Experts have warned that tobacco smoking by pregnant women may adversely affect the developing fetus.
Smoking during pregnancy is linked to numerous negative outcomes,
including low birth weight, sudden infant death syndrome, and increased
risk for attention deficit disorder, conduct disorder, and nicotine use in offspring.
Nevertheless, it is estimated that 13 percent -30 percent of women in the United States continue to smoke while pregnant.
A new 40-year study, published in the journal Biological Psychiatry, provides additional evidence that prenatal exposure to maternal stress hormones predicts nicotine dependence later in life.
The new findings, however, suggests the nicotine dependence occurs only for daughters.
It also confirms previous research that babies born to moms who
smoked when pregnant have an increased risk of nicotine addiction in
adulthood.
“While maternal smoking during pregnancy has been shown to be an
independent risk factor for nicotine dependence, we didn’t really know
which pathways or mechanisms were responsible. Most prior research
involving biological mechanisms had been conducted in animals not
humans,” said Dr. Laura Stroud, the first author on this study.
“Our study suggests that maternal smoking and high stress hormones
represent a ‘double-hit’ in terms of increasing an offspring’s risk for
nicotine addiction as an adult.
“Because mothers who smoke are often more stressed and living in
adverse conditions — these findings represent a major public health
concern.”
To conduct the study, Stroud and her colleagues used data from a
large, national, long-term project that began in 1959 and enrolled over
50,000 pregnant women.
The offspring of those women were ultimately followed by researchers for 40 years.
For this particular project, 1,086 mothers participated, where their
hormone levels (cortisol and testosterone) were measured during
pregnancy and their smoking status was recorded.
Their children, 649 of whom were daughters and 437 of whom were sons,
were interviewed as adults and their smoking status was also recorded.
Classic Silver
The findings revealed that in female but not male offspring, elevated
prenatal cortisol exposure and exposure to maternal smoking during
pregnancy were associated with increased rates of nicotine dependence as
adults.
No links were found between elevated prenatal testosterone exposure
and adult nicotine dependence. There were also no findings among male
offspring.
“Our findings highlight the particular vulnerability of daughters to
long-term adverse outcomes following maternal stress and smoking during
pregnancy .
“We don’t yet know why this is, but possible mechanisms include sex
differences in stress hormone regulation in the placenta and adaptation
to prenatal environmental exposures,” added Stroud.
“Also, cortisol and nicotine may affect developing male and female
brains differently. Furthermore, if daughters of smoking mothers are
more likely to grow up nicotine dependent, the result is dangerous cycle
of intergenerational transmission of nicotine addiction.”
“These new data may help us to focus our attention on individuals at
greatest risk for later smoking,” said Dr. John Krystal, Editor of Biological Psychiatry.
“It is interesting that female, but not male, offspring seemed to be
at greatest risk. Sex differences in the vulnerability to smoking are
important and merit further study.”
No comments:
Post a Comment