Parent's occupation and isolated orofacial clefts in Norway: a population-based case-control study.
OBJECTIVE
Occupational factors have been associated with risk of orofacial clefts in offspring, although data are limited. We explored associations between parent's occupation and isolated orofacial clefts using a population-based case-control study.


METHODS
Cases were restricted to infants born with an isolated orofacial cleft in Norway during the period 1996 to 2001 (314 with cleft lip with or without palate [CLP] and 118 with cleft palate only [CPO]). Controls (n = 763) were chosen randomly from all Norwegian live births. We considered full-time employment during the first 3 months of pregnancy.


RESULTS
Several maternal occupations previously associated with clefts showed some evidence of association, including hairdressers (CLP; adjusted odds ratio = 4.8; 95% confidence interval [CI]: 0.99-23). Mothers working in manufacturing and in food production had increased odds for babies with CPO (3.8; 1.3-11, and 7.1; 1.5-33, respectively). Among fathers' occupations previously associated with clefts, an association was suggested for woodworking both for CLP (1.7; 0.85-3.2) and for CPO (2.0; 0.82-4.7). Fathers working as professional housekeepers showed substantial increased odds of CPO (12; 3.3-46).


CONCLUSIONS
Taken together with previous studies, these results suggest that exposures in certain occupations may influence the risk of orofacial clefting in offspring. Specific exposures accompanying these occupations warrant exploration.
Nguyen
Ruby H N
RH
National Institute of Environmental Health Sciences, National Institutes of Health, Durham, NC 22709, USA. nguyen5@niehs.nih.gov
Wilcox
Allen J
AJ
Moen
Bente E
BE
McConnaughey
D Robert
DR
Lie
Rolv T
RT
D000328:Adult; D002971:Cleft Lip / Q000453:epidemiology*; D002972:Cleft Palate / Q000453:epidemiology*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D009664:Norway / Q000453:epidemiology; D009790:Occupations / Q000706:statistics & numerical data; D010290:Parents