Endotoxin Levels In House Dust Research Articles

Association between house dust endotoxin and kidney injury: findings from the national health and nutrition examination survey (NHANES) 2005-2006.

House dust endotoxin is thought to be associated with systemic inflammatory responses and respiratory diseases. Previous studies have indicated that lung injury and systemic inflammation could lead to kidney damage. However, the potential link between house dust endotoxin and the increased risk of kidney injury remains unexplored. This cross-sectional study and retrospective study aim to investigate the relationship between house dust endotoxin levels and renal markers, specifically the urinary albumin-to-creatinine ratio (UACR) and estimated glomerular filtration rate (eGFR), utilizing data from the NHANES 2005-2006 survey cycle. Proteinuria was assessed using the UACR, with values categorized into negative (UACR ≤ 30mg/g) and positive (UACR > 30mg/g) groups. Significant differences in house dust endotoxin levels were observed between these groups (p value = 0.003). Weighted logistic regression analysis indicated that higher levels of house dust endotoxin were associated with an increased rate of positive UACR (OR [95% CI]: 1.57 [1.20, 2.05]; p value = 0.003). This association remained significant after adjusting for covariates such as age, gender, race, poverty income ratio (PIR), Type 2 Diabetes Mellitus (T2DM), and hypertension (OR [95% CI]: 1.46 [1.08, 1.97]; p-Value = 0.021). However, no significant correlation was found between house dust endotoxin levels and eGFR (Estimate [95% CI]: 1.19 [-1.28, 3.66]; p value = 0.32). Our findings suggest a significant association between house dust endotoxin levels and proteinuria, based on data from the NHANES 2005-2006 survey cycle. This association indicates that elevated levels of house dust endotoxin may be linked to kidney damage. Further research is necessary to elucidate the specific relationship between exposure to house dust endotoxin and the risk of developing kidney disease.

Endotoxin, Food Allergen Sensitization, and Food Allergy: A Complementary Epidemiologic and Experimental Study

A Tsuang, A Grishin, G Grishina. Allergy. 2020;75(3):625–635 The epidemiologic aspect of the study aimed to describe the association between exposure to house dust endotoxin and sensitization to food allergens, while the experimental component compared the measurement of cytokines secreted from peripheral blood mononuclear cells (PBMCs) after stimulation with endotoxin in allergic and nonallergic children. 6963 participants, ages 1 to 84 years, from the 2005–2006 NHANES were included in the epidemiologic study. Twenty-one children (ages 1–19 years) from pediatric clinics at the Mount Sinai Health System with food allergy to either egg, milk or peanut, and healthy controls were included in the experimental study. Dust endotoxin measurement in the household was …

Can Increased Endotoxin Levels in House Dust be used as an Indicator of a Mould Problem?

Endotoxins are common indoor biocontaminants. Our purpose was to investigate the association of endotoxin content with mould problems in house dust in buildings, to determine whether endotoxins can be used as an indicator of the presence of moulds in buildings. The participants were selected from the Clinic for Indoor Air Health Problems on the basis of symptoms attributed to indoor air problems. We examined their health status. House dust was collected in new vacuum cleaner bags from surfaces in the rooms of their homes or workplaces. We measured the endotoxin concentrations in the house dust of 13 homes and 9 workplaces of the 19 participants, using a quantitative limulus test. The median endotoxin concentrations in the house dust of their homes was 9.9, and the range was 1.9–103 EU/mg; and in the house dust of workplaces it was 4.5, and the range 0.5–81 EU/mg. We found higher house dust endotoxin concentrations in rooms in which moisture problems had been identified or in dwellings in which pets were kept. Our pilot study suggests that endotoxins may be a useful additional tool for estimating possible mould contamination at homes or workplaces.

House Dust Endotoxin Levels Are Associated with Adult Asthma in a U.S. Farming Population.

