Sibling number and prevalence of allergic disorders in pregnant Japanese women: baseline data from the Kyushu Okinawa Maternal and Child Health Study

Abstract

BackgroundAlthough an inverse relationship between number of siblings and likelihood of allergic disorders has been shown in many epidemiological studies, the biological mechanism underlying this phenomenon has not yet been identified. There is no epidemiological research regarding the sibling effect on allergic disorders in Japanese adults. The current cross-sectional study examined the relationship between number of siblings and prevalence of allergic disorders among adult women in Japan.MethodsSubjects were 1745 pregnant women. This study was based on questionnaire data. The definitions of wheeze and asthma were based on criteria from the European Community Respiratory Health Survey whereas those of eczema and rhinoconjunctivitis were based on criteria from the International Study of Asthma and Allergies in Childhood. Adjustment was made for age, region of residence, pack-years of smoking, secondhand smoke exposure at home and at work, family history of asthma, atopic eczema, and allergic rhinitis, household income, and education.ResultsThe prevalence values of wheeze, asthma, eczema, and rhinoconjunctivitis in the past 12 months were 10.4%, 5.5%, 13.0%, and 25.9%, respectively. A significant inverse exposure-response relationship was observed between the number of older siblings and rhinoconjunctivitis, but not wheeze, asthma, or eczema (P for trend = 0.03); however, the adjusted odds ratio (OR) for having 2 or more older siblings was not significant although the adjusted OR for having 1 older sibling was statistically significant (adjusted OR = 0.71 [95% CI: 0.56-0.91]). Number of total siblings and number of younger siblings were not related to wheeze, asthma, eczema, or rhinoconjunctivitis.ConclusionsThis study found a significant inverse relationship between the number of older siblings and the prevalence of rhinoconjunctivitis among pregnant Japanese women. Our findings are likely to support the intrauterine programming hypothesis; however, we could not rule out the hygiene hypothesis.

The Prevalence, Risk Factors and Changes in Symptoms of Self Reported Asthma, Rhinitis and Eczema Among Pregnant Women in Ogbomoso, Nigeria

“…There is increasing need for the improvement of socio economic conditions of dwellers in the sub-Sahara Africa and emission control of air pollutant. We did not find sibship, and pets, as an important association factor for the development of any of the allergic conditions as found by Miyake et al, [19,33].…”

“…Only few prevalence surveys have been conducted on allergic disorders among the adults' populations [19][20][21][22][23]. None of the few African studies examine the changes in the symptoms of allergic disorders in pregnancy.…”

“…The semi-structured questionnaire was initially pre-tested at the Medical Outpatient Clinic using 40 patients with different medical illnesses for content and structural correction. The three allergic disorders were diagnosed using the standardized ISAAC protocol [18] for asthma, eczema and rhinitis as used by Miyake et al, for female adult population [19]. The questionnaires were mostly selfadministered, but were administered by trained assistants to few rural women who could not read or write.…”

“…The inclusion criteria for eczema include affirmative answer to ever presence of itchy rash which was coming and going for at least 6 months, or the presence of itchy rash at any time in the last 12 months and itchy rash at any time that affected skin folds such as the folds of the elbows, behind the knees, in front of the ankles, under the buttocks, or around the neck, ears, or eyes. For rhinitis, participants were included if problem with sneezing, runny or blocked nose were present when there was no cold or flu in the last 12 months [18,19]. Similarly, patients with wheeze were included if there have been wheezing in the chest at any time in the last 12 months.…”

Prevalence, severity and risk factors of allergic disorders among people in south India

“…12 The risk of developing allergy was significantly associated with family history of the same in this study and several other studies. 2,[29][30][31] Studies have also observed that this increased risk seemed to be present no matter whichever type of allergic diseases were in family members indicating strong genetic component irrespective of varying prevalence and environmental risk factors of allergies in different societies. 4,32 These genetic factors form the non-modifiable factors in causation of allergies which cannot be controlled.…”