News / Health

Studies Show Maternal Smoking Triggers Asthma in Grandchildren

A woman smokes a cigarette in a parking lot in Bangkok, Thailand, May 27, 2010.A woman smokes a cigarette in a parking lot in Bangkok, Thailand, May 27, 2010.
A woman smokes a cigarette in a parking lot in Bangkok, Thailand, May 27, 2010.
A woman smokes a cigarette in a parking lot in Bangkok, Thailand, May 27, 2010.
Jessica Berman
Everyone knows that smoking cigarettes and other tobacco products is bad for your health... and for those around you. Now, there’s new evidence from studies with lab rats that the habit can cause asthma not only in smokers' children, but in their grandchildren, as well.

Researchers at Harbor-UCLA Medical Center in Los Angeles, California, have found evidence of a generational effect of tobacco-smoking on lung development. The scientists gave a group of pregnant rats injections of nicotine, the amount an average smoker would receive, exposing the animals' unborn pups to the chemical. Nicotine is one of more than 4,000 chemicals in tobacco smoke known to adversely affect lung development. As predicted, the injections caused changes in the fetal animals' upper and lower airway development consistent with asthma.  

The chronic and potentially fatal respiratory condition, which afflicts growing numbers of people worldwide, causes fits of coughing, wheezing, gasping and chest tightness.    

After they were born, the rat pups were never again exposed to nicotine. Nor were their offspring. Nevertheless, researchers found that these second-generation rat pups showed the same physical signs of asthma.
“So even if they are not exposed to any smoke or nicotine in the second generation pregnancy or [even] third generation pregnancy, they still go on to have asthma,” said neurologist Verinder Rehan, who led the study.

The change in lung function in the second generation of rat pups NOT exposed to nicotine in the womb was caused, Rehan said, by so-called epigenetic factors - alterations in how DNA functions as a result of environmental factors, such as the first generation’s exposure to nicotine.
The researchers saw what turned out to be a significant generational ripple stemming from the initial nicotine exposure.
“We have for the first time developed this experimental model where we are showing these changes actually happening... and we are also providing a mechanism that is the epigenetic mechanism responsible for these changes," said Rehand. "And actually even more importantly we have shown if you can block these changes, you can block the transmission of asthma.”

To demonstrate this, Rehan's group gave a separate group of rat mothers that had been injected with nicotine a drug that normalized their lung function. That healing prevented lung damage in two subsequent generations of pups.

Rehan said his study shows that the effects of cigarette exposure can be both far-reaching and long-lasting - another reason pregnant women should avoid lighting up or exposing themselves to second-hand smoke.
An article on the generational effects of nicotine exposure in causing asthma is published in BioMed Central's open access journal BMC Medicine.

You May Like

Video Americans, Tourists, Reflect on Meaning of Thanksgiving

VOA garnered opinions from several people soon after November 13 Paris attacks, which colored many of their thoughts

Video Thais Send Security Concerns Down the River

In northern Thailand, the annual tradition of constructing floating baskets to carry away the year’s bad spirits highlights the Loy Krathong festival

Video Tree Houses - A Branch of American Dream

Workshops aimed at teaching people how to build tree houses have become widely popular in America in recent years

This forum has been closed.
Comment Sorting
by: John Davidson
November 01, 2012 8:02 PM
In more rational times, before the anti-tobacco hysteria began in earnest, women who smoked continued to smoke and enjoy other normal pleasures of life without guilt during their pregnancies. Many even smoked during labor to help them relax and take the edge off their pain. If their doctors mentioned smoking at all, it would be to advise them to perhaps cut down if they were heavy smokers, something which most did intuitively because they didn’t “feel” like smoking as much.
But pity the poor Bolton smoker today who becomes pregnant, because she will be told that if she continues to smoke at all (or have any alcohol or caffeine) during her pregnancy, she is putting her developing fetus at high risk of death or disability.

Nothing could be further from the truth.