Endotoxin initiates a proinflammatory response from the innate immune system. Studies in children suggest that endotoxin exposure from house dust may be an important risk factor for asthma, but few studies have been conducted in adult populations. To investigate the association of house dust endotoxin levels with asthma and related phenotypes (wheeze, atopy, and pulmonary function) in a large U.S. farming population. Dust was collected from the bedrooms (n = 2,485) of participants enrolled in a case-control study of current asthma (927 cases) nested within the Agricultural Health Study. Dust endotoxin was measured by Limulus amebocyte lysate assay. Outcomes were measured by questionnaire, spirometry, and blood draw. We evaluated associations using linear and logistic regression. Endotoxin was significantly associated with current asthma (odds ratio [OR], 1.30; 95% confidence interval [CI], 1.14-1.47), and this relationship was modified by early-life farm exposure (born on a farm: OR, 1.18; 95% CI, 1.02-1.37; not born on a farm: OR, 1.67; 95% CI, 1.26-2.20; Interaction P = 0.05). Significant positive associations were seen with both atopic and nonatopic asthma. Endotoxin was not related to either atopy or wheeze. Higher endotoxin was related to lower FEV1/FVC in asthma cases only (Interaction P = 0.01). For asthma, there was suggestive evidence of a gene-by-environment interaction for the CD14 variant rs2569190 (Interaction P = 0.16) but not for the TLR4 variants rs4986790 and rs4986791. House dust endotoxin was associated with current atopic and nonatopic asthma in a U.S. farming population. The degree of the association with asthma depended on early-life farm exposures. Furthermore, endotoxin was associated with lower pulmonary function in patients with asthma.

Slow Salivary Secretory IgA Maturation May Relate to Low Microbial Pressure and Allergic Symptoms in Sensitized Children

It is unknown why allergic symptoms do not develop in all sensitized children. We analyzed prospectively the postnatal secretory IgA (SIgA) development and whether high SIgA levels would protect sensitized infants from developing allergic symptoms. Salivary total IgA and SIgA levels were determined by ELISA, and allergy development was investigated at 3, 6, and 12 mo and at 2 and 5 y in two birth cohorts in Estonia (n = 110) and Sweden (n = 91), two geographically adjacent countries with different living conditions and allergy incidence. Total and SIgA levels increased with age, reaching adult levels at the age of 5. Virtually, all salivary IgA in Estonian children was in the secretory form, while a major part of IgA in Swedish saliva lacked the secretory component up to 2 y of age. In Sweden, high levels of salivary IgA without secretory component correlated inversely with house dust endotoxin levels. High SIgA levels were associated with less development of allergic symptoms in sensitized Swedish children. In conclusion, postnatal maturation of the salivary SIgA system proceeds markedly slower in Swedish than Estonian children, possibly as a consequence of low microbial pressure. SIgA may limit allergy-mediated tissue damage at mucosal surfaces in sensitized individuals.

Levels of endotoxin in 390 Swedish homes: determinants and the risk for respiratory symptoms in children

Endotoxins are microbiological agents which ubiquitously exist in an indoor environment, and are believed to be causal agents for a number of diseases. This study investigated the indoor levels and determinants of endotoxins and their impact on asthma and allergy diseases among Swedish pre-school children. House dust samples from 390 homes of 198 case children with asthma and allergy and 202 healthy control children were collected in the Dampness Building and Health (DBH) study. House dust endotoxin levels in the child's bedroom and living rooms ranged from 479–188,000 EU/g dust and from 138–942,000 EU/g dust, respectively. Pet-keeping and agricultural activities were significantly associated with the higher endotoxin concentration levels in indoor dust. Endotoxins in theindoor environment did not associate to asthma and allergy diseases in the children. However, we found an association between endotoxins and the presence of disease symptoms in the sub-group of families without indoor pets.

The Urban Environment and Childhood Asthma (URECA) birth cohort study: design, methods, and study population.

BackgroundThe incidence and morbidity of wheezing illnesses and childhood asthma is especially high in poor urban areas. This paper describes the study design, methods, and population of the Urban Environment and Childhood Asthma (URECA) study, which was established to investigate the immunologic causes of asthma among inner-city children.Methods and ResultsURECA is an observational prospective study that enrolled pregnant women in central urban areas of Baltimore, Boston, New York City, and St. Louis and is following their offspring from birth through age 7 years. The birth cohort consists of 560 inner-city children who have at least one parent with an allergic disease or asthma, and all families live in areas in which at least 20% of the population has incomes below the poverty line. In addition, 49 inner-city children with no parental history of allergies or asthma were enrolled. The primary hypothesis is that specific urban exposures in early life promote a unique pattern of immune development (impaired antiviral and increased Th2 responses) that increases the risk of recurrent wheezing and allergic sensitization in early childhood, and of asthma by age 7 years. To track immune development, cytokine responses of blood mononuclear cells stimulated ex vivo are measured at birth and then annually. Environmental assessments include allergen and endotoxin levels in house dust, pre- and postnatal maternal stress, and indoor air nicotine and nitrogen dioxide. Nasal mucous samples are collected from the children during respiratory illnesses and analyzed for respiratory viruses. The complex interactions between environmental exposures and immune development will be assessed with respect to recurrent wheeze at age 3 years and asthma at age 7 years.ConclusionThe overall goal of the URECA study is to develop a better understanding of how specific urban exposures affect immune development to promote wheezing illnesses and asthma.

