Third Follow-Up of the Study on Occupational Allergy Risks (SOLAR III) in Germany: Design, Methods, and Initial Data Analysis

Introduction: Asthma and allergies are complex diseases affected by genetic and environmental factors, such as occupational and psychosocial factors, as well as interactions between them. Although childhood is a critical phase in the development of asthma and allergies, few cohort studies on occupational outcomes followed up participants from childhood onwards. We present design, methods, and initial data analysis for the third follow-up of SOLAR (Study on Occupational Allergy Risks), a prospective and population-based German asthma and allergy cohort.Methods: The SOLAR cohort was initially recruited in 1995–1996 for Phase II of the German branch of the International Study of Asthma and Allergies in Childhood (ISAAC II) and followed up three times since, in 2002–2003, 2007–2009, and 2017–2018. During the third follow-up (SOLAR III), participants were between 29 and 34 years old. Since SOLAR focuses on occupational exposures, follow-ups were conducted at important points in time of the development of participants' career. To evaluate the potential of selection bias, responders and non-responders were compared based on variables from earlier study phases. In responders, frequency and pattern of missing values were examined and compared within the subsets of paper and online versions of the used questionnaires.Results: In total, 1,359 participants completed the questionnaire of the third follow-up (47.3% of eligible participants). Initially, the cohort started with 6,399 participants from the ISAAC II questionnaire study. A selection process led to a study population that is more female, higher educated, smokes less and has a higher proportion of certain asthma and allergy symptoms (also in their parents) than the initial cohort. Pattern and frequency of missing values were different for paper and online questionnaires.Discussion: The third follow-up of the SOLAR cohort offers the opportunity to analyze the course of asthma and allergies and their associations to environmental, occupational and psychosocial risk factors over more than 20 years from childhood to adulthood. Selection processes within the cohort might lead to bias that needs to be considered in future analyses.

Predicting occupational allergy in culinary and hairdressing apprentices

Background Apprentices are usually exposed to the same workplace agents as qualified professionals. There is therefore a risk of the development of occupational allergy in apprentices exposed to high (HMW-A) and low molecular inhalant allergens (LMW-A). Aims To evaluate and compare the occurrence of work-related allergy-like symptoms in apprentices exposed to HMW-A and LMW-A in a culinary and hairdressing school during the first and second year of vocational training. Methods We asked culinary and hairdressing apprentices in their first and second year of vocational training to complete a questionnaire about work-related allergy-like symptoms. In first-year apprentices, we undertook spirometry, skin prick tests for occupational allergens and blood tests for allergen-specific Immunoglobulin E (IgE) antibodies. Results Hypersensitivity to occupational allergens was more frequent in first-year apprentices exposed to HMW-A compared to LMW-A (P < 0.05). Apprentices exposed to LMW-A reported increasing occurrence of skin disorders and upper respiratory tract symptoms between the first and second years of training. First-year apprentices exposed to HMW-A more frequently reported rhino-conjunctivitis and dyspnoea (approximately P < 0.001 and P < 0.05) and those exposed to LMW-A more often reported skin symptoms (P < 0.05). Conclusions Periodic skin and respiratory health surveillance for apprentices exposed to LMW-A or HMW-A might help with early identification and management of occupational allergy.