Removal of Dermal Exposure to Phthalate Ester by Hand Washing
Condition: Environmental Exposure; Exposure to Pollution
Study type: Interventional

Summary: 
      The aim of the study is to evaluate the effectiveness in removing chemical exposure on hand,
      the investigators compare removal efficiency of Di-(2-ethylhexyl)phthalate (DEHP) on hands by
      hand washing with soap and water vs. water only. In two three-day N-of-1 trials, residual
      DEHP was measured in a single female adult who washed exposed hands with soap-and-water or
      water-only. Subsequently, a crossover study was performed by randomly assigning another 28
      subjects equally to wash with soap-and-water or with water-only, and then each one received
      the other treatment 24 hrs later.
    

Detailed description: 
      Three studies, consisting of two N-of-1 trials and one crossover study, were used to compare
      the effect of handwashing with soap and water (intervention) and handwashing with water only
      (placebo) on phthalate removal from hands. The soap was plain soap, consisting of vegetable
      oil and sodium hydroxide. First, the investigators recruited one healthy female aged 25 yrs
      to participate in two N-of-1 trials. In each trial, her hands would be exposed to DEHP and
      then be treated with either soap intervention or placebo for three times over the course of
      three days. The first trial started on 15 May 2013. On day one, after the subject prewashed
      her hands, she allowed her hands to be exposed to a designated amount of DEHP. She then
      washed them with water only and rinsed them sequentially in three separate polyethylene (PE)
      bags, each containing 200 mL water to collect DEHP residue. One hour later, the same protocol
      was followed, except the exposed hands were treated with soap and water instead of water only
      (Figure 1a). The water rinsing in three separate bags remained the same. The pairs of studies
      were repeated on two subsequent days (16 and 17 May).

      In the second N-of-1 trial, which was also performed over three days (22-24 May), the
      protocol using the same subject remained the same for all three days, except that the subject
      underwent intervention first then placebo. The water rinsing remained the same.

      A randomized 2 × 2 crossover study was subsequently conducted between June and September
      2013. The investigators assigned one group of 7 females and 7 males to perform handwashing
      with soap and water (intervention) and another group of 7 females and 7 males to perform
      handwashing with water only (placebo). Briefly, on the first day, the two groups washed their
      DEHP exposed hands using either soap and water or water only and then rinsed them in a PE bag
      with 200 mL water to collect DEHP. After 24 hrs, the experiment was crossed-over with the
      same two groups receiving the opposite treatments.
    

Intervention name(s): handwashing with soap; handwashing with water
Intervention type(s): Behavioral; Behavioral
Intervention description(s): handwashing with soap by a standardized 6-step handwashing technique; handwashing with water by a standardized 6-step handwashing technique
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: Double (Participant, Investigator)
Primary purpose: Prevention
Keywords: Diethylhexyl Phthalate; Hand hygiene; Soaps; N-of-1 design; Cross-Over Studies