Abstract
Background: There is increasing interest in environmental exposures as heritable risk factors. Animal studies have linked grand-maternal nicotine exposure to lung changes in grand-offspring of unexposed mothers. This has been partially corroborated in limited human studies, although inconsistently.
Aim: To investigate the association between grand-maternal smoking during pregnancy and asthma risk in grandchildren
Methods: From 1982-1986, 44,583 grandmothers gave birth to children in Sweden. Subsequently 46,197 of these children (aka mothers) gave birth to 66,271 grandchildren (aka children) (born 1996-2000).Smoking exposure was recorded at 10-12 weeks gestation for both mothers and grandmothers. Also 3 months preconception and third trimester smoking were recorded for mothers. Purchased asthma medication was recorded for children (2005-2013). Current asthma in any year was defined as purchasing inhaled steroids. Maternal smoking, gender, county, social allowance, grand-paternal smoking, grandmothers BMI and grandmothers age, were included as covariates. There was no interaction by maternal smoking.
Results: Grandmothers smoking during pregnancy there was associated with an increased asthma risk for grandchildren from 1-6 years (Adjusted odds ratios: 1-2yr, 1.19; 95%CI 1.10,1.27; 2-3yr, 1.22; 1.14,1.31, 3-4yr, 1.11; 1.02,1.21, 4-5yr,1.10; 0.99,1.22, 5-6yr ,1.14; 1.00,1.31).
Conclusions: Children aged 1-6 years had a 10- 22% increased risk of asthma if their grandmothers smoked during early pregnancy. These findings support possible epigenetic transmission of risk from environmental exposures in previous generations.
- Copyright ©ERS 2015
