London - Fathers who do certain jobs may be more at risk of having children with birth defects, a study has found.

They include artists, photographers, hairdressers, mathematicians and office support workers, the researchers said.

But stonemasons, firemen, painters and car assembly workers, among others, have no added risk from their work.

Researchers at the University of North Carolina examined data from the US National Birth Defects Prevention Study.

They obtained the career histories of around 1,000 men who had fathered a child with one or more birth defects born between 1997 and 2004.

This data was compared with information from 4,000 men whose children did not have congenital abnormalities.

Researchers used a mathematical model for their analysis, classifying the jobs into 63 groups based on assumed exposure to chemicals or other potential hazards.

Just over two-thirds of the jobs analysed seemed to be linked to having a child with a birth defect. A third were not associated with any increased risk at all.

These included architects and designers, healthcare professionals, dentists, firefighters, fishermen, car assembly workers, entertainers, smelters and foundry workers, stonemasons and glass blowers/cutters, painters, train drivers/maintenance engineers, soldiers and commercial divers.

The study, published online in Occupational and Environmental Medicine, also found some jobs were associated with specific types of defect.

These were artists (mouth, eyes and ears, gut, limbs, and heart), photographers and photo processors (cataracts, glaucoma, absence of or insufficient eye tissue), drivers (absence of or insufficient eye tissue, glaucoma) and landscapers and groundsmen (gut abnormalities).

Dr Andrew Olshan, of the university’s North Carolina Centre for Birth Defects Research and Prevention, said some occupations were even associated with more than one defect within the same part of the anatomy.

He said: 'For example, photographers and photo-processing workers were associated with three distinct eye defects.

'Landscapers and groundskeepers were associated with three categories of gastrointestinal defects.

'Artists were associated with the most number of individual defects, including several eye/ear defects, oral clefts and defects of the gastrointestinal system.

'To our knowledge, an increased prevalence of birth defects among offspring of artists has not been previously reported.'

The researchers did not attempt to look at particular exposures to chemical or other potentially harmful hazards, but they said the findings reflect those of other research on dads’ roles in foetal damage and may help to inform further study on specific occupational harms.

Previous research has linked certain occupations with a higher risk of birth defects in offspring. But it has tended to lump together very different types of defects and occupations, in order to achieve large sample sizes, with the attendant potential to skew the results, said the researchers.

Dr Olshan added: 'Findings from this broad screening analysis 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.' - Daily Mail