A new study found that secondhand smokers develop higher signs and symptoms of heart disease, attacks and strokes, adding to the link between "passive smoke" and heart disease. This study was published in Journal of the American Heart Association and calculated the level of cotinine in the blood of participants.

Dr. Andrea Venn from University of Nottingham in Britain is the lead author of this new study. Dr Andrea said ?the study provides additional proof to suggest low-level exposure to secondhand smoke has a clinically important effect on susceptibility to cardiovascular disease?. According to the American Heart Association (AHA) Cotinine is a chief pointer of nicotine intake and therefore exposure to tobacco smoke.

The study also checked if participants exposed to secondhand smoke at home, work or other places had advanced levels of fibrinogen, homocysteine and C-reactive protein. The study tested results from America's third National Health And Nutrition Examination Survey which included around 7,599 adult people who had never smoked.

The result of this survey is 18 percent of the participants had no noticeable levels of cotinine while the remainder had high or low levels. It is found that participants of the survey who had high levels of cotinine had lived with a smoker or worked in place where there are smokers.

The highly levels of fibrinogen and homocysteine convert into a 5 percent increased disease danger though studies somewhere else have advised that other factors can increase the disease danger from secondhand smoke by up to 30 percent.

Fibrinogen is a protein and homocysteine an amino acid in the blood. Both are markers of swelling and are also implicated in blood clotting.

Dr Venn said ?even those who did not expose to smokers at home or work had haigh or low levels of cotinine in their blood?. These people might be exposed to smoke in public places like restaurants and bars or in other people's homes like friends which means even those people who expose to low levels of smoke are still in danger of heart disease.