Endotoxin Levels in Rural Thai and Urban Singaporean Homes

Lee, A.; Sangsupawanich, Pasuree; Ma, Stefan; Tan, Teng Nging; Goh, Denise; Ho, Bow; Bever, Hugo Van; Lee, B.W.

doi:10.1159/000095467

Cited by 12 publications

(7 citation statements)

References 17 publications

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“…For example, studies from farms in Europe show an inverse relationship between environmental endotoxin levels and the prevalence of hayfever, atopic wheeze and atopic sensitization [40]. Our group has demonstrated higher home endotoxin levels in rural South Thailand compared with urban Singapore, where higher prevalences of asthma, allergic rhinitis and eczema are seen [41]. Apart from external microbial exposure, differences in gut microflora may also play a role.…”

Section: What Are the Possible Causes For The Difference In Epidemiolmentioning

confidence: 49%

Allergies in Asia: differences in prevalence and management compared with Western populations

Gerez¹,

Lee²,

Bever³

2010

Expert Review of Clinical Immunology

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There is wide variability in the epidemiology and management of childhood asthma and related atopic diseases globally. Urbanized, affluent Western countries tend to have a higher prevalence of these diseases compared with Asian nations. However, recent studies have shown that the prevalence in Asia is increasing, although the rate of increase has slowed in the more developed Asian cities. Some possible causes for these differences are socioeconomic status, degree of urbanization, rates of infection, healthcare practices and genetic factors. Importantly, there are significant differences in the way asthma and allergic diseases are managed within Asia. This is of great concern because of the health implications, as these diseases are some of the most common chronic conditions that affect both adults and children. This review compares the differences in prevalence and management between Asia and the West, and discusses some of the possible reasons behind these variations.

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Section: What Are the Possible Causes For The Difference In Epidemiolmentioning

confidence: 49%

Allergies in Asia: differences in prevalence and management compared with Western populations

Gerez¹,

Lee²,

Bever³

2010

Expert Review of Clinical Immunology

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“…This finding is similar to those of previous longitudinal studies for eczema 28 and asthma, 29 but to our knowledge, this is the first study to prospectively examine this relationship for the development of food allergy. Previous studies have demonstrated that endotoxin levels are lower in urban environments than in rural farming areas, 30,31 and a recent study examining the indoor microbiome in the same URECA cohort found that exposure to specific allergens and bacteria was associated with reduced sensitization to inhalant allergens as well as recurrent wheeze (in press). Therefore, while it has been previously suggested that the high rates of allergy and asthma in the inner city contradict the hygiene hypothesis, 32 both of these studies suggest that this is not actually the case.…”

Section: Discussionmentioning

confidence: 98%

Influence of early-life exposures on food sensitization and food allergy in an inner-city birth cohort

McGowan¹,

Bloomberg²,

Gergen³

et al. 2015

Journal of Allergy and Clinical Immunology

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Rationale Previous data suggest that food allergy may be more common in inner-city children; however, these studies have not collected data on both sensitization and clinical reactivity, or early life exposures. Methods Children in the URECA birth cohort were followed through age 5 years. Household exposures, diet, clinical history, and physical examinations were assessed yearly; specific-IgE to milk, egg, and peanut were measured at 1, 2, 3, and 5 years. Based on sensitization (IgE≥0.35 kU/L) and clinical history over the five-year period, children were classified as food allergic (FA), possibly allergic, sensitized but tolerant, or not allergic/not sensitized. Results 516 children were included. Overall, 55.4% were sensitized (milk 46.7%, egg 31.0%, peanut 20.9%), while 9.9% were categorized as FA (peanut 6.0%, egg 4.3%, milk 2.7%, 2.5% >1 food). The remaining children were categorized as possibly allergic (17.0%), sensitized but tolerant (28.5%), and not sensitized (44.6%). Eighteen (3.5%) reported reactions to foods for which IgE was not measured. Food-specific IgE levels were similar in FA versus sensitized but tolerant children, except for egg, which was higher in FA at ages 1 and 2. FA was associated with recurrent wheeze, eczema, aeroallergen sensitization, male gender, breastfeeding, and lower endotoxin exposure in year 1, but not with race/ethnicity, income, tobacco exposure, maternal stress, or early introduction of solid foods. Conclusions Even given that this was designed to be a high-risk cohort, the cumulative incidence of food allergy is extremely high, especially considering the strict definition of food allergy that was applied and that only 3 common allergens were included.

