α-Gal specific-IgE prevalence and levels in Ecuador and Kenya: Relation to diet, parasites, and IgG4.

BACKGROUND: IgE to α-Gal is a cause of mammalian meat allergy and has been linked to tick bites in North America, Australia, and Eurasia. Reports from the developing world indicate that α-Gal sensitization is prevalent but has been little investigated. OBJECTIVE: We sought evidence for the cause(s) of α-Gal sensitization and lack of reported meat allergy among children in less developed settings in Ecuador and Kenya. METHODS: IgE to α-Gal and total IgE were assessed in children from Ecuador (n = 599) and Kenya (n = 254) and compared with children with (n = 42) and without known (n = 63) mammalian meat allergy from the southeastern United States. Information on diet, potential risk factors, and helminth infections was available for children from Ecuador. IgG4 to α-Gal and antibodies to regionally representative parasites were assessed in a subset of children. RESULTS: In Ecuador (32%) and Kenya (54%), α-Gal specific IgE was prevalent, but levels were lower than in children with meat allergy from the United States. Sensitization was associated with rural living, antibody markers of Ascaris exposure, and total IgE, but not active infections with Ascaris or Trichuris species. In Ecuador, 87.5% reported consuming beef at least once per week, including 83.9% of those who had α-Gal specific IgE. Levels of α-Gal specific IgG4 were not high in Ecuador, but were greater than in children from the United States. CONCLUSIONS: These results suggest that in areas of the developing world with endemic parasitism, α-Gal sensitization is (1) common, (2) associated with Ascaris exposure, and (3) distinguished by a low percentage of specific/total IgE compared with individuals with meat allergy in the United States.

Complex relationships between vitamin D and allergic sensitization among Puerto Rican 2-year-old children.

BACKGROUND: In the United States, Puerto Ricans have a higher prevalence of asthma than other Latino ethnicities. Low vitamin D levels for children living in northern climates could be a factor. OBJECTIVE: To assess serum 25-hydroxyvitamin D [25(OH)D] distributions (a marker of vitamin D) and associations among vitamin D, allergic sensitization, early wheeze, and home/demographic factors. METHODS: Puerto Rican infants born in New York City, with a maternal history of atopy, were enrolled in a birth cohort. Blood was collected at age 2 years (n = 154; 82 males and 72 females). Serum 25(OH)D and immunoglobulin E (IgE) (indoor allergen-specific and total) were determined using immunoassays. Home/demographic characteristics and respiratory symptoms were assessed by questionnaire. RESULTS: The median concentration of 25(OH)D was 22.6 ng/mL; 32% were at risk of deficiency or inadequacy (<12 or 12-19 ng/mL). Serum 25(OH)D levels were lower in the heating (a surrogate for less sun exposure in colder months) compared with nonheating (26.1 vs 22.7 ng/mL, P = .02) season, but were not associated with allergen-specific IgE levels or with level of acculturation (measured by maternal birthplace). However, low 25(OH)D levels (below median) were associated with high total IgE >100 IU/mL (P = .01). Also, 25(OH)D concentrations differed between children who attended daycare and those who did not (21.8 vs 24.5 ng/mL; t test, P = .02). Serum 25(OH)D was not associated with wheeze or asthma by 2 years of age (P = .43). CONCLUSION: Vitamin D deficiency, possibly linked with allergic pathways, may partially explain the trajectory for disproportionate asthma burden among Puerto Ricans, especially those born and raised in colder climates.

Mold populations and dust mite allergen concentrations in house dust samples from across Puerto Rico.

Lifetime childhood asthma prevalence (LCAP) percentages in Puerto Rico Health Regions (HR) are substantially higher in northeastern vs. southwestern HR. Higher average relative humidity in the northeast might promote mold and mite exposures and possibly asthma prevalence. To test this hypothesis, mold contamination, Environmental Relative Moldiness Index (ERMI) values were measured in floor dust (n = 26) and dust mite allergen concentrations in bed dust (n = 14). For this analysis, the eight HR were divided into those with LCAP > 30% (n = 3) and < 30% (n = 5). The average ERMI value was significantly greater (Wilcoxon Rank Sum, p < 0.001) in high than in low LCAP HR (14.5 vs. 9.3). The dust mite antigens Der p 1, Der f 1, and Blo t 5 were detected in 90% of bed samples, but the concentrations were not significantly different in high vs. low LCAP HR. Mold exposures might partially explain the differences in LCAP HR in Puerto Rico.

