Association of hairdressing with cancer and reproductive diseases: A systematic review

Cancer mortality and premature deaths among hairdressers in Brazil

Hairdresser is an occupation classified by the International Agency for Research on Cancer as probably carcinogenic (Group 2A) for lung and bladder cancer, but evidence is accumulating on its association with other cancer types. To our knowledge, this is the first study aimed to compare the cancer mortality and premature mortality between hairdressers and other workers in Brazil.

METHODS

In this exploratory study, information on deaths by selected cancers that occurred in Brazil, from 1996 to 2020, among workers aged 20-70y, with identified occupation was gathered from the Brazilian Mortality Information System. Sociodemographic characteristics, sex-specific mortality ratio, and Years of Potential Life Lost (YPLL) were compared between hairdressers, service workers, and general workers. We used logistic regression models to estimate crude (ORC) and adjusted (ORADJ) odds ratios. Models were adjusted by age, educational level, and ethnicity. We also used Poisson regression models to compare the YPLL rates across the occupational groups.

RESULTS

From 1996 to 2020, 23 557 deaths occurred among hairdressers, 576 428 among service workers, and 13 332 996 among general workers in Brazil. Higher mortality ORs and YPLL were observed for several types of cancer among hairdressers, compared to service and general workers, especially for women. Hairdressers' mortality was significantly higher among whites, women, younger workers, and those who completed high school. Female hairdressers had significantly higher odds of dying from cancer of the digestive, respiratory, reproductive, urinary, and hematological systems, both in crude and adjusted models. For male hairdressers, higher odds were found only for urinary tract and bladder cancer, while other significant associations indicated lower mortality than the comparison groups. YPLL analyses revealed significant premature deaths among Brazilian hairdressers. In women, this was more evident among those who died of neoplasms of salivary glands, bones and articular cartilages, and acute lymphoid leukemia; in men, tongue, pharynx, and thyroid.

CONCLUSIONS

Our results suggest that Brazilian female hairdressers are more likely to die from several cancers, with potential consequences on premature deaths. Causal associations to occupational risks, such as exposure to chemicals, should be investigated by observational epidemiologic studies. Meanwhile, it is important to promote public policies, regulations, and Occupational Safety and Health (OSH) strategies to protect hairdressers' health, mitigate occupational risks, and ensure safe workplaces.

Association between cigarette smoke exposure and urinary bladder cancer in Scottish terriers in a cohort study

Canine urothelial carcinoma (UC) initially responds favorably to treatment, but is ultimately lethal in most cases. Research to identify modifiable risk factors to prevent the cancer is essential. The high breed-associated risk for UC, e.g. 20-fold higher in Scottish terriers, can facilitate this research. The objective was to identify environmental and host factors associated with UC in a cohort of Scottish terriers. Information was obtained through dog owner questionnaires for 120 Scottish terriers ≥ 6 years old participating in a bladder cancer screening study, with comparisons made between dogs that did or did not develop UC during the 3 years of screening. Univariable models were constructed, and variables with P < 0.20 were included when building the multivariable model, and then removed using a backward stepwise procedure. P < 0.05 was considered statistically significant. Urine cotinine concentrations were measured by liquid chromatography-mass spectrometry to further investigate potential cigarette smoke exposure. Biopsy-confirmed UC which was found in 32 of 120 dogs, was significantly associated with the dogs living in a household with cigarette smokers (odds ratio [OR], 6.34; 95 % confidence intervals [CI], 1.16-34.69; P = 0.033), living within a mile of a marsh or wetland (OR, 21.23; 95 % CI, 3.64-123.69; P = 0.001), and history of previous bladder infections (OR, 3.87; 95 % CI, 1.0-14.98; P = 0.050). UC was diagnosed in 18 of 51 dogs (35.3 %) with quantifiable cotinine concentrations, and six of 40 dogs (15.0 %) without quantifiable cotinine concentrations in their urine (P = 0.0165). In conclusion, the main modifiable risk factor for UC in this cohort of dogs was exposure to second-hand tobacco smoke.

Self-reported symptoms in Swedish hairdressers and association with exposure to volatile organic compounds (VOCs), including aldehydes

BACKGROUND

Working as a hairdresser involves combined exposure to multiple chemicals in hair treatment products that may induce symptoms in airways and skin.

METHODS

In this cross-sectional study, perceived symptoms among Swedish hairdressers at 10 hair salons were surveyed through a questionnaire. Associations with personal exposure to volatile organic compounds (VOCs), including aldehydes, and their corresponding hazard index (HI), based on the estimated risk for non-cancer health effects, were examined. The prevalence of four out of 11 symptoms was compared to available reference datasets from two other studies of office workers and school staff.

RESULTS

All 11 surveyed symptoms were reported among the hairdressers (n = 38). For the whole study group, the most prevalent symptoms were dripping nose (n = 7) and headache (n = 7), followed by eczema (n = 6), stuffed nose (n = 5), cough (n = 5) and discomfort with strong odors (n = 5). Significant relationships between exposure and symptoms were scarce. The exception was total VOC (TVOC) exposure adjusted to worked years in the profession; a difference was observed for any symptom between hairdressers in the group with 20 + years compared to 0-5 years in the profession (logistic regression, OR 0.03, 95% CI 0.001-0.70). Out of the four symptoms available for comparison, the prevalence of headache and cough was significantly higher in hairdressers than in controls (OR 5.18, 95% CI 1.86-13.43 and OR 4.68, 95% CI 1.17-16.07, respectively).

CONCLUSIONS

Adverse health effects related to occupation was common among the hairdressers, implying a need for exposure control measures in hair salons. Symptoms of headache and cough were more frequently reported by hairdressers than staff in offices and schools. A healthy worker effect among the hairdressers was indicated in the group with 20 + years compared to 0-5 years in the profession. Significant relationships between measured exposure and symptoms were scarce but gave information about advantages and disadvantages of the different exposure measures. The study design could be improved by increasing the size of the study population, using a better match of reference data and increasing the applicability and representability over time of the measured exposure.