SUN-LB72 The Relationship Between Estrogen Exposure and Bone Health in Women With Cystic Fibrosis

Patients with cystic fibrosis (CF) are at risk for cystic fibrosis-related bone disease (CFBD) characterized by low bone mineral density and fractures. Nutritional status, cystic fibrosis-related diabetes (CFRD), lung health, and sex hormone insufficiency affect CFBD. CF Foundation guidelines recommend exogenous estrogen treatment for women with CFBD and sex hormone deficiency. There is a lack of data regarding effects of exogenous estrogen supplementation on the bone health of CF women. This Emory IRB approved case-control study examined the association of estrogen on bone health in CF women. Data included demographics, sex hormone treatments, CFBD modifiers, and bone mineral density. 35 estrogen exposed subjects were matched 1:2 to 70 estrogen unexposed subjects for age, BMI, and transplant status. Statistical tests analyzed differences in bone health outcomes between the estrogen and non-estrogen exposed groups. At baseline, age, BMI, transplant status, and CFRD were not statistically different (p>0.05) between the two groups. The unexposed group had higher rates of pancreatic insufficiency (p=0.02). The exposed and unexposed subjects did not have statistically significant differences in areal bone mineral density at lumbar spine, femoral neck, or total hip (p>0.05). Our study demonstrates that there are no differences in bone mineral density at 3 different sites between estrogen exposed versus estrogen unexposed women. One limitation is that factors that may also influence bone density including vitamin D status, family history, and severity of CF mutation were not corrected for. Future longitudinal studies should determine if estrogen treatment can increase bone density over time in CF women.