Urine Iodine Levels of Surgical Staff
Condition: Urine Iodine
Study type: Observational [Patient Registry]

Summary: 
      Objective: The routine use of topical iodinated antiseptic could be a possible cause of
      iodine contamination. The aim of this study is to evaluate iodine concentrations in
      operation-room staff who routinely use iodine-containing antiseptics for cleansing of the
      hands after salt iodization.

      Methods: The study included 40 surgeons and surgical nurses who use surgical hand-scrub
      solutions. Participants applied an iodized brush for a minimum of three times a day on
      weekdays and were iodine-free on the weekends. Morning spot urine specimens were collected
      from all participants to analyze the urinary iodine concentration (UIC) twice a week.
    

Detailed description: 
      Iodine is a major component of thyroid hormones. The recommended dietary allowance for adults
      is 150 µg per day. Measurement of the urinary iodine concentration (UIC) has been recommended
      to evaluate the daily nutritional intake of iodine.

      According to the 2007 guidelines of the World Health Organization (WHO), the median UIC
      should be in the range of 100-199 µg/L for adequate daily iodine intake. Before iodization,
      the use of iodinated antiseptics by operating room staff provided only adequate iodine levels
      (125 μg/L) and did not lead to toxic doses. When iodization of table salt became mandatory in
      Turkey in 1998, the median UIC increased to 87 μg/L in 2001, 117 μg/L in 2004, and 130 μg/L
      in 2007, suggesting sufficient median iodine intake in the general population of Turkey.

      In a previous study, the median UIC reached 167 μg/L at least 13 years after iodization,
      which suggested that iodine prophylaxis is sufficient in Istanbul. However, as a result of
      the widespread use of amiodarone and iodinated radiological contrast agents in clinical
      practice, humans are exposed to high doses of exogenous iodine. Furthermore, most surgical
      hand-scrub solutions contain large amounts of iodine, and transcutaneous and mucosal
      absorption of iodine from these solutions has been demonstrated. Therefore, the routine use
      of topical iodinated antiseptic could be a possible cause of iodine contamination after
      iodization. However, the results of iodine absorption from topical iodine-containing
      antiseptics are contradictory in several studies. The aim of this study is to reevaluate
      iodine concentrations in operation-room staff who routinely used iodine-containing
      antiseptics for cleansing of the hands after a long period of iodization.

      MATERIALS AND METHODS This study was carried out between November 2017 and February 2018 with
      the operating-room staff of Istanbul University Faculty of Medicine. The study included 40
      surgeons and surgical nurses who routinely use iodine-containing surgical hand brushes
      (Surgical Hand Brush Impregnated with 7.5% povidone-iodine). Participants applied the iodized
      brush for a minimum of three times a day for 3-5 minutes. The exclusion criteria were the use
      of intravenous iodinated contrast, the use of iodized medications, the use of thyroid hormone
      replacement, and salt restrictions. The study protocol was approved by the University
      Hospital Ethics Committee for Human Studies (No: 2017/1127). All volunteer participants
      provided written informed consent. The subjects used iodine-containing hand scrub solutions
      on weekdays and were iodine-free on the weekends. Early-morning spot urine specimens were
      collected from all participants to analyze the UIC twice a week: once at the beginning of the
      working period (the washout period of the antiseptic) and once at the end of the working
      period (the antiseptic exposure period). Urine samples were collected in deionized test tubes
      with tight lids and were immediately transported to the laboratory, acidified, and stored at
      -80 ºC until analysis.

      UICs were determined using the Modified Microplate Method for the Determination of Urinary
      Iodine Concentration recommended by the CDC's Ensuring the Quality of Urinary Iodine
      Procedures (EQUIP) booklet with minor modifications as described by Tang et al (CDC, 2011),
      (Tang et al, 2015). Briefly, urine samples were dissolved at room temperature and incubated
      with ammonium persulfate (0.9 M final concentration) at 95 ºC on a thermal cycler for 30
      minutes. After cooling, 50 µl of digested urine samples were pipetted into microplate wells.
      100 µl of 0.05 M arsenious acid solution was added to each well and mixed. Finally, 50 µl of
      0.019 M ceric ammonium sulfate solution was added to each well. After incubation for 30
      minutes at 25 °C, absorbance at 405 nm was recorded. UICs were determined using a standard
      curve and expressed in μg/l.

      For internal quality control analysis, urine pools (high level: 350 μg/l, low level: 80 μg/l)
      were prepared from patient samples, portioned, and stored at -80°C. Two levels of pooled
      urine samples were included in each run for quality control. Between-run coefficients of
      variation (CV%) for urine iodine measurements were 8.65% for the low level and 11.1% for the
      high level. Values of 50-99 μg/L were defined as mild iodine deficiency, values of 20-49 μg/L
      were defined as moderate deficiency, and values < 20 μg/L were defined as severe deficiency.
      Values of 100-199 μg/L were defined as adequate iodine intake, values of 200-299 μg/L were
      defined as exceeding iodine requirements, and values ≥ 300 μg/L were defined as potentially
      harmful to healthy thyroid function.
    

Intervention name(s): Using Antiseptic solution
Intervention type(s): Diagnostic Test
Intervention description(s): Using of iodine including antiseptic solutions. The investigators investigate the urine iodine status of staff before and after the using of antiseptic solution
Intervention MeSH terms: Anti-Infective Agents, Local
Observational model: Case-Only
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        The surgical staff used iodine-containing hand scrub solutions for antisepsis
      
Biospecimen description: 
      Blood
    
Keywords: Iodine; Surgical; Staff; Antiseptic