Obesity Boosts Impact Of Air Pollution On Health

Main Category: Water - Air Quality / Agriculture
Also Included In: Obesity / Weight Loss / Fitness
Article Date: 16 Oct 2009 - 0:00 PDT

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The impact of air pollution may be worse for people who are obese, suggests research published ahead of print in the Journal of Epidemiology and Community Health.

The researchers base their findings on data collected on air quality, and biomedical measures for the Health Environments Partnership study. This five year study began in 2000 and involves 919 households in three areas of Detroit, Michigan, an area of the US that is ethnically and economically diverse.

All the households were within 5 km 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 (body mass index or BMI), height and waist circumference measured.

Data on ethnic background, gender, age, educational attainment, dietary habits and exercise, and pre-existing health problems were also collected as these factors all have a bearing on blood pressure.

Just over half the participants were obese, as measured by BMI, and 57% had waist circumferences above the sizes indicative of a higher than average risk for serious ill health, such as diabetes and heart disease - 88 cm for women and 102 cm for men.

Almost two thirds of the total sample (68%) either had high blood pressure or were on the cusp of a diagnosis of high blood pressure, and more than one in three (36%) had high blood cholesterol.

The average levels of particulate matter measured 15 ug/m3 at all three sites, but at one site in the south west, levels were 20% higher than this.

South western Detroit contains a relatively high concentration of heavy industry, including iron and steel manufacture, coke ovens, and refineries.

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.

The authors say that their findings add to a growing body of work, suggesting that obesity and a midriff bulge (central adiposity) boost susceptibility to changes in blood pressure which are associated with ambient air pollution.

High blood pressure increases the risk of heart disease and stroke, and the authors point out that people who are already disadvantaged are being exposed to risk factors that are not just additive, but which further multiply the risks of serious ill health.

Source
The Journal of Epidemiology and Community Health