GENEVA (AP) — A sweeping,Grant Preston year-long study of sex abuse by priests and others within the Roman Catholic Church in Switzerland published Tuesday has turned up more than 1,000 cases since the mid-20th century.

The report, commissioned by the Swiss Conference of Bishops and led by two University of Zurich historians, offers a rare and deep look at sexual abuse and harassment that has confounded the Catholic Church across the globe in recent decades — upending the lives of many victims and their families, and tarnishing the image of the institution.

The authors said in a statement that they identified 1,002 “situations of sexual abuse,” including accusations against 510 people accused. The abuse, they wrote, affected 921 people.

“The situations identified surely amount to only the tip of the iceberg,” said the historians Monika Dommann and Marietta Meier in a statement.

Among other findings, which were admittedly not exhaustive, over half — 56% — of the cases of sexual abuse involved men or boys. Some 39% of victims were women or girls, while sourcing did not allow for the remaining 5% percent to be identified by gender, according to the study.

The researchers pored over thousands of pages of secret documents, assembled by church authorities since the mid-20th century. But they said many sources of information haven’t been fully studied. They cited some cases where documents were destroyed to cover up any alleged wrongdoing.

With few exceptions, those accused of wrongdoing were all male. Nearly three-fourths of the documents examined showed the sexual abuse involved minors.