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Biomedical subjects

M Kerkhof

Publications and source records attributed to M Kerkhof.

At least 19 recordsLinked to original sources
PubMed2006

The burden of upper gastrointestinal endoscopy in patients with Barrett's esophagus.

BACKGROUND AND STUDY AIMS: Patients with Barrett's esophagus are recommended to undergo regular surveillance with upper gastrointestinal endoscopy, an invasive procedure that may cause anxiety, pain, and discomfort. We assessed to what extent patients perceived this procedure as burdensome. PATIENTS AND METHODS: A total of 192 patients with Barrett's esophagus were asked to fill out questionnaires at 1 week and immediately before endoscopy, and at 1 week and 1 month afterwards. Four variables were assessed: (i) pain and discomfort experienced during endoscopy; (ii) symptoms; (iii) psychological burden, i. e., anxiety, depression and distress levels (Hospital Anxiety and Depression scale, Impact of Event Scale); and (iv) perceived risk of developing adenocarcinoma. RESULTS: At least one questionnaire was returned by 180 patients (94 %), 151 completed all four (79 %). Of all patients, only 14 % experienced the endoscopy as painful. However, 59 % reported it to be burdensome. Apart from an increase in throat ache (47 % after endoscopy versus 12 % before), the procedure did not cause physical symptoms. Patients' anxiety, depression, and distress levels were significantly increased in the week before endoscopy compared with the week after. Patients perceiving their risk of developing adenocarcinoma as high reported higher levels of psychological distress and that the procedure was a greater burden. CONCLUSIONS: Upper gastrointestinal endoscopy is burdensome for many patients with Barrett's esophagus and causes moderate distress. Perception of a high risk of adenocarcinoma may increase distress and the burden experienced from the procedure. The benefits of endoscopic surveillance for patients with Barrett's esophagus should be weighed against its drawbacks, including the short-term burden for patients.

Adenocarcinoma↗
PubMed2006

Does CDX2 expression predict Barrett's metaplasia in oesophageal columnar epithelium without goblet cells?

BACKGROUND: Intestinal metaplasia (Barrett's oesophagus), but not cardiac-type mucosa in columnar-lined oesophagus, is regarded as premalignant. As intestinal metaplasia and cardiac-type mucosa are endoscopically indiscernible, it is difficult to take targeted samples from columnar-lined oesophagus with consequently a risk of having undetected intestinal metaplasia. AIM: To investigate whether the intestinal markers CDX2, MUC2 and villin can predict the presence of undetected intestinal metaplasia in columnar-lined oesophagus. Methods Presence of intestinal metaplasia or cardiac-type mucosa was identified in 122 biopsy sets of columnar-lined oesophagus from 61 patients, collected at two subsequent follow-up upper endoscopies. CDX2, MUC2 and villin expression were determined by immunohistochemistry. RESULTS: All intestinal metaplasia samples (55) were positive for CDX2 and MUC2 and 32 of 55 for villin. CDX2 expression was detected in 23 of 67 (34%) samples with only cardiac-type mucosa. Detection of CDX2 in cardiac-type mucosa increased the likelihood of finding intestinal metaplasia in another biopsy set of columnar-lined oesophagus (odds ratio 3.5, 95% CI = 1.2-10, P = 0.02). MUC2 was positive in 13 of 23 (57%) of CDX2-positive cardiac-type mucosa samples, whereas villin was detected in seven of 23 (30%). CONCLUSIONS: CDX2 expression in cardiac-type mucosa might be able to predict the presence of undetected intestinal metaplasia in columnar-lined oesophagus, and thus may be a putative marker for the presence of intestinal metaplasia in the absence of goblet cells.

Adult↗
PubMed2006

Repeated measurements of mite and pet allergen levels in house dust over a time period of 8 years.

