The ‘take home’ burden of workplace sensitizers: Flour contamination in bakers' families

BACKGROUND: Exposure to flour/flour constituents is a leading cause of occupational asthma. Paternal occupational exposure to flour has been associated with increased likelihood of childhood asthma, raising the possibility of para-occupational exposure whereby family members are exposed to sensitizers ‘taken home’ on contaminated skin/clothing. OBJECTIVE: To establish whether workplace contamination of skin/clothing with wheat flour allergen (WFA) and fungal α-amylase (FAA) is associated with increased levels of these allergens in bakers' homes. METHODS: Bakeries in north-east Scotland were invited to participate. Control subjects were recruited from University of Aberdeen staff and students. Exposure assessment was carried out in bakeries, bakers' cars and the homes of bakers and controls using surface wipe and vacuum sampling; samples were analyzed for total protein, FAA and WFA. RESULTS: 164 wipe samples and 49 vacuum samples were collected from 38 bakers (from 5 bakeries) and 10 controls. Compared to non-bakers, bakers had higher median levels of WFA and FAA in house vacuum samples; the difference was statistically significant for WFA/total protein (515.8×10⁻⁶ vs. 163.7×10⁻⁶, p=0.031), FAA/total protein ratios (1.45×10⁻⁶ vs. 0.04×10⁻⁶, p<0.001) and FAA loading (median 1.2pg/cm² vs. 0.1pg/cm², p<0.001) with workplace exposure–home contamination relationships between bakers with higher and lower workplace contamination. We found positive correlations between WFA contamination of the bakers' foreheads and cars (rₛ0.57, p=0.028), foreheads and houses (rₛ0.46, p=0.025), shoes and houses (rₛ0.45, p=0.029); and between FAA contamination of shoes and houses (rₛ0.46, p=0.023), and cars and houses (rₛ0.70, p=0.008). There was no evidence of bakers using work-sourced flour for domestic baking. CONCLUSIONS: This work demonstrates pathways for ‘take home’ exposure of occupationally sourced flour. Taken with our previous work, showing that bakers' children are more likely to have asthma, this supports the need for further investigation to establish whether ‘take home’ of occupationally sourced flour is widespread with health consequences.