Which population level environmental factors are associated with asthma, rhinoconjunctivitis and eczema? Review of the ecological analyses of ISAAC Phase One

Abstract

The International Study of Asthma and Allergies in Childhood (ISAAC) Phase One showed large worldwide variations in the prevalence of symptoms of asthma, rhinoconjunctivitis and eczema, up to 10 to 20 fold between countries. Ecological analyses were undertaken with ISAAC Phase One data to explore factors that may have contributed to these variations, and are summarised and reviewed here.In ISAAC Phase One the prevalence of symptoms in the past 12 months of asthma, rhinoconjunctivitis and eczema were estimated from studies in 463,801 children aged 13 - 14 years in 155 centres in 56 countries, and in 257,800 children aged 6-7 years in 91 centres in 38 countries. Ecological analyses were undertaken between symptom prevalence and the following: Gross National Product per capita (GNP), food intake, immunisation rates, tuberculosis notifications, climatic factors, tobacco consumption, pollen, antibiotic sales, paracetamol sales, and outdoor air pollution.Symptom prevalence of all three conditions was positively associated with GNP, trans fatty acids, paracetamol, and women smoking, and inversely associated with food of plant origin, pollen, immunisations, tuberculosis notifications, air pollution, and men smoking. The magnitude of these associations was small, but consistent in direction between conditions. There were mixed associations of climate and antibiotic sales with symptom prevalence.The potential causality of these associations warrant further investigation. Factors which prevent the development of these conditions, or where there is an absence of a positive correlation at a population level may be as important from the policy viewpoint as a focus on the positive risk factors. Interventions based on small associations may have the potential for a large public health benefit.

Association between obesity and asthma – epidemiology, pathophysiology and clinical profile

“…Nevertheless, environmental, behavioural and socioeconomic risk factors significantly modulate the development and course of the disease (19,20) .…”

Effects of home environment and lifestyles on prevalence of atopic eczema among children in Wuhan area of China

“…Like other atopic diseases such as some asthma and hay fever, the prevalence of atopic eczema has increased substantially over the last 30 years, for reasons largely unknown [5,6]. Although a genetic predisposition to the disease has been implicated, evidence from a range of sources suggests that environmental and lifestyle factors play a crucial role in the disease expression [7]. In a Korea study, atopic eczema of children 6-13 years old was found to be highly correlated with environmental tobacco smoke (ETS), especially among children whose mothers had smoked during pregnancy and/or in the first year after birth [8].…”

Meta-analysis of the prevalence of asthma-like symptoms and asthma in Russia (according to the results of ISAAC)

“…Результаты исследования дали воз-можность руководящему комитету этой всемирной программы проанализировать ее итоги в различных странах на разных континентах, составить пред-ставление о вариабельности и динамике распростра-ненности астмоподобных симптомов в различных возрастных группах, определить ведущие факторы риска, чему посвящен ряд детальных метаанализов (рис. 1) [11][12][13].…”

“…Одна-ко, несмотря на более чем 20-летнюю историю эпи-демиологических исследований бронхиальной аст-мы у детей в России, не было выполнено ни одного обобщенного анализа полученных данных. Поэтому в европейских и мировых документах, подытоживаю-щих результаты ISAAC по всему миру, Россия практи-чески не представлена [6,9,10,12,13,20]. Мы пред-приняли попытку восполнить этот пробел.…”

“…Исследования I фазы ISAAC проведены с 1992 по 1997 г. среди школьников 13-14 лет в 155 центрах из 56 стран мира (n=463 801) и среди детей 6-7 лет в 91 центре из 38 стран (n=257 800) [9,13]. Выявлено 20-кратное различие в распространенности «теку-щего хрипящего свистящего дыхания» (за последние 12 мес) между разными центрами в мире (колеба-ния от 1,8 до 36,7%); 7-кратное различие между 10-м и 90-м перцентилем (4,4%; 30,9%).…”