The contribution of cannabis use to the increased psychosis risk among minority ethnic groups in Europe.

BACKGROUND: We examined whether cannabis use contributes to the increased risk of psychotic disorder for non-western minorities in Europe. METHODS: We used data from the EU-GEI study (collected at sites in Spain, Italy, France, the United Kingdom, and the Netherlands) on 825 first-episode patients and 1026 controls. We estimated the odds ratio (OR) of psychotic disorder for several groups of migrants compared with the local reference population, without and with adjustment for measures of cannabis use. RESULTS: The OR of psychotic disorder for non-western minorities, adjusted for age, sex, and recruitment area, was 1.80 (95% CI 1.39-2.33). Further adjustment of this OR for frequency of cannabis use had a minimal effect: OR = 1.81 (95% CI 1.38-2.37). The same applied to adjustment for frequency of use of high-potency cannabis. Likewise, adjustments of ORs for most sub-groups of non-western countries had a minimal effect. There were two exceptions. For the Black Caribbean group in London, after adjustment for frequency of use of high-potency cannabis the OR decreased from 2.45 (95% CI 1.25-4.79) to 1.61 (95% CI 0.74-3.51). Similarly, the OR for Surinamese and Dutch Antillean individuals in Amsterdam decreased after adjustment for daily use: from 2.57 (95% CI 1.07-6.15) to 1.67 (95% CI 0.62-4.53). CONCLUSIONS: The contribution of cannabis use to the excess risk of psychotic disorder for non-western minorities was small. However, some evidence of an effect was found for people of Black Caribbean heritage in London and for those of Surinamese and Dutch Antillean heritage in Amsterdam.

[Referral of a stabilized patient with psychotic disorder to the general practitioner: a pilot study]. / Verwijzing van gestabiliseerde patiënt met psychotische stoornis naar huisarts: kan dat? Een vooronderzoek.

BACKGROUND: In various countries, general practitioners (GPs) play an important role after treatment for non-affective psychotic disorder (NAPD) in mental health care. It is unclear how these patients fare. AIM: To compare the clinical course of patients largely recovered from NAPD and referred to the GP with the course of patients who remain in treatment at mental healthcare. METHOD: In a retrospective cohort study, 20 patients referred to GPs by mental healthcare (GP cohort) were compared to 20 patients who remained in treatment at mental healthcare (MH cohort), matched by age and gender. The clinical course was evaluated with the GPs and the mental healthcare practitioner, respectively. In addition, medication adherence and reasons for referral to the GP and mental healthcare were registered. RESULTS: In the GP cohort more patients (70%) deteriorated than in the MH cohort (5%) (p <0.001). In the MH cohort more patients showed therapeutic compliance (90%) than in the GP cohort (67%) (p = 0.078). After about four years, 65% of the patients in the GP cohort were back in treatment at mental healthcare. Among the 13 patients who were referred to the GP while functioning stably, more patients (54%) deteriorated than their matched counterparts in the MH cohort (8%) (p = 0.034). CONCLUSION: The results confirm that caution is needed in referring patients recovered from non-affective psychotic disorder to the GP.

Delegating Clozapine Monitoring to Advanced Nurse Practitioners: An Exploratory, Randomized Study to Assess the Effect on Prescription and Its Safety.

To test whether: (1) psychiatrists will prescribe clozapine more often if they can delegate the monitoring tasks to an advanced nurse practitioner (ANP), (2) clozapine monitoring by an ANP is at least as safe as monitoring by a psychiatrist. Patients from 23 Dutch outpatient teams were assessed for an indication for clozapine. ANPs affiliated to these teams were randomized to Condition A: clozapine monitoring by an ANP, or Condition B: monitoring by the psychiatrist. The safety of monitoring was evaluated by determining whether the weekly neutrophil measurements were performed. Staff and patients were blinded regarding the first hypothesis. Of the 173 patients with an indication for clozapine at baseline, only seven in Condition A and four in Condition B were prescribed clozapine (Odds Ratio = 2.24, 95% CI 0.61-8.21; p = 0.225). These low figures affected the power of this study. When we considered all patients who started with clozapine over the 15-month period (N = 49), the Odds Ratio was 1.90 (95% CI 0.93-3.87; p = 0.078). With regard to the safety of the monitoring of the latter group of patients, 71.2% of the required neutrophil measurements were performed in condition A and 67.3% in condition B (OR = 0.98; CI = 0.16-3.04; p = 0.98). Identifying patients with an indication for clozapine does not automatically lead to improved prescription rates, even when an ANP is available for the monitoring. Clozapine-monitoring performed by an ANP seemed as safe as that by a psychiatrist.

