A Descriptive Mixed-Methods Analysis of Sexual Behavior and Knowledge in Very Young Children Assessed for Sexual Abuse: The ASAC Study.

Child sexual abuse (CSA) is a worldwide problem with serious consequences. We hypothesized that worrisome sexual behavior and knowledge would frequently be reported in children assessed after CSA. We therefore investigated (A) what types of sexual behaviors and knowledge were reported by parents of young children assessed for CSA; (B) in what cases such behaviors and knowledge were worrisome; and (C) how such children responded verbally and non-verbally during child interviews. We conducted a mixed-methods study, including qualitative inductive content analysis and quantitative analysis. It included 125 children (76 boys, 60.8%; median age 3.3 years, age range 0-11), all involved in the Amsterdam sexual abuse case (ASAC) and examined for highly suspected (n = 71) or confirmed CSA (n = 54). We identified themes from (1) the parent reports: sexual behavior (e.g., self-stimulation, touching others, imitation of sexual acts), fears and anxiety with regard to sexuality, and sexual utterances (sexual slang, references to sexual acts); and (2) the child interviews: behavioral reactions (avoidance, distractive behaviors), emotional reactions (anger, aggression), and verbal reactions (conspicuous utterances, refusal to talk about specific subjects). In 37% of the children the sexual behavior was deemed worrisome or very worrisome. Clinicians who assess children for CSA are advised to focus in particular on sexual behavior problems and inappropriate sexual knowledge.

Psychosocial symptoms in very young children assessed for sexual abuse: A qualitative analysis from the ASAC study.

Child sexual abuse (CSA) is a worldwide problem with serious consequences. No recognizable symptom pattern for suspected CSA has yet been identified in very young children. We aim to investigate psychosocial symptoms in a sample of children with confirmed or strongly suspected CSA and the interpretations given to such symptoms by independent clinical experts. Secondly we examined whether experts were able to identify confirmed victims of severe CSA. A qualitative study including inductive content analysis of medical files and focus group discussions with independent experts on the interpretation of psychosocial symptoms was conducted. We included 125 children (76 boys, 60.8%, and 49 girls, 39.2%; median age 3.3 years; age range 0-11) who were involved in the Amsterdam sexual abuse case (ASAC) and had been examined for strongly suspected CSA. We identified four themes among the psychosocial symptoms: problems concerning emotions, behavior, toilet training, and development, whether or not associated with the daycare center or the perpetrator. Clinical experts identified signs of posttraumatic stress disorder (PTSD), regression in continence skills (not otherwise explained), and problems triggered by exposure to the perpetrator or the abuse location as concerning symptoms for CSA. Less concerning symptoms were designated as worrisome if they were numerous and there was no clear explanation for these symptoms. A clear symptom pattern was lacking and about half of the confirmed severe victims of CSA did not display any psychosocial problems. Therefore, it is difficult for experts to identify confirmed CSA victims. Thus, the assessment of suspected CSA should be over time and multidisciplinary.

[Increased proportion of elementary school children with asthmatic symptoms in the Netherlands, 1984/85-1994/95; a literature review]. / Toegenomen percentage basisschoolkinderen met astmatische klachten in Nederland, 1984/'85-1994/'95; een literatuuronderzoek.

OBJECTIVE: To investigate whether the prevalence of asthmatic symptoms among children in the Netherlands has changed. DESIGN: Literature study. METHOD: Investigations into the prevalence of children with asthmatic symptoms were collected from Medline, Embase and various libraries if they had been performed between 1984/'85 and 1994/'95 and had used the so-called WHO or Region list. 23 studies were selected with data on 76,353 elementary school pupils. Linear regression analysis, weighed for the number of children, was used to determine if the proportions of children with asthmatic symptoms had increased over the years. RESULTS: In 10 years the prevalence of recent shortness of breath had increased by 107% (from 4.16 to 8.63%), that of recent wheeze by 16% (from 10.64 to 12.35%), that of recent attacks of breathlessness with wheezing by 17% (from 5.29 to 6.19%), and for chronic cough by 259 (from 1.05 to 3.77%) to 272% (from 3.14 to 11.68%). The prevalence of doctor-diagnosed asthma had increased by 120% (from 2.82 to 6.19%). CONCLUSION: There had been a pronounced increase in the percentage of primary schoolchildren with asthmatic symptoms between 1984/'85 and 1994/'95. The prevalence of doctor-diagnosed asthma increased faster then did key symptoms of asthma.

