New research linked outdoor air pollution to an increased risk of diabetes (糖尿病) globally, according to a study from Washington University in St. Louis and the Veterans Affairs (VA) St. Louis Health Care System. The findings raised the possibility that reducing pollution might lead to a drop in diabetes cases.

“Our research shows a significant link between air pollution and diabetes globally,” said Ziyad Al-Aly, a professor at Washington University. “We found an increased risk, even at low levels of air pollution currently considered safe by the US Environmental Protection Agency (EPA) and the World Health Organization (WHO). This is important because many industry groups argue that current levels are too strict. Evidence shows that current levels are still not sufficiently safe and need tightening.” The findings were published on June 29 in The Lancet Planetary Health.

To evaluate outdoor air pollution, the researchers looked at small pieces of dust, smoke and liquid droplets. In diabetes, pollution was thought to reduce insulin (胰岛素) production and prevent the body from changing blood glucose (葡萄糖) into energy that the body needed to maintain health.

The researchers also found that poverty-stricken countries faced a higher diabetes-pollution risk including Afghanistan, Papua New Guinea and Guyana, while richer countries such as France, Finland and Iceland experienced a lower risk. The US experienced a middle risk of pollution-related diabetes.

In the US, the EPA’s pollution limit was 12 micrograms per cubic meter of air, the highest level of air pollution considered safe for the public, as was set by the Clean Air Act of 1990 and was updated in 2012. However, using mathematical models, Al-Aly’s team set an increased diabetes risk at 2.4 micrograms per cubic meter of air. Based on VA data, among a sample of citizens exposed to pollution at a level of between 5 to 10 micrograms per cubic meter of air, about 21 percent developed diabetes.

“The team in St. Louis is doing important research to firm up links between pollution and health conditions such as diabetes,” said commission member Philip J. Landrigan, MD, a pediatrician and epidemiologist at Mount Sinai School of Medicine in New York. “I believe their research will have a significant global effect.”

Nail biting is a common habit. A lot of people tend to bite their finger nails when nervous and anxious. It is a good way to reduce their stress. However, nail biting affects 30 percent of adults, 45 percent of teens and 30 percent of children. It can invite bacteria to enter the body and the blood, increasing your chances of catching a cold or the flu, according to the Mayo Clinic. Not to mention that it can ruin your smile.

The most common virus hiding under your nails is staphylococcus, which can enter the body through breaks in your skin after you bite your nails. If that is not enough a warning, just imagine parasites, hanging out in your nail tissue as you open mouth and put in your finger. So next time the anxiety comes in, try taking five deep breaths instead.

According to the Center for Disease Control, there are more than 200 cold viruses floating around at any given time. You may get one because of exposure to the sick. However, you can reduce your chances of catching a virus by keeping your hands away from your mouth. Viruses that cause the cold are active on your skin as well, so often wash your hands with soap and water, and avoid nail biting by chewing gum.

Nail biting can also damage the teeth. Check with your dentist whether having a mouth guard can help you to stop biting your nails or at least reduce some of the damage it can cause. She may be able to suggest some other ways to help you give up the habit for good.