Risk of non-affective psychotic disorder or bipolar disorder in autism spectrum disorder: a longitudinal register-based study in the Netherlands.

BACKGROUND: Individuals with autism spectrum disorder (ASD) appear to be at increased risk of non-affective psychotic disorder (NAPD) and bipolar disorder (BD). However, most previous studies examined the co-occurrence of ASD and NAPD or BD, ignoring possible diagnostic bias and selection bias. We used longitudinal data from Dutch psychiatric case registers to assess the risk of NAPD or BD among individuals with ASD, and compared the results to those obtained for the Dutch population in earlier studies. METHODS: Individuals with ASD (n = 17 234) were followed up between 16 and 35 years of age. Kaplan-Meier estimates were used to calculate the risk of NAPD or BD. We conducted separate analyses to reduce possible bias, including an analysis among individuals diagnosed with ASD before age 16 years (n = 8337). RESULTS: Of the individuals with ASD, 23.50% (95% confidence interval 21.87-25.22) were diagnosed with NAPD and 3.79% (3.06-4.69) with BD before age 35 years. The corresponding figures for the general population were 0.91% (0.63-1.28) and 0.13% (0.08-0.20). Risk estimates were substantially lower, but still higher than general population estimates, when we restricted our analyses to individuals diagnosed with ASD before age 16, with 1.87% (1.33-2.61) being diagnosed with NAPD and 0.57% (0.21-1.53) with BD before age 25 years. The corresponding figures for the general population were 0.63% (0.44-0.86) and 0.08% (0.05-0.12). CONCLUSIONS: Individuals with ASD are at increased risk of NAPD or BD. This is likely not the result of diagnostic or selection bias.

[Residents in supported housing and factors related to moving towards independent living]. / RIBW-bewoners en de factoren die samenhangen met een overgang naar een andere woonsituatie.

BACKGROUND: Few data are available on predictors for the transition of individuals with mental illness to more independent forms of housing.
AIM: To analyse which variables predict the transition of individuals with severe mental illness from supported housing within the Dutch community housing programs (CHP) to more independent ways of living.
METHOD: Data of 1569 participants were analysed using Cox regression analysis.
RESULTS: Individuals with a personality disorder, current alcohol misuse or who received ambulant care prior to admission in CHP had the highest probability of moving to a more independent way of living. Individuals who received clinical care prior to admission in CHP, individuals with admission in Supported Housing, and individuals with a history of substance dependency had the highest probability of clinical relapse.
CONCLUSION: The predictors found in this study can be used as a starting point both for hypotheses for additional aetiological research and for guidelines covering specific interventions.

Educational achievement in psychiatric patients and their siblings: a register-based study in 30 000 individuals in The Netherlands.

BACKGROUND: Poor educational achievement is associated with a range of psychiatric disorders. Several studies suggest that this underperformance is due to cognitive deficits that commence before disease onset and reflect a genetic risk for this disorder. However, the specificity and the familial contribution of this cognitive deficit are not clear. We analysed lifetime educational achievement of psychiatric patients diagnosed with schizophrenia, bipolar or depressive disorder and their unaffected siblings. METHOD: In a register-based case-control study, 1561 patients with schizophrenia, 813 patients with bipolar disorder, 8112 patients with depression, and their siblings were each matched with eight population controls. Patients, siblings and controls were compared on the highest educational stream they completed. RESULTS: Lower educational achievement was present in schizophrenia patients from primary school onwards [completing primary school: odds ratio (OR) 0.69; completing secondary school: OR 0.69; completing academic education: OR 0.46], compared to patients with bipolar disorder or depression. Siblings of schizophrenia, bipolar or depressed patients showed no underachievement at primary or secondary school, but siblings of schizophrenia patients as well as siblings of depressed patients were less successful in their educational achievement after secondary school (completing academic education, schizophrenia siblings: OR 0.90; depressive disorder siblings: OR 0.91). CONCLUSIONS: Educational underachievement from primary school onwards is specifically related to schizophrenia and not to bipolar disorder or depression. Moreover, it appears to be a harbinger of the illness, since it is not found in their siblings. These results add to evidence that early cognitive deficits are a distinct feature of the schizophrenia phenotype.

An incidence study of diagnosed autism-spectrum disorders among immigrants to the Netherlands.

