Lifetime occupational physical activity and risk of hip fracture in women

Abstract

A case-control study was conducted to examine the effects of occupational activity on the risk of hip fracture in women. Only women who worked full-time or part-time for more than 6 months and for more than 15 h/wk since the age of 16 were considered for study. Case patients were between the ages of 55 and 84 years and had a diagnosis of hip fracture in 1989 in Metropolitan Toronto ( n = 331). Control subjects were a population-based random sample of women frequency-matched by 5-year age groups ( n = 1002). Those who worked for 20 years or less in any type of job were not at a decreased risk of hip fracture (odds ratio (OR) = 0.96; 95% confidence interval (CI), 0.70 to 1.32) compared to those who worked for more than 20 years in a sedentary job. However, those who worked for more than 20 years in moderate- to heavy-activity jobs were strongly protected against hip fracture (OR = 0.53; 95% CI, 0.30 to 0.95). Past and recent leisure-time activity, estrogen use, obesity, having epilepsy, and a previous fracture were significant risk factors. There was no statistically significant interaction between occupational activity and leisure-time physical activity, suggesting that both types of activity are independently associated with the risk of hip fracture. This study showed that being employed for more than 20 years in a job that requires heavy activity reduces the risk of hip fracture in postmenopausal women.