Single-payer advocates say insurers put profits over health.

Three Harvard doctors found billions in tobacco industry stocks in the investment portfolios of several leading U.S. and British health and life insurance companies.

“In case there is any doubt that insurers place profit above health, consider their investments in tobacco,” the physicians wrote in a letter published in the June 4 New England Journal of Medicine.

A chart shows that U.S.-based Prudential Financial, which sells life insurance and long-term disability coverage, owns $264.3 million of tobacco stock, National Public Radio reported. And the U.K.-based Prudential has more than $1.38 billion in tobacco stock.

The physicians -- J.Wesley Boyd, David Himmelstein, and Steffie Woolhandler -- cited a conflict of interest for the insurers: “Although investing in tobacco while selling life or health insurance may seem self-defeating, insurance firms have figured out ways to profit from both,” they wrote. “Insurers exclude smokers from coverage or, more commonly, charge them higher premiums. Insurers profit -- and smokers lose -- twice over.”