Parent or self-reported history of fractures in a group of patients ag
ed from 0.3 to 33.6 years on dietary treatment for phenylketonuria was
studied by means of a questionnaire. Twenty-one of 85 patients had a
history of fracture compared with 18/98 sibling controls. There was no
significant difference in the lifetime risk of fracture between patie
nts and controls (x(2) = 1.43, df = 1, p = 0.23), but a significantly
higher risk of fracture was reported over the age of 8 y (x(2) = 5.11,
df = 1, p = 0.024), with a relative risk of 2.6 (95% confidence inter
val 1.1, 6.1). We suggest this may be related either to deterioration
in dietary control in this age group or to a cumulative disease-relate
d or diet-related reduction in bone mass.