ab215011

Identification of possible areas of high prevalence of Paget's disease of bone in Spain

G. López-Abente¹, A. Morales-Piga^2,3, F.J. Bachiller-Corral², O. Illera-Martín², R. Martín-Domenech², V. Abraira⁴

¹Evironmental Epidemiology and Cancer Department, National Center for Epidemiology, Carlos III Institute of Health, Madrid; ²Department of Rheumatology, Ramón y Cajal Hospital, Madrid; ³Alcalá University Medical School, Madrid; 4Unit of Biostatistics, Ramón y Cajal Hospital, Biomathematics Department, Complutensis University of Madrid, Spain.

ABSTRACT
Objetive
In view of the fact that Paget's disease of bone (PD) tends to appear in so-called 'foci', a case-control study was undertaken with the dual aim of: 1) identifying areas having a higher likelihood of constituting PD 'foci'; and 2) detecting the geographic origin of 'PD-carrier' families

Methods
Two data sets were analysed, one covering the place of birth of 231 cases and 436 controls, and the other covering the place of birth of cases, controls and their parents. Analysis was restricted to six Autonomous Regions accounting for 60% of Spain's towns and cities. To identify geographical areas of high prevalence we used the scan statistic

Results
In the first analysis, 6 possible clusters were detected, corresponding to the districts of Avila (Avila), Lozoya-Somosierra (Madrid), Tierra de Campos (Palencia), the Guadalajara Range, South-west Madrid and Cuenca Hills. The second analysis confirmed the 6 groupings identified by the above procedure and, in addition, detected a further 8 possible clusters. Geographical proximity suggests that in some cases, rather than individual groupings, these may instead constitute larger foci.

Conclusion
The results point to the possible existence of different PD foci, some coinciding with clusters that have already been reported, and others indicating familial origin in areas that had never previously received PD-specific attention.

Key words
Osteitis deformans, space-time clustering, epidemiology, case-control studies.

Please address correspondence to: Gonzalo López-Abente, MD, Area de Epidemiología Ambiental y Cáncer, Centro Nacional de Epidemiología, c/Sinesio Delgado 6, 28029 Madrid, Spain.
E-mail: glabente@isciii.es