OBJECTIVE: To estimate the risk of developing autism-spectrum disorder (ASD) in children born to immigrants as compared with children of Dutch-born parents. METHOD: Retrospective, population-based cohort study of all live births (n = 106 953) between 1998 and 2007 in a circumscribed geographical region in the Netherlands. Cohort members were linked to the Psychiatric Case Register to identify diagnosed cases. RESULTS: A total of 518 cases of ASD were identified, including 150 children with autism and 368 children with Asperger syndrome or Pervasive Developmental Disorder Not Otherwise Specified (PDD-NOS). Children born to migrants from developing countries were at significantly lower risk of ASD [rate ratio (RR) = 0.6, 95% confidence interval (CI) 0.5-0.9] than children of Dutch-born parents. Within the ASD group, the risk for the subgroup with Asperger syndrome and PDD-NOS was reduced (RR = 0.4, 95% CI 0.3-0.6), whereas that for narrowly defined autism was non-significantly increased (RR = 1.4, 95% CI 0.9-2.4). Migrant groups did not differ in age at diagnosis. CONCLUSION: The results echo Swedish findings indicating a reversal of risk gradient in children of parents from developing countries, specifically a decreased risk for high-functioning and increased risk for low-functioning autism.

Comparison of outcome and characteristics between 6343 COVID-19 patients and 2256 other community-acquired viral pneumonia patients admitted to Dutch ICUs.

PURPOSE: Describe the differences in characteristics and outcomes between COVID-19 and other viral pneumonia patients admitted to Dutch ICUs. MATERIALS AND METHODS: Data from the National-Intensive-Care-Evaluation-registry of COVID-19 patients admitted between February 15th and January 1th 2021 and other viral pneumonia patients admitted between January 1st 2017 and January 1st 2020 were used. Patients' characteristics, the unadjusted, and adjusted in-hospital mortality were compared. RESULTS: 6343 COVID-19 and 2256 other viral pneumonia patients from 79 ICUs were included. The COVID-19 patients included more male (71.3 vs 49.8%), had a higher Body-Mass-Index (28.1 vs 25.5), less comorbidities (42.2 vs 72.7%), and a prolonged hospital length of stay (19 vs 9 days). The COVID-19 patients had a significantly higher crude in-hospital mortality rate (Odds ratio (OR) = 1.80), after adjustment for patient characteristics and ICU occupancy rate the OR was respectively 3.62 and 3.58. CONCLUSION: Higher mortality among COVID-19 patients could not be explained by patient characteristics and higher ICU occupancy rates, indicating that COVID-19 is more severe compared to other viral pneumonia. Our findings confirm earlier warnings of a high need of ICU capacity and high mortality rates among relatively healthy COVID-19 patients as this may lead to a higher mental workload for the staff.

Effect of thalidomide with melphalan and prednisone on health-related quality of life (HRQoL) in elderly patients with newly diagnosed multiple myeloma: a prospective analysis in a randomized trial.

Thalidomide with melphalan/prednisone (MPT) was defined as standard treatment in elderly patients with multiple myeloma (MM) based on five randomized trials. In one of these trials, HOVON49, a prospective health-related quality-of-life (HRQoL) study was initiated in order to assess the impact of thalidomide on QoL. Patients aged >65 years with newly diagnosed MM were randomized to receive melphalan plus prednisone (MP) or MPT, followed by thalidomide maintenance in the MPT arm. Two hundred eighty-four patients were included in this side study (MP, n=149; MPT n=135). HRQoL was assessed with the EORTC Core QoL Questionnaire (QLQ-C30) and the myeloma-specific module (QLQ-MY24) at baseline and at predetermined intervals during treatment. The QLQ-C30 subscales physical function (P=0.044) and constipation (P<0.001) showed an improvement during induction in favour of the MP arm. During thalidomide maintenance, the scores for the QLQ-MY24 paraesthesia became significantly higher in the MPT arm (P<0.001). The QLQ-C30 subscales pain (P=0.12), insomnia (P=0.068), appetite loss (P=0.074) and the QLQ-MY24 item sick (P=0.086) scored marginally better during thalidomide maintenance. The overall QoL-scale QLQ-C30-HRQoL showed a significant time trend towards more favourable mean values during protocol treatment without differences between MP and MPT. For the QLQ-C30 subscales emotional function and future perspectives, difference in favour of the MPT arm from the start of treatment was observed (P=0.018 and P=0.045, respectively) with no significant 'time × arm' interaction, indicating a persistent better patient perspective with MPT treatment. This study shows that the higher frequency of toxicity associated with MPT does not translate into a negative effect on HRQoL and that MPT holds a better patient perspective.

