Air pollution impact 'worse' for obese

The impact of air pollution could be worse for people who are obese, researchers have said today.

The US-based study has been published ahead of print in the Journal of Epidemiology and Community Health.

Authors of the study said their findings suggest obesity and midriff bulge (central adiposity) boost a person's susceptibility to changes in blood pressure which are associated with ambient air pollution.

The research has been based on air quality data in a five year study involving 919 households in the Detroit, Michigan area of the US. All the households were within 5km of an air quality monitoring site, which measured levels of fine particulate matter every 30 minutes between 2000 and 2003.

Out of the 919 households, 348 people agreed to give blood samples and have their blood pressure, weight, height and waist circumference measured, as well ethnicity, age gender etc. Just over half were obese.

Almost two thirds of the total sample either had high blood pressure or were on the cusp of a diagnosis of high blood pressure, and more than one in three had high blood cholesterol.

The researchers said: 'Unsurprisingly, those who lived closest to heavy traffic and other sources of particulate matter pollution had higher pulse pressure.

'Pulse pressure measures the difference in diastolic (minimum) and systolic (maximum) blood pressure during a heart beat. They also had higher systolic blood pressure, irrespective of whether they were lean or fat.

'But the effect was greater still among those classified as obese (BMI of 30 or higher and a large waist), and most evident 48 to 96 hours after exposure to the pollutant.'