BACKGROUND: Studies of the association between indoor allergen exposure and the development of allergic diseases have often measured allergen exposure at one point in time. OBJECTIVE: We investigated the variability of house dust mite (Der p 1, Der f 1) and cat (Fel d 1) allergen in Dutch homes over a period of 8 years. METHODS: Data were obtained in the Dutch PIAMA birth cohort study. Dust from the child's mattress, the parents' mattress and the living room floor was collected at four points in time, when the child was 3 months, 4, 6 and 8 years old. Dust samples were analysed for Der p 1, Der f 1 and Fel d 1 by sandwich enzyme immuno assay. RESULTS: Mite allergen concentrations for the child's mattress, the parents' mattress and the living room floor were moderately correlated between time-points. Agreement was better for cat allergen. For Der p 1 and Der f 1 on the child's mattress, the within-home variance was close to or smaller than the between-home variance in most cases. For Fel d 1, the within-home variance was almost always smaller than the between-home variance. Results were similar for allergen levels expressed per gram of dust and allergen levels expressed per square metre of the sampled surface. Variance ratios were smaller when samples were taken at shorter time intervals than at longer time intervals. CONCLUSION: Over a period of 4 years, mite and cat allergens measured in house dust are sufficiently stable to use single measurements with confidence in epidemiological studies. The within-home variance was larger when samples were taken 8 years apart so that over such long periods, repetition of sampling is recommended.

Air Pollution, Indoor↗
PubMed2006

Gas cooking, kitchen ventilation, and asthma, allergic symptoms and sensitization in young children--the PIAMA study.

BACKGROUND: Several studies reported inconsistent associations between using gas for cooking and respiratory symptoms or lung function in children. Kitchen ventilation characteristics may modify the relationship between gas cooking and respiratory health. The aim of this study was to investigate the effect of kitchen ventilation (while cooking) on the relationship between gas cooking, combustion product dispersal, and respiratory and allergic outcomes in children. METHODS: Data on respiratory and allergic symptoms and diagnoses were collected by yearly questionnaires in a population of over 3000 children participating in a birth cohort study on development of allergy and asthma. At 4 years of age, a sub-sample of 647 children provided blood samples for antibody testing. Data on gas cooking and kitchen ventilation were collected when the children were 5 years old. Based on these data a model was constructed to determine the chance of accumulation of combustion products (CACP) in the kitchen. RESULTS: No relationship was found between gas cooking and any of the respiratory or allergy outcomes except nasal symptoms. The overall results did not change when the 'CACP' was used as exposure variable instead, while the association for nasal symptoms decreased to borderline significance. CONCLUSION: Our results suggest that gas cooking per se is associated with nasal symptoms in young children and not with the other respiratory symptoms that were investigated. Taking kitchen ventilation characteristics into account did not lead to different conclusions in this population where, according to the classification system, the majority of households using gas for cooking have insufficient kitchen ventilation.

Air Pollution, Indoor↗
PubMed2006

Gas cooking, kitchen ventilation, and exposure to combustion products.

We evaluated a questionnaire-based system for classifying homes into groups with distinctly different chances of accumulating combustion products from cooking appliances. The system was based on questions about type of cooking appliance, type and use of ventilation provisions, and kitchen size. Real-time measurements were made of CO, CO(2), temperature, and water vapor, and passive sampling was performed of nitrogen oxides, over a week-long period in 74 kitchens. During the measurements, inhabitants kept a diary to record appliance use time and use of ventilation provisions. The questionnaire-based and diary-based home classifications for the 'Chance of Accumulation of Combustion Products' (CACP) turned out to agree fairly well. For CO(2) as well as for CO a significant difference between the 'high' and 'low' CACP groups was found for the mean accumulation in the kitchen during cooking of the combustion generated concentrations. These facts are considered to be important experimental evidence of the CACP stratification being valid for our study population. In the homes studied, NO(2) as well as CO concentrations were found to be lower compared with previous studies in The Netherlands. Practical Implications Previous studies on indoor combustion product dispersal conducted in the early- to mid-1980s in the Netherlands showed much higher NO(2) and CO concentrations than the present study. Apparently, the removal of combustion products formed during cooking is more efficient in the (mostly newer) homes that we studied than in the homes studied in the early- to mid-1980s. More detailed knowledge of kitchen situations is needed to improve the CACP model. Future studies can achieve this by using questionnaires on the kitchen situation, diaries and real-time measurements of the combustion products under consideration.

