NEW YORK When swings in the stock market cause anxiety to spike, like it is now, many investors aim to get healthy.

Stocks don't come with guarantees, but health care stocks have held up better than others during past downturns. People get sick regardless of the economy's strength, after all, and an aging population around the world means more demand for prescription drugs and hospital care. That has brought more attention to health care stock funds, as worries about a weak global economy have sent stocks sinking in recent weeks.

Health-care stock funds have returned an average of 19.1 percent annually over the last five years, more than any of the other 101 fund categories tracked by Morningstar. The strong returns are luring more dollars: Investors put more into health care funds last month than they pulled out, contrary to the trend for stock funds in general. But it's important to keep in mind that conditions are much different for the sector than they were five years ago. Here's a look at some questions to consider before buying a health care fund.

ARE HEALTH-CARE STOCK FUNDS REALLY SAFER INVESTMENTS?

Everything is relative, but they have been in the past.

"We're investing in demand for health, and that comes in drugs, devices and hospital services," says Jean Hynes, manager of the Vanguard Health Care fund (VGHCX), whose $40.9 billion in assets makes it the largest fund in the category by far. Demand for those tends to be more stable than it is for, say, electronics or other non-essentials.

Consider how the financial crisis dragged the Standard & Poor's 500 index to a loss of 37 percent in 2008, even after factoring in dividends. That year, health care stock funds lost an average of 23.4 percent.

Many of the big pharmaceutical companies and insurers in the sector also pay dividends, which can help offer a smoother ride. Johnson & Johnson, Pfizer and Merck are the three largest health care stocks in the S&P 500, and all have a higher dividend yield than the index.

WHAT SHOULD I LOOK FOR IN A HEALTH CARE STOCK FUND?

Even within the health care sector, some types of stocks are safer than others. On the more volatile end are biotechnology stocks, which can be boom-or-bust investments depending on how much excitement their drugs under development are generating.

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