Prevalence of asthma and allergies in the Greek (G/C) and Turkish (T/C) communities in Cyprus

Background: The G/C and T/C communities have been living apart for more than 30 years, with the former presumably leading a more westernised lifestyle. Aim: To estimate the prevalence of allergic diseases in both communities and investigate whether any lifestyle characteristics underlie the observed differences. Methods: The ISAAC questionnaire enriched with questions on lifestyle was completed for 10156 children aged 7-8 and 13-14 years. Odds ratios of asthmatic and allergic symptoms between communities were estimated after controlling for potential risk factors in multiple logistic regression models. Results: With the exception of eczema, slightly but consistently lower prevalence was observed for all other outcomes among G/C community in both age-groups. The prevalence of wheezing among 7-8 year-olds was 8.7% vs 11.4% (OR=0.74, p<0.01). Family history of atopy and early nursery attendance were elevated amongst the G/C. Other favourable factors as projected in the hygiene hypothesis were more frequent in the T/C community, including higher proportion in less urban areas (60% vs 34%), bedroom sharing (52% vs 37%) and exposure to farm animals (4.7% vs 0.6%). The same picture emerged in the 13-14 year old group. Controlling for participants' characteristics did not overturn the observed pattern in terms of community in either age-group e.g. the adjusted OR for wheezing remained at 0.73 (p=0.03) in the younger age-group. Conclusions: Observed differences in the prevalence of risk factors between the two communities did not account for the lower prevalence of asthma and allergies among G/C children, suggesting that other factors not related to the hygiene hypothesis might be at play.