Air Pollution, Indoor↗
PubMed2005

Phenotype definition, age, and gender in the genetics of asthma and atopy.

When studying genetics of complex diseases it is important to have a clearly described and objective phenotype. When drawing conclusions in association studies, age and gender of the population should be considered. Until we know what causes phenotypic differences between males and females and between children and adults, we should try to study longitudinal cohorts with phenotype assessment at different time points and stratify our analyses for gender. To acquire sufficient power for these types of analyses, international collaboration may be the only way to elucidate the intricate, gene-environmental interactions in atopy and asthma in an age- and gender-dependent manor.

Age Factors↗
PubMed2005

La mano de DIOS...was the PIAMA intervention study intervened upon?

The PIAMA study evaluates whether application of mite impermeable mattress covers reduces exposure to mite allergen sufficiently to reduce the incidence of asthma and mite allergy. The study started in 1996. Baseline measurements of mite allergen levels were conducted on mattresses of newborn children and their parents, mostly in 1997. Mite allergen levels were surprisingly low in this study compared with previous studies among school children and infants. Mite allergen levels were measured again on mattresses in the PIAMA study in the years 2000/2001 when the children were 4 years old, and in a new study among 6-12 year old school children conducted in the fall of 2001. Data on winter climate were collected as well. In the winters of 1995/1996 and 1996/1997, which preceded and coincided with the PIAMA baseline measurements, temperatures had been extremely low, and precipitation had been extremely low as well. It is likely that these unusual winter weather conditions affected the baseline allergen levels in the PIAMA study so that the effect of the planned intervention (mite impermeable mattress covers) was considerably smaller than it could have been.

Antigens, Dermatophagoides↗
PubMed2005

Exhaled nitric oxide in 4-year-old children: relationship with asthma and atopy.

Airway inflammation is an early feature of asthma. Early detection and anti-inflammatory treatment may have important therapeutic impact. Exhaled nitric oxide is a noninvasive marker of airway inflammation. The current study investigated the association between exhaled nitric oxide and asthma, wheezing phenotypes, atopy and blood eosinophilia in a large group of 4-yr-old children from the general population. All children participated in the Prevention and Incidence of Asthma and Mite Allergy study, a birth cohort study of high-risk (atopic mother) and low-risk children in the Netherlands. Nitric oxide levels were successfully determined in 429 children. Although there was overlap in the distribution of values of children with and without asthma or atopy, mean values were higher in children with atopy or doctor's diagnosed asthma (geometric mean (ppb) 9.4 and 10.0, respectively) as compared to those without (7.7 and 7.9). Values were highest in atopic symptomatic children. Values were not associated with wheezing phenotype or blood eosinophilia. This study is one of the few large-scale epidemiological studies among 4-yr-old children from the general population showing that children with symptoms of asthma and atopy have higher levels of exhaled nitric oxide than those without.

Asthma↗
PubMed2003

Role and interpretation of total serum IgE measurements in the diagnosis of allergic airway disease in adults.

BACKGROUND: While total IgE measurements are often used in clinical practice, it is unclear how they should be interpreted for the diagnosis of allergic disorders. We studied whether total IgE may be used to rule out or predict sensitization and whether there are age or gender differences. METHODS: ROC curves were assessed in subjects with asthma or allergy symptoms from a general population sample. We studied predictive values and likelihood ratios. At least one positive skin test (Phazet) or specific IgE measurement (CAP) served as reference. RESULTS: High negative predictive values, suitable to rule out sensitization, were not found. In younger subjects, high total IgE levels strongly increase the probability of sensitization. The relationship between monosensitization and total IgE was less strong, but meaningful positive likelihood ratios were found at higher levels of total IgE. The discriminating ability of total IgE was better in the age group 20-44 than 45-70 years and comparable in males and females. CONCLUSION: Total IgE is not useful to rule out sensitization to common inhalant allergens. High total IgE may indicate a high probability of sensitization and may be useful to decide whether further investigation is warranted in patients with negative specific allergy tests to a panel of common inhalant allergens.

