ correctly identified 85% of the children consuming less calcium than the age-specific Recommended Dietary Allowance [RDA] [1300 mg/d]. Pearson's correlation for repeated administrations was 0.65. Cross-classification analysis of the repeated administration of FFQ classified 81% of the subjects in the same or adjacent quartiles, and 3.3% in the extreme categories. The FFQ underestimates mean calcium intake of a group, and has limited use to estimate calcium intake for individuals. However, it has acceptable validity and reproducibility for epidemiologic studies to assess a group's mean calcium intake
RESUMO
This study was undertaken to assess vitamin C status in allergic children. Twenty-six allergic patients and 46 apparently healthy controls aged 7-16 years of both sexes were introduced. All patients were diagnosed being allergic based on their histories, physical examinations and laboratory findings. Blood samples were obtained between 09.00-11.00 to determine total serum immunoglobulin E, histamine, plasma vitamin C and complete blood cell count. Stool examinations and urinealysis were also done. Although total serum immunoglobulin E levels were significantly higher in patients than in controls, the serum histamine and plasma vitamin C levels showed no significant difference between the two groups. Surprisingly, patients with allergic dermatitis and food allergy had significantly lower plasma vitamin C levels than patients with asthma and rhinitis. Also, female patients tended to have higher plasma vitamin C but lower total serum immunoglobulin E levels compared to the male patients but none of these differences were significant. Healthy boys, on the other hand, had significantly higher plasma vitamin C than healthy girls. Our findings did not confirm the previous reports which showed decreased plasma vitamin C levels in allergic patients. We concluded that the plasma vitamin C levels in different allergies might be infuenced by such factors, such as sex, type and the stage of allergic disease, besides those affecting intake