Sickle Cell Disease (SCD) Bone Pain Study

The investigators hypothesize that adults with sickle cell disease (SCD) and low bone density and/or vertebral compression fractures on a dual X-ray absorptiometry (DXA) scan (adjusted for age, sex, SCD genotype, relevant labs, presence of osteonecrosis, and SCD-modifying therapies) will report more severe pain than those with normal bone density or no vertebral fractures. The Adult Sickle Cell Quality of Life Measurement System (ASCQ-Me) is a validated patient-reported outcome measure of physical, mental, and social health in adults with SCD. This cross-sectional observational study involves obtaining a baseline DXA scan, vertebral fracture analysis (VFA) and pain assessment using ASCQ-Me pain impact scores. The investigators plan to recruit 50 adults with SCD followed at University of California Davis Medical Center between Nov 2022- Dec 2023 and anticipate enrolling up to 4 adults with SCD per month. The study endpoints are listed below: * To determine the association between bone density Z-scores and ASCQ-Me pain impact scores in a prospective cohort of adults with SCD * To study the association between Spine Deformity Index scores (SDI, a proxy for vertebral fracture analysis) and ASCQ-Me pain impact scores in a prospective cohort of adults with SCD * To assess the correlation between baseline hematological and biochemical laboratory parameters (including bone biomarkers), bone density, and/or vertebral fractures in a prospective cohort of adults with SCD The investigators' goal is to complete primary data analysis by Mar 2024. As an exploratory endpoint, 1cc of serum and 5cc of urine will be collected from each study participant once (at baseline), after an overnight fast, for bone biomarker analyses.