Adult↗
PubMed2003

Mattress encasings and mite allergen levels in the Prevention and Incidence of Asthma and Mite Allergy study.

BACKGROUND: Reduction of allergen exposure from birth may reduce sensitization and subsequent allergic disease. OBJECTIVE: To measure the influence of mite allergen-impermeable mattress encasings and cotton placebo encasings on the amount of dust and mite allergen in beds. METHODS: A total of 810 children with allergic mothers took part in the Prevention and Incidence of Asthma and Mite Allergy (PIAMA) study. Allergen-impermeable and placebo mattress encasings were applied to the childrens' and the parents' beds before birth. Dust samples were taken from the beds of children and their parents before birth and 3 and 12 months after birth. Extracts of dust samples were analysed for mite allergens (Der p 1 and Der f 1). RESULTS: Active mattress encasings were significantly more effective in reducing dust and mite allergen levels than placebo encasings. Mite allergen levels were low in general and the treatment effect was modest. Twelve months after birth, mattresses with active mattress encasings had about half the amount of Der 1 (Der p 1 + Der f 1)/m2, compared to mattresses with placebo encasings, for the child's and the parental mattress. CONCLUSION: This study shows that mite-impermeable mattress encasings have a significant but modest effect on dust and mite allergen levels of mattresses with low initial mite allergen levels, compared to placebo.

Allergens↗
PubMed2003

Risk factors for atopic dermatitis in infants at high risk of allergy: the PIAMA study.

BACKGROUND: It has been suggested that the period immediately after birth is a sensitive period for the development of atopic disease. OBJECTIVE: We investigated whether birth characteristics and environmental factors are associated with the development of atopic dermatitis in the first year of life. METHODS: Seventy-six children with and 228 without atopic dermatitis, all children of mothers with respiratory allergy or asthma (PIAMA birth cohort study) were included in the study. Atopic dermatitis was defined as a positive history of an itchy skin condition with at least two of the following characteristics: visible dermatitis, history of outer arms/leg involvement, or general dry skin. Multiple logistic regression analysis was performed to study the independent effects of various risk factors. RESULTS: A birth weight >/=4000 g compared to 3000-4000 g was a significant risk factor for atopic dermatitis (odds ratio (OR)=2.4; 95% CI: 1.1-5.1) as was day care attendance (OR=2.9; 95% CI: 1.5-5.9). Exclusive breastfeeding in the first 3 months was negatively associated with atopic dermatitis (OR=0.6; 95% CI: 0.3-1.2), especially with visible dermatitis (OR=0.4; 95% CI: 0.2-1.0). Gender, gestational age, the presence of siblings or pets, and parental smoking were not significantly associated with atopic dermatitis. CONCLUSION: This study shows that a high birth weight and day care attendance increase the risk of atopic dermatitis in the first year of life, while exclusive breastfeeding is a protective factor when dermatitis is found on inspection.

Birth Weight↗
PubMed2003

Allergic sensitization to indoor and outdoor allergens and relevance to bronchial hyperresponsiveness in younger and older subjects.

BACKGROUND: Most previous epidemiological studies on the relationship between allergy and bronchial hyperresponsiveness (BHR) have made no distinction between sensitization to indoor and outdoor allergens. We studied the relationship between specific sensitization to allergen and BHR and further assessed whether this was different in young adults and older subjects. METHODS: Specific IgE to indoor allergens (house dust mite and cat) and outdoor allergens (timothy grass and birch) were measured using the CAP System. BHR was defined as PD20 </= 2 mg methacholine. Multiple logistic regression analysis was performed to study independent relationships between BHR and specific IgE to indoor and outdoor allergens in 1018 young adults (20-44 years) and 909 older subjects (45-70 years). RESULTS: In the older age group specific IgE to indoor allergens was associated with BHR at a lower level (class 2) than in young adults (class >/= 3). Young adults with multiple sensitization had the highest risk of BHR. Subjects who were exclusively sensitized to pollen did not show increased BHR in both age groups. Total IgE had, independently of sensitization, only a significant dose-response relationship with BHR in the oldest age group. CONCLUSIONS: The association between sensitization and BHR is dependent on the nature of the allergen and the level of specific IgE. Furthermore, this study shows for the first time that total IgE is associated with BHR at older ages, independently of sensitization.

