Tag: public health

Saliva tests may help identify marijuana-impaired drivers

Photo by ashton
Photo by ashton

As of the recent election, seven states and the District of Columbia have now legalized marijuana for recreational use and 19 other states have legalized medical marijuana. And this legalization has raised concerns about driving under the influence of marijuana.

A number of research groups are now focusing on ways to identify drivers impaired by marijuana. As recently reported by KQED, the Center of Medicinal Cannabis Research at the University of California, San Diego, are working to “gather data about dosages, time and what it takes to impair driving ability — and then create a viable roadside sobriety test for cannabis.” And a group of Stanford engineers have created a test called a ‘potalyzer.’

The Stanford effort was led by Shan Wang, PhD, a Stanford professor of materials science and engineering and of electrical engineering. He and his colleagues developed a mobile device that detects the amount of tetrahydrocannabinol (THC) molecules in saliva. (THC is the main psychoactive agent in marijuana.)

The test would allow police officers to collect a saliva sample from the driver’s mouth with a cotton swab, analyze it with the new device, and then read the results on a smartphone or laptop in as little as three minutes.

The technology combines magnetic nanotechnology with a competitive immunoassay. During the test, saliva is mixed with antibodies that bind to both THC molecules and magnetic nanoparticles. The mixture is placed on a disposable test chip, inserted into the handheld device and the THC-antibody-nanoparticles are detected by magnetic biosensors. The biosensor signal is then displayed on a Bluetooth-enabled device.

Wang’s group focused on developing a THC saliva test because it is less invasive and may correlate better with impairment than THC urine or blood tests. Also key is the need for a very sensitive test. A Stanford news release explains:

“Wang’s device can detect concentrations of THC in the range of 0 to 50 nanograms per milliliter of saliva. While there’s no consensus on how much THC in a driver’s system is too much, previous studies have suggested a cutoff between 2 and 25 ng/ml, well within the capability of Wang’s device.”

There is still a lot to do before police can deploy this ‘potalyzer’ device, including making it more user-friendly, getting it approved by regulators and investigating whether there is a better biomarker to detect marijuana impairment than THC. In addition, the test may not work well for THC edibles, the researchers wrote in a recent paper published in Analytical Chemistry.

On the upside, the Stanford technology could also be used to test for morphine, heroin, cocaine or other drugs — and for multiple drugs at the same time.

More research is needed, but there is now a new funding source in California: Proposition 64 allots millions of dollars per year to research marijuana and develop ways to identify impaired drivers.

This is an expanded version of my Scope blog story, courtesy of Stanford School of Medicine.

Quitting smoking: Best drug differs for men and women

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Photo by Tomasz Sienicki

It’s tough to quit smoking. I’ve seen friends and family members struggle with nicotine withdrawal symptoms: cravings for tobacco, anxiety, anger, irritation, increased hunger and even trouble thinking.

One out of six adults in the United States currently smoke and about half of them are trying to quit, but the success rate remains low. What’s the best way to stop smoking? A new study may help point the way — for women.

The study found that a medication frequently used to help smokers quit is more effective for women than men. Philip Smith, PhD, assistant medical professor at the City College of New York, led the multi-institutional study: a network meta-analysis of 28 randomized clinical trials involving a total of 14,389 smokers (51 percent female).

The researchers did a head-to-head comparison between the three common types of medications used for smoking cessation: the nicotine patch, varenicline (sold as Chantix and Champix) and sustained-release bupropion (sold as Wellburtin or Zyban). The quit rate of the participants was based on biochemical verification of their abstinence after six months.

The authors reported in their new paper in Nicotine & Tobacco Research:

“Women treated with varenicline were 41 percent more likely to achieve 6-month abstinence compared to women treated with TN [transdermal nicotine patch], and were 38 percent more likely to achieve 6-month abstinence than women treated with bupropion. For men, the benefit of varenicline over TN and bupropion were smaller and were not statistically significant.”

“Before our study, research had shown that among the choices for medications for smokers who wanted to quit, varenicline was the clear winner when it came to promoting quitting,” said Smith in a recent news release. “Our study shows this is clearly the case for women. The story seems less clear among men, who showed less of a difference when taking any of the three medications.”

The research findings identify varenicline as a particularly potent first option treatment for women. However, the good news for all smokers is that all three medicines significantly improved quit rates for both men and women, when compared with placebo.

If you’re trying to quit smoking, a combination of counseling and medication has been shown to be an effective way to treat tobacco dependence — speak with your doctor or contact a smoking cessation program.

This is a reposting of my Scope blog story, courtesy of Stanford School of Medicine.

Stanford expert calls for more targeted anti-obesity policies

U. S. Department of Agriculture's helps educate shoppers about the value of food labeling in December 1975. Photo courtesy National Archives and Records Administration.
U. S. Department of Agriculture helps educate shoppers about the value of food labeling in 1975. Photo courtesy National Archives and Records Administration.

Reality TV shows like “The Biggest Loser” are popular in part because the audience can relate to the participants — more than two-thirds of adults and about one-third of children and adolescents are obese or overweight in the US. The Surgeon General and the Centers for Disease Control and Prevent have declared obesity to be a national epidemic and a major contributor to leading causes of death, including heart disease, stroke, diabetes and some types of cancer.

Although our country is committed to finding solutions to the increase in obesity, public policies have fallen short, according to Deborah Rhode, JD, a Stanford law professor and legal ethics scholar. In a recent journal article, she wrote:

Many policy responses have proven controversial, and those most often recommended have frequently faced an uphill battle at the federal, state, and local level. At the same time that obesity rates have been rising sharply, many jurisdictions have resisted, or rolled back, strategies such as soda taxes or regulation of advertising directed at children.

In the journal article, Rhode evaluates anti-obesity policies, including calorie disclosure requirements, taxes or bans on sugar-sweetened beverages, food stamp modifications, zoning regulations, children’s marketing restrictions, physical activities initiatives, food policies and education. She suggests that a more targeted approach is needed to combat obesity. For instance, Rhode recommends creative zoning regulations that restrict the location of fast-food restaurants near schools while encouraging healthy food retailers in underserved neighborhoods.

In a Stanford news release, Rhode noted that the first lady Michelle Obama’s “Let’s Move!” campaign against childhood obesity applies to politics as well as physical activity. Rhode summarized, “Although we need more evaluation of policy strategies, we know enough about what works to chart a course of reform. We should act now on what we know.”

This is a reposting of my Scope blog story, courtesy of Stanford School of Medicine.