Osteoporotic-like vertebral fracture with less than 20% height loss is associated with increased further vertebral fracture risk in older women: the MrOS and MsOS (Hong Kong) year-18 follow-up radiograph results.

Background: For osteoporotic fractures in men (MrOS) and in women (MsOS) (Hong Kong) baseline (BL) study, Chinese men and women ≥65 years were recruited during 2001 to 2003. This study presents the year-18 follow-up (FU) results. We were particularly interested in whether women with 'minimal' grade osteoporotic-like vertebral fracture (OLVF) of <20% height loss have an increased vertebral fracture (VF) risk than those without BL OLVF.

Methods: At year-18 FU, spine radiography was performed on 144 males (mean: 87.4±3.1 years) and 156 females (mean: 87.0±3.2 years). OLVF classification included no OLVF (grade 0), and OLVFs with <20%, ≥20-25%, ≥25%-1/3, ≥1/3-40%, ≥40%-2/3, ≥2/3 height loss (grades 1-6). With an existing OLVF, a further height loss of ≥15% was an OLVF progression. A new incident OLVF was a change from grade 0 to ≥ grade 2 or to grade 1 with the appearance of endplate and/or cortex fracture (ECF) during FU. Both OLVF progression and incident OLVF were considered incident VF. Acquired short vertebra (aSV) was defined as with decreased vertebral anterior and middle heights, while without anterior wedging and bi-concave changes, and only those with at least two adjacent aSVs were recorded as aSV cases.

Results: For subjects without BL OLVF, 12.5% of the males and 27.1% of the females had incident VF. For subjects with BL OLVF of ≥20% height loss, males' and females' incident VF rate were 20% and 66.7% respectively. Females subjects with BL minimal OLVF, while all without radiographic ECF, had an incident VF rate of 59.3% during the FU. For males with and without aSV, 11.8% and 15% have incident fracture of other vertebrae. For females with and without aSV, 35.3% and 34.5% have incident fracture of other vertebrae. Recovery from minimal or mild grades OLVF to normal shape was observed in a number of cases.

Conclusions: OLVF with less than 20% height loss is associated with increased VF risk in older females, but not in older males. Acquired short vertebra (SV) is not associated with increased incident fracture risk for other vertebrae, both for females and males. OLVF among older subjects can repair and heal.