Asthma and allergic symptoms in relation to house dust endotoxin: Phase Two of the International Study on Asthma and Allergies in Childhood (ISAAC II)

Several studies have consistently reported inverse associations between exposure to endotoxin in house dust and atopy. With regard to the association between house dust endotoxin and asthma, the results are inconsistent. To study the association between house dust endotoxin levels and respiratory symptoms and atopy in populations from largely different countries. Data were collected within the International Study on Asthma and Allergies in Childhood Phase Two, a multi-centre cross-sectional study of 840 children aged 9-12 years from six centres in the five countries of Albania, Italy, New Zealand, Sweden and the United Kingdom. Living room floor dust was collected and analysed for endotoxin. Health end-points and demographics were assessed by standardized questionnaires. Atopy was assessed by measurements of allergen-specific IgE against a panel of inhalant allergens. Associations between house dust endotoxin and health outcomes were analysed by logistic regression. Odds ratios (ORs) were presented for an overall interquartile range increase in exposure. Many associations between house dust endotoxin in living room floor dust and health outcomes varied between countries. Combined across countries, endotoxin levels were inversely associated with asthma ever [adjusted OR (95% confidence interval (CI)) 0.53 (0.29-0.96) for endotoxin levels per m(2) of living room floor] and current wheeze [adjusted OR (95% CI) 0.77 (0.64-0.93) for endotoxin levels per gram of living room floor dust]. There were inverse associations between endotoxin concentrations and atopy, which were statistically significant in unadjusted analyses, but not after adjustment for gender, parental allergies, cat and house dust mite allergens. No associations were found with dust quantity and between endotoxin exposure and hayfever. These findings suggest an inverse association between endotoxin levels in living room floor dust and asthma in children.

Opposite effects of CD14/-260 on serum IgE levels in children raised in different environments

Most complex diseases are the result of interactions between polymorphisms in the genome and environmental exposures. We sought to investigate the previously reported association between a polymorphism in the promoter region of CD 14 (CD 14/-260 C-->T) and serum IgE levels in relation to the environment to which children are exposed. In 624 children living in 2 rural communities in Europe, we compared total and specific serum IgE levels between the genotypes of CD 14/-260 in relation to exposure to animals and in relation to house dust endotoxin. We found that the C allele of CD 14/-260 was associated with higher levels of both total and specific serum IgE to aeroallergens in children with regular contact with pets, whereas an association in the opposite direction was found in children with regular contact with stable animals. This modifying effect of animal exposure was not explained by levels of house dust endotoxin. However, in children with high levels of house dust endotoxin, the C allele was associated with less specific IgE, independently from animal exposure. Because CD 14 is a pattern recognition receptor for microbial molecules, the results suggest that the type and concentrations of such molecules present in the environment strongly determine the direction of the association between CD 14/-260 and serum markers of atopy.

Exposure to house dust endotoxin and allergic sensitization in adults.

It has been suggested that exposure to elevated levels of endotoxin decreases the risk of allergic sensitization. To examine the associations between current exposure to bacterial endotoxin in house dust and allergic sensitization in adults. In 1995-1996, we conducted a nested case-control study following a cross-sectional study performed within the European Community Respiratory Health Survey (ECRHS). Data of 350 adults aged 25-50 years was analysed. Allergic sensitization was assessed by measurement of specific immunoglobulin E (IgE) against several inhalant allergens. Living room floor dust samples were taken. The endotoxin content was quantified using a chromogenic kinetic Limulus amoebocyte lysate test. Multiple logistic regression analysis showed a negative association between exposure to house dust endotoxin and severe allergic sensitization. Odds ratios (95% CI) adjusted for place of residence, gender, age, and 'caseness' were 0.80 (0.64-1.00) for sensitization to >/=1 allergen and 0.72 (0.56, 0.92) for sensitization to >/=2 allergens using 3.5 kU/l as a cut-off value for sensitization. With regard to single allergens, the protective effect of endotoxin was strongest for pollen sensitization [aOR (95% CI) = 0.74 (0.58, 0.93)]. Our results indicate that current exposure to higher levels of house dust endotoxin might be associated with a decreased odds of allergic sensitization in adults.

