Studying Blood Toxicity in Workers Exposed to Formaldehyde

A Cross-Sectional Study of Hematotoxicity in Workers Exposed to Formaldehyde

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.

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.

• INCLUSION CRITERIA:
• The eligible age range for the study will be 18 to 60 years old

EXCLUSION CRITERIA:

Exclusion criteria for both formaldehyde-exposed and control workers will be:

- A history of cancer, chemotherapy, and/or radiotherapy, as well as previous or current occupational exposure to benzene, butadiene, styrene and radiation.