Jan. 14 (Bloomberg) — Obamacare and an aging U.S. population are spurring purchases of medical office buildings, with investors sending prices to a record on bets that Americans' demand for health services will increase.

Sales of properties leased by doctors and other health-care providers reached $6.67 billion in 2013, the second-highest total in 13 years of data-keeping by Real Capital Analytics Inc. Buyers including real estate investment trusts paid an average of $270 a square foot, up from $262 in 2012 and the most on record. The increase partly reflects deals for newer buildings with the latest technology, according to the research firm.

"It's a really competitive space," said Steve Sikes, manager of real assets at the Alaska Retirement Management Board, which is considering buying $150 million to $200 million of medical offices in what would be its first direct purchases of the properties. "Hopefully there's enough of these out there for everyone."