Craniosynostosis and maternal smoking.
BACKGROUND
Several previous studies suggested increased risk of craniosynostosis among infants born to women who smoked.


METHODS
This study used data from the National Birth Defects Prevention Study, a multi-state, population-based case-control study of infants delivered from 1997-2003. Nonmalformed, liveborn controls were selected randomly from birth certificates or birth hospitals. Data from maternal telephone interviews were available for 531 cases and 5008 controls.


RESULTS
Smoking during the first month of pregnancy was not associated with craniosynostosis. Smoking later in pregnancy was associated with increased risk, but only among mothers who smoked at least one pack/day. For example, during the second trimester, the odds ratio for smoking <5 cigarettes/day was 1.0 (95% confidence interval [CI] 0.6, 1.8), but the odds ratio (OR) for smoking 15 or more cigarettes/day was 1.6 (95% CI 0.9, 2.8), after adjustment for maternal age, education, race-ethnicity, sub-fertility, parity, folic acid supplement intake, body mass index, and study center. Among women who did not smoke, adjusted odds ratios suggested that secondhand smoke exposure at home, but not at work/school, was associated with modestly increased risk; the OR for home exposure was 1.3 (95% CI 0.9, 1.9). Results followed a similar pattern for some, but not all, specific suture types, but numbers for some groupings were small.


CONCLUSIONS
The results suggest moderately increased risk of craniosynostosis among mothers who were the heaviest smokers and who continued to smoke after the first trimester. Results are somewhat equivocal, given that most confidence intervals included one.
Carmichael
Suzan L
SL
March of Dimes Foundation, California Research Division, Oakland, California, USA. scarmichael@marchofdimes.com
Ma
Chen
C
Rasmussen
Sonja A
SA
Honein
Margaret A
MA
Lammer
Edward J
EJ
Shaw
Gary M
GM
D000328:Adult; D016022:Case-Control Studies; D003398:Craniosynostoses / Q000453:epidemiology*; D005260:Female; D006801:Humans; D008425:Maternal Behavior; D018811:Maternal Exposure / Q000009:adverse effects*; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects / Q000453:epidemiology; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects*; D014028:Tobacco Smoke Pollution / Q000009:adverse effects
D014028:Tobacco Smoke Pollution