Depressive symptoms and antidepressant use in relation to white blood cell count among postmenopausal women from the Women's Health Initiative.

Inflammation can play a role in the pathophysiology of depression, and specific types of antidepressants may have inflammatory or anti-inflammatory properties. Furthermore, depression and antidepressant use has been linked to white blood cell (WBC) count, a routinely measured inflammatory marker. We examined the cross-sectional and longitudinal relationships of depressive symptoms and/or antidepressant use with WBC count among postmenopausal women. Analyses of cross-sectional data at enrollment were performed on 125,307 participants, 50-79 years of age, from the Women's Health Initiative Clinical Trials and Observational Studies who met eligibility criteria, and a subset of those with 3-year follow-up data were examined for longitudinal relationships. Depressive symptoms were defined using the Burnam Algorithm whereas antidepressant use was defined using therapeutic class codes. WBC count (Kcell/ml) was obtained through laboratory evaluations of fasting blood samples. Multivariable regression modeling was performed taking sociodemographic, lifestyle and health characteristics into consideration. At enrollment, nearly 85% were non-users of antidepressants with no depressive symptoms, 5% were antidepressant users with no depressive symptoms, 9% were non-users of antidepressants with depressive symptoms, and 2% were users of antidepressants with depressive symptoms. In fully-adjusted models, cross-sectional relationships were observed whereby women in the 2