The number of Americans living beyond their 100th birthday has surged nearly 44 percent since the turn of the century, a U.S. study released on Thursday showed.

Better medical care and healthier lifestyles helped to boost U.S. centenarians' ranks to 72,197 in 2014 from 50,281 in 2000, the Centers for Disease Control and Prevention report said. More than 80 percent of the centenarians were female.

The numbers should keep rising, since the death rate for centenarians has fallen since 2008, noted the study's author, Jiaquan Xu. Some projections show there could be 387,000 U.S. centenarians in 35 years, he noted.

"People are more aware of their health, of the importance of staying active and eating healthy food," Xu said.

Genetic research indicates that about 17 percent of the U.S. population has traits that increase their chances of living past 100, said Dr. Thomas Perls, a geriatrician and director of the New England Centenarian Study at Boston Medical Center.

"In the early 1900s and before, people could count on losing about a quarter of their children to infectious diseases and other public health problems," Perls said.

But with improvements in fighting diseases, people who are genetically prone to live past 100 are now far more likely to survive childhood, he said.

Baby boomers, born after World War II through the mid-1960s, are likely to swell the ranks of centenarians even further, Perls noted.

The top causes of death among centenarians in 2014 were heart disease, Alzheimer's disease, stroke, cancer, influenza and pneumonia, the CDC study found.

Deaths from Alzheimer's increased 119 percent between 2000 and 2014, which Xu attributed to greater awareness of the disease, resulting in more diagnoses.