It is common knowledge that smoking is bad for you. From heart disease to emphysema and even circulation issues, smoking is the leading and pretty much only cause of lung cancer in the world (80 to 90 percent of cases). Now adding fuel to the argument of smoking's harm to the body, researchers at the University of Pennsylvania Medical School have found that smoking cigarettes extends the time it takes bone breaks to heal and can complicate post-operation recovery by increasing rates of infection.

With around 1 in 5 Americans smoking and over 6 million bone fractures occurring a year in the US, this is a serious public health issue.

"Cigarette smoking is widely recognized as one of the major causes of preventable disease in the US, but there has been a lack of evidence showing other side effects of smoking, such as how it changes the way our bones heal," said Samir Mehta, MD, chief of the Orthopaedic Trauma and Fracture Service at Penn Medicine. "Our study adds substantial support to a growing body of evidence showing that smoking presents a significant risk to fracture patients. These risks need to be addressed with the patient both at the time of injury and when considering surgical treatment."

The study showed that for all types of bone injuries, patients who smoked had around six weeks longer time to heal fractures than people who did not smoke (30.2 weeks for smokers and 24.1 weeks for non-smokers). Smokers were also twice as likely to have bone breaks that resulted in the bones not fusing together and healing by more than two times.

Researchers assessed the risk of smoking in the recovery from fractures of the tibia, femur or hip, ankle, humerus, and multiple long bones, in total, 6,480 patient cases.

"The effects of smoking intervention programs need to be discussed and instituted to promote better outcomes for post-fracture patients," says Mehta. "We have an opportunity to help patients understand that it's about more than just heart health, and that smoking puts you at a higher risk of complications and leads to longer healing times."

Researchers hope to conduct future studies to evaluate if there is a dose dependence factor, implicating how much someone smoked and the healing time or complications that they encountered.

The full of the study are going to be presented this week at the 2013 American Academy of Orthopaedic Surgeons annual meeting in Chicago.