WASHINGTON — Children of divorced or separated parents run a greater risk of becoming ill than those who grow up in intact families, a study concludes.

Researcher Jane Mauldon of the University of California at Berkeley said children of broken families run a 35-percent risk of developing health problems over a three-year period. That compares with a 26-percent risk among all children.

Tonsilitis, repeated ear infections and pneumonia accounted for nearly one-third of the reported illnesses, according to the study. Other problems included allergies, asthma, chronic skin conditions, chronic lung problems and urinary infections.

The problems persist even after the mother has remarried, the report also noted.

The results of the study appear in the August edition of the journal Demographics, published by the Washington-based Population Association of America.

Mauldon wrote that the “children are likely to have experienced very significant stress because their living standards changed dramatically.”

“They probably also lost many of the resources that contribute to good health — a safe, comfortable environment relatively free of environmental hazards and risks of infection, good food, and constant adult supervision,” she wrote.

Mauldon, of the Graduate School of Public Policy at Berkeley, studied 6,000 children’s health histories. In families where a divorce occurs, children average 0.13 more illnesses per year after their parents’ divorce than before, Mauldon concluded.