Studying Blood Toxicity in Workers Exposed to Formaldehyde
Condition: Blood; Chemical Industry
Study type: Observational

Summary: 
      Background:

      - Formaldehyde has many uses in industry and medicine. However, exposure to formaldehyde has
      been associated with increased risk for myeloid leukemia. There are still questions about how
      the chemical reacts with bone marrow to increase this cancer risk. Some smaller studies have
      looked at how it affects stem cells, which are found in bone marrow. Researchers want to
      develop a much larger study of workers in China. The study will look at different levels of
      formaldehyde exposure. It will focus on how the chemical affects the blood cells and bone
      marrow.

      Objectives:

      - To study the effects of formaldehyde exposure on blood cells and bone marrow.

      Eligibility:

      - Individuals between 18 and 60 years of age who work in selected factories in Guangdong
      Province, China.

      Design:

        -  Participants will be screened with a physical exam and medical history. They will also
           be screened with a work history. Those who have been exposed to benzene, butadiene,
           styrene, or radiation will not be included.

        -  Participants will be studied based on their regular formaldehyde exposure level.
           One-third will be those exposed to more than 1 part per million (ppm) of the chemical.
           One-third will be those exposed to 0.3 to 1 ppm. A control group will have no exposure
           to formaldehyde or any other known toxic chemical.

        -  Participants will provide blood and cheek swab samples. They will also answer questions
           about their work habits.

        -  To look at chemical exposure levels, participants will wear a small monitor to work on 3
           different days. They may provide additional blood and cell samples as directed.

        -  No treatment will be provided as part of this study.
    

Detailed description: 
      Research in industrial workers and professionals exposed to formaldehyde suggests that
      occupational exposure to this important chemical is associated with increased risk for
      myeloid leukemia. However, there is still uncertainty about the biologic plausibility of the
      association because of questions regarding the ability of formaldehyde, which is extremely
      reactive, to directly or indirectly cause toxicity to the bone marrow. There have been
      several relatively small studies of the impact of occupational formaldehyde exposure on
      peripheral blood cells that found some evidence that peripheral blood cells of the myeloid
      lineage (i.e., granulocytes, platelets) were significantly decreased in exposed workers. We
      propose to follow-up these findings in a relatively large study population in China. We will
      study hematologic parameters in 240 higher exposed workers (>1 ppm), 240 workers exposed to
      lower levels of formaldehyde (0.3 to 1 ppm), and a group of 240 unexposed controls
      frequency-matched to exposed workers. This study will make an important contribution to our
      understanding of the leukemogenic potential of formaldehyde, which has important public
      health and regulatory implications.
    

Observational model: Other
Time perspective: Cross-Sectional
Sampling method: Non-Probability Sample
Study population: 
        We will identify formaldehyde-exposed manufacturing workers during the cross-sectional
        study. The exposed workers have to have held the same job for at least 3 months in the same
        factory. We expect that the age and sex distribution will be similar in the lower and
        higher exposed workers. We will enroll controls without previous occupational exposure to
        formaldehyde or any other genotoxic, hematotoxic or immunotoxic chemicals in two factories
        that manufacture clothes located in the same@@@geographic area as the utensil producing
        factories.
      
Biospecimen description: 
      Plasma, buffy coat/Red blood cell, whole blood in PAXgene, Urine, Buccal rinse, Buccal
      scrape.
    
Keywords: Hematotoxicity; Formaldehyde; Cross-Sectional Study; Occupational Exposure