Clinical implementation of hyperthermia treatment planning guided steering: A cross over trial to assess its current contribution to treatment quality.

PURPOSE: To assess the current feasibility of online hyperthermia treatment planning guided steering (HGS) and its current contribution to treatment quality in deep hyperthermia for locally advanced cervical cancer. MATERIALS AND METHODS: 36 patients were randomized to receive either their second and fourth (arm A) or their third and fifth (arm B) hyperthermia treatment of the series with the aid of HGS. The other treatments were conducted according to the Rotterdam Empirical Steering Guidelines (RESG). RESULTS: During period I (second and third treatment of the series) similar results were found for HGS and RESG with a slight, non-significant difference found in favour of HGS. The average temperature T50 was 40.3 degrees C for both (p = 0.409) and the dose parameter CEM43T90 was 0.64 for RESG and 0.63 for HGS (p = 0.154). However, during period II (fourth and fifth treatment of the series) HGS performed less well, with significant lower thermal dose parameters, minimum, mean and maximum intraluminal temperatures, tolerance measures and net integrated power. T50 was 40.4 degrees C after RESG and 40 degrees C after HGS (p = 0.001) and CEM43T90 0.57 and 0.38 (p = 0.01) respectively. CONCLUSION: We found that the procedure of online treatment planning guided steering is feasible. For maximal exploitation of its possibilities, however, better control and understanding of several patient, tumour and technical parameters is required. This study has been very helpful in identifying some of the challenges and flaws that warrant further investigation in the near future, such as patient positioning and the prevention of hotspot-related complaints.

Mentalizing impairment as a mediator between reported childhood abuse and outcome in nonaffective psychotic disorder.

Reported childhood abuse has been linked to the severity of clinical symptoms and social dysfunction in non-affective psychotic disorder. Impaired mentalizing ability may be one of the mechanisms accounting for this effect. This study examined whether impaired mentalizing mediates the effect of reported childhood abuse on positive symptoms, negative symptoms, and social dysfunction. Eighty-seven patients with non-affective psychotic disorder were examined. Reported childhood abuse was measured using the Childhood Experience of Care and Abuse interview. Additionally, the Social Functioning Scale and the Positive and Negative Syndrome Scale were used. The Hinting Task was used to measure mentalizing impairment. Reported childhood abuse was significantly related to the severity of positive and negative symptoms, not to social dysfunction. Reported childhood abuse was also related to mentalizing impairment. Mentalizing impairment was related to negative symptoms, but not to positive symptoms or social dysfunction. Mentalizing impairment accounted for 40% of the association between reported childhood abuse and negative symptoms, indicating partial mediation. A sensitivity analysis revealed that the mediating effect was only observed in those who reported fairly severe childhood abuse.

A birth cohort analysis of AIDS in Europe: high incidence among young persons at risk.

OBJECTIVES: To study trends in AIDS incidence in Europe by age and year of birth. DESIGN: Age-period-cohort analyses were adopted to distinguish the different time factors of calendar year, age and year of birth. METHODS: Non-aggregate AIDS incidence data from 12 European countries (1978-1994) were adjusted for reporting delay and expressed per unit of population (per 100000 persons or 100000 person-years). Age-specific incidence patterns (absolute level and rate of increase) were compared between 5-year birth cohorts for homo-/bisexual men, injecting drug users (IDU) and heterosexual contact cases. RESULTS: Mean age at diagnosis increased strongly amongst IDU, but less so among homo-/bisexual men and heterosexual contact cases. Of a total 110646 reported cases (116311 after adjustment for reporting delay), 87167 (78.8%) were among people born in 1950-1974 [91951 (79.1%) after adjustment for reporting delay]. The relative impact on specific birth cohorts differed strongly by exposure group. Incidences at age ranges of 20-24 and 25-29 years among cohorts born in 1965 and after were about the same level (homo-/bisexual men, IDU) or higher (heterosexual contact cases) than older birth cohorts when these were in the same age range; rates of increase were less among homo-/bisexual men and IDU, but higher among heterosexuals. There were large differences between counties. CONCLUSIONS: Overall, AIDS incidence among cohorts born in 1965 and after is about the same level (homo-/bisexual men, IDU) or higher (heterosexual contact cases) than older cohorts when these were in the same age range. Rates of increase of AIDS incidence curves suggest reduced HIV transmission amongst the most recent cohorts of homo-/bisexual men and IDU, but among young heterosexuals the epidemic is still expanding.