Though there is considerable evidence showing that on average the babies of women who smoke during pregnancy weigh on average a few ounces less than babies of women who do not smoke and that the rate of low birthweight babies is somewhat higher for smokers, there is no credible evidence for the hyperbolic claims that the babies of smokers have a higher mobidity and mortality rate. Quite the contrary, the babies of women who smoke during pregnancy have a better survival rate ounce for ounce, a somewhat lower rate of congenital defects, a lower rate of Down’s syndrome, a lower rate of infant respiratory distress syndrome and a somewhat lower rate of childhood cancer than do the babies of non-smokers.

Dr. Richard L. Naeye, a leading obstetrical researcher who studied more than 58,000 pregnancies, states unequivocally:

“We recently found no significant association between maternal smoking and either stillbirths or neonatal deaths when information about the underlying disorders, obtained from placental examinations, was incorporated into the analyses. Similar analyses found no correlation between maternal smoking and preterm birth. The most frequent initiating causes of preterm birth, stillbirth, and neonatal death are acute chorioamnionitis, disorders that produce chronic low blood flow from the uterus to the placenta, and major congenital malformations. There is no credible evidence that cigarette smoking has a role in the genesis of any of these disorders.”

Featured Videos

Your JavaScript is turned off or you have an old version of Adobe's Flash Player. Get the latest Flash player.
Belgium-Germany Border Remains Porous, Even As Manhunt For Paris Attacker Continuesi
Ayesha Tanzeem
November 25, 2015 10:46 PM
One of the suspected gunmen in the Nov. 13 Paris attacks, Salah Abdeslam, evaded law enforcement, made his way to Belgium, and is now believed to have fled to Germany. VOA correspondent Ayesha Tanzeem makes the journey across the border from Belgium into Germany to see how porous the borders really are.

Video Belgium-Germany Border Remains Porous, Even As Manhunt For Paris Attacker Continues

One of the suspected gunmen in the Nov. 13 Paris attacks, Salah Abdeslam, evaded law enforcement, made his way to Belgium, and is now believed to have fled to Germany. VOA correspondent Ayesha Tanzeem makes the journey across the border from Belgium into Germany to see how porous the borders really are.

Video Islamic State Unfazed by Losses in Iraq, Syria

Progress in the U.S.-led effort to beat Islamic State on its home turf in Iraq and Syria has led some to speculate the terror group may be growing desperate. But counterterror officials say that is not the case, and warn the recent spate of terror attacks is merely part of the group’s evolution. VOA National Security correspondent Jeff Seldin has more.

Video Taiwan Looks for Role in South China Sea Dispute

The Taiwanese government is one of several that claims territory in the hotly contested South China Sea, but Taipei has long been sidelined in the dispute, overshadowed by China. Now, as the Philippines challenges Beijing’s claims in an international court at The Hague, Taipei is looking to publicly assert its claims. VOA’s Bill Ide has more from Beijing.

Video Syrian Refugees in US Express Concern for Those Left Behind

Syrian immigrants in the United States are concerned about the negative tide of public opinion and the politicians who want to block a U.S. plan to accept 10,000 Syrian refugees. Zlatica Hoke reports many Americans are fighting to dispel suspicions linking refugees to terrorists.

Video After Paris Attacks, France Steps Up Fight Against IS

The November 13 Paris attacks have drawn increased attention to Syria, where many of the suspected perpetrators are said to have received training. French President Francois Hollande is working to build a broad international coalition to defeat Islamic State in Syria and in Iraq. Zlatica Hoke reports.

Video US, Cambodian Navies Pair Up in Gulf of Thailand

The U.S. Navy has deployed one of its newest and most advanced ships to Cambodia to conduct joint training drills in the Gulf of Thailand. Riding hull-to-hull with Cambodian ships, the seamen of the USS Fort Worth are executing joint-training drills that will help build relations in Southeast Asia. David Boyle reports for VOA from Preah Sihanouk province.

