Between 2005 and 2015, for every 10 additional primary care physicians per 100,000 residents, life expectancy rose by nearly 52 days. File Photo by piotr_pabijan/Shutterstock

Feb. 18 (UPI) -- Having more doctors may lead to seeing longer lifespans in the United States, new findings show.

Between 2005 and 2015, for every 10 additional primary care physicians per 100,000 residents, life expectancy rose by nearly 52 days, according to research published Monday in JAMA Internal Medicine.


Specifically, these numbers led to an almost one percent reduction in cardiovascular mortality, a 1 percent reduction in cancer mortality and a 1.4 percent decline in respiratory mortality.

"Greater primary care physician supply was associated with improved population mortality, suggesting that observed decreases in primary care physician supply may have important consequences for population health," researchers wrote in the study.

The study shows that the nationwide number of primary care physicians has risen. Still, U.S. population growth has also thinned out the density of primary care physicians per 100,000 people from 46.6 to 41.4 per between 2005 to 2015. Also, the gains are lopsided, with primary care physicians fleeing rural areas over the same period.

"We tried to test whether this is just an 'association' at the area level, or more likely to be a causal connection," Sanjay Basu, assistant professor of medicine and of health research and policy at Stanford, said in a news release. "We looked at people who moved between ZIP codes and compared how their survival changed when moving to higher-primary care physicians ZIP codes versus lower, controlling for other individual and area characteristics."

When people moved to zip codes with more doctors, they added up to 114.2 days per decade for every 10 additional primary care physicians per 100,000 people in the community.

The Association of American Medical Colleges predicts that by 2030, the U.S. will experience a big decrease in primary care physicians.

"Primary care physicians serve as the primary point of contact for most of the population and often perform preventive care, cancer screening and early diagnosis," Basu said.