Identifying Predictors of Bone Density and Metabolism in Premenopausal Women with Type 1 Diabetes

Identifying Predictors of Bone Density and Metabolism in Premenopausal Women with Type 1 Diabetes Amber S. Kujath, PhD, RN, ONC Department of Biobehavioral Health Science University of Illinois at Chicago Chicago, Illinois (2011) Dissertation Chairperson: Lauretta T. Quinn, PhD, RN, FAAN Bone fragility is one complication of type 1 diabetes mellitus (T1DM), though reasons are unknown. Oxytocin (OT) is an anabolic hormone to bone, decreased levels of which have been linked to diabetes complications. This study was a cross-sectional analysis of 165 premenopausal women (n = 89) with T1DM and (n = 76) matched controls. Peripheral and central measures of bone density, dietary and lifestyle factors, and measures of bone formation (osteocalcin) and resorption (N-terminal cross-linked telopeptide) were initially collected. This study added analysis of OT, Bone-Specific Alkaline Phosphatase (BAP), tartrate-resistant acid phosphatase isoform 5b (TRAP5b), Receptor Activator for Nuclear Factor kB Ligand (RANKL), and Osteoprotegerin (OPG). Multivariable regression modeling was used to determine significant associations. Older age was associated with lower bone resorption and formation in controls but not T1DM. Body mass index (BMI) and vigorous physical activity were positively associated with peripheral and central BMD in controls but only peripheral BMD in T1DM. Waist-to-hip ratio was positively associated with forearm BMD in controls but not in T1DM. Caffeine, alcohol, smoking, oral contraception, blood pressure medication and higher A1C were detrimental to bone turnover in women with T1DM. Women with T1DM had lower OT levels when adjusted for caffeine, alcohol, age at menarche, anti-hypertension medications, and progesterone-only contraception. Contraception was associated negatively with OT in women with T1DM but positively with OT in controls. Adiposity measures (waist-to-hip ratio, leptin, and weight change) were associated positively with OT in women with T1DM but negatively in controls. Some traditional clinical predictors of bone fragility may not be associated with bone in women with T1DM. Caffeine, alcohol, smoking, contraception, blood pressure medications, and poor glycemic control may negatively impact bone in women with T1DM, whereas sun exposure, healthy weight, thyroid replacement, and vigorous physical activity may positively affect their bone health. Modifiable behaviors play a large role and offer opportunities for education and intervention to improve bone health of women with T1DM. For women with T1DM, OT levels appeared more sensitive to lifestyle factors such as alcohol, caffeine, and vitamin supplements, and adiposity and contraception had different associations with OT.