Incidence of vertebral fractures in Thai women and men: a prospective population-based study.

Background: Vertebral fracture is the most common but the least well-investigated osteoporotic fracture. A population-based prospective study was conducted to determine incidence of vertebral fracture in Thai older adults.

Methods: Lateral thoracic and lumbar spine radiographs obtained in 1997 and 2002 of 322 participants were evaluated morphometrically. Incidence of fracture was considered if the vertebra was determined as normal at baseline and any of the anterior, central, posterior vertebral heights on the follow-up film showed a decrease of at least 20% or 4 mm compared with baseline height.

Results: Incidences of vertebral fracture in women and men were 32.1/1000 and 54.5/1000 person-year, respectively. Incident rates in men were higher than those in women in all age groups. Incidence increased with age, ranging from 27.4/1000 person-year at ages 50-59 years to 46.1/1000 person-year at ages of 70 years or more for women, and 42.3/1000 person-year at ages 50-59 years to 66.7/1000 person-year at ages of 70 years or more in men. The incidence was markedly high compared with other studies conducted in white older adults. Thai older adults with incidental vertebral fractures had a much higher proportion of having multiple-level fractures compared with white older adults.

Conclusions: This study showed a remarkably high incidence of vertebral fractures in a Thai population, particularly in men. The main contributing factor for incidental vertebral fracture was likely to be trauma or micro-trauma associated with strenuous physical activity or work rather than osteoporosis, particularly among the younger age group and men.