[House dust mite allergens and COPD in children; a case-control study]. / Huisstofmijtallergeen en CARA bij kinderen; een patiënt-controleonderzoek.

OBJECTIVE: To determine the relationship between mite allergen (Der p I) concentrations in house dust and presence of chronic respiratory symptoms in children. DESIGN: Case control study. SETTING: The provinces of Gelderland and North-Holland in the Netherlands. METHOD: Questionnaires were handed to pupils of 38 schools to take home; about 6000 were returned (80% response). A home visit was paid to 259 children with chronic respiratory symptoms ('cases') and to 257 symptom-free 'control' children. Using an enzyme immunoassay the Der p I concentrations of living room floor dust, bedroom floor dust and mattress dust were determined. Specific IgE was determined in serum. RESULTS: Der p I concentrations higher than 2000 ng/g were found in 86% of the dwellings and concentrations higher than 10,000 ng/g in 55%. Cases were exposed to lower Der p I concentrations than controls. However, cases sensitised to dust mites were exposed to higher Der p I concentrations than non-sensitised cases, both living in homes where no allergen avoidance measures had been taken in the past. CONCLUSION: Exposure to Der p I in the home was associated with sensitisation to dust mites in children with chronic respiratory symptoms living in homes where no allergen avoidance measures had been taken.

[Travel advice on the prevention of infectious diseases insufficiently obtained by indigenous and non-native inhabitants of Amsterdam, the Netherlands]. / Onvoldoende bereik van reizigersadvisering over infectieziektepreventie onder autochtone en allochtone Amsterdammers.

OBJECTIVE: To determine the travel behaviour of inhabitants of Amsterdam, the Netherlands, with respect to age and ethnicity, as well as the impact of travel advice, in particular regarding hepatitis A vaccination of Turkish and Moroccan children. DESIGN: Descriptive. METHOD: In a sample of 2000 inhabitants of Amsterdam, a survey was carried out during the period October 1999-November 2000 on seeking medical advice prior to travelling. In addition, 429 Turkish and Moroccan parents were questioned about hepatitis A vaccination of their children when travelling to their country of origin. RESULTS: In the three years preceding the survey one third of the Amsterdam population travelled to a country where infectious diseases such as malaria and hepatitis A were endemic. Many travellers (18%) went to Asia, Central or Latin America and Africa. Others (12%) travelled to the Middle-East or North Africa. One third of the travellers had sought advice from the Municipal Public Health Service of Amsterdam. Other travellers were advised by their general practitioner (10%). A large group (38%) did not seek any advice at all. Almost one third of the travellers went to their country of origin, particularly Turkish and Moroccan inhabitants of Amsterdam. Seventy percent of Turkish and Moroccan travellers had not sought travel advice. More than half the Turkish and Moroccan parents did not have their children vaccinated against hepatitis A when travelling to their country of origin. CONCLUSION: One fifth of the indigenous Dutch population received no travel advice. More than half of Turkish and Moroccan children travelling to their country of origin were not vaccinated against hepatitis A.

Obesity and cardiovascular disease risk among Turkish and Moroccan migrant groups in Europe: a systematic review.

Migrants from Turkey and Morocco are among the largest ethnic minority groups in several European countries. In this review, we aimed to systematically search, assess and describe the available literature on cardiovascular disease (CVD), obesity and other endogenous cardiovascular risk factors among these groups. Although the number of publications covering this topic among Turkish and Moroccan migrants has increased in the past decades, studies among these groups, especially the Moroccan, are still limited. There is a particular lack of information on CVD mortality and morbidity rates. Furthermore, studies are often hampered by low participation rates, small sample sizes and self-reported data. This further complicates drawing sound conclusions on CVD and risk factors among these migrant groups. The results with regard to CVD morbidity and mortality rates are inconclusive. With regard to CVD risk factors, we tentatively conclude that obesity and diabetes are more common among Turkish and Moroccan migrant groups in Europe than the western European population. In the Turkish population there is also a fair amount of evidence for unfavourable high-density lipoprotein cholesterol levels. However, more research on this topic among these major ethnic minorities is of high importance.

Psychometric properties of an interviewer-administered version of the Kessler Psychological Distress scale (K10) among Dutch, Moroccan and Turkish respondents.

