Smoking mothers increase autism risk in grandchildren

Women who smoke not only risk their health but also that of their children and grandchildren. PHOTO | FOTOSEARCH 

By SARAH OOKO

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Summary

• The exact cause of autism is still unknown.
• Tobacco smoke has more than 7,000 chemicals, hundreds of which are toxic and negatively affect almost all organ systems.

Mothers who smoke increase the risk of their grandchildren developing autism.

A new study published in the Scientific Reports journal shows that the grandchildren of these smoking women have a 53 per cent risk of being diagnosed with autism spectrum disorder (ASD) compared to other children.

The situation is especially worse for granddaughters who are 67 per cent more likely to display certain traits associated with autism such as poor social communication skills and repetitive behaviours.

The researchers noted that these findings suggest that if a girl is exposed to cigarette smoke while she is still in her mother’s womb, the toxic fumes could affect her developing ovaries and cause irreversible changes that may eventually affect the development of her own children.

The exact cause of autism is still unknown. But researchers have over the years linked the condition to environmental factors such as smoking and genetic influences.

Initially, it was assumed that a mother’s genes played a key role in determining whether her children were likely to be born of autism or not.

Studies taking this approach yielded inconclusive results leaving scientists with more questions than answers.

The findings of this new study seem to have finally unravelled this mystery by showing that when it comes to autism, it is likely the genes of a child’s grandmother — and not the mother — determine the risk of autism.

This indicates a trans-generational influence on autism that the researchers would like to explore further.

“In terms of mechanisms, there are two broad possibilities. There is DNA damage that is transmitted to the grandchildren or there is some adaptive response to the smoking that leaves the grandchild more vulnerable to autism,” stated Prof Marcus Pembrey, one of the scientists from the University of Bristol in the UK who authored of the study.

He also noted that smoking can damage or cause mutations in the DNA of mitochondria (structures that create energy to run body cells). “And whereas the initial mutations usually have no major effect on the mother herself, the impact tends to increase when they are transmitted to her children.”

Prof Jean Golding, another author of the study added: “We already know that protecting a baby from tobacco smoke is one of the best things a woman can do to give her child a healthy start in life. Now we’ve found that not smoking during pregnancy could also give their future grandchildren a better start too.”

A recent study published in the Lancet showed that middle and low income countries in Africa such as Kenya that have historically enjoyed low levels of tobacco use, are now witnessing an influx in smoking cases.

The researchers attributed this challenge to a deliberate effort by the tobacco industry to expand its business in the region by exploiting the continent’s patchwork tobacco control regulations and limited resources to combat the industry’s marketing tactics.

Joel Gitari, chairperson of the Kenya Tobacco Control Alliance, told the Business Daily that most of the multinational tobacco companies are running away from strict policies and increased pressure by anti-tobacco lobby groups that have made their business difficult in developed nations. He said they are thus looking for ‘friendlier’ countries in Africa.

“We know that they are also finding it easier to bribe some of our politicians here so as to gain support for their cause.”

Mr Gitari said in a bid to expand its market reach, the tobacco industry is also looking at various ways to increase the number of female smokers in the region through new tobacco products (such as shisha) that are considered by women to be ‘much cooler’ than cigarettes which are a favourite for men.

The study showed that such expansion strategies, which took place during the 1990s in Eastern Europe, have been a major contributor to the increase in smoking prevalence among women in those regions.

“So we need to be on the look out to prevent that from happening here.”

Whereas Shisha has been banned in other East African countries, it is still legal in Kenya where it is mostly consumed by women.

Tobacco smoke has more than 7,000 chemicals, hundreds of which are toxic and negatively affect almost all organ systems.

Smokers and non-smokers who are exposed to second-hand smoke are at higher risk of a long list of serious health conditions, including cancer, lung diseases and heart problems.