title: Longitudinal changes in BMD and bone geometry in a population-based study.
abstract: We prospectively examined vBMD and structural bone parameters assessed by QCT among participants of the InCHIANTI study over a 6-yr follow-up. Periosteal apposition occurred both in men and women. Endocortical resorption causes bone loss in older women despite periosteal apposition.
  
  
  BACKGROUND
  To address the hypothesis that age-related changes in BMD and bone geometry may be different in men and women, we prospectively examined volumetric BMD (vBMD) and structural bone parameters assessed by QCT among participants of the InCHIANTI study over a 6-yr follow-up.
  
  
  METHODS
  Three hundred forty-five men and 464 women 21-102 yr of age from the InCHIANTI study, a population-based study in Tuscany, Italy, were included. Tibial QCT bone parameters were measured at enrollment (1998-2000) and at 3- (2001-2003) and 6-yr (2004-2006) follow-ups.
  
  
  RESULTS
  Periosteal apposition occurred both in men and women. The annual rate of bone periosteal apposition was higher in younger than in older men, whereas in women, the rate of apposition was homogenous across age groups. The age-related medullary expansion, expression of endocortical resorption, was significantly higher in women compared with men. In women, but not in men, accelerated endocortical resorption not sufficiently balanced by periosteal apposition caused accelerated loss in cortical bone mass. The cross-sectional moment of inertia decreased progressively over the life span in both sexes.
  
  
  CONCLUSIONS
  Endocortical resorption causes bone loss in older women despite periosteal apposition. Obtaining a balance between endocortical resorption and periosteal apposition should be the target for interventions aimed to decrease bone loss and prevent osteoporosis in older women.
authors.affiliation: Tuscany Regional Health Agency, Florence, Italy.
authors.forename: Fulvio
authors.initials: F
authors.lastname: Lauretani
authors.forename: Stefania
authors.initials: S
authors.lastname: Bandinelli
authors.forename: Michael E
authors.initials: ME
authors.lastname: Griswold
authors.forename: Marcello
authors.initials: M
authors.lastname: Maggio
authors.forename: Richard
authors.initials: R
authors.lastname: Semba
authors.forename: Jack M
authors.initials: JM
authors.lastname: Guralnik
authors.forename: Luigi
authors.initials: L
authors.lastname: Ferrucci
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000378:metabolism / Q000473:pathology*; D015519:Bone Density; D001862:Bone Resorption / Q000378:metabolism / Q000473:pathology* / Q000517:prevention & control; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007558:Italy; D008297:Male; D008875:Middle Aged; D010024:Osteoporosis / Q000378:metabolism / Q000473:pathology* / Q000517:prevention & control; D010521:Periosteum / Q000378:metabolism / Q000473:pathology*; D011446:Prospective Studies; D012737:Sex Factors