title: [Influence of season on bone mineral densitometry].
abstract: OBJECTIVE
  In places where sun exposure during the winter is limited, bone mineral density (BMD) may present seasonal variations, increasing during the summer and decreasing during the winter period. There have been suggestions that this variation could influence prospective evaluations of BMD studies. The aim of this study was to evaluate if the seasons of the year (summer/winter) are associated to variations in BMD values.
  
  
  METHODS
  Clinic based cross-sectional study, conducted in the state of Rio Grande do Sul (RS). Densitometric studies representative of the periods of winter/summer were selected. The densitometric studies were realized in a Hologic 4500 unit, using dual energy X-ray absorptiometry.
  
  
  CONCLUSIONS
  Of 853 densitometric measurements realized during a 12-month period, 201 were realized in the summer, and 321 in the winter. The BMD measurements, corrected to body weight, did not differ between the group of individuals that were tested in the summer or winter (P>0.05). In conclusion, in RS, the season of the year did not affect the BMD results, and does not need to be taken into account when analyzing densitometry measurements. This finding probably could be extrapolated to other regions of Brazil, since winter in those areas is less severe than in RS.
authors.affiliation: Serviço de Densitometria Ossea, Nuclimagem Vale, São Leopoldo, RS.
authors.forename: Fernanda F
authors.initials: FF
authors.lastname: Stringari
authors.forename: Eliane
authors.initials: E
authors.lastname: Zanette
authors.forename: Francisca
authors.initials: F
authors.lastname: Machado
authors.forename: Belmonte J
authors.initials: BJ
authors.lastname: Marroni
authors.forename: Luís H
authors.initials: LH
authors.lastname: Canani
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015519:Bone Density; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008875:Middle Aged; D012621:Seasons