Survey on iodine nutrition among college students in Tianjin

Objective To investigate the iodine nutrition among the college students in Tianjin and the main influencing factors.Methods Random sampling was used in this survey.Morning urines of 296 college students were collected from five universities in Tianjin.Three samples of water and two of salts were collected from each school.The iodine contents in urine and water were measured by As3+-Ce4+ catalytic spectrophotometry using the ammonium persulfate digestion.The iodine content in salt was measured by direct titration.Questionnaires were collected from the students on site for analyzing impact factors on iodine nutrition from Oct.,2010 to May,2011.Results The median of urine iodine contents in the total 296 observations was 211.20 μg/L.The median of urine iodine of the medical students was higher(263.86 μg/L) than that of the non-medical students(166.61 μg/L) with statistical significance(P0.05).The median of urine iodine of smokers,vegitarian and alcohol user had a reducing trend compared with those of the non-smokers,people who eat a little meat or frequently and who usually drank tea.Besides,drinking purified water or tap-water and gender did not seem to influence urine iodine levels.Meanwhile,students who had a better knowledge about iodine nutrition had a rising trend compared with those who did not.The iodine contents of the 15 water samples collected from the five universities were 7.60 μg/L to 10.67 μg/L.Four of 10 salt samples were non-iodized salt.Conclusion The iodine nutrition among college students in Tianjin is sufficient and acceptable.The iodine nutrition is affected by living habits and iodine nutrition knowledge.