Birth weight, gestational age, fetal growth and childhood asthma hospitalization

Abstract

BackgroundChildhood asthma may have a fetal origin through fetal growth and development of the immunocompetence or respiratory organs.ObjectiveWe examined to which extent short gestational age, low birth weight and fetal growth restriction were associated with an increased risk of asthma hospitalization in childhood.MethodsWe undertook a cohort study based on several national registers in Denmark, Sweden and Finland. We included all live singleton born children in Denmark during 1979-2005 (N = 1,538,093), in Sweden during 1973-2004 (N = 3,067,670), and a 90% random sample of singleton children born in Finland during 1987-2004 (N = 1,050,744). The children were followed from three years of age to first hospitalization for asthma, emigration, death, their 18th birthday, or the end of study (the end of 2008 in Denmark, and the end of 2007 in Sweden or Finland), whichever came first. We computed the pseudo-values for each observation and used them in a generalized estimating equation to estimate relative risks (RR) for asthma hospitalization.ResultsA total of 131,783 children were hospitalized for asthma during follow-up. The risk for asthma hospitalization consistently increased with lower birth weight and shorter gestational age. A 1000-g decrease in birth weight corresponded to a RR of 1.17 (95% confidence interval (CI) 1.15-1.18). A one-week decrease in gestational age corresponded to a RR of 1.05 (95% CI 1.04-1.06). Small for gestational age was associated with an increased risk of asthma hospitalization in term but not in preterm born children.ConclusionsFetal growth and gestational age may play a direct or indirect causal role in the development of childhood asthma.

Association of PCBs and allergies in children

“…In addition, various studies have detected positive correlations between in utero PCB exposure, which is frequently associated with the consumption of fish, and the risk of a low birth weight [48,49]. We did not detect a significant relationship between birth weight and PCB in the present study (data not shown); however, some studies have indicated that a link exists between low birth weight and childhood allergies [50,51]. Furthermore, it remains unclear which types of PCB congeners and PCB homologs are associated with childhood conditions, such as allergies.…”

Birth weight is not causally associated with adult asthma: results from instrumental variable analyses

“…Indeed, by using a propensity score approach to control for confounders, it has been showed that birth weight is not associated with the risk of asthma during the first six years of life 68 . In addition, after considering the maternal smoking status in pregnancy 27 and gestational age 26,69 , the estimated association size between lower birth weight with asthma is much reduced. Therefore, our MR results are consistent with these observational studies that properly controlled for confounding effects, providing additional evidence supporting that birth weight may not be directly associated with adult asthma.…”

Is preterm birth associated with asthma among children from birth to 17 years old? -A study based on 2011-2012 US National Survey of Children’s Health

“…The prevalence rate varies among countries, the increase pattern usually observed in many Low- and Middle-Income counties, especially in Eastern Europe and Latin American, as well as Northern African countries [4, 5]. The cause of asthma remains unclear and current research paints a complex picture [6, 7].…”