Scientists say that with increasing numbers of babies surviving premature birth, childhood asthma is set to become a significant health problem.
The research showed that average asthma rates rose to 14% in babies born prematurely, defined as at least three weeks early.
Those born more than three weeks before the usual 40-week pregnancy term were almost 50% more likely than full-term babies to develop asthma. And babies born more than two months early were three times more at risk.
More top news
Disney has sealed a £39 billion takeover of 21st Century Fox's entertainment assets, including the group's 39% stake in Sky.
The Iraqi citizens won High Court damages against the government for alleged ill-treatment and unlawful detention during the Iraq War.
Médecins Sans Frontières says at least 6,700 of the deaths have been attributed to violence - including 730 children aged five or below.