(CORDIS) — A study of both city slickers and country bumpkins has shown that those living in urban areas are almost twice as likely as are their country cousins to suffer from coronary artery calcification (CAC), a condition that can lead to heart disease.
Writing in the Journal of Internal Medicine, the Danish researchers present the findings of their analysis, based on a study of 1 225 men and women aged 50 and 60 living both in and out of town.
The study found people who lived in the city centre were 80% more likely to develop CAC than those living in other areas, and that males, older participants, diabetics and smokers were also more at risk.
Lead study author, Dr Jess Lambrechtsen from the Department of Cardiology at Svendborg Hospital, Denmark explains: ‘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.’
Participants were selected at random from a government database; once they had consented to take part, they filled out questionnaires about their medical condition to determine that they had not suffered from any previous heart problems. The team also needed to know about any prescribed medications, smoking habits, and whether there was a history of heart disease in participants’ families. The clinical examination included height, weight, blood pressure, blood tests and scans.
CAC was found to be more common in people living in city centres than for those living in urban or rural areas: in men (69% v 56% respectively), women (42% v 30% respectively), 50 year-olds (48% v 32% respectively) and 60 year-olds (61% v 53% respectively).
After looking at the odds ratio, it transpired that people living in city centres were 80% more likely to develop CAC than were those living in urban or rural areas. Men were more than three times as likely as were women to develop CAC, with a 220% higher odds risk.
Those aged 60 were approximately twice as likely to develop CAC as were 50-year-olds (120% higher); likewise, smokers were found to be more susceptible than non-smokers (90% higher), as were people with diabetes when compared with those without diabetes (100% higher).
Having high cholesterol raised the odds of developing CAC by 60%; high blood pressure and a family history of heart disease both raised the odds by 50%.
Dr Lambrechtsen sums up the implications of the research: ‘Our study shows that living in a city centre and traditional risk factors for heart disease were independently associated with the presence of CAC in a group of middle-aged subjects who did not display any symptoms. The place where a person lives is often used as a surrogate for exposure to air pollution in research. In this study we found that, even after adjusting for demographic and clinical variables, where people lived was independently associated with CAC, and that CAC levels were highest in people living in city centres. A number of factors can also influence CAC, such as noise and stress levels, and it could be assumed these would be higher in city centres. However, in this study, stress levels, as measured by average blood pressure, were actually lower in city centre dwellers than people living in urban areas. Heart rates, another predictor of stress, were the same across the groups. The mechanisms by which air pollution may contribute to CAC are not well understood. But what is clear from this study is that the links between air pollution and CAC need further investigation.’