Cytokines, Depression, and Bone Health: Exploring the Associations in Healthy Adolescent Females
Open Access
- Author:
- Sucharski, Monica Lynn
- Area of Honors:
- Nursing
- Degree:
- Bachelor of Science
- Document Type:
- Thesis
- Thesis Supervisors:
- Lorah D Dorn, Thesis Supervisor
Harleah Graham Buck, Thesis Honors Advisor - Keywords:
- cytokines
depression
bone health
adolescence
females
nursing - Abstract:
- Background: Cytokines such as interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α are cellular messengers related to immune and inflammatory responses in the body. Cytokines have been implicated as being involved in both depression, a mental health condition affecting over 350 million people worldwide, and bone breakdown, a disease process leading to increased risk for osteoporosis and in turn, potential fracture. Specifically, these pro-inflammatory markers have been associated with increased depressive symptoms in adolescent females and have also been identified as osteoclastogenic factors in bone resorption in both animals and humans. However, the nature of the role each factor plays is unclear. Given the inter-developmental stage variability and lifetime trajectory of bone growth and breakdown, it is important to identify potential contributing factors in order to improve health promotion during key periods of development in females. The purpose of this thesis is to address the following clinical question in healthy adolescent girls: What are the associations of baseline cytokine levels with depressive symptoms and bone mass one year later? Methods: This is a secondary analysis of an existing cross-sequential, longitudinal dataset collected (2003-2006) in a three-year study of 262 female adolescents. Data related to levels of cytokines IL-1β, IL-6, and TNF-α, measured via bioassay, from Time 1 (initial clinic visit) were analyzed in connection with levels of depressive symptoms measured by the Children’s Depression Inventory (CDI). Then measures of bone mass (Whole Body Bone Mineral Content; BMC, Hip Bone Mineral Density; BMD, and Lumbar Spine BMD), via dual energy x-ray absorptiometry, from Time 1 and Time 2 (one year later) were used to consider change in bone mass across time. Multiple covariates were included: (e.g., gynecological age, serum 25-hydroxy Vitamin D, weight). The association of depressive symptoms and bone-specific cytokines on bone mass was then analyzed. Data analysis involved descriptive statistics, correlations, and three separate stepwise regression models. Results: The majority of the sample was white (61.80%); averaged 5.25 (SD = 0.26) feet in height and 137.02 (SD = 40.12) pounds in weight. Subjects reported age at menarche (N = 253, M = 12.40, SD = ±1.24) in years, and gynecological age in years was subsequently calculated (N = 209, M = 3.39, SD = 1.90). None of the observed independent variables (Time 1 IL-1β, IL-6, TNF-α, CDI were significantly correlated with any observed dependent variables (Time 1 Whole Body BMC, Lumbar Spine BMD, and Hip BMD). Only IL-1β was significantly related to Lumbar BMD (B = -.0002, SE = .0001, p < .01) upon stepwise regression analysis. Multiple covariates such as weight, Vitamin D intake, and gynecological age exhibited significant effects on bone health. Conclusions and Implication: Psychological assessment during adolescence remains a crucial consideration for females, but proof of the impact of depressive symptoms on bone health was not reflected in these particular analyses. With one exception, the specific cytokines also showed no association with bone health. Future research should capitalize on the longitudinal changes in these factors and if cytokines may play a mediating role in how depressive symptoms may influence bone health. Health promotion and teaching regarding behaviors promoting long-term bone health continues to be a significant area of interest for the adolescent female population and those primary care providers involved in their care.