Did Your Grandma Smoke? You bet your asthma she did.
Smoking cigarettes is unhealthy. Second hand smoke exposure is unhealthy. Everybody knows that! When pregnant women smoke, their child is more likely to have low lung function in childhood and adulthood. But, what happens to her grandchildren when granny smoked when she was pregnant?
This question was addressed in a study from the European Lung Foundation entitled: “Grandmother’s smoking when pregnant with the mother and asthma in the grandchild: the Norwegian Mother and Child Cohort Study.” The article was published in 2015 in the medical journal Thorax and may be accessed at Thorax article on Grandma Smoking
Researchers used data from the Swedish Registry that included 44,853 grandmothers from 1982 to 1986 to
investigate whether grandmothers who smoked while they were pregnant with their daughters were linked with an increased risk of asthma in grandchildren. Information from questionnaires completed at 18 and 30 gestational weeks (during pregnancy), and when the child was 6 months, 3 years and 7 years old were evaluated.
To evaluate whether the grandmother’s smoking had an independent association with asthma development in the grandchild from maternal smoking during pregnancy, the researchers classified the children into 4 mutually exclusive exposure groups:
- Not exposed to smoking.
- Only exposed to the grandmother’s smoking.
- Only exposed to the mother’s smoking during pregnancy
- Both the grandmother and the mother smoked.
Results: The risk of asthma in grandchildren was increased by 15 to 21%, even if the child’s own mother had not smoked in their pregnancy!
Why does this happen?
- It’s not entirely clear, but a possible explanation is “trans-generational epigenetics.” This 25 cent word means that the smoking by grandmother led to a change in the methylation of the DNA (the way the gene works) that is passed on to the mother, then to the grandchild making them more susceptible to asthma.
What if grandpa smoked? That data is not yet available. For women who intend on having children and eventually grandchildren, we hope you stop smoking so you leave your grandchildren a better legacy than asthma.
At Family Allergy & Asthma Care of Montana, we treat asthma and encourage smoking cessation in all family members. It’s in our name!