Smoking grandmothers increase the risk of autism in female grandchildren

Researchers are studying the effects of grandmothers' smoking on their grandchildren
It is generally known that smoking is unhealthy and can cause health problems. Researchers have now found that grandmothers who smoke during pregnancy greatly increase the risk that their female grandchildren will develop autism later.

Scientists at the University of Bristol found that pregnancy-smoking grandmothers have a significant impact on the likelihood that their female grandchildren will one day develop autism. The doctors published the results of their study in the scientific journal "Scientific Reports".

Researchers analyze the data from 14,500 subjects
For their study, the experts examined the data from 14,500 people. They found that smoking grandmother can have an unpleasant impact on female grandchildren. When grandmothers smoked during pregnancy, female grandchildren later showed a 67 percent higher chance of having poor social communication skills and repetitive behavior. In addition, the risk of autism increased by 53 percent, the study authors explain.

Men suffer from autism more often than women
The incidence of autism has increased in recent years. Some experts attribute this increase to an improved diagnosis. However, the researchers in the current study believe that environmental impacts such as smoking during pregnancy could also play a major role. About one in 100 people suffer from autism, and in total more men than women are affected.

Smoking grandmothers only increases the risk of autism in female grandchildren
However, the negative impact of smoking on the likelihood of autism was only seen in girls. Scientists therefore suspect that smoking can damage the so-called mitochondrial DNA, which is only passed on to the female lineage.

Protect your young children from tobacco smoke
We already know that protecting a baby from tobacco smoke is of fundamental importance in order to give her child a healthy start in life, emphasizes the author Prof. Jean Golding.

Why is there a link between smoking and autism?
There are two options with regard to the underlying mechanisms. There is DNA damage that is transmitted to the grandchildren. Or there is an adaptive response to smoking that makes the grandchild more vulnerable to autism, adds author Prof. Marcus Pembrey.

Increased risk of autism only in the second generation?
The initial mitochondrial DNA mutations often do not have an open effect in the first generation, but the effects can increase if these are transmitted to the offspring, the experts explain.

Why is cigarette smoke so harmful?
Cigarette smoke contains more than 4,000 chemicals, including cyanide, lead, and at least 60 cancer-causing compounds. However, it is mostly nicotine and carbon monoxide that are responsible for the complications associated with smoking during pregnancy, the scientists explain.

Effects of smoking
Nicotine throttles the baby's oxygen by constricting the blood vessels throughout the mother's body, including those in the umbilical cord, the experts say. Red blood cells transport oxygen in humans. When smoking, these molecules begin to absorb carbon monoxide. This exacerbates the problem, the doctors report. Smoking in pregnancy has been shown to lead to stillbirth, premature birth, low birth weight and a variety of developmental problems. (as)

Author and source information

Video: Reconsidering the Autism Spectrum. Ronit Molko. TEDxSedona (January 2022).