妊娠中の両親の喫煙が児の心血管障害を引き起こす

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2012年01月10日(Tue) 16:34 by drharasho

Parental Smoking Linked With Vascular Damage in Offspring

News Author: Laurie Barclay, MD
CME Author: Désirée Lie, MD, MSEd

CME Released: 01/04/2012; Valid for credit through 01/04/2013


Clinical Context

According to the current study by Geerts and colleagues, the effect of maternal smoking
during pregnancy on the vasculature of offspring is largely unknown. Autopsy studies have
demonstrated that smoking during early age promotes development of plaques and fatty
streaks in aortas as precursors of atherosclerosis. Passive exposure to cigarette smoking
during childhood has been linked to vascular damage in young adult offspring.

This study of offspring of women who smoked vs women who did not smoke during pregnancy
examines its effect on arterial properties in their 5-year-old offspring.


Study Synopsis and Perspective
研究要約と展望

Parental smoking during pregnancy may cause vascular damage when the children reach
5 years of age, according to the results of a birth cohort study published online December 26
and in the January 2012 print issue of Pediatrics.

"Smoking during pregnancy has been related to thicker carotid intima media thickness
 in young adults, and this was also shown in neonates," write Caroline C. Geerts, MD, from
the Julius Center for Health Sciences and Primary Care and University Medical Center
Utrecht in the Netherlands and colleagues. "The relation between smoke exposure in early
 life, the prenatal period in particular, and the vascular development of young children is
largely unknown."

To evaluate the association between parental smoking during pregnancy and subsequent
vascular characteristics in their children, the investigators used data from the birth cohort
enrolled in the Wheezing Illnesses Study Leidsche Rijn (WHISTLER)-Cardio study.
At 5 years of age, 259 participants underwent ultrasonographic measurement of carotid
artery intima-media thickness (CIMT) and arterial wall distensibility. Parental smoking
data were also updated.

After adjustment for the child's age and sex, maternal age, and breast-feeding, children
of mothers who had smoked throughout pregnancy had more vascular damage than
children of mothers who did not smoke during pregnancy. CIMT was 18.8 μm thicker
in the former group (95% confidence interval [CI], 1.1 - 36.5; P = .04), and distensibility
was 15% lower (95% CI, −0.3 to −0.02; P = .02).

Children of mothers who smoked after pregnancy, but not during pregnancy, did not
have these adverse effects on CIMT and distensibility. If both parents smoked during
pregnancy, the associations were even stronger than with only maternal smoking:
CIMT was 27.7 μm thicker (95% CI, 0.2 - 55.3), and distensibility was 21% lower
(95% CI, −0.4 to −0.03).

"This study is the first to show that the effect of smoking during pregnancy on
the vasculature of children is (still) visible at the age of 5 years," the study authors
write. "Pregnancy appears to be the critical period for this damage to occur."

Limitations of this study include slightly different profiles in participants than
in nonparticipants, lack of cotinine measurements at birth, and reliance on parental
self-report of smoking.

"In view of the early origins of cardiovascular disease, preventive measures against
smoking should be specifically directed at the gestational period," the study
authors conclude.

The Netherlands Organization for Health Research and Development supported
the WHISTLER birth cohort. The University Medical Center Utrecht supported
WHISTLER-Cardio. The authors have disclosed no relevant financial relationships.

Parental Smoking and Vascular Damage in Their 5-year-old Children
http://pediatrics.aappublications.org/content/129/1/45.full

Pediatrics. Published online December 26, 2011. Abstract
Study Highlights

●The WHISTLER-Cardio cohort is an ongoing, large prospective birth cohort
initiated in 2001 in a single city with infants recruited at age 2 weeks.

● All children who had reached 5 years old were invited to participate in this study
for vascular measurements and parental questionnaires.

●At the 4-week neonatal visit, parents completed a questionnaire about prenatal,
perinatal, and postnatal factors, and further information was derived from a linked health database.

● During this visit, mothers filled in a questionnaire asking specifically about smoking during pregnancy.

● The questionnaire asked about smoking in the first and second halves of pregnancy
and number of cigarettes smoked daily.

● Smoking during pregnancy was defined as smoking a minimum of 1 cigarette
a day during the entire pregnancy.

●Data on nonsmoking women and early quitters were pooled into a single group.

● At the 5-year follow-up visit, both parents completed questionnaires about smoking,
including type of tobacco, number of cigarettes smoked daily, and the child's exposure to smoking.

● Passive exposure to smoking in the first 5 years was examined as a confounder
for exposure during pregnancy.

●Vascular conditions of the right common carotid artery were studied ultrasonographically
with use of high-resolution echo-tracking technology.

● CIMT was measured.

● During the ultrasound study, blood pressure was recorded, and properties of
the carotid artery including distensibility and elastic modulus were assessed.

● CIMT and distension measurements were completed in 97.7% and 89.8% of
children, respectively. A total of 259 children with complete data on maternal smoking
exposure and these measurements were included in the analysis.

● At birth, the offspring of smoking mothers were lighter (3447 vs 3493 g) and
shorter than those of nonsmoking mothers.

● Other characteristics were similar.
 
● At the first neonatal visit, weight was similar as was length, with 58.6% of offspring
of nonsmoking mothers vs 26.7% of those of smoking mothers being breast-fed.

● Maternal smoking during pregnancy was associated with fathers smoking during pregnancy.

● The number of cigarettes smoked by women with and without smoking fathers was similar.
 
●After controlling for exposure during infancy, the children exposed to maternal smoking
had increased CIMT vs children without such exposure during (CIMT thickness, 18.8 µm thicker).

● Maternal smoking explained 0.57 SD of CIMT in this study.
 
● The children of mothers who smoked also had 15% lower arterial distensibility.
 
● There was a trend toward increasing CIMT and decreasing distensibility with the greater
number of cigarettes smoked by the mother during pregnancy.

● Paternal smoking during pregnancy did not affect these outcomes unless the mother
also smoked, in which case paternal smoking had an added effect.

● The authors concluded that parental smoking during pregnancy had structural and
 functional effects on the arterial vascular wall of young children.

Clinical Implications

● Maternal smoking during pregnancy is associated with higher CIMT and lower arterial
distensibility in the offspring at age 5 years.

● Parental smoking during pregnancy is associated with greater vascular damage in the offspring,
but paternal smoking alone during pregnancy appears not to be associated with vascular damage in the offspring.


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