Susceptibility to COPD strongly influenced by genes
MedWire News: Results from a study of twins suggest that genes play a major role in individual susceptibility to chronic obstructive pulmonary disease (COPD).
Writing in the journal Respiratory Medicine, Truls Ingebrigtsen (Bispebjerg Hospital, Copenhagen, Denmark) and colleagues explain: “Genes that contribute to the risk of developing COPD have been identified, but an attempt to accurately quantify the total genetic contribution to COPD has to our knowledge never been conducted.”
To address this, the researchers studied hospital data on COPD diagnoses in 22,422 twin pairs, aged 20–71 years, from the population-based Danish Twin Registry, and 27,668 Swedish twin pairs, aged 45–108 years, from the nationwide Swedish Twin Registry.
The team assessed the genetic risk for severe COPD by analyzing whether a co-twin developed the condition after an affected twin, and the discordant time from the age at first hospital admission for the first twin admitted in an affected twin pair to the age at which the co-twin developed the condition.
Overall, 1.4% of the Danish twin population and 2.0% of the Swedish twin population had been admitted to hospital with a diagnosis of COPD.
The researchers found that the concordance rate for COPD was higher in monozygotic (MZ) than in dizygotic (DZ) twins, at 0.19 versus 0.07 in the Danish population, and 0.20 versus 0.08 in the in the Swedish population.
After accounting for factors such as smoking, gender, and age at first hospital admission, the researchers found that the risk for developing COPD in the co-twin of an affected twin was higher in MZ than DZ twins, at hazard ratios of 4.3 in the Danish twin population and 3.4 in the Swedish twin population.
Further analysis showed that additive genetic factors explained 63% of individual susceptibility to COPD in the Danish population and 61% in the Swedish population.
Ingebrigtsen and team conclude: “Our results support the view of a very significant genetic impact on the susceptibility to COPD and we give here the first attempt to accurately quantify the overall genetic contribution to the individual susceptibility to the disease.
“We estimate that approximately 60% of the individual differences observed in COPD hospitalizations can be explained by genetic factors.”
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By Mark Cowen