A Survey on Health Effects in a Human Population Exposed to Permanent‐Waving Solution Containing Thioglycolic Acid

Abstract

higher than that before waving (3.13‰, p<0.001). The rate decreased progressively after 24 h. Our results suggest that the reproductive function of hairdressers may be affected by long-term exposure to PWS, probably due to the presence of TGA, and more attention should be paid to its potential carcinogenic effects. Hairdressers are exposed to a variety of chemicals on a daily basis, which may be absorbed, inhaled or possibly even ingested 1) . Chemical waving is the most common means of hair styling and permanent-waving solution (PWS) is usually used for this purpose. The active ingredient of PWS is thioglycolic acid (TGA), which may potentially damage the health of both the hairdressers and their customers.Few data regarding the health effects of TGA are available in the literature. Early toxicological data on TGA were found in a Russian periodical in the 1960s. Rotenberg et al. reported parameters of its acute oral toxicity in rat and mouse, acute inhalation toxicity in mouse, acute dermal toxicity in rabbit, and chronic inhalation toxicity in rat 2) . Thereafter a few more toxicological studies on TGA have been published. According to the US EPA document, LC 50 for TGA as determined by an acute inhalation toxicity study on rat (4-h exposure) was 0.21 mg/l (standard error 0.040 mg/l) 3) . RW Tyl reported the results of studies which evaluated the developmental toxicity of sodium thioglycolate administered topically to CD rats and New Zealand white rabbits from days 6 to 19 or 29 of gestation 4,5) . As to the mutagenicity of TGA, the results were negative in the Ames test system on Salmonella typhimurium strains TA100, TA1535, TA97 and TA98, with and without metabolic activation 6) . Although epidemiological studies conducted by Kersemaekers and Blatter indicated that exposure to chemicals increased the risk of reproductive Received Jan 18, 2003; Accepted Sep 29, 2003

Health Assessment of Self‐employed Hairdressers in France

“…Workplace exposure to these chemicals causes bronchial mucosal inflammation. For example, persulfate salts cause occupational asthma and airway hyperresponsiveness via an immunological mechanism 7) . Bleach and ammonia can cause mucosal membrane irritation and are associated with occupational asthma and chronic bronchitis 8) .…”

Increased micronucleus frequency in exfoliated cells of the buccal mucosa in hairdressers

“…The percutaneous administration of TGA caused a disorder in the reproductive cycle of rats and increased the frequency of micronuclei in bone marrow cells. Taking into account these results, Gan et al (2003) recommended studies on humans that would evaluate reproductive and mutagenic problems. In a subsequent case study and control, Gan et al (2003) hairdressers in China, using a sample of 65 women between the ages of 20 and 40 years, with an average working time of 6 to 7 years and exposed constantly to straighteners, the composition of which was 12% TGA (99% purity), 8% ammonia solution, approximately 2 g sodium carbonate and 80% deionized water.…”

“…Taking into account these results, Gan et al (2003) recommended studies on humans that would evaluate reproductive and mutagenic problems. In a subsequent case study and control, Gan et al (2003) hairdressers in China, using a sample of 65 women between the ages of 20 and 40 years, with an average working time of 6 to 7 years and exposed constantly to straighteners, the composition of which was 12% TGA (99% purity), 8% ammonia solution, approximately 2 g sodium carbonate and 80% deionized water. In this study, Gan et al (2003) found anomalies in the menstrual cycle and an increase in cells with micronuclei in female hairdressers.…”

“…In a subsequent case study and control, Gan et al (2003) hairdressers in China, using a sample of 65 women between the ages of 20 and 40 years, with an average working time of 6 to 7 years and exposed constantly to straighteners, the composition of which was 12% TGA (99% purity), 8% ammonia solution, approximately 2 g sodium carbonate and 80% deionized water. In this study, Gan et al (2003) found anomalies in the menstrual cycle and an increase in cells with micronuclei in female hairdressers. They concluded that the reproductive function of the female hairdressers can be affected after long periods of exposure.…”

“…The coloring used can contain oxidants and dying substances, like pphenylenediamine or 2-nitro-p-phenylenediamine and even hydrogen peroxide, whereas the progressive colorings contain metallic salts, such as lead acetate or bismuth citrate (Cho et al, 2003). Thioglycolic acid is used in the straightening or curling process, which can potentially damage the health of users and the hairdresser (Gan et al, 2003).…”