Ascaris lumbricoids Infection as a Risk Factor for Asthma and Atopy in Rural Bangladeshi Children

Abstract

Controversy persists as to whether helminth infections cause or protect against asthma and atopy. The aim of this study was to investigate the effects of helminth infection on asthma and atopy among Bangladeshi children. A total of 912 children aged 4.5 years (mean = 54.4, range = 53.5–60.8 months) participated in a cross-sectional study nested into a randomized controlled trial in Bangladesh. Ever-asthma, ever-wheezing and current wheezing were identified using the International Study of Asthma and Allergies in Childhood questionnaire. Current helminth infection was defined by the presence of helminth eggs in stools, measured by routine microscopic examination. Repeated Ascaris infection was defined by the presence of anti-Ascaris IgE ≥ 0.70 UA/ml in serum measured by the CAP-FEIA method. Atopy was defined by specific IgE to house dust mite (anti-DP IgE) ≥ 0.70 UA/ml measured by the CAP-FEIA method and/or positive skin prick test (≥ 5 mm). Anti-Ascaris IgE was significantly associated with ever asthma (odds ratio (OR) = 1.86, 95% CI: 1.14–3.04, highest vs. lowest quartile; P for trend 0.016). Anti-Ascaris IgE was also significantly associated with positive anti-DP IgE (OR = 9.89, 95% CI: 6.52–15.00, highest vs. lowest; P for trend < 0.001) and positive skin prick test (OR = 1.69, 95% CI: 1.01–2.81, highest vs. lowest, P for trend 0.076). These findings suggest that repeated Ascaris infection is a risk factor for asthma and atopy in rural Bangladeshi children. Further analysis is required to examine the mechanism of developing asthma and atopy in relation to helminth infection.

Concurrent decreases in the prevalence of wheezing and Ascaris infection among 5‐year‐old children in rural Bangladesh and their regulatory T cell immunity after the implementation of a national deworming program

“…25 Furthermore, a 2008 study reported a 19.7% prevalence of current wheezing in the same area among 5-year old children. 18 In contrast to these trends, the present study found a significant decrease in the prevalence of wheezing. During the period between 2001 and 2016, we found substantial changes in the socioeconomic status.…”

“…In one of our studies conducted later, we reported that the prevalence of current wheezing was 16% in 2001 among children aged 5 to 6 years in a rural area . Furthermore, a 2008 study reported a 19.7% prevalence of current wheezing in the same area among 5–year old children . In contrast to these trends, the present study found a significant decrease in the prevalence of wheezing.…”

“…More than 72% of the children in a study we conducted in Matlab, Bangladesh, were infected with Ascaris between 2001 and 2005, although it was not a risk factor for wheezing. This prevalence decreased after the introduction of a national deworming program in 2004, which was developed to administer antihelminthic drugs to children aged 24 to 59 months, with an another program (also initiated in 2004) that delivered the drugs to primary school children. We expected this program to have some impact on the prevalence of wheezing.…”

Comment on IgE responses to Ascaris and mite tropomyosins are risk factors for asthma

“…A subsequent study conducted in 2000 among the schoolchildren aged 6–7 years documented 9.1% of current wheezing 5. Our later research reported a further increase to a 16% prevalence of current wheezing in 2001 among children aged 5–6 years in a rural area 2, while a 2008 study described a 19.7% prevalence of current wheezing in the same area among 5‐year‐old children 3. This sudden increase of the prevalence from 2000 to 2001 and the subsequent slow increase between 2001 and 2008 also attracts our attention.…”

“…A study performed later in the same area of Bangladesh in 2008, when the infection prevalence was 17.4%, reported that anti‐ Ascaris IgE was associated with increased risk of ever asthma in 5‐year‐old children as well 3. These findings suggest that anti‐ Ascaris IgE is associated with increased risk of wheezing regardless of exposure levels to Ascaris .…”