Dad's Job Tied to Baby's Risk of Birth Defects
By Todd Neale, Senior Staff Writer, MedPage Today, Published: July 17, 2012. Reviewed by Robert Jasmer, MD; Associate Clinical Professor of Medicine, University of California, San Francisco
Rates of a wide range of birth defects were influenced by occupational exposures in the children's fathers, an exploratory study showed.
In particular, workers regularly exposed to solvents -- for example, artists, chemical workers, pharmacists, janitors, painters, and dry cleaning and laundry workers -- were more likely to have children with various birth defects, including defects of the eye, neural tube defects, and oral clefts, according to Tania Desrosiers, PhD, MPH, of the University of North Carolina at Chapel Hill, and colleagues.
The findings of this screening study, which were reported online in Occupational and Environmental Medicine, "can be used to inform further investigation of specific paternal occupations found to be associated with birth defects and to generate hypotheses about chemical or physical exposures and exposure mixtures common to such occupations," they wrote.
Desrosiers and colleagues examined data from the National Birth Defects Prevention Study, an ongoing case-control study using surveillance systems in 10 states.
The current analysis included 9,998 fathers of children with one of more than 60 birth defects and 4,066 fathers of children free from birth defects. All of the children were born from October 1997 through December 2004.
The children's mothers reported fathers' occupational histories covering 3 months before the estimated conception date through the first month of the pregnancy. Jobs were classified into 63 groups based on shared exposure profiles.
The most common occupational groups were managers and administrators (10%), sales-workers (9%), and construction workers (9%). The first two groups were combined to serve as the reference for all comparison because of a low likelihood of chemical exposure.
After using statistical techniques to account for the limited data across a large range of occupations and birth defects, several paternal occupational groups were associated with higher rates of at least three birth defects:
- Mathematical, physical, and computer scientists
- Photographers and photo processors
- Food service workers
- Landscapers and groundskeepers
- Hairdressers and cosmetologists
- Office and administrative support workers
- Sawmill workers
- Petroleum and gas workers
- Chemical workers not elsewhere classified
- Material moving equipment operators
- Motor vehicle operators
Certain occupations were associated with more than one defect within the same anatomic system, including artists, photographers and photo processors, motor vehicle operators, and landscapers and groundskeepers, "suggesting the possibility of varied effects from an early insult on morphogenesis, or perhaps differences in effects on components of an anatomic system depending on timing or dose of a teratogenic exposure," according to the researchers.
None of the occupations was associated with lower odds of more than one birth defect within the same anatomic system. Nearly one-third of the occupations were not associated with any defects.
The authors acknowledged that this exploratory study had some limitations, including the use of the mothers' reports of paternal occupation, possible misclassification of exposure because of the grouping of different occupations, and possible recall bias resulting from a lag between the baby's birth and the interview of the mother.
The study was supported by the CDC and the U.S. National Institute of Environmental Health Sciences.
The authors reported no conflicts of interest.