An age-period-cohort analysis of 50,875 AIDS cases among injecting drug users in Europe.

BACKGROUND: The long average incubation time from HIV infection to AIDS makes it difficult to estimate recent HIV transmission from AIDS incidence data. Age-period-cohort (APC) analysis can separate out the effects of age, calendar time and birth cohort to provide a clearer picture of transmission trends. METHODS: AIDS incidence data from 1981 to 1994 among intravenous drug users (IDU) for 12 Western European countries were used. Yearly incidences per 100,000 population or 100,000 person-years were calculated by age at diagnosis and 5-year birth cohort (1950-1954, 1955-1959, 1960-1964, 1965-1969 and 1970-1974), and corrected for reporting delay. Incidence patterns were compared between birth cohorts and countries. RESULTS: For most countries the impact was greatest on the cohort born 1960-1964. Comparing incidence patterns in the 1965-1969 to 1960-1964 cohorts suggest the epidemic has plateaued at low to intermediate levels in Austria, Greece and the North-Western European countries, and at high levels in France, Italy and Switzerland. For most countries transmission amongst the 1970-1974 as compared to the 1965-1969 cohorts could not be assessed due to small numbers and short follow-up time. In Spain the epidemic was uncontrolled with a high incidence among recent birth cohorts. In Portugal the epidemic was still at an early and expanding phase. CONCLUSIONS: The APC analysis revealed large country differences in the dynamics of the HIV/AIDS epidemic among IDU. Full interpretation of these differences is dependent on information from other sources about the local public health response and trends in drug injecting behaviours. Earlier introduction of the virus and higher prevalence of injecting drug use may explain some of the generally higher incidence in Southern European countries, but the larger part of it is most likely explained by local characteristics of drug users, such as younger age and more frequent sharing of needles and syringes, and a less effective public health response.

Prevalence and correlates of herpes simplex virus type 2 infection: evaluation of behavioural risk factors.

OBJECTIVE: To examine the prevalence and correlates of infection with herpes simplex virus type 2 (HSV-2) among sexually transmitted disease (STD) clinic attenders, we studied the prevalence of antibodies to HSV-2 and their association with risk behaviour. METHODS: Data were collected in a cross-sectional study among STD clinic attenders in Amsterdam. Seropositivity for HSV-2 was determined in 1798 serum samples by means of a monoclonal antibody-blocking enzyme-linked immunoassay. RESULTS: The prevalence of HSV-2 antibodies was higher than expected: 32.3% in a population in which 3% had current genital herpes and 8% gave a history of genital herpes. Of those with HSV-2 antibodies, only 18% had a history of genital herpes. A strong independent association with the presence of HSV-2 antibodies was found for sexual behaviour, more specifically: homosexual orientation, increasing number of years of sexual activity, increasing number of lifetime partners, number of past gonococcal infections, having receptive anal and (or) vaginal contact. CONCLUSION: The presence of HSV-2 antibodies had a strong association with past sexual behaviour and, for both sexes, with receptive anal intercourse. HSV-2 antibodies may be used as a surrogate marker of sexual risk behaviour in comparing different populations over time.

A review of studies on the effects of ultraviolet irradiation on the resistance to infections: evidence from rodent infection models and verification by experimental and observational human studies.

Recent studies on the immunosuppressive effects of ultraviolet radiation (UVR) and the related resistance to infections in rodents and humans are presented. The waveband dependency of trans-to-cis isomerisation of urocanic acid in the stratum corneum and the role of DNA damage in UVR-induced erythema and immunosuppression were investigated to further elucidate the underlying mechanisms. Furthermore, human experimental studies on UVR-induced immunomodulation were performed. It appeared that the doses needed to suppress various immune parameters in humans (e.g. NK activity, contact hypersensitivity) were higher than those needed in experiments in rodents. Still, extrapolation of experimental animal data to the human situation showed that UVR may impair the resistance to different systemic infections at relevant outdoor doses. In observational human studies we aimed to substantiate the relevance of UVR for infections in humans. It was shown that sunny season was associated with a slightly retarded but clinically non-relevant antibody response to hepatitis B vaccination. Furthermore, sunny season appeared to be associated with a small decline in the number of CD4+ T-helper cells in a cohort of HIV-infected persons and a higher recurrence of herpes simplex and herpes zoster in a cohort of renal transplant recipients. However, in a study among young children a higher exposure to solar UVR was associated with a lower occurrence of upper respiratory tract symptoms. As disentangling the effects of UVR from other relevant factors is often impossible in observational studies, concise quantitative risk estimations for the human situation cannot be given at present.

