B Sozańska1, N Pearce2,3, M Błaszczyk4, A Boznański1, P Cullinan5. 1. 1st Department of Pediatrics, Allergology and Cardiology, Wroclaw Medical University, Wroclaw, Poland. 2. London School of Hygiene and Tropical Medicine, London, UK. 3. Centre for Public Health Research, Massey University, Wellington, New Zealand. 4. Faculty of Sociology, University of Wrocław, Wrocław, Poland. 5. Imperial College (NHLI) and Royal Brompton Hospital, London, UK.
Abstract
BACKGROUND: We examined the associations of family size and birth order with atopy prevalence in rural Poland at two time periods. METHODS: Two cross-sectional surveys were conducted in the same villages and a small town of lower Silesia at an interval of 9 years. In 2003, 1700 (88% of eligible individuals), and in 2012, 1730 (86%) inhabitants aged 5 years or more completed a questionnaire and had a skin prick test for atopy. RESULTS: There was an inverse association between family size and atopy in the village population in 2003; the prevalence of atopy was the highest for those with no siblings (15.2%) and decreased to 5.4% for those with three and more siblings (OR = 0.22; 0.07-0.66). In contrast, there was little or no such protective effect in the town population where the prevalence of atopy was much higher (7.3% in the villages, 20.0% in the town). Nine years later, the prevalence of atopy had increased in the village to be similar to that in the town (19.6% and 19.9% respectively), and the protective effects of family size and birth order in the villages were much weaker (OR = 0.64; 95% CI 0.33-1.27 for three or more siblings). Both protective effects were strongest among children. CONCLUSIONS: The protective effects of family size and birth order on atopy were much stronger in children than in adults and among those living in a village. They largely disappeared with the steep increase in atopy prevalence at all ages; this followed environmental changes on the village farms.
BACKGROUND: We examined the associations of family size and birth order with atopy prevalence in rural Poland at two time periods. METHODS: Two cross-sectional surveys were conducted in the same villages and a small town of lower Silesia at an interval of 9 years. In 2003, 1700 (88% of eligible individuals), and in 2012, 1730 (86%) inhabitants aged 5 years or more completed a questionnaire and had a skin prick test for atopy. RESULTS: There was an inverse association between family size and atopy in the village population in 2003; the prevalence of atopy was the highest for those with no siblings (15.2%) and decreased to 5.4% for those with three and more siblings (OR = 0.22; 0.07-0.66). In contrast, there was little or no such protective effect in the town population where the prevalence of atopy was much higher (7.3% in the villages, 20.0% in the town). Nine years later, the prevalence of atopy had increased in the village to be similar to that in the town (19.6% and 19.9% respectively), and the protective effects of family size and birth order in the villages were much weaker (OR = 0.64; 95% CI 0.33-1.27 for three or more siblings). Both protective effects were strongest among children. CONCLUSIONS: The protective effects of family size and birth order on atopy were much stronger in children than in adults and among those living in a village. They largely disappeared with the steep increase in atopy prevalence at all ages; this followed environmental changes on the village farms.
Authors: Maria Angiola Crivellaro; Giancarlo Ottaviano; Pietro Maculan; Alfonso Luca Pendolino; Liviano Vianello; Paola Mason; Francesco Gioffrè; Rosana Bizzotto; Bruno Scarpa; Edi Simoni; Laura Astolfi; Piero Maestrelli; Maria Luisa Scapellato; Mariella Carrieri; Andrea Trevisan Journal: Int J Environ Res Public Health Date: 2020-09-27 Impact factor: 3.390