Conclusions
This study of blood donors in western Norway assessed the association between three risk factors – the number of tick bites ever experienced and the presence of Borrelia IgG and IgM antibodies – with the questionnaire-based outcomes general function, physical fitness and 29 different subjective health complaints.
A limitation of this study is that very few of the study subjects reported ever having had symptoms indicative of systemic LB.
There was no association between general function and the risk factors. However, we found a clear correlation between the number of tick bites ever experienced and good physical fitness. This most probably represents a spurious relationship as both risk factor and outcome are related to a healthy life style.
We did not find any association between more subjective health complaints and tick bites or Borrelia antibodies. Seeing the «pseudoneurological» group of complaints together, there were fewer complaints in subjects with Borrelia IgG antibodies, also probably a non-causal relationship.
The results do not support any association between tick bites or Borrelia antibodies and subjective health complaints in blood donors in an endemic area for Lyme borreliosis.