FREMONT, CA - The first study to look at cancer rates in manicurists in California has found no evidence that nail salon workers have a greater chance of developing cancer than other women. But continued tracking is needed and could stilll reveal a higher risk over the long term, researchers say.
For the study, published in the American Journal of Epidemiology, researchers obtained files for every person licensed to do nail care in the state since 1970 and linked them to a state database that includes cancer patients from 1988 to 2005. The scientists identified more than 9,000 cancer cases among the state’s 325,228 female licensed manicurists.
Cancer rates among the workers were no higher than in the general population, with two exceptions: thyroid cancer (for both manicurists and hairdressers licensed to do nails) and lung cancer (which was higher only among manicurists).
The percentage of the rate increase "is too small for me to highlight,” said Dr. Thu Quach, the study’s lead scientist and a senior researcher at the Fremont, Calif.–based Cancer Prevention Institute of California (CPIC).
But she added that this did not necessarily mean that nail-care work poses no cancer risk to women in the long term. The state’s cancer registry tracks cases to 2005, but growth in the nail industry didn’t take off until 1990, which gives the researchers at most 15 years of data, Quach said. What's more, the women in the study were relatively young, and cancer becomes more prevalent with age.
“Cancer is a disease that takes many years to develop, " she said. "There hasn’t been enough time for cancer to develop in this group.”
Quach says she was interested in conducting the study because nail-care workers are routinely exposed to hazardous and unregulated chemicals on the job, some of which are known to cause cancer.
“Anytime anyone is exposed to carcinogens, there’s a worry, but anytime it happens in a workplace, they are more exposed, so there’s greater worry,” Quach added. During an initial pilot study of nail
salon workers by CPIC, manicurists reported health problems such as eye and skin irritation, breathing problems and headaches.
The study, published last month, found that white women made up 60 percent of the more than 9,000
cancer cases, followed by Latina and Asian and Pacific Islander women. But demographic shifts in the industry could yield a very different ethnic breakdown among cancer cases in the future. The number of licensed manicurists has tripled in the last two decades, owing mostly to an influx of immigrant women workers, including large numbers of Vietnamese.
Dr. Tung Nguyen, a professor of medicine at UC San Francisco and co-director of the school’s Vietnamese Community Health Promotion Project, says that because many manicurists are Asian, and cancer rates for Asians are lower than in the general population, “the comparison to cancer rates in a population of Californian Asian women may have led to very different results.”
Nguyen added that the CPIC results did not take into account the incidence of other types of health problems among nail-care workers that are less easy to quantify and track. “The real issue, I think, is that the authors used cancer primarily because it has the best available database for this kind of analysis, whereas other potential health problems, asthma, for example, do not have these databases available,” Nguyen said
Quach said the study lays the groundwork for future research. The next step, she said, is to look more specifically at the Vietnamese workers and compare their rates of cancer to that of other Vietnamese. Follow-up studies will also track whether manicurists who have worked in the business longer are at a greater risk of developing cancer.
Dr. Cora Roelofs, a researcher at the School of Health and Environment at the University of Massachusetts Lowell, said that except for specific diseases such as mesothelioma, a rare form of cancer linked to working with asbestos, “if someone gets cancer, it’s hard to pinpoint a cause.”
Roelofs has studied acute health problems among nail salon workers and found that many reported “feeling unwell” on the job.
“Let’s not wait until we have that definitive science," Roelofs said. "Ultimately, it will be fairly elusive,” she added. “These chemicals are demonstrated in rats and mice to be toxic. They shouldn’t be in cosmetics.”