The incidence of spina bifida occulta in a historic and a modern London population.

The incidence of spina bifida occulta was assessed in two London populations, one historic and the other contemporaneous. No significant differences were found between the two groups with regard to either overall frequency or frequency at specific sites within the lumbosacral column. This finding was compared to other studies reporting secular increases in the frequency of spina bifida occulta in areas outside the United Kingdom.