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Genetic and environmental influence on lung function impairment in Swedish twins.

Hallberg J, Iliadou A, Anderson M, de Verdier MG, Nihlén U, Dahlbäck M, Pedersen NL, Higenbottam T, Svartengren M - Respir. Res. (2010)

Bottom Line: Fully adjusted heritability for VC was 59% and did not differ by sex, with smoking and symptoms explaining only a small part of the total variance.Further, smoking and symptoms explained genetic variance in women, but was primarily associated with shared environmental effects in men.As a consequence the results suggest that patients with lung diseases such as COPD could benefit from interventions that are sex specific.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Public Health Sciences, Karolinska Institutet, Stockholm, Sweden.

ABSTRACT

Background: The understanding of the influence of smoking and sex on lung function and symptoms is important for understanding diseases such as COPD. The influence of both genes and environment on lung function, smoking behaviour and the presence of respiratory symptoms has previously been demonstrated for each of these separately. Hence, smoking can influence lung function by co-varying not only as an environmental factor, but also by shared genetic pathways. Therefore, the objective was to evaluate heritability for different aspects of lung function, and to investigate how the estimates are affected by adjustments for smoking and respiratory symptoms.

Methods: The current study is based on a selected sample of adult twins from the Swedish Twin Registry. Pairs were selected based on background data on smoking and respiratory symptoms collected by telephone interview. Lung function was measured as FEV1, VC and DLco. Pack years were quantified, and quantitative genetic analysis was performed on lung function data adjusting stepwise for sex, pack years and respiratory symptoms.

Results: Fully adjusted heritability for VC was 59% and did not differ by sex, with smoking and symptoms explaining only a small part of the total variance. Heritabilities for FEV1 and DLco were sex specific. Fully adjusted estimates were 10 and 15% in men and 46% and 39% in women, respectively. Adjustment for smoking and respiratory symptoms altered the estimates differently in men and women. For FEV1 and DLco, the variance explained by smoking and symptoms was larger in men. Further, smoking and symptoms explained genetic variance in women, but was primarily associated with shared environmental effects in men.

Conclusion: Differences between men and women were found in how smoking and symptoms influence the variation in lung function. Pulmonary gas transfer variation related to the menstrual cycle has been shown before, and the findings regarding DLco in the present study indicates gender specific environmental susceptibility not shown before. As a consequence the results suggest that patients with lung diseases such as COPD could benefit from interventions that are sex specific.

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Related in: MedlinePlus

Unadjusted and adjusted genetic, shared and non-shared environmental variance components for VC, FEV1, and DLco in men and women. Variance is expressed in absolute numbers and is shown for unadjusted data (% pred), data adjusted for pack years (PY) and data adjusted for pack years and respiratory symptoms (PY + SYM).
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Figure 2: Unadjusted and adjusted genetic, shared and non-shared environmental variance components for VC, FEV1, and DLco in men and women. Variance is expressed in absolute numbers and is shown for unadjusted data (% pred), data adjusted for pack years (PY) and data adjusted for pack years and respiratory symptoms (PY + SYM).

Mentions: In summary, a model including additive genetic factors (A), shared environmental factors (C) and non-shared environmental factors (E) was used for VC and FEV1. The comparisons of variance models indicated that the importance of genetic and environmental effects was the same in men and women (figure 2). For FEV1, the same genes are of importance for men and women (comparing model 2 and 1 in table 5), but the influence of genes and environment differs by sex (significantly different fit between model 2 and 3).


Genetic and environmental influence on lung function impairment in Swedish twins.

Hallberg J, Iliadou A, Anderson M, de Verdier MG, Nihlén U, Dahlbäck M, Pedersen NL, Higenbottam T, Svartengren M - Respir. Res. (2010)

Unadjusted and adjusted genetic, shared and non-shared environmental variance components for VC, FEV1, and DLco in men and women. Variance is expressed in absolute numbers and is shown for unadjusted data (% pred), data adjusted for pack years (PY) and data adjusted for pack years and respiratory symptoms (PY + SYM).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2914039&req=5

Figure 2: Unadjusted and adjusted genetic, shared and non-shared environmental variance components for VC, FEV1, and DLco in men and women. Variance is expressed in absolute numbers and is shown for unadjusted data (% pred), data adjusted for pack years (PY) and data adjusted for pack years and respiratory symptoms (PY + SYM).
Mentions: In summary, a model including additive genetic factors (A), shared environmental factors (C) and non-shared environmental factors (E) was used for VC and FEV1. The comparisons of variance models indicated that the importance of genetic and environmental effects was the same in men and women (figure 2). For FEV1, the same genes are of importance for men and women (comparing model 2 and 1 in table 5), but the influence of genes and environment differs by sex (significantly different fit between model 2 and 3).

Bottom Line: Fully adjusted heritability for VC was 59% and did not differ by sex, with smoking and symptoms explaining only a small part of the total variance.Further, smoking and symptoms explained genetic variance in women, but was primarily associated with shared environmental effects in men.As a consequence the results suggest that patients with lung diseases such as COPD could benefit from interventions that are sex specific.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Public Health Sciences, Karolinska Institutet, Stockholm, Sweden.

ABSTRACT

Background: The understanding of the influence of smoking and sex on lung function and symptoms is important for understanding diseases such as COPD. The influence of both genes and environment on lung function, smoking behaviour and the presence of respiratory symptoms has previously been demonstrated for each of these separately. Hence, smoking can influence lung function by co-varying not only as an environmental factor, but also by shared genetic pathways. Therefore, the objective was to evaluate heritability for different aspects of lung function, and to investigate how the estimates are affected by adjustments for smoking and respiratory symptoms.

Methods: The current study is based on a selected sample of adult twins from the Swedish Twin Registry. Pairs were selected based on background data on smoking and respiratory symptoms collected by telephone interview. Lung function was measured as FEV1, VC and DLco. Pack years were quantified, and quantitative genetic analysis was performed on lung function data adjusting stepwise for sex, pack years and respiratory symptoms.

Results: Fully adjusted heritability for VC was 59% and did not differ by sex, with smoking and symptoms explaining only a small part of the total variance. Heritabilities for FEV1 and DLco were sex specific. Fully adjusted estimates were 10 and 15% in men and 46% and 39% in women, respectively. Adjustment for smoking and respiratory symptoms altered the estimates differently in men and women. For FEV1 and DLco, the variance explained by smoking and symptoms was larger in men. Further, smoking and symptoms explained genetic variance in women, but was primarily associated with shared environmental effects in men.

Conclusion: Differences between men and women were found in how smoking and symptoms influence the variation in lung function. Pulmonary gas transfer variation related to the menstrual cycle has been shown before, and the findings regarding DLco in the present study indicates gender specific environmental susceptibility not shown before. As a consequence the results suggest that patients with lung diseases such as COPD could benefit from interventions that are sex specific.

Show MeSH
Related in: MedlinePlus