The Kessler Psychological Distress scale (K10) is an instrument that is widely used to screen for mental disorders, but information is lacking on its psychometric qualities in non-Western samples. This study used a population-based sample (N = 725) to assess the reliability and validity of the K10 across ethnic groups in an urban area. The results were generally supportive of the K10 as a reliable and valid instrument to screen for anxiety and depression in all three groups. Cronbach's alpha was high (0.93) and the results indicated the existence of a solid single factor structure. Item bias in relation to ethnic background was minor. In each group, there was good criterion validity with respect to one-month DSM-IV diagnosis for depressive and/or anxiety disorder. The results nevertheless highlight the importance of cross-cultural validation, as we found different cut-off values for ethnic subgroups to obtain optimal sensitivity and specificity for detecting depressive and/or anxiety disorders.

Health risk assessment of fungi in home environments.

LEARNING OBJECTIVES: Reading this article will enable the readers to recognize the public health importance of fungi in the home environment. In view of the recognized impact of fungi on human health, the large population being exposed to fungi, and the large population risk for developing allergic diseases, there is a need to establish guidelines for allowable exposure to fungi based on a health risk assessment. The aim of this study was to evaluate the status of the data on the relationship between exposure to fungi in the home environment and allergic health effects with respect to the development of such guidelines. DATA SOURCES: The past 10 years of peer-reviewed literature focused on the relationships between respiratory disease and exposure to fungi in indoor environments was examined, Indexing terms included mold, fungi, allergy, asthma, and indoor environment, among others. Each study was evaluated on the following criteria: aim and design of the study, methods for assessing exposure and health effects, and data analysis. STUDY SELECTION: Nine population based studies were identified that examined the relationship between allergy and the presence of fungi in the home environment. These studies included quantitative measures of fungal presence in either air or dust. RESULTS: One or more positive associations were found between fungal levels and health outcomes in seven of the nine cross-sectional studies identified. CONCLUSIONS: Despite these positive associations it remains impossible to set guidelines for fungi in home environments based on health risk assessment. This is in part because of the cross-sectional study designs, and inconsistency and inadequate validation of the measures used to evaluate exposure and health effects. Future research designed to generate data that can be used for the development of health risk assessment based guidelines for fungi in home environments should focus on susceptible populations, and use measures that accurately represent exposure and adverse health effects.

Residential indoor air contamination by screen printing plants.

The presence of organic solvents was investigated by means of environmental monitoring of the indoor air during one workweek in each of ten selected small screen printing plants and the houses surrounding them in the inner city of Amsterdam. In the indoor air of the screen printing plants, 14 to 17 organic solvents were identified. The concentrations of the identified organic solvents varied widely from sampling location and period. In the indoor air of the houses situated above the plants, zero to fifteen organic solvents were identified. The concentration of organic solvents in the indoor air of the houses situated above was related to the type of construction materials. The highest concentrations were found in the houses situated above moderately maintained screen printing plants with wooden floors and ceilings (n = 5). The concentration of organic solvents in the indoor air of the houses situated above well maintained screen printing plants with wooden floors and ceilings (n = 3) was much smaller, while the plants situated in concrete new buildings (n = 2) were not a source of organic solvents. The calculated effect specific exposure index (EI), assuming an additive effect and based on the effect specific limit values (ESLVs) for two critical effects [irritation mucous membranes and (pre) narcotic effects] exceeded unity in one workroom in two of the screen printing plants. The calculated EIs for the residents of the houses on the first floor, based on the same ESLVs, but adjusted to potential continuous exposure and interindividual differences in susceptibility, did not exceed unity. However, episodes of irritation of mucous membranes and (pre) narcotic effects may occur.

Mite antigen in house dust: relationship with different housing characteristics in The Netherlands.

