Skepticism about our elected leaders' ability to fix the nation's ills may be at an all-time high, but a study released last month finds that well-considered government intervention actually works when it comes to promoting health.

Research published in the New England Journal of Medicine and reported by MedPage Today found that things like smoking bans, taxes on high trans-fat or salty foods, building parks to encourage exercise, and similar government actions to promote health are, in the long run, less expensive and provide longer-term benefits than clinical or personal interventions.

Researchers cite one study that found a tax on sodium reduced the public's salt intake by 6 percent, cut heart disease and strokes, and saved $22.4 billion over the lifetime of adults ages 44 to 85.

"It can be far less expensive to alter an environmental element to which many people are exposed than to interact with each person directly. Even if the effect of an altered environment on each person is small, the cumulative population effect can be large," according to the researchers, Dave A. Choksi, M.D., of Harvard and Brighman and Women's Hospital, and Thomas A. Farley, M.D., of the New York City Department of Health and Mental Hygiene.

The theory that policy changes help boost healthful habits got added support in studies published in two other journals and again reported by MedPage Today.

Researchers writing in the Annals of Internal Medicine found that the amount of trans-fat consumed by New Yorkers at lunch at a fast-food chain has fallen by about 22 calories per purchase since the city banned trans-fat from restaurant food.

A study in Pediatrics found that elementary students in schools where strong laws govern the nutrition content of food and beverages sold in vending machines, nearby stores and a la carte in their own cafeterias gained fewer body mass index units and were on track for less weight gain than kids attending schools where regulations are not strong.

On another front, researchers at the University of Virginia School of Medicine found that the Needlestick Safety and Prevention Act has significantly reduced the number of needlestick injuries among health care workers.

The law requires employers to provide safety-engineered devices to staff at risk of exposure to bloodborne pathogens and to let frontline workers have a say in selecting the devices. Needlestick injuries had been increasing annually until 2001 when NPSA went into effect. That year, injuries fell 38 percent and the annual totals continue to be well below pre-NPSA levels. The findings were published in February in the New England Journal of Medicine and reported by Occupational Health & Safety on Feb. 18.