Study protocol of the iMPaCT project : A longitudinal cohort study assessing psychological determinants, sexual behaviour and chlamydia (re)infections in heterosexual STI clinic visitors

Acknowledgements We are grateful to the staff at the STI clinics of Amsterdam, Kennemerland, Hollands Noorden, Twente, who are involved in the recruitment and data collection of participants, and Marlous Ratten and Klazien Visser from Soapoli-online, who are involved in the coordination of laboratory testing of the home-based sampling kits at six-month follow-up. We also thank the staff at the STI department at the National Institute for Public Health and the Environment, especially Birgit van Benthem. Funding This project is funded by the Strategic Programme (SPR) of the National Institute for Public Health and the Environment (RIVM) (project number S/113004/01/IP). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Availability of data and materials The dataset (anonymised) generated during this study will be made available for interested parties on request.Peer reviewedPublisher PD

A Multidimensional Approach to Assess Infectious Disease Risk: Identifying Risk Classes Based on Psychological Characteristics.

This project was supported by the Strategic Programme of the National Institute for Public Health and the Environment (project S/113004/01/IP).Peer reviewedPublisher PD

A Multidimensional Approach to Assessing Infectious Disease Risk : Identifying Risk Classes Based on Psychological Characteristics

Prevention of infectious diseases depends on health-related behavior, which is often influenced by psychological characteristics. However, few studies assessing health-related behavior have examined psychological characteristics to identify risk groups, and this multidimensional approach might improve disease risk assessment. We aimed to characterize subgroups based on psychological characteristics and examine their influence on behavior and disease risk, using chlamydia as a case study. Selected participants (heterosexuals aged 18-24 years and females aged 18-24 years who had sex with both men and women) in a Dutch longitudinal cohort study (the Mathematical Models Incorporating Psychological Determinants: Control of Chlamydia Transmission (iMPaCT) Study) filled out a questionnaire and were tested for chlamydia (2016-2017). Latent class analysis was performed to identify risk classes using psychological predictors of chlamydia diagnosis. Two classes were identified: class 1 (n = 488; 9% chlamydia diagnosis) and class 2 (n = 325; 13% chlamydia diagnosis). The proportion of participants with high shame, high impulsiveness, and lower perceived importance of health was higher in class 2 than in class 1. Furthermore, persons in class 2 were more likely to be male and to report condomless sex compared with class 1, but the number of recent partners was comparable. Thus, risk classes might be distinguished from each other by psychological characteristics beyond sexual behavior. Therefore, the impact of the same intervention could differ, and tailoring interventions based on psychological characteristics might be necessary to reduce chlamydia prevalence most effectively

A Multidimensional Approach to Assessing Infectious Disease Risk: Identifying Risk Classes Based on Psychological Characteristics

Prevention of infectious diseases depends on health-related behavior, which is often influenced by psychological characteristics. However, few studies assessing health-related behavior have examined psychological characteristics to identify risk groups, and this multidimensional approach might improve disease risk assessment. We aimed to characterize subgroups based on psychological characteristics and examine their influence on behavior and disease risk, using chlamydia as a case study. Selected participants (heterosexuals aged 18-24 years and females aged 18-24 years who had sex with both men and women) in a Dutch longitudinal cohort study (the Mathematical Models Incorporating Psychological Determinants: Control of Chlamydia Transmission (iMPaCT) Study) filled out a questionnaire and were tested for chlamydia (2016-2017). Latent class analysis was performed to identify risk classes using psychological predictors of chlamydia diagnosis. Two classes were identified: class 1 (n = 488; 9% chlamydia diagnosis) and class 2 (n = 325; 13% chlamydia diagnosis). The proportion of participants with high shame, high impulsiveness, and lower perceived importance of health was higher in class 2 than in class 1. Furthermore, persons in class 2 were more likely to be male and to report condomless sex compared with class 1, but the number of recent partners was comparable. Thus, risk classes might be distinguished from each other by psychological characteristics beyond sexual behavior. Therefore, the impact of the same intervention could differ, and tailoring interventions based on psychological characteristics might be necessary to reduce chlamydia prevalence most effectively