Risk factors for acute asthma in tropical America: a case-control study in the City of Esmeraldas, Ecuador.

BACKGROUND: Despite the high asthma rates described in Latin America, asthma risk factors in poor urban settings are not well established. We investigated risk factors for acute asthma among Ecuadorian children. METHODS: A matched case-control study was carried out in a public hospital serving a coastal city. Children with acute asthma were age- and sex-matched to non-asthmatics. A questionnaire was administered, and blood, as well as stool, and nasopharyngeal swabs were collected. RESULTS: Sixty cases and 119 controls aged 5-15 were evaluated. High proportions of cases were atopic with population-attributable fractions for atopy of 68.5% for sIgE and 57.2% for SPT. Acute asthma risk increased with greater titers of mite IgE (3.51-50 kU/l vs. <0.70kU/l - OR 4.56, 95% CI 1.48-14.06, p = 0.008; >50kU/l vs. <0.70kU/l - OR 41.98, 95% CI: 8.97-196.39, p < 0.001). Asthma risk was significantly independently associated with bronchiolitis (adj. OR: 38.9, 95% CI 3.26-465), parental educational level (adj. OR 1.26, 95% CI: 1.08-1.46), and presence of sIgE (adj. OR: 36.7, 95% CI: 4.00-337), while a reduced risk was associated with current contact with pets (adj. OR: 0.07, 95% CI: 0.01-0.56). Rhinovirus infection was more frequent in cases (cases 35.6% vs. controls 7.8%, p = 0.002). None of the cases were on maintenance therapy with inhaled corticosteroids and most relied on emergency department for control. CONCLUSIONS: A high proportion of children presenting to a public hospital with acute asthma were allergic to mite, particularly at high IgE titer. Poor asthma control resulted in overuse of emergency care.

Sociocultural characteristics, obesity and inflammatory biomarkers in Puerto Rican toddlers born in New York City.

BACKGROUND: In the USA, Puerto Rican children have a higher prevalence of asthma than other Latino ethnicities, and acculturation is one of hypothesized reasons for this difference. We examined associations between sociocultural characteristics and serum leptin, high-sensitivity C-reactive protein (hsCRP), and body mass index (BMI), and further, among hsCRP, leptin levels, BMI percentiles, and allergic sensitization in 2-year-old children. METHODS: IgE antibodies, leptin, and hsCRP concentrations were measured in serum from Puerto Rican toddlers (n = 143) born in New York City with a maternal history of allergy and/or asthma. Demographic and home characteristics questionnaires were administered to the mother, postpartum and two years later. Children's weight and height were measured to determine BMI percentiles. RESULTS: More girls (60%) had leptin levels above the median compared with boys (37%) (p = 0.0063). Leptin was positively correlated with BMI (r = 0.25; p = 0.0042). Children in daycare were more likely to be obese (40% vs. 24% p < 0.06). Maternal birthplace was significantly associated with children's leptin but not with hsCRP. Leptin levels were lower for children whose mothers were born on the US mainland (GM = 2.5 ng/ml, 95% CI [2.2-2.7]) compared with those whose mothers were born in Puerto Rico or another country (GM = 3.2 ng/ml, 95% CI [2.2-3.9], t-test p = 0.01). Mothers born in another country were more likely than those born in the US mainland or Puerto Rico to have obese children (60% vs. 26% p < 0.02). Leptin, hsCRP, and BMI percentile were not associated with sensitization to any of the measured inhalant allergens or total IgE. CONCLUSION: Even at a very young age, some acculturation factors were associated with biomarkers and anthropometric measures of obesity among this Puerto Rican pediatric population. To our knowledge, this is the first study demonstrating the association of mother's birth place with child BMI and leptin as early as 24 months.

