Introduction In the Netherlands, there are strong disparities in Chlamydia trachomatis (CT) prevalence among ethnic groups. The highest prevalence is found among individuals from Surinamese descent. Previous research suggested that socio-economic status (SES) may be important in explaining these differences. In ethnic groups with high CT prevalence, low SES might lead to infrequent sexual healthcare seeking behaviour. We investigated whether differences in sexual healthcare seeking behaviour could explain disparities in CT prevalence between ethnic groups in the Netherlands.
Methods We used the 2011–2014 baseline data of HELIUS, a population-based multi-ethnic cohort study in Amsterdam, the Netherlands. CT was diagnosed using a multiplex serology assay. A directed acyclic graph was created to depict the hypothesised causal links between ethnicity and CT infection. The associations between CT seropositivity and its determinants were assessed with logistic regression analyses.
Results The sample consisted of 1977 individuals, with a median age of 28 (IQR 24–31) of which 52.9% were female. CT seropositivity was highest among African-Surinamese (69.7%), followed by Ghanaian (67.9%), South-Asian Surinamese (39.8%), Dutch (36.4%), Moroccan (35.2%) and Turkish (30.5%) participants. Sexual healthcare seeking behaviour was highest among Afro-Surinamese and Ghanaian participants. After adjusting for sexual healthcare seeking behaviour, SES and sexual risk behaviour, being of African-Surinamese (adjusted Odds Ratio [aOR]: 3.97; 95% CI 2.41–6.55) or Ghanaian (aOR: 2.48; 95% CI 1.27–4.86) descent remained strongly associated with CT seropositivity when compared to Dutch participants.
Conclusion Disparities in CT (sero)prevalence across ethnic groups in Amsterdam were observed and in line with literature. Higher CT seroprevalence in African-Surinamese and Ghanaian participants could not be explained by differences in sexual healthcare seeking behaviour, or other potential mediators of the association (e.g. SES and sexual risk behaviour).