Study Design Matters: Using a Rigorous Analytic Design to Examine the Association Between Rectal Douching and...

Area of Science:

• Sexual health research
• Infectious disease epidemiology
• Public health interventions

Background:

• Previous studies suggest a link between rectal douching and prevalent rectal Neisseria gonorrhoeae (GC) and Chlamydia trachomatis (CT).
• Limited research has explored the association between douching and the incidence of these infections.

Purpose of the Study:

• To investigate the association between rectal douching and incident rectal GC and CT infections.
• To address the gap in understanding douching's role in the acquisition of these sexually transmitted infections.

Main Methods:

• A 48-week cohort study (ExGen) in Seattle, WA (2016-2018) with weekly surveys and self-collected rectal specimens.
• Primary analysis used a case-crossover design comparing douching frequency during infection weeks versus control weeks.
• Multivariate conditional logistic regression estimated the association between douching and incident GC/CT.

Main Results:

• The case-crossover analysis found no significant association between douching and incident rectal GC (aOR = 0.47; 95% CI = 0.07-3.10).
• Similarly, douching was not significantly associated with incident rectal CT (aOR = 1.16; 95% CI = 0.26-5.07).
• An exploratory synthetic cross-sectional analysis showed a significant association between douching and rectal GC, but not CT.

Conclusions:

• This rigorous analysis indicates that rectal douching is not associated with incident rectal GC or CT.
• Further investigation into the mechanisms of action of douching products and the effects of long-term use is warranted.