Adult↗
PubMed2003

Association of consumption of products containing milk fat with reduced asthma risk in pre-school children: the PIAMA birth cohort study.

BACKGROUND: Environment and lifestyle contribute to the development of asthma in children. Understanding the relevant factors in this relationship may provide methods of prevention. The role of diet in the development of asthma in pre-school children was investigated. METHODS: Data from 2978 children participating in a prospective birth cohort study were used. Food frequency data were collected at the age of 2 years and related to asthma symptoms reported at the age of 3 years. RESULTS: The prevalence of recent asthma at age 3 was lower in children who consumed (at age 2) full cream milk daily (3.4%) than in those who did not (5.6%) and in those who consumed butter daily (1.5%) than in those who did not (5.1%). The prevalence of recent wheeze was lower in children who consumed milk products daily (13.7%) than in those who did not (18.4%) and in children who consumed butter daily (7.7%) than in those who did not (15.4%). These effects remained in a logistic regression model including different foods and confounders (adjusted odds ratio (CI) for recent asthma: full cream milk daily v rarely 0.59 (0.40 to 0.88), butter daily v rarely 0.28 (0.09 to 0.88)). Daily consumption of brown bread was also associated with lower rates of asthma and wheeze, whereas no associations were observed with the consumption of fruits, vegetables, margarine, and fish. CONCLUSIONS: In pre-school children, frequent consumption of products containing milk fat is associated with a reduced risk of asthma symptoms.

Animals↗
PubMed2002

Early respiratory and skin symptoms in relation to ethnic background: the importance of socioeconomic status; the PIAMA study.

AIMS: To evaluate ethnic differences in the prevalence of respiratory and skin symptoms in the first two years of life. METHODS: A total of 4146 children participated in the Prevention and Incidence of Asthma and Mite Allergy (PIAMA) study. Parents completed questionnaires on respiratory and skin symptoms, ethnic background, and other potential confounders during pregnancy, and at 3 months, 1 year, and 2 years of age. RESULTS: In the first year, "non-Dutch" children (compared with "Dutch" children) had a higher prevalence of runny nose with itchy/watery eyes (11.0% versus 5.0%). In the second year, a higher prevalence of wheeze at least once (26.7% versus 18.5%), night cough without a cold (24.6% versus 15.5%), runny nose without a cold (34.1% versus 21.3%), and runny nose with itchy/watery eyes (13.7% versus 4.6%) was found. Adjustment for various confounders, especially adjustment for socioeconomic factors, reduced most associations between ethnicity and respiratory symptoms. Only runny nose with itchy/watery eyes in the second year of life was independently associated with non-Dutch ethnicity (adjusted odds ratio 2.89, 95% CI 1.3-6.4). CONCLUSIONS: Non-Dutch children more often had respiratory symptoms in the first two years of life than Dutch children. This could largely be explained by differences in socioeconomic status. Follow up of the cohort will determine whether this higher prevalence of respiratory symptoms in children with non-Dutch ethnicity represents an increased risk of developing allergic disease rather than non-specific or infection related respiratory symptoms.

Adult↗
PubMed2001

Are children at high familial risk of developing allergy born into a low risk environment? The PIAMA Birth Cohort Study. Prevention and Incidence of Asthma and Mite Allergy.

