January 2011 marks a significant milestone for the baby-boomer generation when its first members, born in 1946, begin the year in which they will celebrate their 65th birthdays.

The boomers' transition into the years that traditionally denote the beginning of senior citizenship also draws attention to the graying of America.

Dr. Stephen G. Jones, a geriatrician and expert in gerontology and director of the Center for Healthy Aging at Greenwich Hospital, in Greenwich, Conn., says the impact these so-called "geri-boomers" will have on American health care will be significant on numerous fronts.

"It is wonderful news that we are living longer, but it also creates an entirely new set of challenges for families and the health-care system," says Jones. "The face of medicine is going to start to change rapidly because of this transition," he adds.

While the leading cause of death in America 100 years ago was infection, "now true diseases of aging—cancer, heart disease, and Alzheimer's disease—are the leading causes," he says.

One of the looming issues, Jones says, will be the shortage of doctors trained to care for an aging population. Geriatrics, the subspecialty that focuses on the specific health needs of the elderly, is facing an acute shortage of physicians. Low insurance reimbursement rates for the care they provide and other factors have reduced the ranks of doctors seeking geriatrics training. In 2007 only 91 American-trained doctors sought to specialize in geriatrics, compared with 167 in 2003, and spots in many geriatric fellowship programs weren't filled.

Who will care for this population? While the care burden, in many instances, falls on primary-care physicians, they, too, are facing similar challenges to keep their practices solvent and viable.

Jones notes that boomers are expected to number 70 million by 2030, making them the oldest generation of seniors in history, and he says their children will struggle to manage care for multiple generations in their families. Rather than the sandwich generation, which refers to adults caring for both their parents and their children, Jones refers to the "club sandwich generation," as more adult children will be faced with the responsibilities of caring for their parents and sometimes grandchildren.

He also points out that longevity is advancing faster than our ability to keep up with the diseases of aging, as arthritis, orthopedic problems, and chronic illnesses are anticipated to burden the population and the health-care system.

Alzheimer's disease, which impacted about 4.5 million Americans in 2000, will more than double in incidence by the year 2030 and is likely to reach epidemic proportions by 2050, Jones says. To put this illness in perspective: A new case is diagnosed every 71 seconds and one out of eight Americans 65 and older will be diagnosed.

The statistics are more staggering for those 85 and older where one out of two seniors faces a possible diagnosis.

Seniors age 85 and older are predominately female, raising new issues for women who will spend their later years widowed or single, Jones says, noting that their numbers will increase from 4 million in 2000 to an estimated 31 million in 2030.