Video Americans Sharpen Focus on Terrorism

Washington will be quieter than usual this week due to the Thanksgiving holiday, even as Americans across the nation register heightened concerns over possible terrorist threats. VOA’s Michael Bowman reports new polling data from ABC News and the Washington Post newspaper show an electorate increasingly focused on security issues after the deadly Islamic State attacks in Paris.

Video World Leaders Head to Paris for Climate Deal

Heads of state from nearly 80 countries are heading to Paris (November 30-December 11) to craft a global climate change agreement. The new accord will replace the Kyoto Protocol on Climate Change that expired in 2012.

Video Uncertain Future for Syrian Refugee Resettlement in Illinois

For the trickle of Syrian refugees finding new homes in the Midwest city of Chicago, the call to end resettlement in many U.S. states is adding another dimension to their long journey fleeing war. Organizations working to help them integrate say the backlash since the Paris attacks is both harming and helping their efforts to provide refugees sanctuary. VOA's Kane Farabaugh reports.

Video Creating Physical Virtual Reality With Tiny Drones

As many computer gamers know, virtual reality is a three-dimensional picture, projected inside special googles. It can fool your brain into thinking the computer world is the real world. But If you try to touch it, it’s not there. Now Canadian researchers say it may be possible to create a physical virtual reality using tiny drones. VOA’s George Putic reports.

Video New American Indian Village Takes Visitors Back in Time

There is precious little opportunity to experience what life was like in the United States before its colonization by European settlers. Now, an American Indian village built in a park outside Washington is taking visitors back in time to experience the way of life of America's indigenous people. Carol Pearson narrates this report from VOA's June Soh.

Video Even With Hometown Liberated, Yazidi Refugees Fear Return

While the northern Iraqi town of Sinjar has been liberated from Islamic State forces, it's not clear whether Yazidi residents who fled the militants will now return home. VOA’s Mahmut Bozarslan talked with Yazidis, a religious and ethnic minority, at a Turkish refugee camp in Diyarbakır. Robert Raffaele narrates his report.

Video Nairobi Tailors Make Pope Francis’ Vestments

To ensure the pope is properly attired during his visit, the Kenya Conference of Catholic Bishops asked the Dolly Craft Sewing Project in the Nairobi slum of Kangemi to make the pope's vestments, the garments he will wear during the various ceremonies. Jill Craig reports.

Video Cross-Border Terrorism Puts Europe’s Passport-Free Travel in Doubt

The fallout from the Islamic State terror attacks in Paris has put the future of Europe’s passport-free travel area, known as the "Schengen Zone," in doubt. Several of the perpetrators were known to intelligence agencies, but were not intercepted. Henry Ridgwell reports from London European ministers are to hold an emergency meeting Friday in Brussels to look at ways of improving security.

Video El Niño Brings Unexpected Fish From Mexico to California

Fish in an unexpected spectrum of sizes, shapes and colors are moving north, through El Niño's warm currents from Mexican waters to the Pacific Ocean off California’s coast. El Nino is the periodic warming of the eastern and central Pacific Ocean. As Faiza Elmasry tells us, this phenomenon thrills scientists and gives anglers the chance of a once-in-a-lifetime big catch. Faith Lapidus narrates.

Video Terrorism in Many Forms Continues to Plague Africa

While the world's attention is on Paris in the wake of Friday night's deadly attacks, terrorism from various sides remains a looming threat in many African countries. Nigerian cities have been targeted this week by attacks many believe were staged by the violent Islamist group Boko Haram. In addition, residents in many regions are forced to flee their homes as they are terrorized by armed militias. Zlatica Hoke reports.

Video Study: Underage Marriage Rate Higher for Females in Pakistan

While attitudes about the societal role of females in Pakistan are evolving, research by child advocacy group Plan International suggests that underage marriage of girls remains a particularly big issue in the country. VOA’s Ayesha Tanzeem reports how such marriages leads to further social problems.

VOA Blogs