As part of a case-controlled study on the relationship between home dampness and respiratory symptoms of children, the concentration of the major allergen of Dermatophagoides pteronyssinus (Der p I) in floor dust and mattress dust in 516 dwellings in the Netherlands was measured. A checklist, completed by the investigators, was used to obtain information on home and occupant characteristics, which may have an impact on the Der p I concentration in house dust. The geometric mean mite antigen concentrations were 2370 ng Der p I/g floor dust for the living room, 2201 ng Der p I/g floor dust for the bedroom and 5075 ng Der p I/g mattress dust. In 86% of the houses the maximum concentration was higher than 2000 ng Der p I/g dust, that is regarded as representing a risk for genetically predisposed individuals for the development of specific IgE to house dust mite allergen. In 55% of the houses the maximum concentration exceeded 10,000 ng Der p I/g dust, regarded as a risk factor for acute attacks of asthma for mite allergic patients. The Der p I concentrations in dust from carpeted floors were six to 14 times higher than in dust from floors with a smooth floor covering. Higher Der p I concentrations in floor dust were also significantly associated with increasing age of the dwelling and of the floor covering, with an increasing number of occupants, and with the absence of floor insulation. For mattress dust, the age of the mattress, the presence of an outer cavity wall and mechanical ventilation were important factors. Older mattresses had higher levels, and mattress dust from bedrooms with solid brick outer walls had higher levels than that from bedrooms with outer cavity walls. Mattresses in homes with continuous mechanical ventilation had almost twice lower levels than mattresses in homes with natural ventilation. There was a tendency towards higher Der p I concentrations in dust in homes with reported or observed signs of dampness. The Der p I concentrations in dust from carpeted bedroom floors and mattresses were positively associated with the average relative humidity in the bedroom over a period of 3-6 weeks in a subset of the homes where relative humidity was measured. Similar results were obtained using the concentrations of Der p I in ng/m2 instead of ng/g dust. The results obtained in this study are of importance for planning and evaluating allergen avoidance measures advised to mite allergic patients.

House dust mite allergen (Der p I) and respiratory symptoms in children: a case-control study.

The association between house dust mite allergen in house dust and childhood respiratory symptoms was investigated in a case-control study of 259 children with reported chronic respiratory symptoms and 257 control children without reported respiratory symptoms. The Der p I concentration in floor dust of the living room and bedroom and in mattress dust was determined using an enzyme immunoassay. Venous blood samples were taken from all children for serum IgE determination against house dust mite (Dermatophagoides pteronyssinus) by radioallergosorbent assay (RAST). A questionnaire was administered to the parents of the children to elicit information about the home, about changes made to the home in the past in relation to respiratory symptoms, and about a number of risk factors for childhood respiratory disease. In 83% of the dwellings of cases and 89% of those of controls, Der p I concentrations higher than 2000 ng/g were found, and in 54% of the dwellings of cases and 57% of those of controls, the concentrations exceeded 10,000 ng/g dust. In a crude analysis, cases were generally exposed to lower Der p I concentrations than controls. Restriction of the analysis to cases sensitized to dust mites, and non-sensitized controls, taking the type of floor covering into account, showed not significantly higher Der p I concentrations in bedroom floor dust of cases. However, restriction of the analysis to cases sensitized to dust mites and cases not sensitized to house dust mites--adjusting for allergen avoidance measures taken in the past--revealed a positive association between the Der p I concentrations in bedroom floor dust and mattress dust and sensitization.(ABSTRACT TRUNCATED AT 250 WORDS)

Air pollution and daily mortality in Amsterdam.

Few data are available on the association between the present low levels of air pollution in Western Europe and mortality. Daily mortality counts and the concentrations of black smoke, inhalable particles (PM10), sulfur dioxide (SO2), carbon monoxide (CO), and ozone (O3) were available for Amsterdam from 1986 to 1992. We used Poisson regression analysis to control for seasonal and other long-term temporal patterns. Black smoke and PM10 were positively associated with increased risk of mortality. The relative risk for a 100-micrograms per m3 increase in black smoke on the same day was 1.19 [95% confidence interval (CI) = 1.02-1.38], and that for a 100-micrograms per m3 increase in PM10 was 1.06 (95% CI = 0.99-1.14). The relative risk for individuals over 64 years of age was higher. We found no consistent association between the levels of SO2 or CO and daily mortality, but ozone lagged 2 days was positively associated with daily mortality. The effect of particulates on acute mortality was independent of these pollutants. The results of the present study are consistent with the relation reported between particulate air pollution and daily mortality in other communities in Europe and the United States.

The exposure of cyclists, car drivers and pedestrians to traffic-related air pollutants.