House dust endotoxin exposure mitigates asthma severity in a tropical environment

Rationale Studies have shown exposure to bacterial endotoxin to be associated with asthma severity. Asthma prevalence and morbidity has been increasing disproportionately in tropical, developing countries, where sources of domestic endotoxin, especially humidity, animals in close proximity to humans, and high allergen levels are extreme. To date, no studies have characterized domestic endotoxin exposure in the tropics nor examined the impact of this exposure on asthma. Methods To investigate the relationship between exposure to house dust endotoxin (HDE) and asthma severity in an Afro-Caribbean asthmatic population from Barbados, we measured HDE concentrations in the homes of 87 asthmatic sib-pairs. Asthma severity was assessed using a validated questionnaire that yields a quasi-quantitative Asthma Severity Score. Household characteristics considered to reflect overall household hygiene were assessed and tested for association with HDE concentrations. Results We observed HDE concentrations to be high relative to reports in urban settings in non-tropical environments (mean living room composite=21,061 EU/m 2, range=2649-185,468 EU/m 2). Several household characteristics were positively associated with HDE levels, including carpeting (p=0.01), decreased frequency of vacuuming (p=0.003), and cats in the home (p=0.001). Increasing endotoxin content was associated with decreasing asthma severity scores among skin test negative individuals only (p=0.01). Conclusions HDE levels were high in this tropical environment, but comparable to levels observed in farming populations. Despite early and significant exposure to endotoxin, asthma prevalence is high in this population. The inverse relationship between HDE levels and asthma severity supports the idea that microbial load may be protective and highlights the complex role of HDE in disease expression.

Metropolitan endotoxin exposure, allergy and asthma.

To review the role of metropolitan endotoxin exposure in asthma and allergy, emphasizing recently published articles (i.e. April 2002-June 2003). In infants and toddlers in metropolitan communities, higher endotoxin levels in house dust are associated with less atopy and increased wheezing in infancy, but this increased risk may normalize by age 4 years. Increased endotoxin levels and exposure in metropolitan households with dogs and sometimes cats is intriguing in light of recent studies suggesting that animal exposure early in life is associated with less allergen sensitization and asthma. Dust endotoxin also appears to serve as a marker for other similar innate immune-stimulatory microbial components called pathogen-associated molecular patterns. Pathogen-associated molecular patterns, such as bacterial DNA, may augment and steer endotoxin-initiated immune responses in an immune-regulatory direction. These findings support the premise that the differences in health outcomes from endotoxin exposure are due to important moderating variables, such as age of exposure, timing of exposure relative to disease development, dose and frequency of exposure, co-exposures, and genetic predispositions in response to endotoxin. We will discuss (1) endotoxin's ability to exacerbate established atopic disease and asthma; (2) factors influencing endotoxin levels in metropolitan homes; (3) relationships between endotoxin, pet exposure, and atopic disease; (4) endotoxin's paradoxical potential to both abrogate as well as exacerbate asthma; and (5) endotoxin's role as a marker for other similar pathogen-associated molecular patterns.

EXPOSURE TO HOUSE DUST ENDOTOXIN AND ALLERGIC SENSITIZATION IN ADULTS

Introduction It has been suggested that the decreased prevalence of asthma, hay fever, and atopy associated with farm environments and pet ownership may result from exposure to elevated levels of endotoxin. Rationale: To examine the associations between current exposure to bacterial endotoxin in house dust and allergic sensitization in adults. Methods In 1995–96 we conducted a nested case-control study follwing a cross-sectional study performed in the two German cities of Erfurt and Hamburg within the European Community Respiratory Health Survey (ECRHS). Data of 350 adults aged 25–50 years was analyzed. Allergic sensitization was assessed by measurement of specific Immunoglobuline E (IgE) against several inhalant allergens using the IgE CAP system. House dust was sampled on the living room floors. Endotoxin content was quantified using a chromogenic kinetic Limulus amoebocyte lysate (LAL) test. Results Multiple logistic regression analysis showed a negative association between exposure to house dust endotoxin and severe allergic sensitization. Odds ratios (95 % CI) adjusted for place of residence, gender, age, and ‘caseness’ were 0.80 (0.64; 1.00) for sensitization to at least one allergen and 0.78 (0.64, 0.95) for sensitization to at least two allergens using 3.5 kU/L as a cut-off value for sensitization. With regard to single allergens, the protective effect of house dust endotoxin was strongest for sensitization to pollen [aOR (95 %) = 0.74 (0.58, 0.93)]. Conclusion Our results indicate that exposure to higher levels of house dust endotoxin might be associated with a decreased prevalence of allergic sensitization in adults.

