Long term depression or anxiety in mothers has been associated with a 25 per cent higher risk of asthma in their children. Professor Anita Kozyrskyj, an associate professor in faculty of pharmacy at the University of Manitoba, Canada, stated that it is important for mother’s not to assume these findings mean they are to blame.
“I think the significance of the results is that there is an association,” said Kozyrskyj.
People who are unfamiliar with statistics can easily find themselves confused over terminology like ‘association’. Certainly as a young undergraduate it was drummed into me that ‘correlation does not mean causation’. In other words, it is easy to find some fairly curious relationships that are meaningless. In our class, for example, we found an association between scores on a test and preference for a car color. Of course it means nothing, so the job of the researcher is to try to eliminate these spurious issues so what remains is at least plausible.
Kozyrskyj and her research team attempted just this, although they remain uncertain of the exact meaning of the relationship. The medical records of 14,000 children aged 7 were cross-checked with the mother’s medical records. In the case of the mother attention was paid to doctor visits, hospitalization, maternal distress and prescriptions for depression or anxiety since the birth of the child. Post-partum (baby blues) depression was ruled out of the study. For the child, asthma status was defined as having received at least two medical consultations for the condition.
When asked to speculate on the possible reasons for the association, Kozyrskyj pointed out that mother’s under greatest stress or who suffer from depression are more likely to smoke, breast feed less, and pay less attention to their children.
“Animal studies tell us that decreased attention from the mother affects the infants’ stress and immune response, but we are a ways from knowing whether this is true in humans.”
It is estimated that over 300 million people worldwide suffer from asthma. Asthma symptoms result from the lining of the air passages becoming inflamed and swelling when the person comes in contact with something that irritates the airway. These irritants or ‘triggers’ as they are known can be highly varied, just a few examples are smoke, pollution, animal hair, dust, pollen and certain foods.
Emotions also have a role to play in asthma. In some people laughing can trigger asthma symptoms. However, longer term issues are probably more common and include depression, work-stress and financial problems. Roughly 1 in 10 children are affected by asthma, which often runs in families. Roughly half of all children with asthma will grow out of it.
Kozyrskyj, A.L., Mai, X-M., McGrath, P., HayGlass, K.T., Becker, A.B., MacNeil, B (2008) Continued Exposure to Maternal Distress in Early Life Is Associated with an Increased Risk of Childhood Asthma
Am. J. Respir. Crit. Care Med. 177: 142-147.
Published On: January 22, 2008