Article Text


266 Endotoxin and glucan exposure protects against atopy and hay fever: a longitudinal study
  1. E A J Spierenburg1,
  2. Smit1,
  3. Robbe2,
  4. Heederik1,
  5. Hylkema2,
  6. Wouters1
  1. 1Utrecht University, Utrecht, Nederland
  2. 2University Medical Center, Groningen, Nederland


Objectives We previously showed that occupational endotoxin exposure in agricultural workers was associated with wheeze and negatively associated with atopy. We recently completed a 5“year follow” up of the initial study population. This study aimed to analyse change and persistence in status of atopic sensitizaton, (self reported) allergy, hay fever and wheeze in relation to baseline endotoxin and glucan exposure.

Methods We studied an occupational cohort of 259 Dutch farmers and agricultural workers recruited in 2006 and followed up in 2011. Endotoxin and glucan exposure were assigned based on measurements in a subset of the population and exposure modelling. Allergic sensitisation to common allergens (house dust mite, grass, cat, and dog) was based on serum IgE. Atopy was defined as sensitisation against ≥one common allergens. Self-reported wheeze, allergy and hay fever were determined by questionnaire. Associations between exposure and health outcomes were analysed by multinomial logistic regression using four categories based on presence or absence of the outcome at baseline and at follow-up. Analyses were adjusted for possible confounders age, gender, smoking and farm childhood.

Results Baseline glucan and endotoxin exposure levels were highly correlated (r > 0.9). Glucan and endotoxin exposure were negatively associated with persistent reporting of hay fever symptoms (OR 0.58, 95% CI [0.41-0.82] and 0.69 [0.48-0.98] respectively) or atopy (OR 0.7 [0.56-0.90] and 0.74 [0.56-0.98] respectively). Higher endotoxin exposure tended to be negatively associated with persistent self reported allergy and sensitisation against grasspollen (OR 0.84 [0.68-1.02] and 0.79 [0.62-1.02]). Presence of house dust mite-specific IgE or wheeze was not associated with glucan or endotoxin exposure. Changes in outcome status were rare and not clearly associated to exposure.

Conclusions Exposure to both endotoxin and glucan protects from persistent atopic disease. These results could be suggestive of a healthy worker selection. However, a previously performed healthy worker survivor analysis showed no such selection.

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