Association of living in a farming environment with asthma incidence in Canadian children

Maternal preconception occupational exposure to cleaning products and disinfectants and offspring asthma

BACKGROUND

Emerging research suggests health effects in offspring after parental chemical exposures before conception. Many future mothers are exposed to potent chemicals at work, but potential offspring health effects are hardly investigated.

OBJECTIVE

We sought to investigate childhood asthma in relation to mother's occupational exposure to cleaning products and disinfectants before conception.

METHODS

The multicenter Respiratory Health In Northern Europe/Respiratory Health In Northern Europe, Spain and Australia generation study investigated asthma and wheeze starting at age less than 10 years in 3318 mother-offspring pairs. From an asthma-specific Job-Exposure Matrix and mothers' occupational history, we defined maternal occupational exposure to indoor cleaning agents (cleaning products/detergents and disinfectants) starting before conception, in the 2-year period around conception and pregnancy, or after birth. Never-employed mothers were excluded. Exposed groups include cleaners, health care workers, cooks, and so forth. Associations were analyzed using mixed-effects logistic regression and ordinary logistic regression with clustered robust SEs and adjustment for maternal education.

RESULTS

Maternal occupational exposure to indoor cleaning starting preconception and continuing (n = 610) was associated with offspring's childhood asthma: odds ratio 1.56 (95% CI, 1.05-2.31), childhood asthma with nasal allergies: 1.77 (1.13-2.77), and childhood wheeze and/or asthma: 1.71 (95% CI, 1.19-2.44). Exposure starting around conception and pregnancy (n = 77) was associated with increased childhood wheeze and/or asthma: 2.25 (95% CI, 1.03-4.91). Exposure starting after birth was not associated with asthma outcomes (1.13 [95% CI, 0.71-1.80], 1.15 [95% CI, 0.67-1.97], 1.08 [95% CI, 0.69-1.67]).

CONCLUSIONS

Mother's occupational exposure to indoor cleaning agents starting before conception, or around conception and pregnancy, was associated with more childhood asthma and wheeze in offspring. Considering potential implications for vast numbers of women in childbearing age using cleaning agents, and their children, further research is imperative.

Risk factors associated with rhinitis, allergic conjunctivitis and eczema among schoolchildren in Uganda

Background

The prevalence of allergy-related diseases (ARDs), including rhinitis, allergic conjunctivitis and eczema, is on the increase globally. The causes of this increase are not well established.

Objectives

To investigate the risk factors associated with ARDs among schoolchildren in Uganda.

Methods

We conducted a secondary data analysis of a large asthma case–control study involving 1700 schoolchildren, 5–17 years, in urban Uganda. ARDs were defined according to the International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire. Skin prick testing (SPT) was conducted using standard procedures and allergen-specific IgE (asIgE) using ImmunoCAP^®. We employed inverse probability weighted analysis to generate estimated prevalence data and weighted odds ratios.

Results

The lifetime estimated weighted prevalence of reported rhinitis, allergic conjunctivitis and eczema was 43.3%, 39.5% and 13.5%; weighted prevalence in 12 months was 10.1%, 9.1% and 2.3%, respectively. There was overlap of ARDs, with 66.3% of 1193 schoolchildren who reported having ever an ARDs (including asthma) reporting two or more. Risk factors associated with reported rhinitis in the last 12 months were city residence at birth [adjusted odds ratio (95% confidence interval) 2.66 (1.42–4.99) compared to rural]; father’s [2.62 (1.79–3.83)] and mother’s history of allergic disease [2.12 (1.48–3.02)]; frequent de-worming in the last 12 months [2.01 (1.30–3.11), ≥2 versus none]; current high frequency of ‘trucks passing on the street near home’ [2.59 (1.48–4.52), ‘almost all the time’ versus rarely] and positive SPT [1.54 (1.09–2.18)] but not asIgE [1.38 (0.60–3.15)]. The same pattern of risk factors was observed for allergic conjunctivitis and eczema.

Conclusion

We found extensive multi-morbidity of, and overlap in the risk factors for, rhinitis, conjunctivitis and eczema—similar to asthma risk factors—among schoolchildren in urban Uganda. This suggests a similar underlying cause for all ARDs, associated with exposure to urban lifestyles and environment in Uganda.

[Prevalence of pediatric asthma in the rural areas of China: a Meta analysis]

OBJECTIVE

To systematically review the prevalence of pediatric asthma in the rural areas of China, and to provide data for the prevention and treatment of pediatric asthma.

METHODS

PubMed, Cochrane, China National Knowledge Infrastructure, Wanfang Database, and Embase were searched for cross-sectional studies on the prevalence of pediatric asthma in the rural areas of China published up to August 31, 2019. Two researchers independently conducted preliminary screening and data extraction. Stata 14.0 and R software were used to perform a Meta analysis of prevalence rate. Subgroup analysis was also performed.

