Determinants of osteoporotic thoracic vertebral fracture. Screening of 57,000 Finnish women and men.

A population sample of 27,000 Finnish women and 30,000 men was studied for the presence of a thoracic vertebral fracture. In both sexes, the prevalence of such fractures increased with age: after 40 years of age in the men and after 55 years of age in the women. The interaction of sex and age was significant, and even when the other determinants were adjusted for. In the women aged 35-44, 55-64, and 75 years or more, the prevalence per 1,000 was respectively 2.4, 5.1, and 29, and in the men in the corresponding age groups 5.2, 15, and 28. A previous history of trauma was a fracture determinant in both sexes. In the men, but not in the women, there was an increased risk of fracture when there was a history of tuberculosis and/or peptic ulcer, and in current smokers. Thus, contrary to observations on extremity fractures, the men had an increased risk of sustaining a thoracic vertebral fracture compared with the women. This may reflect differences in the development of osteoporosis in the axial skeleton versus the appendicular skeleton.