Reporting of lifetime fractures: methodological considerations and results from the Thai Cohort Study

OBJECTIVES To provide estimates of fracture incidence among young adults in Thailand. DESIGN Cross-sectional analysis of a large national cohort. SETTING Thailand. PARTICIPANTS A total of 60 569 study participants residing nationwide responded to the 2009 follow-up survey; 55% were women and median age was 34 years (range 19-92). OUTCOME MEASURES Self-reported lifetime fractures, along with age at fracture. Fracture incidence rates per person-year were then compared using lifetime fracture reports, and again selecting only fractures reported for the last year. Incidence rates were compared by age and sex. RESULTS 18 010 lifetime fractures were reported; 11 645(65%) by men. Lifetime fracture prevalence was 30% for men and 15% for women. Lifetime incidence per 10 000 person-years was 83; analysing only fractures from the last year yielded a corresponding incidence rate of 187. For ages 21-30, fractures per 10 000 person-years were more common among men than women (283 (95% CI 244 to 326) and 150 (130 to 173), respectively); with increasing age, rates decreased among men and increased among women (for ages 51-60, 97 (58 to 151) and 286 (189 to 417), respectively). CONCLUSIONS Large-scale surveys provide a feasible method for establishing relative fracture incidence among informative subgroups in a population. Limiting analyses to fractures reported to have occurred recently minimises bias due to poor recall. The pattern of self-reported fracture incidence among Thais aged 20-60 was similar to that reported for Western countries: high falling rates in young men and high rising rates in older women.