Clothing–Potentially a Significant Source of Endotoxin Exposure

Clothing–Potentially a Significant Source of Endotoxin Exposure

TLR4 gene variants modify endotoxin effects on asthma

Background: Environmental exposure to endotoxin might have a crucial role in immune maturation and development of asthma. Objective: The aim of this study was to investigate whether the effect of endotoxin concentration in settled house dust on asthma is modified by the presence of variation in the TLR4 gene. Methods: We performed a cross-sectional study within the German follow-up of the European Community Respiratory Health Survey. Multivariate logistic regression analysis and nonparametric effect estimates (S-Plus) were applied to examine the association between endotoxin exposure and diagnosed asthma, related clinical symptoms, and bronchial hyperreactivity (BHR) stratified for noncarriers and carriers of G299/I399 polymorphism in the TLR4 gene. Results: In the noncarrier group (n = 279), the prevalence of asthma was significantly increased with elevated endotoxin levels in house dust with adjusted odds ratio 6.24 (95% CI, 1.33-29.17) in the second tertile, and 4.54 (95% CI, 0.94-21.96) in the third tertile compared with the lowest endotoxin tertile. The carriers of the polymorphisms (n = 55) showed a nonsignificant trend to have a lower risk of asthma (crude odds ratio, 0.67; 95% CI, 0.06-8.06 for the second tertile and 1.33; 95% CI, 0.17-10.58 for the third tertile). We found a similar association for wheeze and endotoxin exposure that was also attenuated in subjects with G299/I399 polymorphisms. Conclusions: The G299/I399 polymorphisms were associated with a modified response to endotoxin, but the functional relationship still needs clarification. (J Allergy Clin Immunol 2003;112:323-30.)

The Editors' Choice

The Editors' Choice

Endotoxin levels in Estonian and Swedish house dust and atopy in infancy.

Immune responses, including those to allergens, may be T helper (Th)2 skewed in newborns. In order to redress the fetal Th1/Th2 imbalance, Th1-stimulating factors, such as bacterial endotoxin, may be required. The increasing prevalence and severity of atopic diseases in industrialized countries, which are in marked contrast with the low prevalence of allergy among children in the formerly socialist countries of Europe, have been suggested to be caused by a reduced microbial stimulation. To relate the endotoxin levels in house dust from two countries with a low (Estonia) and a high (Sweden) prevalence of allergy to the development of atopic disease and sensitization in the children during the first 2 years of life. The study included 108 children from Tartu, Estonia and 111 children from Linköping, Sweden. Skin prick tests were performed at 3, 6, 12 and 24 months of age, and questionnaires were distributed to the families. At 24 months, a paediatrician examined the children. Dust samples were collected from mattresses and carpets and the endotoxin concentration was determined by a chromogenic Limulus assay. The endotoxin levels were higher in Estonian than in Swedish house dust (median levels 29 (range 0.25-280) and 14 (range 0.25-99) EU/mg dust, respectively, P < 0.001). Furthermore, the levels were inversely related to the development of atopic disease and sensitization in the Swedish, but not in the Estonian, children. The low prevalence of atopic disease in Estonia may, at least in part, be related to the high endotoxin levels in this country. The findings support that high levels of endotoxin, or other bacterial products with Th1-stimulating properties, might protect children from developing atopic disease.

Beyond our pages

Beyond our pages

Dust mite allergens: mitigation and control.

In recent years, greater attention has been given to the role of indoor allergens as a cause of sensitization and allergic respiratory diseases. Although indoor allergen control measures to reduce symptoms in individuals allergic to mites have produced controversial results, environmental allergen avoidance is today one of the four primary goals of asthma management recommended in several guidelines of asthma treatment. Exposure to high indoor aeroallergen levels, especially to house dust mite allergens, is an important environmental risk factor for allergic sensitization and the subsequent development and exacerbation of asthma. Therefore, effective aeroallergen avoidance is of use to prevent and treat allergic diseases. Although endotoxin exposure may be protective in early life, it has been demonstrated that the inhalation of endotoxin may exacerbate asthma in house dust mite sensitized patients. Mite-allergic asthmatic patients should be aware of the dangerous combination of mite allergen exposure associated with high endotoxin levels in house dust. These two immunologically active substances have been associated with severe asthma and seasonal exacerbation of symptoms. Effective house dust mite allergen avoidance will never be achieved using a single control measure; various methods are required to affect the multiple factors that facilitate high indoor allergen levels. Education of the patients and their families is also an important component of environmental control strategies.

Lower prevalence of asthma, rhinitis and atopy in rural india is associated with higher house-dust endotoxinlevels

Lower prevalence of asthma, rhinitis and atopy in rural india is associated with higher house-dust endotoxinlevels