The role of anti inflammatory treatment and of obesity/overweight
We tested whether a stronger effect occurred in women without ICS treatment, as hypothesized from results in the EGEA survey [17]. Unlike previous studies, we had access to comprehensive dispensed drug database for the whole population. The association of spray use with current asthma was restricted to women without anti-inflammatory therapy. Beyond the hypothesis of an irritant effect of cleaning agents, one hypothesis to explain our results may be an inflammatory role of cleaning agents. We further tested the potential modifying effect of overweight/obesity. It is worth noting that in those without anti-inflammatory therapy (ICS), the effect was nearly twice as high in overweight/obese women than in others, even if the test for interaction between spray use and BMI was not statistically significant. Systemic/airway inflammation is one of the mechanisms which can explain the association of asthma and obesity [22] and [42], an association already clearly evidenced in a larger sample from the E3N survey [43]. There are still limited studies on interaction between overweight and environmental factors with asthma, but it is an active topic of research with recent findings demonstrating that overweight increased the effect of indoor pollutants on asthma in children [23]. Interaction of overweight/obesity in the effect of environment has biological plausibility as an underlying state of inflammation which could increase the effect of pro inflammatory exposures, such as cleaning exposures. Caution in the interpretation of our findings is necessary in relation to sample size. Further studies should clarify the potential modifying role of overweight/obesity on the effect of spray exposure on asthma, in particular in relation to the increasing prevalence of overweight worldwide.
Cleaning sprays and asthma: a public health issue over the life course
There is increasing evidence that the use of cleaning products in spray form, both at work and at home increases the risk of asthma [8], [9], [15] and [20]. The use of cleaning products in spray form has increased in last decades [1] and many people, and especially women, are exposed worldwide without knowledge on their potential toxicity. Cleaning products and especially fragrance, contained in products in spray form, have been shown to contain a lot of toxic compounds [44]. Household cleaning substances are classified as the most frequently involved in all human exposure complaints [45]. Our results extend in elderly women without household help results regarding the potential deleterious effect of domestic cleaning sprays observed in adults from two previous surveys [8] and [9]. Furthermore, a deleterious effect was observed between the use of cleaning sprays by parents during pregnancy or early childhood and the risk of wheezing in children, in two European studies [37] and [38]. Together with the literature, results suggest a deleterious effect of cleaning sprays in the population at all stages of life and thus, represent a life course public health problem.