Why do some people get asthma? (In the last 25 years, the number of new asthma cases in the UK has increased six fold among children and three to four fold in adults) Well, as is the case with pretty much every single disease we know about, nobody knows. We are meaning-seeking creatures. We want to make sense of what we experience in life. Who gets any disease without thinking “why me?” And that is a very, very hard question to answer. It would be more convenient if human beings were more like machines. We’d be able to work out exactly why a particular fault had occurred, we’d be able to understand the consequences of that fault and we’d be able to fix it. But human beings are not like machines (even if the way we treat people who are ill seems to assume that they are). Not only do we not know why asthma afflicts more and more people every year, but we cannot explain to any single, individual patient – this is why you have asthma.
One of the main reasons we can’t answer these questions is that we’ve only recently begun to understand that human beings, biologically, are complex adaptive systems. As such, they have particular characteristics which make the answers to these questions hard to find.
Disease is multi-factorial. There are many things which contribute to the development of a disease in an individual. Causation is, therefore, not simple. We can’t say “X’ causes “Y”. However, we can still observe carefully, and experiment and explore to try and understand what the factors are and how they interact.
Here’s an interesting study which tries to uncover some of the factors involved in the causation of asthma. It’s that old factor “stress” again. But this time, they’ve found something interesting and thought-provoking. Not only have they found that life stresses occurring during childhood seem more common in those who develop asthma, but they’ve discovered something interesting about exactly what kind of life stresses can have this impact. In a nutshell, the stress of parents splitting up and the stress of moving home seem associated with an increased risk of developing asthma. Other major events, such as the death of a close relative, or parental unemployment don’t seem to have the same impact. How do they know? The researchers used the finding of increased blood concentrations of the neuropeptide VIP (vasoactive intestinal polypeptide) as the objective manifestion of the stress response. This, and other substances which were also found to be raised, are known to be factors in producing allergic responses, like asthma.
I think this is a useful study. It shows us some of the mechanisms that connect life events to disease and it shows us that we can’t consider all life events to be the same. What matters is what is most stressful for the person experiencing the stress, not how others rate the stressfulness of an event.
