Introduction: Use of paracetamol has been associated with an
increased risk of asthma in several epidemiological studies. In
contrast, it has been suggested that non-steroidal anti-inflammatory
drugs (NSAIDs) might be protective (Kanabar, Clin Ther 2007), but
data relating to these drugs are scarce.
Methods: Prevalence of asthma and intake of analgesics in the past
2 years were assessed by questionnaire in 2008 in young adults
(≥;16 years) diagnosed with cancer between 1976 and 2003 (Swiss
Childhood Cancer Survivor Study). In a multivariate logistic regression
we analysed the association between asthma and intake of
paracetamol only, NSAIDs only or their combination, adjusting for age,
sex, cancer diagnosis, cancer therapy and time since diagnosis.
Results: Of the 1293 participants (response rate 68%), 83 (6%)
reported asthma and 845 (65%) intake of analgesics in the past
2 years. Of these, 257 (29%) took paracetamol only, 224 (25%)
NSAIDs only, 312 (35%) a combination of both and 52 (6%) other
analgesics. Adjusted Odds ratios for asthma were 2.2 (95% CI 1.0-4.7;
p = 0.04), 1.9 (0.9-4.3; p = 0.12) and 2.9 (1.4-6.1; p <0.01) in those
using paracetamol only, NSAIDs only or their combination respectively.
Conclusion: These cross-sectional data in a selected population do
not support a protective effect of NSAIDs against asthma, neither
taken alone nor in combination with paracetamol. All analgesics were
positively associated with reported asthma episodes in the past
two years. This can be explained by reverse causation, with intake
of analgesics being a result rather than a cause of asthma events.
Randomised controlled trials in unselected populations are needed
to clarify the direction of causation.