INTRODUCTION

Genital infection of Chlamydia trachomatis (CT) is increasing among the Catalan population, most frequently among youngsters¹. The last available prevalence of the population under 25 years of age was around 8.5%². This is a highly transmissible infection, mainly asymptomatic, but with the potential to produce serious complications, most importantly pelvic inflammatory disease in women and infertility in both men and women. Early detection and treatment are crucial to guarantee prevention and control³. However, there is no good-quality evidence to suggest that widespread testing strategies have had an impact on the transmission of chlamydia in the population⁴ while other studies suggest that partner notification is more cost-effective than screening for CT control⁵.

Since 2007, the Catalan government has regularly conducted cross sectional studies of CT screening among youngsters under 25, either in correctional facilities^6-7 or in primary health centres but the situation among persons over 25 is poorly known, particularly in key populations such as individuals in correctional facilities. It is suspected that adult inmates have a higher risk of CT infection because of potentially hazardous sexual behaviour (clients of sex workers)⁸. The only study in our country that specifically considers such issues is one from 2011 among inmates of 18 to 35 years old⁹. The only available information on prisoners older than 25 to 35 years is from 2008, which shows a CT prevalence of 4%9. However, the increasing trend of infection, from 5.7% in 2008 to 7.5% in 2014 among under 25 years old suggests the need to explore the situation among persons over that age.

It is unclear whether CT screening of inmates over 25 years old should be recommended in Catalan prisons. There are no European Guidelines regarding CT screening in prisons and the Centres for Disease Control (CDC) of Atlanta¹⁰ recommend screening on entering prison for all women and men younger than 35 and 30, respectively. On the other hand, some Spanish Scientific Societies recommend screening for STIs in people entering correctional centres¹¹. The objective of this study is to determine the prevalence of CT, the risk factors for infection in inmates aged 25 to 65 years old in four Catalan prisons so as to provide more information for the debate on systematic screening among this population.

MATERIAL AND METHOD

There are two prison administrations in Spain: the Central Government and the Catalan administration. The Catalan administration manages nine prisons containing mainly two types of inmate: preventive (those on short time stays, mostly recently incarcerated and still not sentenced) and convicted inmates (those with a longer average stay). The socio-demographic and behavioural characteristics of these inmates are expected to be different and may have an effect on CT infection. This is a cross sectional study with a representative sample of the prison population of 25 to 65 years of age in Catalonia. In 2017, there were 5214 new prisoners in Catalonia and the total prison population was 14,868 people¹². There were 2053 preventive inmates (13.8%) and 12,815 convicted prisoners (86.2%). The sex distribution of this population was 13657 men (93%) and 1028 women (7%). The average stay in prison was 267 and 1232 days among preventive and convicted prisoners, respectively. Weekend leave permits were given to 2204 inmates. Most of the inmates, except the ones with security restrictions, have one or two conjugal visits a month. This study is conducted in two prisons for convicted inmates and two for preventive inmates as this makes the study more representative and also because of the availability of health professionals within prison system.

RESULTS

1498 inmates were evaluated during the period of study. After excluding 29 (1.9%) of inmates who were found to be younger than 25 or older than 65, there were 1374 men and 95 women eligible for participation. The average age was 40 years (range: 25-65 years). There were 12 (0.8%) and 21 (1.5%) out of 1374 men who mentioned having had sex with men (MSM) or who were bisexual, respectively. Half of the participants were foreigners. Most of them came from Western Europe (54%) followed by Latin America (16%), North Africa (10%) and Central Europe and Central Asia (6%). Most of them (91%) had gone to school and had received a primary (39%), secondary (43%) or university (9%) education.

DISCUSSION

This analysis of CT prevalence amongst inmates over 25 is one of the few studies available in Catalonia. Until now, there was no robust data to aid in deciding on the advisability of CT screening in inmates over 25. Our findings show that CT prevalence is very low in this population. Prevalence was higher in men than in women, unlike CT prevalence studies in the general population and similarly to other results from prison studies, although not significantly so^15-18. In Catalonia, because of this low prevalence in correctional facilities, systematic screening of CT in inmates older than 25 years is not justified. In addition, it is noteworthy that preventive inmates (most recently admitted to prison) and convicted inmates (incarcerated for much longer periods) despite not showing significant differences in infection (0.5% vs. 1.2%), their prevalence is still very low compared to the CT prevalence of inmates under 25 (7.5% in the year 2014). The prevalence of CT is low, but it is consistent with the history of previous STIs, which were mentioned only by 10%. It is also noteworthy that all cases occurred in heterosexual men, probably because in these correctional centres heterosexual orientation was more frequent in men (97.3%) than in women (85.1%). Additionally, women showed a lower risky sexual behaviour (fewer different sporadic partners than men, lower mean number of sexual partners, less practice of sex in clubs, use of chats to find new partners or drug consumption while having sex), explaining the lower CT prevalence.

In a population study conducted in the city of Barcelona, the increase of STIs was observed in men who have sex with men (MSM), men who have sex with women (MSW) and women who have sex with men (WSM), with the exception of women infected with HIV, in which a reduction was observed¹⁹. They have also found an increase in risky sexual behaviour: basically an increase in the number of partners and subgroups prone to higher-risk sexual practices (Chemsex) mainly associated with MSM.

In our setting, risky sexual behaviour (different sporadic sex partners, concurrency of sexual partners, sex in clubs, drug consumption) is found more frequently among convicted than preventive inmates. This may be explained by the fact that convicted inmates may be more prone to living dangerously when they are under have a leave permit to be outside prison, or even within prison, while having their conjugal visits. However, the use of condoms in previous relationship is not a differential factor between types of inmates.

Further qualitative observation should enable the reasons explaining such differences to be identified.

This study presents some limitations: Firstly, the low prevalence obtained may have limited the identification of other possible predictors of infection and may explain the borderline significance of the risk factors associated with infection. Secondly, the study characterizes a specific population: prison inmates in Catalonia. Prisoners from other regions or countries may have similar or different STI risk behaviours. Finally, the questionnaire was mainly administered by health professionals who may have influenced the sense of some answers. We should not discount the “look good effect” on some occasions.

On the other hand, the study provides real data on the prevalence of CT infection in prisoners over 25 for the first time, which allows the Health Administration to make decisions with greater guarantees. In addition, this type of work allows the most affected groups to be identified, which should help to redesign preventive programs in order to find the most efficient way to reach these groups in the population. In our study, CT infection was more frequent among inmates with multiple diverse sporadic partners. No other socio demographic or behavioural characteristic was found to be associated. Therefore, the use of condoms should be particularly reinforced amongst these inmates. Being in prison should become an opportunity for inmates to get full training on STI prevention. In primary health care centres, partner notification has proven to be more cost-effective than opportunistic screening to stop transmission of CT and other curable STI, we therefore think that the same situation may apply to prisons. Although most of the inmates who have had an STI mentioned notifying all their partners, there were still a considerable number (27%) who did not. Similarly to the findings of other studies conducted in Catalonia among MSM19 or among users of primary health care centres²⁰, not being able to locate their partners, feeling ashamed or believing that there was no obligation to notify were the main reasons for not notifying their partners. This may be explained by low motivation, low health education and a lack of appropriate tools for notification.

Health professionals have a crucial role in enforcing partner notification and in convincing persons recently diagnosed with an STI about the need to do so. Unfortunately, most of these health professionals are overworked, lack awareness of the importance of partner notification in stopping transmission of STIs or do not have appropriate tools that show how to notify partners. In this era of new technologies, the use of internet or new phone applications could facilitate partner notification promoted by health professionals. This should be part of the caring process in prisons.