BACKGROUND: A family history of allergy, reflecting genetic risk factors, increases the risk of developing allergic diseases, but environmental factors, especially those present in early life, also contribute to the actual development of allergic phenomena. OBJECTIVE: To identify differences in lifestyle between allergic and non-allergic parents, which may influence the prevalence of environmental risk factors in their homes. METHODS: Data were collected in a Dutch birth cohort study by postal questionnaire about 2 months before and 3 months after the birth of the child. RESULTS: Of the 3147 infants in the study 1910 (61%) had two non-allergic parents, of 315 infants (10%) only the mother was allergic, of 787 infants (25%) only the father was allergic and 135 (4%) infants had two allergic parents. If both parents were allergic, 53% reported that allergy was taken into consideration when they furnished their home and significantly more of their homes were free of cats and free of cigarette smoke; adjusted odds ratio's for two allergic parents vs. two non-allergic parents were 0.30 (confidence interval (CI) 0.17-0.50) for the presence of cats and 0.46 (CI 0.27-0.75) for smoking in the home. Parental allergy was also associated with having a smooth floor in the baby's bedroom and with postponement of the introduction of fruits and vegetables until the age of 26 weeks. The presence of dogs at home, the prevalence of mothers' smoking during pregnancy and the decision to breast feed were unrelated to parental allergy. CONCLUSION: We conclude that studies on the relationship between allergy in parents and allergy in their offspring should always consider the home environment as a potential confounder. For allergy prevention our results imply that among allergic parents there is awareness and willingness to take measures that reduce exposure to indoor allergens.

Animals↗
PubMed2001

Respiratory infections in infants: interaction of parental allergy, child care, and siblings-- The PIAMA study.

OBJECTIVE: To investigate the association between contacts with other children and the development of respiratory infections in the first year of life in children with or without genetic predisposition for allergy. METHODS: Children (n = 4146) who participate in a prospective birth cohort study (Prevention and Incidence of Asthma and Mite Allergy study) were investigated. Questionnaires were used to obtain information on doctor-diagnosed upper respiratory tract infection (URTI) and lower respiratory tract infection (LRTI), child care attendance, having siblings, family history of allergic disease, and various potential confounders. RESULTS: Child care attendance in the first year of life was associated with doctor-diagnosed URTI (adjusted odds ratio [AOR]: 2.7; 95% confidence interval [CI]: 2.1-3.4 for large child care facility vs no child care) and doctor-diagnosed LRTI (AOR: 5.6; 95% CI: 3.9-7.9). Having siblings was associated with doctor-diagnosed LRTI (AOR: 2.6; 95% CI: 2.0-3.4). In addition, children who have allergic parents and attend child care or have older siblings have a higher risk of developing doctor-diagnosed LRTI than do children who have nonallergic parents. CONCLUSIONS: Child care attendance or having siblings increases the risk of developing doctor-diagnosed LRTI in the first year of life to a greater extent in allergy-prone children than in children who are not allergy prone.

Adult↗
PubMed2000

The association of sensitization to inhalant allergens with allergy symptoms: the influence of bronchial hyperresponsiveness and blood eosinophil count.

BACKGROUND: We investigated whether the association of allergy symptoms with sensitization to inhalant allergens depends on bronchial hyperresponsiveness, blood eosinophil count, or the degree and nature of sensitization. METHODS: Data on asthma and rhino-conjunctivitis symptoms were obtained from 1904 subjects from a random sample of the Dutch population, aged 20-70 years by the ECRHS questionnaire. Total IgE and specific IgE to four inhalant allergens were measured using CAP System. Bronchial hyperresponsiveness (BHR) was defined as PD20 </= 2 mg methacholine and 'high eosinophil count' as an eosinophil count in the highest quartile. RESULTS: Forty-three percent of the subjects with specific IgE to inhalant allergens was asymptomatic. These subjects had a lower degree of sensitization than symptomatic sensitized subjects and had 'normal' prevalences of BHR and 'high eosinophil count'. Logistic regression showed that the presence of BHR increased the risk of having symptoms for subjects who were sensitized to indoor allergens. Low levels of specific IgE to indoor allergens were only associated with symptoms when BHR was present. Sensitization to outdoor allergens was associated with symptoms at all levels of specific IgE, independently of BHR or eosinophils. CONCLUSION: Our epidemiological data suggest that whether low levels of specific IgE to indoor allergens lead to allergic symptoms is probably determined by the concurrent existence of inflammation of the airways.

Administration, Inhalation↗