Urban tree canopy and asthma, wheeze, rhinitis, and allergic sensitization to tree pollen in a New York City birth cohort.

BACKGROUND: Urban landscape elements, particularly trees, have the potential to affect airflow, air quality, and production of aeroallergens. Several large-scale urban tree planting projects have sought to promote respiratory health, yet evidence linking tree cover to human health is limited. OBJECTIVES: We sought to investigate the association of tree canopy cover with subsequent development of childhood asthma, wheeze, rhinitis, and allergic sensitization. METHODS: Birth cohort study data were linked to detailed geographic information systems data characterizing 2001 tree canopy coverage based on LiDAR (light detection and ranging) and multispectral imagery within 0.25 km of the prenatal address. A total of 549 Dominican or African-American children born in 1998-2006 had outcome data assessed by validated questionnaire or based on IgE antibody response to specific allergens, including a tree pollen mix. RESULTS: Tree canopy coverage did not significantly predict outcomes at 5 years of age, but was positively associated with asthma and allergic sensitization at 7 years. Adjusted risk ratios (RRs) per standard deviation of tree canopy coverage were 1.17 for asthma (95% CI: 1.02, 1.33), 1.20 for any specific allergic sensitization (95% CI: 1.05, 1.37), and 1.43 for tree pollen allergic sensitization (95% CI: 1.19, 1.72). CONCLUSIONS: Results did not support the hypothesized protective association of urban tree canopy coverage with asthma or allergy-related outcomes. Tree canopy cover near the prenatal address was associated with higher prevalence of allergic sensitization to tree pollen. Information was not available on sensitization to specific tree species or individual pollen exposures, and results may not be generalizable to other populations or geographic areas.

Prenatal exposure to butylbenzyl phthalate and early eczema in an urban cohort.

BACKGROUND: Recent cross-sectional studies suggest a link between butylbenzyl phthalate (BBzP) in house dust and childhood eczema. OBJECTIVES: We aimed to evaluate whether concentrations of monobenzyl phthalate (MBzP), the main BBzP metabolite in urine, during pregnancy are associated prospectively with eczema in young children, and whether this association varies by the child's sensitization to indoor allergens or serological evidence of any allergies. METHODS: MBzP was measured in spot urine samples during the third trimester of pregnancy from 407 African-American and Dominican women residing in New York City in 1999-2006. Repeated questionnaires asked mothers whether their doctor ever said their child had eczema. Child blood samples at 24, 36, and 60 months of age were analyzed for total, anti-cockroach, dust mite, and mouse IgE. Relative risks (RR) were estimated with multivariable modified Poisson regression. Analyses included a multinomial logistic regression model for early- and late-onset eczema versus no eczema through 60 months of age. RESULTS: MBzP was detected in > 99% of samples (geometric mean = 13.6; interquartile range: 5.7-31.1 ng/mL). By 24 months, 30% of children developed eczema, with the proportion higher among African Americans (48%) than among Dominicans (21%) (p < 0.001). An interquartile range increase in log MBzP concentration was associated positively with early-onset eczema (RR = 1.52 for eczema by 24 months; 95% confidence interval: 1.21, 1.91, p = 0.0003, n = 113 reporting eczema/376 total sample), adjusting for urine specific gravity, sex, and race/ethnicity. MBzP was not associated with allergic sensitization, nor did seroatopy modify consistently the MBzP and eczema association. CONCLUSIONS: Prenatal exposure to BBzP may influence the risk of developing eczema in early childhood.

The New York City Puerto Rican asthma project: study design, methods, and baseline results.

OBJECTIVE: We examined asthma risk factors among 274 Puerto Rican children born in New York to atopic mothers. METHODS: We prospectively followed the cohort to measure aeroallergens in their homes and assess allergic sensitization. Baseline data are presented. RESULTS: Maternal smoking was significantly higher among women born on the continental United States (25%) vs. those born elsewhere (11%). Cat ownership was more frequent among mainland-born women (15%) compared with those born in Puerto Rico (4%). While some aeroallergens were prevalent, few dust samples contained detectable dust mite allergens. CONCLUSIONS: By following this cohort, we hope to identify the roles that socio-cultural factors play in the process of allergic sensitization.