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“…There was one study that examined sensitization in Thai children suffering from allergic rhinitis, reporting that the predominant aeroallergen to which patients were sensitized in Bangkok was house dust mite [60]. A subsequent exposure study collected dust from the mattresses of young children in Thailand and Singapore [61]. Dust mite allergen in rural Thailand was less than in urban Singapore and positively correlated with air-conditioning use, while the endotoxin level in rural Thailand was higher (particularly in agricultural areas) compared to Singapore.…”

Section: Resultsmentioning

confidence: 99%

“…Likewise, house-dust and/or cockroach allergens represent another more widespread indoor air exposure across Thailand [80]. Sensitization to these allergens is very common in Asian countries, including Thailand [6061]. Some sources of indoor air pollution are also linked with outdoor air pollution and children tend to spend more time in indoors than outdoors.…”

Section: Discussionmentioning

confidence: 99%

“…Some sources of indoor air pollution are also linked with outdoor air pollution and children tend to spend more time in indoors than outdoors. For example, children can be exposed via direct transfer of chemicals from parents working in agriculture [14]; dust in households living close to boat repair yards contain higher levels of lead [31]; and endotoxin levels are higher in households located in agricultural areas [61]. The latter observation may be linked to the hygiene hypothesis and might explain the lower prevalence of allergic disease in Thailand compare to other Western countries [81].…”

Section: Discussionmentioning

confidence: 99%

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Children’s Environmental Health in Thailand: Past, Present, and Future

Sinitkul¹,

Wongrathanandha

Sirirattanapruk

et al. 2018

Annals of Global Health

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Background:There is increasing evidence of a link between environmental pollution and preventable diseases in developing countries, including Thailand. Economic development has generated several types of pollution that can affect population health. While these environmental health effects can be observed throughout life, pregnant women and children represent particularly vulnerable and sensitive groups.Methods:The published epidemiological literature investigating environmental chemical exposure in Thai children was reviewed, highlighting those that investigated associations between exposure and subsequent health outcomes.Results:The majority of the Thai epidemiological studies on environmental health in children were cross-sectional in design, with some demonstrating associations between exposure and outcome. The three main types of chemical exposure in Thai children were pesticides, heavy metals, and air pollution, which resulted from agricultural activities in countryside areas, industrial zones (both registered and unregistered establishments), mining, and traffic in inner cities. Major health outcomes included detrimental effects on cognitive function and cancer risk. Pesticide exposure was focused on, but not limited to, agricultural areas. The success of the Thai environmental policy to introduce lead–free petrol can be demonstrated by the decline of mean blood lead levels in children, particularly in urban areas. However, unregistered lead-related factories and smelters act as hidden sources. In addition, there is increasing concern, but little acknowledgement, about the effects of chronic arsenic exposure related to mining. Lastly, air pollution remains a problem in both dense city populations due to traffic and in rural areas due to contamination of indoor air and house dust with heavy metals, endotoxins and other allergens.Conclusions:The increasing number of published articles demonstrates an improved awareness of children’s environmental health in Thailand. Chemical hazards, including the improper use of pesticides, environmental contamination with heavy metals (lead and arsenic), and air pollution in inner cities and indoor air, continue to be growing issues.

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Endotoxin Levels in Rural Thai and Urban Singaporean Homes

Cited by 12 publications

References 17 publications

Allergies in Asia: differences in prevalence and management compared with Western populations

Allergies in Asia: differences in prevalence and management compared with Western populations

Influence of early-life exposures on food sensitization and food allergy in an inner-city birth cohort

Children’s Environmental Health in Thailand: Past, Present, and Future

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