An investigation of iodine intake and iodine nutritional status of adults in Tianjin City

Objective To study the intake of iodine and iodine nutritional status of adults and provide a scientific basis for choosing appropriate salt iodine content in the region. Methods By using multi stage random sampling method, according to the four corners of 4 directions, 4 non water iodine counties or districts were selected from Nankai District, Jixian County, Dagang District and Hangu District. Totally 1 to 4 administrative villages were selected (neighborhood committees) from each district or county as the survey points. Ten to 15 households were selected from each survey points. All the members more than 18 years old of each household were investigated(excluding pregnant and lactating women). Of the 225 households, 404 people, salt iodine of the family, urinary iodine and water iodine were detected. The questionnaire survey was used to investigate the daily salt intake of residents per capita. The daily intake of iodine was calculated by the method of dietary frequency. Salt iodine content was detected by direct titration method; iodine in water was detected by cerium sulfate catalytic spectrophotometry; urinary iodine was detected by arsenic cerium catalytic spectrophotometry. Results A total of 24 drinking water samples were tested, the median water iodine was 8.0 μg/L. A total of 225 salt samples and 404 urine samples were tested, the medians of family salt and urinary iodine were 23.30 mg/kg and 149.0 μg/L, respectively. Investigation was done on salt intake and dietary intake of 393 people, the per capita consumption of salt intake was (11.45 ± 5.70) g/d. Salt supplied 148.75 μg/d iodine and food supplied 82.47 μg/d iodine. The total contribution rate of iodized salt to the total iodine intake was 68.99% (193.18/280.00) in the population of iodized salt consumer. The value of urinary iodine and iodine intake were correlated (r = 0.170,P < 0.05). Conclusions The adult iodine nutrition in Tianjin city is in the appropriate level. Iodized salt is the main source of iodine intake for adults, so salt iodine is a indispensable iodine nutrition source for adults. Key words: Adult; Iodine; Salts; Food