问答题 More Americans are giving up their landlines for cell phones, but new research indicates that there may be health risks associated with long term wireless use. What"s a mobile addict to do?
Americans logged more than 1 trillion cell-phone minutes in the first half of 2007 alone, so it came as little surprise that this is the year cellular-phone spending is predicted to surpass that of landlines, according to Labor Department data released this week. 1 But even as more people give up their traditional home phones altogether and ever younger kids get their own cell phones, there are still questions in the scientific community about whether this new American staple is safe for heavy or long-term use.
2 Experts say the concern over cell-phone use stems from a form of radiation that"s produced when the devices communicate with their base station. Wireless phones transmit via radio frequency (RF), a low-frequency form of radiation that is also used in microwave ovens and AM/FM radios. While high-frequency radiation (the kind used in X-rays) is known to cause cancer at high doses. The risks of this milder form remain unclear. A cell phone"s main source of RF is its antenna, from which it sends a signal to the nearest base-station antenna. The further a cell phone is from the base station, the more RF it needs to establish and maintain a connection. So, the theory is that any risks posed by RF would be greater for people who live and work in areas with fewer base stations. 3 In fact, Israeli researchers reported earlier this month in the A merican Journal of Epidemiology that long-term cell-phone users living in rural areas faced a "consistently elevated risk" of developing tumors compared with users who live in suburban or urban areas.
Other research, including an ongoing multinational initiative known as INTERPHONE, has yielded mixed results so far. While a number of studies have found no correlation between cell-phone use and various types of brain tumors, most of those studies focused on people who had been using cell phones for three to five years. Long-term cell-phone use may be another story. 4 A handful of small studies have indicated that using a cell phone for an hour each day over a 10-year period can increase the risk of developing a rare brain tumor and that those tumors are more likely to be on the side of your head that you use to talk on the phone.
But quantifying the health risks of cell phones is a trickier proposition than understanding how they work. The gadgets have been widely available for only about a decade; tumors can take twice as long to develop. And hands-free devices minimize a person"s RF exposure by enabling them to keep the phone"s antenna away from their head have only been commonplace for a few years. The data on kids who use cell phones is even scarcer because not enough time has passed to examine the effects on children who use them extensively as they grow. 5 However, many researchers believe younger cell-phone users may face a higher risk of developing tumors because their nervous systems are not fully developed and their skulls are not as thick as those of adults.