P3.209 Age differences between heterosexual partners: implications for the spread of chlamydia trachomatis

Smid, JH; Garcia, V; Mercer, CH; Low, N; Althaus, CL (2017). P3.209 Age differences between heterosexual partners: implications for the spread of chlamydia trachomatis. Sexually transmitted infections, 39(Suppl 2), A171.1-A171. BMJ Publishing Group 10.1136/sextrans-2017-053264.444

[img] Text
Smid STI and HIV World Congress 2017_abstracts.pdf - Published Version
Restricted to registered users only
Available under License Publisher holds Copyright.

Download (78kB)

The consequences of mixing between sexual partners of different ages on the transmission and prevalence of sexually transmitted infections (STI) are still not well understood. Using sexual behaviour data, we obtained a detailed quantitative description of sexual mixing by age. We then investigated the impact of age mixing on the age- and sex-specific prevalence and incidence of Chlamydia trachomatis (Ct) using a dynamic transmission model.
First, we used age- and sex-specific data about the proportion of individuals who are sexually active, sexual partner change rates, and the ages of the three most recent part-
ners at first episode of sexual intercourse from the second and third British National Surveys of Sexual Attitudes and Lifestyles (Natsal-2 and Natsal-3). We used a parametric description of the partner ages using skew-normal distributions
and combined the data to reconstruct age mixing between heterosexual partners. Second, we incorporated the mixing patterns into a compartmental transmission model to investigate the age groups amongst which Ct is most likely to be transmitted and in which direction.
On average, males reported sex with younger female partners (median age difference
5.3; IQR [1.6, – 8.9] years) and females reported having male partners of similar age
(median age difference 0.4; IQR [2.7, 1.9] years). The median and the skewness of partner age distributions depend heavily on the age of the respondent.
Ct-transmitting partnerships are typically between an older male and a younger
female partner. In 60% of Ct-transmitting partnerships, at least one partner was >25 years old.
Our study illustrates the importance of sexual mixing patterns on Ct spread and indicates that a majority oftransmitted infections are in age groups outside of those included in typical Ct screening programs. Our method for the incorporating sexual behaviour data into dynamic transmission models can be used to study the transmission of any STI
and to understand the potential impact of control strategies
that target specific age groups.

Item Type:

Conference or Workshop Item (Abstract)


04 Faculty of Medicine > Pre-clinic Human Medicine > Institute of Social and Preventive Medicine (ISPM)

UniBE Contributor:

Smid, Joost Hubert, Garcia, Victor, Low, Nicola, Althaus, Christian


600 Technology > 610 Medicine & health
300 Social sciences, sociology & anthropology > 360 Social problems & social services




BMJ Publishing Group




Tanya Karrer

Date Deposited:

08 Jun 2018 01:17

Last Modified:

05 Dec 2022 15:14

Publisher DOI:






Actions (login required)

Edit item Edit item
Provide Feedback