[ted id=1648]If you look at mortality data across the United Kingdom, a striking correlation materializes: the higher the latitude, the greater the relative risk of death. This is true even when controlling for risk factors like smoking cigarettes and eating bad food. So, what’s going on?

The answer may lie in sunlight—there’s more in the south than there is in the north, particularly in the winter. Talk about how sunlight affects health usually centers around Vitamin D, an essential vitamin that is, in part, produced in human skin during exposure to ultraviolet B rays. But in today’s talk, given at TEDxGlasgow, dermatologist Richard Weller describes new research that links sunlight to another compound — nitric oxide. This chemical messenger lowers blood pressure by dilating blood vessels. High blood pressure is, of course, a major risk factor for heart disease.

Weller says that stable versions of nitric oxide are stored in the skin and are activated by sunlight, after which the compound makes its way to the circulatory system. In other words, this sunlight-boosted nitric oxide might be lowering the blood pressure of people in sunnier locales, thus lowering their risk of heart disease.

There are many messages in Weller’s charming talk. But perhaps the strongest: that where you live affects your health. And this extends far beyond your distance from the equator or how much sun you get every day. Here are five other TED Talks about ties between health and geographical location.

[ted id=748]Bill Davenhall: Your health depends on where you live
Where you spend your life influences your health, but this information is strangely lacking in your medical record. In this 2009 TEDMED talk, health and human services expert Bill Davenhall explores what he calls his “place history”—from growing up in coal country in northeastern Pennsylvania to living by a plastics plant in Kentucky to commuting in smoggy Southern California—to illustrate how the chemicals he’s breathed may have affected his long-term health. He concludes that doctors typically ignore our geographical history — but probably shouldn’t.

[ted id=268]Dr. Seyi Oyesola tours a hospital in Nigeria
According to anesthesiologist Seyi Oyesola, if you live in an underdeveloped country and are unlucky enough to need medical care, you likely won’t get it. In his talk from TEDGlobal 2007, Oyesola explores what happens when Nigerians — who live in a country lacking in doctors, facilities and resources — need treatment for trauma, heart attack or cancer.

[ted id=1530]Stephen Ritz: A teacher growing green in the South Bronx
Teacher Stephen Ritz has noticed his kids in the South Bronx of New York getting heavier and less healthy by the year. That’s because this is one of the most polluted and economically disadvantaged areas in the United States, where healthy food is hard to find. At TEDxManhattan, Ritz shared an idea—edible walls. He teaches his students to grow delicious produce in their school. And while boosting the community’s health, they also learn valuable job skills.

[ted id=10]Dean Ornish: The world’s killer diet
Cardiovascular disease kills more people than AIDS, cancer and avian flu combined. At TED2006, Dean Ornish looks at how cardiovascular disease is on the rise even on continents where it hasn’t traditionally been a huge health concern, like in Asia and Africa. His thought? That the Americanization of the world means other cultures are eating like us and, consequently, “die like us.” In this talk, he gives bold ideas for how changing diet and exercise can prevent heart disease. (See also: food reporter Mark Bittman sharing “What’s wrong with what we eat” at EG 2007, and disease researcher William Li asking “Can we eat to starve cancer?” at TED2010.)

[ted id=727]Dan Buettner: How to live to be 100+
In this talk from TEDxTC, writer Dan Beuttner describes a National Geographic project that identified locations worldwide where people live to extraordinary age. Dubbed Blue Zones, these far-flung regions share similarities in nine habits of diet and lifestyle. Most important, says Buettner, are specific cultural influences in each Blue Zone that encourage elderly people’s participation in society.