Using a cross-sectional, large-scale and comprehensive dataset on prisoner health, this study portrayed the epidemiological situation of the prison population in the Canton of Vaud, Switzerland. First, unlike other studies that use prison population samples, this study analyzed exhaustive data on prisoners in Vaud Canton over the same time period. Second, while many studies tend to emphasize either male prisoners or young prisoners, we differentiated the disease profiles between groups of inmates (All, Men, Older adults and Women). Third, this study provides direct comparisons between the health of two minority inmate groups (older adults and women) and the younger and male prisoners on four aspects of health: substance abuse, mental health, infectious diseases and chronic conditions. As such, it contributes to the literature on the health burden among prisoners in general, and that of older and female prisoners in particular. Finally, this study underlines the fact that prisoners are suffering from multiple morbidities combining psychiatric and somatic disorders. Beyond these findings, our study also made some specific and important points, which are highlighted below.
From the literature, it is evident that prisoners are at higher risk for drug problems than those living in the community [5, 6]. There is a notable heterogeneity among studies, and estimated prevalence of drug abuse varies from 10 % to 53 % in male offenders. In a Swiss context, active use of illegal drugs was found in 40 % of remand prisoners . In our study, the two available measures on drug problems revealed differences: 18 % of prisoners were diagnosed with drug abuse problems in the psychiatric follow-up, but in the entry examination conducted by nurses, 32 % of inmates self-declared being active drug users. The difference can be explained by 3 factors. The main explanation is that many detainees declared themselves to be drug abusers even when not addicted and without necessarily having or showing symptoms requiring a psychiatrist examination. If such prisoners do not explicitly seek psychiatric help to treat their drug misuse problem, they are not seen by psychiatrists. Also, the estimated rate from self-reports may be overestimated. Some prisoners may report problems for the purpose of obtaining medications/treatments that would help them bear incarceration . Finally, the organizational constraints of incarceration may imply that some prisoners do not have time or opportunity to see a psychiatrist during their stay. The number of prisoners with a psychiatric diagnosis of substance use may thus be underestimated, especially for men, given their greater numbers. The heterogeneity of data on substance abuse in prison underscores the challenge of obtaining an accurate prevalence of drug use/misuse in the prison population , especially when some prisoners hide their dependencies to avoid sanctions .
Our findings indicate that the need for substance abuse treatment is great and important for inmates. It is also now recognized that systematically rehabilitating prisoners with substance abuse problems often remains an empty hope . Previous therapy consisting of providing drug-free programs have now been replaced by substitution –methadone-maintenance programs –at least in some European countries . This has been the therapeutic approach adopted in the prisons included in this study for several years.
Communicable diseases, such as hepatitis B and C and HIV were found at rates between 5 and 10 times greater than those reported in the Swiss general population (Table 3). Our results are consistent with those in France and Canada [20, 41, 42] and those found in the large remand Swiss prison in Geneva . With a rate of tuberculosis among the studied inmates >50 times that of Swiss civilians, our findings confirm the public health issues related to this disease. As pointed out by the WHO (Stop TB Strategy ), the prison population is one of the risk groups that needs special attention. Efforts already implemented to improve detention conditions (including overcrowding, hygiene conditions and nutrition) should be further developed to better contain the transmission of this disease. This is particularly relevant in a population made up of a disproportionate number of individuals with high risk factors for tuberculosis (HIV, intravenous drug use, low socioeconomic background as well as geographical origin ).
The prevalence of common conditions such as back pain, hypertension, diabetes and asthma among prisoners was in the same range as that observed in their counterparts living outside the prison in the country (Table 4). Compared to recent US studies, prisoners from the Canton of Vaud tended to show lower rates of hypertension, asthma and diabetes . Moreover, compared to a publication reporting health problems among detainees in Geneva , our results exhibited lower rates of skin problems, migraines and asthma, but higher rates of back pain, diabetes and hypertension. There are several explanations to account for these differences. First, our study sample was older, which may explain the higher rate of hypertension and diabetes. Second, instead of focusing on remand prisoners, our sample included inmates not only on remand awaiting trial, but also on trial and serving short and long sentences. Prisoners serving sentences have to work in prison under sometimes sub-optimal or not very ergonomic conditions, leading to health problems such as back pain. Third and importantly, the methodology differed in that the health conditions of prisoners were reported according to 2 different international classifications: International Classification of Primary Care versus ICD-10.
Compared to the entire study population, the older adult prisoners showed a different disease profile. First, older prisoners did not suffer from the same type of addictions. Drug abuse was significantly less frequent among prisoners aged 50+, whereas alcohol abuse disorders were more frequent. This finding is in line with results from Scottish prisoners where the group aged 40–64 showed a higher proportion of prisoners with alcohol dependence than the group aged 25–39 . Additionally, a recent analysis of the health profile of older prisoners in north-west England revealed that the prevalence of alcohol abuse was higher than that of drug abuse . A second feature of the disease profile of the older adults was the higher prevalence of mental disorders compared to their younger counterparts. Excluding the dependence disorders, about 40 % of older prisoners had mental health problems. In our study, schizophrenia was reported at 6.5 % and personality disorders at 26 %, while the English study found rates of 5 % and 20 % respectively . Third, communicable infections were significantly less frequent among older prisoners than younger prisoners. Finally, older prisoners showed a higher prevalence of more common chronic diseases than their younger counterparts, and than older people living outside the prison. Overall, these findings confirmed the previous results indicating that a large proportion of older prisoners suffer from psychiatric illnesses and chronic health problems [44, 45]. The differences in disease profiles between younger and older prisoners raise questions about the required healthcare needs of prisoners, not only now but also in the future.
