Our health, especially as we age, becomes a greater and greater concern. But health care can be expensive, depending on our circumstances. Why does U.S. health care cost so much?

Curiosity contributor Susan Sherwood took a look at some of the factors that impact the rising cost of health care.

How much is "SO" much? According to the Kaiser Family Foundation, Americans spent almost $2.6 trillion on health care in 2010 -- a more than tenfold increase in 30 years. Researchers disagree about the reason for it, but a consensus targets two problems: higher medical costs, and the system's use of costly interventions.

A study from Columbia University compared the income of primary care physicians and specialists across six developed countries. The bottom line: American doctors make more than their counterparts in other developed countries. An American primary care physician earns, on average, $186,582, while the same position in Australia grosses less than half that. Labor costs account for about 70 percent of health care expenditures. That's due primarily to the for-profit status of most of the American health care system.

While the governments of other countries exert more control over medical costs, expensive procedures in the U.S. are not curbed by government intervention. Americans have tremendous access to health care. For example, the U.S. excels in cancer care, its survival rates among the highest worldwide. Sick Americans receive treatment not broadly available in other countries, though this helps increase the cost of care.

Prescription drugs are also widely available and lack price regulation. In the last 10 years, drug purchases have increased almost 40 percent. During most of those years, the cost of drugs has increased at a greater rate than have other medical costs, a trend that's expected to continue. More than 50 percent of adults regularly use prescription medications, the rate far higher for the elderly. Many of these drugs are employed as an alternative to more invasive and expensive intervention. Although prescription drugs account for just 10 percent of American health care costs, in 2008 pharmaceutical companies were the third-most profitable U.S. industry [source: Kaiser].

Other factors contributing to high costs include increased life span, lack of health insurance, a greater prevalence of chronic illnesses and higher rates of obesity.