Volunteers provided with personal air sampling (PAS) equipment covered concurrently, by car or bicycle, various selected routes. These comprised two inner city routes in Amsterdam (ICR 1 and 2) as well as a route including a tunnel on a busy highway (TR) and a rural route just south of Amsterdam (RR). A third inner city route, a busy narrow street, was subsequently also selected, and covered by bicycle or walking (ICR 3). Each run lasted about 1 h; the sampling time on the TR route was approximately 30 min. The sampling periods in January and May lasted 2 weeks with four sampling days per week. In August only ICR 3 was covered, this sampling period lasted 2 days. CO, NO2, benzene, toluene and xylenes were measured in the personal air samples. A monitoring vehicle covered the routes concurrently and measured CO, NO2 and pm10 (semi) continuously. Lead and PAH content in pm10 was determined. The ventilation of the volunteers was measured while they were using a car or a bicycle. The route and the type of transport influenced (P < 0.001) the concentrations of CO, benzene, toluene and xylenes. The daily average temperature was positively associated with the exposure of car drivers and cyclists to most compounds measured. A volunteer exhaled on average 2.3 times more air as a cyclist than as a car driver. Despite the much higher concentrations in the personal air samples of car drivers, the uptake of CO, benzene, toluene and xylenes of cyclists sometimes approached that of the car drivers. The uptake of NO2 of cyclists was clearly higher than that of car drivers.

Damp housing and childhood respiratory symptoms: the role of sensitization to dust mites and molds.

In 1990, a case-control study was conducted in the Netherlands into the association between damp housing, childhood respiratory symptoms, and sensitization to house dust mites and mold allergens. In this study, 259 children with chronic respiratory symptoms and 257 control children were involved. Total serum immunoglobulin E (IgE) and specific IgE against house dust mites and a mixture of molds were determined. A visual inspection for signs of home dampness was performed in all homes. A questionnaire was given to the parents of the children to elicit information about the presence of signs of dampness in the previous 2 years and about risk factors for childhood respiratory disease. In the case group, 94 children had elevated serum IgE levels to house dust mites and 24 children to the mixture of molds. In the control group, house dust mite allergy was found in 31 children and mold allergy in two children. In a crude analysis, cases were slightly more likely to have been living in homes where damp or mold was reported or observed than were the controls. In cases as well as controls, home dampness was associated with increased sensitization to dust mites and molds. There was no relation between home dampness and case-control status after stratification for sensitization, however. Restriction of the analysis to cases with elevated serum IgE levels against dust mites and/or molds, and to controls without elevated serum IgE, increased the odds ratios, and several became significant at p < 0.05. This supports a connection between damp housing and sensitization to dust mites and/or molds and childhood respiratory symptoms.(ABSTRACT TRUNCATED AT 250 WORDS)

Fungal propagules in house dust. I. Comparison of analytic methods and their value as estimators of potential exposure.

The presence of viable mold propagules in house dust was investigated by 10 different analytic methods, in order to determine to what extent different results are obtained when different analytic methods are used. Moreover, the value of this measurement as an estimator of the potential exposure to fungi in epidemiologic studies was assessed. Floor and mattress dust was sampled in 60 homes in The Netherlands during autumn 1990. For investigation of the variability in time, sampling was repeated in 20 homes after 6 weeks. Each analytic method is characterized by a unique combination of culture medium, suspension medium, and dilution step. The highest mean number of colony-forming units (CFU)/g dust was obtained by suspension of at least 100 mg dust in a peptone or sucrose solution in a ratio of 1:50 (w/w), followed by 10-fold dilution and plating on DG18 agar (geometric mean (GM) approximately 60,000 CFU/g dust). The lowest mean number of CFU/g dust was obtained by direct plating of 30 mg dust on V8 agar (GM approximately 5300 CFU/g dust). The mean coefficient of variation of duplicate analyses varied from 11%, for suspension in sucrose and plating on DG18 agar, to 27%, for suspension and dilution in sucrose in combination with V8 agar. The highest mean number of species isolated was obtained by direct plating of 30 mg dust on DG18 agar (mean number of species: 17). Suspension and dilution on DG18 or V8 agars yielded an average of approximately six species. In duplicate analyses, the mean percentage of agreement for the species isolated varied from approximately 35%, for suspension and dilution, to 60%, for direct plating.(ABSTRACT TRUNCATED AT 250 WORDS)

Infant respiratory symptoms in relation to mite allergen exposure.

The relationship between the Dermatophagoides pteronyssinus (Der p) I content of house dust and the respiratory symptoms reported for young infants was studied. One hundred and four infants, aged 3-15 months, were selected during July-September 1993 through the Dutch postnatal health care service, using a short screening questionnaire to identify mothers with respiratory allergy to house dust and/or pets. Forty-eight were selected from this group of mothers ("high risk" infants) and 56 infants were selected when neither of the parents reported allergy or chronic respiratory symptoms ("low risk" infants). All homes were visited in October 1993. Dust samples were collected from the infant's mattress and from other places in the home, and the Der p I content was measured in dust extracts. The results indicate that on more than half of the mattresses, the Der p I level was over 2,000 ng.g-1, the level suggested to be associated with an increased risk of sensitization. Information on respiratory symptoms ("wheeze" and "prolonged cough") experienced since birth was obtained by questionnaire from one of the parents on the dust sampling day. The occurrence of respiratory symptoms in the infants appeared to be positively related to the Der p I concentration of the dust. Although no objective measurements of respiratory symptoms were available, the results of this study suggest that exposure to mite allergen in early life may lead to respiratory symptoms that are suggestive of airway obstruction in the first year of life.