In prison, healthcare needs linked to aging have emerged as great challenges. Addressing the delivery of healthcare services to older prisoners with multiple morbidities as well as age-related degenerative diseases raises inescapable issues with respect to the equivalence of care between prison and the community . Provision of equivalent care takes on an extra dimension with the management of cognitive impairments such as dementia  and transitional end-of-life care needs . Another issue that impacts the health of older prisoners is the structural environment of prison facilities. The prisons were initially designed for vigorous and independent people, and were not built to provide decent care to people who might need assistance with basic personal everyday life tasks and/or who may have geriatric syndromes.
Gender also had an influence on the disease profile among the study population. We found that substance abuse was more often encountered in female than in male prisoners. Our results reinforced previous findings showing gender differences in the prevalence of drug use disorders among prisoners [6, 8]. In Europe, previous studies have found problematic drug use ranging from 10 % to 50 % in female prisoners . Up-to-date results based on DAPHNE Projects data and reported by McDonald  revealed that 75 % of female prisoners in Germany, and 98 % in Scotland, had addiction problems with drugs, alcohol, prescription drugs and eating disorders. We also found that female prisoners were more likely than men to have co-existing psychiatric disorders such as personality disorders, depression and anxiety. This is in line with results reported in the literature [50, 51] showing that women were also more likely to self-harm and commit suicide than male inmates . In addition, although it was not examined in our study due to a lack of available data, many female prisoners might also be mothers or have worries about children. As a result, the mental health needs of female prisoners are complex.
Stress and anxiety associated with incarceration may be compounded by the overcrowded conditions and violence existing in prison facilities. If overcrowding significantly worsens the physical health of prisoners by encouraging the spread of communicable disease, it seems likely that overcrowding could also adversely impact the mental health of prisoners . Mental illness also complicates treatment for co-morbidities, such as HIV, which requires strict adherence to drug therapy and careful monitoring for adverse drug interactions . Addressing the mental health needs of male and female prisoners will improve not only their quality of life but also that of the prison staff and those without mental health illnesses .
Compared to men, women in prison had a higher burden of communicable diseases (almost double), especially for HIV and hepatitis C. This is similar to estimations from French prisons . As for common chronic diseases, the incarcerated women in the study region suffered from the same health conditions as men but the diseases were more prevalent in women. Additionally, female prisoners have specific needs related to reproductive health (menstruation, menopause, pregnancy), and such needs are often more challenging than those of men [30, 51]. The growing number of incarcerated women raises concerns about gender-specific issues and needs in places initially designed for men.
Limitations and strengths
The aim of this study was to describe the health status of prisoners by investigating substance abuse and mental health and chronic health problems, including infectious diseases. The study provides much needed knowledge on health in prison and helps to identify prisoners’ specific healthcare needs in general as well as by age and gender. However, our decision to focus on chronic conditions does not allow us to provide a complete picture of health problems since daily illnesses and symptoms (injuries) were excluded. Special focus on these more acute disorders would be interesting. Errors in collecting and reporting data may exist even if several checks were carried out to ensure coherence. Having restricted the analysis to people who were examined upon entry limited the underestimation errors of not only infectious and communicable diseases, but also chronic diseases. Indeed, the examination upon entry as a routine provides a detailed medical history of the prisoners and as such may identify symptoms leading to a precise diagnosis. Although examination on entry might also help identify other problems that individuals arrive with and that are associated with life experience, they may be more difficult to categorize. Concerning whether the data can be generalized, we analyzed the characteristics of those prisoners who did not receive a physician entry visit and were removed from our results. We found that they were similar to those included in the study in terms of gender, nationality and marital status. The excluded group was slightly younger (mean age of 30 years, SD = 9.5). Their average length of stay was 16 days. We have concluded that excluding these individuals has very little impact on the data and does not prevent the results from being generalized. Finally, it cannot be excluded that the prevalence of psychiatric disorders might be slightly underestimated since not all prisoners had the opportunity to have a psychiatric examination. This is because their stay was short or because they were transferred to another prison in Switzerland (or they were deported to their country of origin). However, this was a very small proportion of the prisoners since specific training for both nurses and penitentiary staff allows them to identify psychiatric needs efficiently. They are therefore able to set up an examination relatively quickly. More than 95 % of new prisoners are seen by nurses, assuring good medical follow-up/management. Thus the percentage of inmates in need of a psychiatric examination who do not get the opportunity is very small indeed and has little impact on the data.
Strengths of this study include the large sample size and use of recent, exhaustive data from a prison population. This population includes different types of inmates, ranging from prisoners on remand awaiting trial to prisoners serving a sentence. Thus it closely mirrors the prison population of all of Switzerland, thereby increasing its external validity and allowing for extrapolation of our results.