Nonwhite patients are more likely than white patients to have troublesome side effects from two common types of drugs used to fight high blood pressure, stroke and heart attack, British researchers report.

But the finding has to be viewed with caution, because experts say it’s not clear whether race or other factors, such as more limited access to health care, may be to blame.

“It is impossible to know how much of the observed differences could be accounted for by factors such as these vs. underlying genetics,” said Carlotta M. Arthur, a psychologist and an Andrew J. Mellon fellow at Smith College in Northampton, Mass.

Smith, a spokeswoman for the nonprofit Council for the Advancement of Health, was not involved in the study, which appears in the May 6 issue of the British Medical Journal.