Cleaner bedroom air may help people with prediabetes keep blood sugar steadier, a new NYU Langone trial suggests.

A portable HEPA filter running overnight cut fine-particle pollution by 36 percent. Daily blood sugar swings dropped by nearly 8 percent.

Total extra glucose after breakfast fell 17 percent, and peak levels after breakfast fell 13 percent.

More than 150 New York City adults with prediabetes took part. Half got real filters for about a month, and half got lookalike sham ones.

Neither participants nor staff knew who had which. Blood sugar was tracked with continuous glucose monitors.

Prediabetes means blood sugar is above normal but not yet diabetes. It raises the risk of type 2 diabetes and heart disease.

The results were presented on 8 November at the American Heart Association's Scientific Sessions in Chicago. They are not yet peer reviewed.

The study lasted four weeks, and was funded by the Doris Duke Foundation, not by any air purifier maker.

Senior author Dr Jonathan Newman said the results may not apply to people who already have diabetes or face different pollution.

Read the full report on the bedroom air filter study on Trends News Stories.

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