Background
Prior research has suggested that depressive symptoms may be related to incidence of sexually transmitted infections (STIs) among women, but the patterns have not been consistent and the types of comparisons that have been made are limited. Here, we address this knowledge gap by estimating the dose-response relationship between depressive symptoms and the 6-month incidence of STIs among reproductive-age women with HIV (WWH) and women without HIV (WWoH) but at increased vulnerability to HIV. We project how shifts in the distribution of depressive symptoms might impact STI incidence.
Methods
Data for this analysis come from the Study of Treatment and Reproductive Outcomes (STAR) cohort in the United States. Depressive symptoms were measured using the 20-item Center for Epidemiologic Studies-Depression (CES-D) scale. Women who reported a new diagnosis of gonorrhea, syphilis, chlamydia, herpes simplex, or trichomoniasis in the six months following baseline were considered to have an incident STI. We used g-estimation to examine the dose-response between depressive symptoms and STI incidence with inverse probability weights to account for missing STI information. We used g-computation to estimate STI incidence under interventions on the distribution of depressive symptoms. Our statistical analyses adjusted for demographic (e.g., age, education, race, marital status) and behavioral (e.g., history of STIs, condom use, number of sexual partners) variables.
Results
Of 851 women enrolled, 308 (36%) had a CES-D score ≥16 at baseline. Among 569 (67%) women with a follow-up visit at six months, 48 (8.4%) reported an STI since their baseline visit. For the dose-response relationship, as depressive symptoms increased, the chance of STI also increased among WWH (Figure). While a CES-D score >30 appeared to increase STI risk relative to a score of zero among WWH, among WWoH greater depressive symptoms did not appear to substantially increase STI risk. A hypothetical intervention that would reduce all women’s CES-D scores by two points was estimated to reduce the incident proportion at six months with STIs by -0.4% (95% confidence interval (CI): -1.2%, 0.4%) relative to the observed incidence. A stronger intervention that reduced CES-D scores by six points would have further reduced the STI incidence (-1.1%; 95% CI: -3.4%, 1.2%).
Conclusions
Reducing depressive symptoms among reproductive-age women provides a number of beneficial health effects, one of which may be the reducing the incidence of STIs.