High Prevalence of Asthma Symptoms in the Canary Islands: Climatic Influence?

Abstract

The worldwide variation in asthma prevalence prompted us to carry out a study to assess the variability of asthma-related symptoms in young adults on the islands of Gran Canaria and Tenerife. We used the questionnaire used in the European Community Respiratory Health Survey with the addition of two questions on smoking and ancestors from the Canary Islands. In each island, this questionnaire was distributed to a random sample of 5000 subjects aged 20-44 years. Of the 10,000 subjects, 9,506 (95.06%) were considered eligible. We obtained 7,132 (75.03%) responses. The prevalence of the different symptoms was wheezing 25.3%, nocturnal thoracic tightness 18.0%, awakened by an attack of shortness of breath 13.1%, attack of nocturnal coughing 33.3%, attack of asthma 4.3%, current asthma treatment 6.2%, and nasal allergies 18.0%. Women and smokers showed a significantly higher prevalence of asthma symptoms. No significant difference in symptoms was found between subjects whose ancestors were of Canarian origin and those with ancestors born outside the Canaries. As has been observed on other islands (Great Britain and New Zealand), asthma is common in individuals from 20 to 44 years of age in the Canaries. We hypothesize that climatic conditions play an important role in the prevalence of asthma symptoms.

Long‐term aerosol measurements in Gran Canaria, Canary Islands: Particle concentration, sources and elemental composition

“…For example, an unusual bloom of the marine diazotrophic cyanobacterium, Trichodesmium erythraeum, was reported in the Northwest African upwelling during a period of exceptionally warm weather and following a massive African dust outbreak [ Ramos et al , 2005]. In addition, intense African dust intrusion episodes have important environmental impacts in the Canary Islands [ Criado and Dorta , 2003; Griffin and Kellogg , 2004] with repercussions for the local economy, particularly affecting agriculture, where atmospheric dust causes temperature increases and coats the leaves of crops [e.g., Criado and Dorta , 2003], and human health, since the inhalation of dust can trigger or aggravate respiratory conditions [e.g., Julià‐Serdà et al , 2005].…”

North African Influences and Potential Bias in Case-Control Association Studies in the Spanish Population

“…population stratification) is imperative to reduce false positive or negative results in case-control and cohort studies of association of genetic variants with disease [24], [25]. In addition, a better characterization of the different genetic strata that are present in the population would enable future studies to address if genetic factors might underlie disparities among Spanish populations for the incidence of complex illness such as asthma [26], type 2 diabetes [27], and hypertension [28].…”

Dirofilaria immitis Could Be a Risk Factor for the Development of Allergic Diseases in Humans

“…The Canary Islands have a very high incidence of allergic diseases. Although allergic comorbidity is a multifactorial pathology, the existence of other unknown factors that influence the high incidence in the Canaries is recognized [ 10 , 11 ].…”

“…The prevalence of asthmatic adults in the Canary Islands is significantly higher when compared to the national average (17.2% and 5.7%, respectively) [ 9 , 10 , 11 , 12 ]. In children, results are similar and prevalence of asthma (18.4%), rhinitis (40.3%) and allergic dermatitis (35.8%) are higher than the national averages [ 13 ].…”

“…Although sensitization to house dust mites, pollen, animal epithelia or fungus are some of the main factors explaining the high prevalence of allergic diseases, other factors are involved, such as pollution of the air by dusty winds from Africa due to the geographical location of the islands, and increasing pollen presence due to global warming. On the other hand, the trade winds free the archipelago from excessive urban pollution together with the fact that industrialization is much lower than in other Spanish continental regions [ 10 , 14 ]. However, it is recognized that there are other as-yet-unknown factors that influence the high incidence of these pathologies in the Canary Islands [ 11 , 13 ].…”