Jouni J K Jaakkola1, Mika Gissler. 1. Institute of Occupational and Environmental Medicine, The University of Birmingham, Birmingham, UK. j.jaakkola@bham.ac.uk
Abstract
BACKGROUND: Prenatal exposure to tobacco smoke through mother's smoking increases the risk of developing asthma later in life. A recent study suggested that this effect is present only in girls. We explored potential differences in susceptibility between boys and girls. METHODS: We followed all 58,841 Finnish singleton babies born in 1987 through 5 nationwide registries for 7 years and identified all cases of doctor-diagnosed asthma (ICD-9 code 493). The birth registry provided categorical information on the mother's smoking during pregnancy: no smoking (reference), low exposure (<10 cigarettes per day), and high exposure (>10 cigarettes per day). RESULTS: In girls the cumulative incidence of asthma was 0.0245 in the reference group, 0.0310 in the low maternal smoking group (risk difference = 0.0065; 95% CI = 0.0053-0.0076), and 0.0360 in the high maternal smoking group (0.0115; 0.0096-0.0133). The corresponding cumulative incidences for boys were 0.0405, 0.0501 (0.0096; 0.0089-0.0103), and 0.0522 (0.0117; 0.0091-0.0142). In logistic regression analysis adjusting for confounding, the combined effect of male sex and high maternal smoking (compared with female sex and no smoking) was 112% excess risk. This corresponded closely to what would be expected from the additive independent effects of male sex (67% excess risk) and high maternal smoking (44% excess risk). CONCLUSIONS: Effects of maternal smoking during pregnancy on the risk of developing asthma are similar in boys and girls, with no interaction on an additive scale.
BACKGROUND: Prenatal exposure to tobacco smoke through mother's smoking increases the risk of developing asthma later in life. A recent study suggested that this effect is present only in girls. We explored potential differences in susceptibility between boys and girls. METHODS: We followed all 58,841 Finnish singleton babies born in 1987 through 5 nationwide registries for 7 years and identified all cases of doctor-diagnosed asthma (ICD-9 code 493). The birth registry provided categorical information on the mother's smoking during pregnancy: no smoking (reference), low exposure (<10 cigarettes per day), and high exposure (>10 cigarettes per day). RESULTS: In girls the cumulative incidence of asthma was 0.0245 in the reference group, 0.0310 in the low maternal smoking group (risk difference = 0.0065; 95% CI = 0.0053-0.0076), and 0.0360 in the high maternal smoking group (0.0115; 0.0096-0.0133). The corresponding cumulative incidences for boys were 0.0405, 0.0501 (0.0096; 0.0089-0.0103), and 0.0522 (0.0117; 0.0091-0.0142). In logistic regression analysis adjusting for confounding, the combined effect of male sex and high maternal smoking (compared with female sex and no smoking) was 112% excess risk. This corresponded closely to what would be expected from the additive independent effects of male sex (67% excess risk) and high maternal smoking (44% excess risk). CONCLUSIONS: Effects of maternal smoking during pregnancy on the risk of developing asthma are similar in boys and girls, with no interaction on an additive scale.
Authors: Regina Grazuleviciene; Sandra Andrusaityte; Inga Uzdanaviciute; Jolanta Kudzyte; Rimantas Kevalas; Mark J Nieuwenhuijsen Journal: Biomed Res Int Date: 2014-07-06 Impact factor: 3.411
Authors: Masood Ali Shaikh; Zahra Zare; Kwok W Ng; Karen L Celedonia; Michael Lowery Wilson Journal: Int J Environ Res Public Health Date: 2020-10-09 Impact factor: 3.390