RESULTS

A total of 24 articles were reviewed, with a sample size of 212 814 children, among whom there were 3 254 children with asthma, with an overall prevalence rate of 2.02% (95%CI: 1.67%-2.36%). Boys had a significantly higher prevalence rate than girls (3.64% vs 2.03%, P<0.001). The annual prevalence rate increased from 1.21% in 1990-1999 to 3.36% in 2011-2015. The prevalence rate of pediatric asthma was 3.15% in South China, which was higher than that in East China (2.31%), Southwest China (2.15%), North China (1.19%), and Central China (1.12%). Preschool children had the highest prevalence rate of 2.63%, followed by infants and young children (2.48%) and school-age children (1.41%).

CONCLUSIONS

The prevalence rate of pediatric asthma is relatively low but tends to increase in the rural areas of China. Boys have a higher prevalence rate of asthma than girls, and the prevalence rate is higher in South China. Preschool children have the highest prevalence rate.

Important Role of Immunological Responses to Environmental Exposure in the Development of Allergic Asthma

Allergic asthma is a public health problem that affects human health and socioeconomic development. Studies have found that the prevalence of asthma has significantly increased in recent years, which has become particularly pronounced in developed countries. With rapid urbanization in China in the last 3 decades, the prevalence of asthma has increased significantly in urban areas. As changes in genetic backgrounds of human populations are limited, environmental exposure may be a major factor that is responsible for the increased prevalence of asthma. This review focuses on environmental components of farms and rural areas that may have protective effects in reducing the development of asthma. Farm and rural related microorganism- and pathogen-associated molecular patterns are considered to be important environmental factors that modulate host's innate and adaptive immune system to induce protection effects later in life. Environmental microbial-related immunotherapy will also be discussed as the future research direction for the prevention of allergic asthma.

Association Between Organic Dust Exposure and Adult-Asthma: A Systematic Review and Meta-Analysis of Case-Control Studies

Background

Exposure to organic dust has been widely investigated as a potential risk factor for asthma with different results. To clarify a potential relationship, we performed the present meta-analysis to integrate the results of studies examining the association of organic dust exposure with asthma.

Methods

A comprehensive literature search in the electronic databases including EMBASE, PubMed and Cochrane Library databases (up to August 2018) was conducted. The adjusted odds ratios (ORs) with corresponding 95% confidence interval (CI) for organic dust exposure and asthma were retrieved and pooled to generate summary effect estimates in Revman 5.2.

Results

Database searches retrieved 1,016 records. A total of 17 studies containing 3,619 cases and 6,585 controls were finally included in our meta-analysis. The summary estimates suggested that organic dust exposure was positively associated with asthma (OR, 1.48; 95% CI, 1.26–1.75; P < 0.00001), whether among population-based case-control studies (OR, 1.24; 95% CI, 1.13–1.35; P < 0.00001) or hospital-based case-control studies (OR, 2.79; 95% CI, 1.27–6.12; P = 0.01). Subgroup analysis showed that paper/wood (OR, 1.62; 95% CI, 1.38–1.90; P < 0.00001), flour/grain (OR, 1.48; 95% CI, 1.11–1.97; P = 0.008), and textile dust (OR, 1.50; 95% CI, 1.08–2.09; P = 0.02) exposure were significantly associated with asthma.

Conclusions

Based on the studies evaluated, our meta-analysis results prompt that organic dust exposure is a risk factor inducing asthma, although precise analysis focus on specific organic dust materials is still warranted.

Association of early daycare attendance with allergic disorders in children: a longitudinal national survey in Japan

The association between early daycare attendance and risk of allergic diseases remains inconclusive. Therefore, we examined the association among Japanese children on a long-term basis using a nationwide longitudinal survey data. We estimated the association between daycare attendance at age 6 or 18 months and allergy development using information on outpatient visits for atopic dermatitis (AD), food allergy (FA), and asthma and admission for asthma up to 12 years of age as a proxy for developing these diseases, with multilevel logistic regression. Early daycare attendance was associated with increased odds of AD at ages 2.5-3.5 years: the adjusted odds ratio (OR) was 1.34 [95% CI: 1.21, 1.47]. The association with FA was equivocal. The odds of asthma was increased before age 3.5 years and afterwards decreased: the adjusted ORs were 1.60 [1.44, 1.77] for ages 1.5-2.5 years and 0.77 [0.69, 0.87] for ages 5.5-7 years. The effect of early daycare attendance depends on the type of allergies.

Agriculture Occupational Exposures and Factors Affecting Health Effects

PURPOSE OF REVIEW

Agriculture environments contain a variety of inflammatory aerosols that may increase risk for lung inflammation and disease in exposed individuals. In addition, epidemiological studies have also identified protective effects of rural environments and farming exposures.

RECENT FINDINGS

In this review, we will discuss recent literature published since 2016 that investigates the impact of differing agricultural exposures on respiratory health. Discussions include the impact of farming modernization, education, and personal protective equipment usage among workers, timing and duration in mediating lung health outcomes, and population studies investigating the association between exposure and risk for numerous lung diseases.

