A sign of the times - fat bums mean longer needles for that jab

Nov 28 2005

It has to be a sign of the times, according to researchers fatter backsides are causing many drug injections to miss their mark, and are requiring longer needles to reach buttock muscle.

In a study at an Irish hospital it was found that the standard-sized needles failed to reach the buttock muscle in 23 out of 25 women whose rears were examined after what was supposed to be an intramuscular injection of a drug.

It seems that two-thirds of the 50 patients in the study did not receive the full dosage of the drug, which instead became lodged in the fat tissue of their buttocks.

The researchers from The Adelaide and Meath Hospital in Dublin say that apart from receiving less than the correct drug dosage, medications that remain lodged in fat can cause infection or irritation in patients.

Researcher Victoria Chan says without question obesity is the underlying cause and the study has identified a new problem related, in part, to the increasing amount of fat in patients' buttocks.

She says the amount of fat tissue overlying the muscles exceeds the length of the needles commonly used for these injections.

Of the 25 men and 25 women studied at the Irish hospital the ages ranged from 21 to 87.

Apparently the buttocks are a good place for intramuscular injections because there are relatively few major blood vessels, nerves and bones that can be damaged by a needle, and there are plenty of smaller blood vessels found in the muscle to carry the drug to the rest of the body, while fat tissue contains relatively few blood vessels.

Figures suggest that obesity affects more than 300 million people worldwide based on a measure of height versus weight that produces a body mass index above 30.

It is estimated that 65 percent of U.S. adults are overweight or obese.

The study was presented to the annual meeting of the Radiological Society of North America.