HPV vaccine, rosacea and COPD

Asthma: nature versus nurture
Clin Respir J (2012) 6:228-237

Environment accounts for around three-quarters of the variation in the severity of asthma symptoms, according to a study of 575 identical and non-identical twins, at least one of whom who suffered from the respiratory disease.

After adjusting for potential confounders (such as age, sex, current airway infection, smoking and body mass), genetic factors accounted for 24% of the difference in severity of asthma symptoms between the twins.

Environmental factors explained the remainder. Genetic factors also accounted for about 12% and 17% of the variation in the severity of wheezing and shortness of breath between the twins, but did not seem to significantly influence the likelihood of experiencing chest tightness or cough.