RSV-hRV co-infection is a risk factor for recurrent bronchial obstruction and early sensitization 3 years after bronchiolitis

To assess risk factors of recurrent bronchial obstruction and allergic sensitization 3 years after an episode of acute bronchiolitis, whether after ambulatory care treatment or hospitalization. A monocentric prospective longitudinal study including infants aged under 1 year with acute bronchiolitis was performed, with clinical (severity score), biological (serum Krebs von den Lungen 6 antigen), and viral (14 virus by naso-pharyngeal suction detection) assessments. Follow-up included a quaterly telephone interview, and a final clinical examination at 3 years. Biological markers of atopy were also measured in peripheral blood, including specific IgEs towards aero- and food allergens. Complete data were available for 154 children. 46.8% of them had recurrent wheezing (RW). No difference was found according to initial severity, care at home or in the hospital, respiratory virus involved, or existence of co-infection. A familial history of atopy was identified as a risk factor for recurrent bronchial obstruction (60% for RW infants versus 39%, P = 0.02), as living in an apartment (35% versus 15%, P = 0.002). 18.6% of the infants were sensitized, with 48.1% of them sensitized to aeroallergens and 81.5% to food allergens. Multivariate analysis confirmed that a familial history of atopy (P = 0.02) and initial co-infection RSV-hRV (P = 0.02) were correlated with the risk of sensitization to aeroallergens at 3 years. Familial history of atopy and RSV-hRV co-infection are risk factors for recurrent bronchial obstruction and sensitization.

Is the "farm effect" hypothesis still current? Atopy and allergic diseases in rural and urban children in Poland

OBJECTIVE

The prevalence of allergic diseases has reached epidemic proportions in the Western world. Although farm-living has been associated with a lower prevalence of asthma and atopy, a marked increase in atopy among rural populations after accession to the European Union has been recently reported in Poland. Here, we aimed to investigate the effect of living environment on the prevalence of atopy and allergic diseases in Polish children.

METHODS

400 schoolchildren aged 10-14 years from the capital city (223) and from traditional rural part of the country (177) were recruited from June to November 2011. Data on allergic diseases and symptoms were collected by means of questionnaire and physical examination. Atopy was assessed based on skin prick tests (SPTs) reactivity to inhalant allergens in 350 children.

RESULTS

A high discrepancy between the prevalence of allergic symptoms (46.7%) and doctor-diagnosed allergic diseases (25%) was demonstrated (p < 0.0001). Urban children had a higher overall prevalence of allergic diseases and atopy than children living in rural areas, 29.3% versus 17.1% (p = 0.007) and 33.5% versus 20% (p = 0.0045), respectively. However, no significant differences in the rates of particular allergic diseases were noted (p > 0.05). There was higher SPT positivity to trees, grass, corn, weeds, animal dander, and molds in urban children (p < 0.05).

CONCLUSIONS

Our data support the protective effect of farm-living on the prevalence of atopy and overall allergic diseases, albeit not on particular allergic diseases, in children in Poland. The underlying mechanisms are not identified, but current socioeconomic changes may be responsible.

Community-level characteristics and environmental factors of child respiratory illnesses in Southern Arizona

BACKGROUND

Lower respiratory illnesses (LRIs) and asthma are common diseases in children <5 years of age. Few studies have investigated the relationships between multiple, home-based social and environmental risk factors and asthma and LRIs in children. Of those that have, none have focused exclusively on children <5 years of age, who are more physiologically vulnerable and spend more time at home compared to older children. Further, no studies have done so at the community level.

METHODS

We modeled relationships between emergency department visits and hospitalization rates for asthma and LRIs for children <5 years and geographic risk factors, including socio-economic and housing characteristics, ambient air pollution levels, and population density in Maricopa and Pima Counties, Arizona, from 2005 to 2009. We used a generalized linear model with a negative binomial observation distribution and an offset for the population of very young children in each tract. To reduce multicollinearity among predictors, socio-economic characteristics, and ambient air pollutant levels were combined into unit-less indices using the principal components analysis (PCA). Housing characteristics variables did not exhibit moderate-to-high correlations and thus were not included in PCA. Spatial autocorrelation among regression model residuals was assessed with the Global Moran's I test.

RESULTS

Following the regression analyses, almost all predictors were significantly related to at least one disease outcome. Lower socio-economic status (SES) and reduced population density were associated with asthma hospitalization rates and both LRI outcomes (p values <0.001). After adjusting for differences between counties, Pima County residence was associated with lower asthma and LRI hospitalization rates. No spatial autocorrelation was found among multiple regression model residuals (p values >0.05).

CONCLUSIONS

Our study revealed complex, multi-factorial associations between predictors and outcomes. Findings indicate that many rural areas with lower SES have distinct factors for childhood respiratory diseases that require further investigation. County-wide differences in maternal characteristics or agricultural land uses (not tested here) may also play a role in Pima County residence protecting against hospitalizations, when compared to Maricopa County. By better understanding this and other relationships, more focused public health interventions at the community level could be developed to reduce and better control these diseases in children <5 years, who are more physiologically vulnerable.