Children exposed before birth to a father smoking tobacco, are more likely to develop asthma due to changes to immunity genes
Children exposed before birth to a father smoking tobacco are more likely to develop asthma. Associated changes to immunity genes predict the level of risk.
These are the findings of a new study published in Frontiers in Genetics. The study reinforces the risks of either parent smoking and could provide DNA targets for the early prediction and reversal of tobacco smoking-associated childhood asthma.
“We found that prenatal exposure to paternal tobacco smoking is associated with increased methylation of certain immune genes, which alters how the genetic code is read,” said lead author Dr. Chih Chiang Wu of Po-Zen Hospital, Taiwan. “This smoking-associated DNA methylation is significantly retained from birth to 6 years of age, and correlates with development of childhood asthma.”
The researchers followed 1629 children from birth to 18 months (1348) to 6 years of age (756), with medical assessment and DNA analysis at each time point. Infants with prenatal PTS exposure had a significantly higher risk of asthma by age of 6 than those without
Exposure to tobacco smoke during development is already known to harm children in a variety of way.
“Twenty-three percent of the fathers (367 in a cohort of 1629 couples with newborns) were smokers, compared to just 3 of the mothers (0.2%). This unique disparity provided the perfect opportunity to study the effects of paternal tobacco smoking (PTS) exposure,” said co-author Dr. Ho Chang Kuo of Kaohsiung Chang Gung Memorial Hospital.
The researchers followed 1629 children from birth to 18 months (1348) to 6 years of age (756), with medical assessment and DNA analysis at each time point.
Infants with prenatal PTS exposure had a significantly higher risk of asthma by age of 6 than those without. The results of the DNA analysis showed that – higher the PTS exposure dose, the higher the level of methylation of LMO2, IL10 and GSTM1 – genes known to have key roles in immune function.
“The combination of higher methylation levels of all three genes corresponded to the highest risk of asthma: 43.48%, compared to 16.67%-23.08% with any other combination,” said senior author Dr. Kuender Yang of Mackay Children’s Hospital, Taipei.
Researchers emphasize though that their study can only show associations between these factors.