Prevalence of allergy symptoms and total IgE in a New York City cohort and their association with birth order.

BACKGROUND: An inverse association between birth order and allergic disease has been widely observed, but has not been examined in the high asthma prevalence, inner-city populations of the United States. As part of an ongoing prospective birth cohort study, the prevalence of early phenotypes of asthma and/or allergy was compared with those reported in other studies, and the association with birth order was evaluated. METHODS: Children of Dominican and African-American mothers living in Northern Manhattan underwent detailed periodic questionnaires. Total IgE from the mothers (n = 321) and the children at birth (n = 291) and at ages 24 (n = 244) and 36 (n = 155) months was measured. The association between birth order and allergy symptoms was evaluated at 12 (n = 350), 24 (n = 290) and 36 (n = 247) months. RESULTS: Total serum IgE was detectable (>0.5 IU/ml) in 35% of the children's cord blood and averaged 15 and 21 IU/ml at ages 24 and 36 months, respectively. They were not significantly different at any age between children with and without older siblings. Additionally, at these ages, there were no consistent associations between birth order and either wheeze, itchy eyes or eczema. CONCLUSIONS: Despite a substantially higher prevalence of asthma in the Northern Manhattan community compared with other areas, total IgE levels at ages 24 and 36 months, but not cord blood, are similar to those reported in other areas of the world. In this community, results at this age do not support a protective effect of higher birth order.

Distribution and determinants of mouse allergen exposure in low-income New York City apartments.

Previous studies of mouse allergens and laboratory-animal-worker-related allergy and asthma suggest that quantifying mouse allergen levels in homes could augment our understanding of inner-city asthma. We hypothesized that levels of mouse allergen in inner-city homes would be related to certain household characteristics. Dust samples were collected from the kitchens and beds of 221 mothers enrolled in a prospective birth cohort study, 92 of African American and 129 of Dominican ethnicity. Samples were analyzed for mouse urinary protein. The geometric mean for kitchen samples was 4.6 micro g/g [95% confidence interval (95% CI), 3.2-6.5] and for bed samples was 0.9 micro g/g (95% CI, 0.8-1.1). The variables associated with mouse allergen levels in the home were frequency of mouse sightings, use of traps or pesticides for mice, presence of holes in ceilings or walls, absence of a cat, and living in a building with fewer than eight floors. Statistically significant neighborhood differences in levels of mouse allergen and report of rodents in the home were also observed. In conclusion, mouse allergen was prevalent among inner-city apartments, and the positive predictive value of self-reported frequent mouse sightings was high (90% for kitchens). However, high levels of mouse allergen were also found in many homes where mothers reported never seeing mice.

Atopy, asthma, and antibodies to Ascaris among rural and urban children in Kenya.

OBJECTIVE: The purpose of this study was to evaluate differences in the relationship between asthma and immune responses to allergens in children living in rural and urban areas of Kenya. STUDY DESIGN: Children (mean age, 11 years) from Kabati (n = 136), a rural village, and Thika (n = 129), a small town, were studied by skin testing and serum immunoglobulin E (IgE) and immunoglobulin G (IgG) antibody measurement. Asthma was evaluated by symptoms, as well as spirometry before and after vigorous exercise to test for exercised-induced bronchospasm (EIB). School children from a study performed in Atlanta, Georgia, were used for comparison of anthropometric and immunologic results. RESULTS: Compared with the urban area of Kenya, children living in the rural area had a lower percentage of body fat, smaller and fewer skin test responses to allergens, a higher prevalence of IgE antibodies to Ascaris (67% vs 26%) and 10-fold higher total IgE. In the urban area of Kenya, there was a strong correlation between EIB and atopy determined both by IgE antibodies (P =.02) and skin tests (P =.002). By contrast, in the rural area, none of the 13 children with EIB were skin-test positive (vs 13/109 of children without EIB). CONCLUSIONS: Among the rural children, there was no association between immune responses to allergens and airway-related symptoms or reactivity. The association between asthma and atopy seen in the town of Thika may represent an important step in the increase in asthma seen both in urban Africa and in the West.