Cockroach allergen in house dust.

The cockroach allergen (Bla g 1) content was determined in the floor dust of 46 homes with recent cockroach extermination in Amsterdam, The Netherlands. IgE antibodies to Blattella germanica, house-dust mite, cat dander, dog dander, and a mixture of molds were determined in venous blood samples of 46 children (4-12 years) and one of their biologic parents (24-54 years). Specific IgE to cockroach was also determined in a sample of the general population studied in a previous case-control study, one group (n = 20) with three groups (n =76) without history of cockroach infestation of the home. Cockroach allergen was detected in floor dust from 44% of the homes, with levels up to 3899 ng Bla g 1/g. Seven of the 46 adults and only one of the 46 children studied had positive RAST to cockroach. Geometric mean cockroach allergen concentrations in living room and master bedroom of sensitized adults were similar to those of nonsensitized adults. In the groups of children without a history of cockroach infestation of the home, positive RAST against cockroach was observed in 16% of the children with respiratory symptoms, in 4% of the children without respiratory symptoms, and in 48% of the children with two or more positive RAST to other allergens. Of the 18 children with positive RAST against cockroach, only one had a history of cockroach infestation of the home and 16 (89%) had also positive RAST against house-dust mite.

Detecting indoor CO exposure by measuring CO in exhaled breath.

CO levels in exhaled breath were measured in 29 residents of flats, equipped with a flueless geiser (an instantaneous gas-fired water heater). The flats were selected because they had a geiser with a CO concentration of more than 250 parts per million in its flue gases. Small, but in some cases statistically significant increases in CO levels in exhaled breath were found in both smokers and non smokers, and after periods of cooking and dishwashing when the geisers had been used. Calculated COHb levels remained well below 2.5% for non smokers, but were generally higher for smokers.

Enumeration and identification of airborne viable mould propagules in houses. A field comparison of selected techniques.

A number of techniques for the enumeration and identification of viable mould propagules in the indoor air of houses were evaluated in order to document to what extent different results are obtained when different methods are used. A comparison was made between the results obtained with five commercially available air sampling devices (Slit-to agar sampler, N6-Andersen sampler, Surface Air System sampler, Reuter Centrifugal Air sampler, Gelatine Filter sampler) and a non-volumetric sampler (the Open Petri Dish), in combination with four culture media (malt extract agar, dichloran glycerol-18 agar, oxytetracycline glucose yeast extract agar and dichloran rose bengal chloramphenicol agar). The coefficients of variation were high (generally greater than 20%) for all combinations. Statistical analysis showed that the Slit sampler and the N6-Andersen sampler in combination with DG18 and MEA gave the best precision and the highest yield in terms of colony forming units per square cubic meter of air (CFU/m3) and number of species isolated.

Presence of viable mould propagules in the indoor air of houses.

The aim of the first part of this study was to select the optimal technique for the enumeration and identification of viable mould propagules in the indoor air of houses. A comparison was made between the results obtained with six commercially available air sampling devices in combination with four culture media. The optimal technique was defined as the technique with the best precision and the highest yield. The coefficients of variation were high (generally greater than 20%) for all combinations. Statistical analysis showed that the Slit sampler and the N6-Andersen sampler in combination with DG18 and MEA gave the best precision and the highest yield in terms of CFU/m3 and number of species isolated. In the second part of this study the presence of viable mould propagules in the indoor air of 46 houses in relation to the dampness of these houses was investigated, using the N6-Andersen sampler in combination with DG18. To assess the variability in time, the measurements were repeated after five weeks. Overall, between the two periods no difference was found between the average number of CFU/m3 in the investigated homes. However, the variation between homes was much smaller than the variation within homes. The mean number of CFU/m3 was somewhat higher in "damp" houses than in "dry" houses. However, this difference was not significant. Furthermore, there were no demonstrable differences in the presence of specific mould species in "damp" and "dry" houses.