Objectives Hairdressers are exposed to chemicals at the workplace which are known to cause respiratory symptoms and asthma. This study aimed to examine changes in self-reported respiratory symptoms over 5 years, as well as to examine the lung function decline and determine whether it is within the expected range, to assess the dropout rate and reasons for leaving the profession, and to examine the associations between occupational factors and lung function changes at follow-up.

Design Prospective study.

Setting Female hairdressing salons in Hebron city, Palestine.

Participants 170 female hairdressers who participated in a baseline survey in 2008 were followed up in 2013. A total of 161 participants participated in 2013.

Outcome measures Change in reported respiratory symptoms and change in lung function over follow-up. Dropout from the profession and reasons for it. Differences between current and former hairdressers in respiratory symptoms and lung function at follow-up. Ambient air ammonia levels in 13 salons.

Results Current hairdressers reported more respiratory symptoms in 2013 compared with baseline. Former hairdressers reported fewer symptoms at follow-up. At follow-up, current hairdressers showed a significant decrease in forced vital capacity of 35 mL/year (95% CI 26 to 44 mL/year) and of 31 mL/year (95% CI 25 to 36 mL/year) for forced expiratory volume in 1 s (FEV₁). 28 (16%) of the hairdressers quit the job during the 5-year follow-up, 8 (28%) because of health problems. Hairdressers who had been working for 4 years or more at baseline showed a stronger decline in FEV₁ compared with those who worked less than 4 years (difference 13, 95% CI 1 to 25).

Conclusions Current hairdressers developed more respiratory symptoms and larger lung function decline than former hairdressers during follow-up. Few hairdressers left their profession because of respiratory health problems. Working for more years is associated with lung function decline among current hairdressers.