Abstract #: 209-S

PRE-MENOPAUSAL OCCUPATIONAL PHYSICAL DEMAND PROTECTS AGAINST HIP FRACTURES. Aimee Palumbo*, Yvonne Michael, Igor Burstyn, Brian Lee, Robert Wallace, (Drexel University School of Public Health, Philadelphia PA )

Bone fractures are a leading cause of disability, morbidity, and mortality and disproportionately affect older women. Few studies have examined the role of women’s occupational exposure throughout the life course in relation to later life bone health. Data from the Women’s Health Initiative Observational Study (n=93,676), a long-term national cohort of women aged 50-79, were used to examine the association between physical demand in jobs outside the home, before and after menopause, and risk of hip fracture. At baseline, women reported age, duration, and description for up to three jobs held since 18 years of age, which were coded using the 2010 Standard Occupational Classification (SOC). A composite score summing multiple dimensions of physical demand was derived from the Occupational Information Network (O-Net) for each SOC code and applied to 88,927 women with complete occupational data. Duration and intensity of physical demand were calculated separately for pre- and post-menopausal time periods. Annual self-report of hip fracture was centrally adjudicated by medical record review; 2.35% of women experienced hip fractures during 8-10 years of follow-up. Poisson regression was used to estimate associations between physical demand and hip fracture. A 10-point increase in the intensity of physical demand during the pre-menopausal period was associated with 5% reduced risk of hip fracture (relative risk: 0.95, 95% confidence interval 0.92-0.99) after adjustment for age at study entry, body mass index, and ethnicity. No association between post-menopausal occupation and hip fracture was observed. These results suggest that occupational physical demand prior to menopause may protect against hip fractures later in life.