Effect of age and gender on the number and distribution of sites in Paget's disease of bone

Paget's disease of bone (PDB) is reportedly declining in prevalence and severity, with increasing numbers of monostotic cases. Some accounts suggest that these findings are more evident in women, and that monostotic disease is unexpectedly frequent at certain sites. We have studied whether birth date or gender is associated with the number of sites affected and with the distribution of sites in monostotic disease and, by reviewing 100 follow-up 99Tc(m) methylene diphosphonate (MDP) scans, whether additional sites appear after initial diagnosis. Scintigraphic scans from 171 male (age 40-91 years) and 179 female (44-88 years) consecutive referrals with PDB were reviewed. Patients were analysed by referral date (1982-1992 and 1993-2001), and by their median date of birth (before (PRE21) and after (POST21) 1921). Mean age of pre-1993 patients was 69 years and 75 years for referrals after 1993. Younger patients had more monostotic disease (POST21 vs PRE21 subjects (47% vs 28%)), with a more marked trend in females (52% vs 25%), and POST21 females had fewer polyostotic sites than males (p