• Korean Journal of Community Nutrition
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• v.10 no.5
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• pp.677-692
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• 2005

The assessment of sodium intake is complex because of the variety and nature of dietary sodium. This study intended to develop a dish frequency questionnaire (DFQ) for estimating the habitual sodium intake and a short DFQ for screening subjects with high or low sodium intake. For DFQ112, one hundred and twelve dish items were selected based on the information of sodium content of the one serving size and consumption frequency. Frequency of consumption was determined through nine categories ranging from more than 3 times a day to almost never to indicate how often the specified amount of each food item was consumed during the past 6 months. One hundred seventy one adults (male: 78, female: 93) who visited hypertension or health examination clinic participated in the validation study. DFQ55 was developed from DFQ112 by omitting the food items not frequently consumed, selecting the dish items that showed higher sodium content per one portion size and higher consumption frequency. To develop a short DFQs for classifying subjects with low or high sodium intakes, the weighed score according to the sodium content of one protion size was given to each dish item of DFQ25 or DFQ14 and multiplied with the consumption frequency score. A sum index of all the dish items was formed and called sodium index (Na index). For validation study the DFQ112, 2-day diet record and one 24-hour urine collection were analyzed to estimate sodium intakes. The sodium intakes estimated with DFQ112 and 24-h urine analysis showed $65\%$ agreement to be classified into the same quartile and showed significant correlation (r=0.563 p<0.05). However, the actual amount of sodium intake estimated with DFQ112 (male: 6221.9mg, female: 6127.6mg) showed substantial difference with that of 24-h urine analysis (male: 4556.9mg, female: 5107.4mg). The sodium intake estimated with DFQ55 (male: 4848.5mg, female: 4884.3mg) showed small difference from that estimated with 24-h urine analysis, higher proportion to be classfied into the same quartile and higher correlation with the sodium intakes estimated with 24-h urine analysis and systolic blood pressure. It seems DFQ55 can be used as a tool for quantitative estimation of sodium intake. Na index25 or Na index14 showed $39\~50\%$ agreement to be classified into the same quartile, substantial correlations with the sodium intake estimated with DFQ55 and significant correlations with the sodium intake estimated with 24-h urine analysis. When point 119 for Na index25 was used as a criterion of low sodium intake, sensitivity, specificity and positive predictive value was $62.5\%,\;81.8\%\;and\;53.2\%$, respectively. When point 102 for Na index14 was used as a criterion of high sodium intake, sensitivity, specificity and positive predictive value were $73.8\%,\;84.0\%,\;62.0\%$, respectively. It seems the short DFQs using Na index 14 or Na index25 are simple, easy and proper instruments to classify the low or high sodium intake group.

• Korean Journal of Ecology and Environment
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• v.33 no.2 s.90
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• pp.109-118
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• 2000

The dynamics of inorganic nutrients and phytoplankton population were examined at eight stations of Shihwa Reservoir, which situated near the cities newly constructed and the industrial complex of West-sea in Korea, from January to December 1999. Among environmental factors, average concentration of $NH_4$, SRP and SRSi were $522.7\;{\mu}g\;N/l$, $9.8\;{\mu}g\;N/l$ and $0.26\;{\mu}g\;Si/l$, respectively. Water quality was extremely deteriorated by a great amount of pollutants load into inner reservoir after the event of rainfall. Nutrients concentration was suddenly decreased toward the lower part. While $NO_3$ concentration did not much varied among stations, but it was relatively high in winter season. Chlorophyll-a concentration was high at the upper part of the reservoir, with average of $37.2\;{\mu}/l$, and closely related to the fluctuation of $NH_4$, SRP and SRSi concentrations. The phytoplankton development in the water column was dominated by diatom (autumn), prasinoid (winter) and dinoflagellate (summer). Dominant phytoplankton were composed to Skeletonema costatum of diatom, Prorocentrum minimum of dinoflagellate, Chroomonas spp. of cryptomonad, Eutreptiella gymnastica of euglenoid and Pyramimonas spp. of prasinoid. The large bloom of phytoplankton at the upper zone of the Shihwa Reservoir after inflow of a seawater were consistently observed. In consequence, water quality management of the inlet stream was assessed to be very important and urgent.