Upsurge of hepatitis A in the Netherlands - early 1998.

Far more cases of hepatitis A were identified in the Netherlands in the first five months of 1998 than in the same period of 1997. In order to investigate the reasons for this upsurge we compared the notified cases of hepatitis A in the first five months

[HIV/AIDS in The Netherlands: improved treatment possibilities necessitate HIV instead of AIDS surveillance]. / HIV/AIDS in Nederland: betere behandelingsmogelijkheden maken HIV- in plaats van aidssurveillance noodzakelijk.

An abrupt decrease of the number of reported new AIDS cases took place in the first half of 1997 in the Netherlands. This decrease was most prominent in homosexual/bisexual men and intravenous drug users, and less conspicuous in heterosexual men and women. The number of heterosexual patients with a non-Dutch nationality even increased compared with the first half of 1996. The most probable explanation of these observations is the introduction of improved treatment possibilities for HIV-infected people starting July 1996, which lead to a longer incubation period. Owing to these developments monitoring the HIV/AIDS epidemic in the Netherlands will depend more and more on HIV status surveillance instead of on registration of new AIDS cases.

[The epidemiology of hepatitis A in the Netherlands, 1957-1998]. / De epidemiologie van hepatitis A in Nederland, 1957-1998.

OBJECTIVE: To describe the incidence of hepatitis A in the Netherlands, 1957-1997 to find an explanation for the increase in 1998. DESIGN: Descriptive. SETTING: National Institute of Public Health and Environment (RIVM), Bilthoven, the Netherlands. METHOD: Following an increase of the number of hepatitis A notifications in 1998 the national notification data over the period 1957-1997 were examined. The impact of waning natural immunity in the Dutch population and of the annual influx from high-endemic countries on the epidemiology of hepatitis A was studied. RESULTS: The number of notifications declined considerably in the early sixties and stabilised in the seventies at 5-7 notifications per 100,000 inhabitants. The age distribution over time showed that the proportion of cases in children is still the largest, although the proportion of notifications of adult cases increased slightly over time. A seasonal fluctuation was demonstrated by a steep increase in the number of notifications among non-Dutch children in autumn, with the infection acquired abroad, probably in Morocco or Turkey, followed by an increase among children and adults who acquired their infection in the Netherlands. The number of notifications doubled in the early months of 1998 compared with 1997. The present epidemic increase can be explained by increased transmission in subgroups who contributed similarly in the same months in the past 5 years and may result from secondary infections related to the relatively high peak in autumn in 1997. CONCLUSION: In 1975-1997 a stable but low incidence of hepatitis A was observed in the Netherlands; the number of cases among adults did not increase over time. The present epidemic increase underlines the potential risk of epidemics and the role of importation of the virus from high-endemic countries.

[AIDS epidemic in The Netherlands: current developments in transmission route, age and nationality]. / AIDS-epidemie in Nederland: recente ontwikkelingen naar transmissieroute, leeftijd en nationaliteit.

OBJECTIVE: To document the recent developments in the course of the AIDS epidemic in the Netherlands, 1982-1995. DESIGN: Descriptive. SETTING: National Institute of Public Health and Environment, Bilthoven, Municipal Health Service, Amsterdam, and Inspectorate of Public Health, Rijswijk, the Netherlands. METHOD: Based on the new AIDS patients reported to the Inspectorate of Public Health, the incidence figures were calculated by risk group (homo/bisexual men, intravenous drug users and heterosexual men and women), by birth cohort defined by 5 successive years of birth, and by nationality, in order to characterise sub-epidemics. RESULTS: Among homo/bisexual men AIDS incidence has been stabilizing in recent years. Among intravenous drug users and heterosexuals incidence continues to rise but at a low level compared with homo/bisexual men. Among homo/bisexual men and intravenous drug users mean age at AIDS diagnosis is rising in conjunction with reduced incidence among young persons born in 1965-1969 when compared with the incidence among persons born in 1960-1964 when at the same age. By contrast, among heterosexuals a decline in mean age at diagnosis is observed and this decline coincides with undiminished rise of incidence among persons born in 1965-1969. Among heterosexual patients an increasing and disproportionate number have the nationality of a sub-Saharan African country. CONCLUSION: Future AIDS incidence among homo/bisexual men and intravenous drug users will probably be lower than it currently is. Regarding heterosexuals the undiminished growth of the number of young AIDS patients and the increasing proportion of patients from abroad make such an assessment more difficult.