Denmark: People residing in city centers are almost twice as likely to suffer from coronary artery calcification (CAC), which can lead to heart disease, than those who live in less polluted urban or rural areas, according to a study.

CAC is the accumulation of calcium deposits in arteries. Researchers, led by Jess Lambrechtsen, cardiologist at Svendborg Hospital in Denmark, spoke to 1,225 men and women aged 50 to 60 years, including 251 who lived in the centres of major Danish cities.

Despite the fact that none of the participants showed any symptoms of heart disease, 43 per cent of the total had CAC, the Journal of Internal Medicine reports.

The study also found that people who lived in city centres were 80 per cent more likely to develop CAC than those living in other areas and that males, older participants, diabetics and smokers also faced higher risks, according to a Svendborg statement.

"Our study aimed to evaluate the association between living in a city centre, which is often used by researchers to indicate exposure to air pollution, and the presence of coronary artery calcification in men and women showing no other symptoms of heart disease," explains Lambrechtsen.

The participants were selected at random from a national government database of Danish adults, and 69 per cent agreed to take part and attend one of four regional hospitals in Southern Denmark.

Three percent were excluded from the study because of previous heart problems, leaving 1,225 people who did not display any symptoms of heart disease. Of these, 47 per cent were male and 53 per cent were female and they were equally split between the 50 year-old and 60 year-old age groups.

Key findings included: CAC was more common in people living in city centres, rather than urban or rural areas - in men (69 per cent vs 56 per cent), women (42 per cent vs 30 per cent ), 50 year-olds (48 per cent vs 32 per cent) and 60 year-olds (61 per cent vs 53 per cent).