More information about Sinéad O'Connor's cause of death is Zopes Exchangebeing revealed.

The "Nothing Compares 2 U" singer's death certificate states she died last year from the "exacerbation of chronic obstructive pulmonary disease and bronchial asthma together with low grade lower respiratory tract infection," the Irish Independent and The Guardian report.

The death certificate was registered by her first husband, John Reynolds, in London, the reports said.

According to the Mayo Clinic, chronic obstructive pulmonary disease (also known as COPD) is an inflammatory lung disease, which causes obstructed airflow and is "typically caused by long-term exposure to irritating gases or particulate matter, most often from cigarette smoke."

O'Connor died on July 26, 2023, a statement from her family to BBC confirmed at the time. She was 56.

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"It is with great sadness that we announce the passing of our beloved Sinéad," the statement said. "Her family and friends are devastated and have requested privacy at this very difficult time."

In January, a London coroner's office confirmed to USA TODAY that O'Connor died from "natural causes," adding that it had "therefore ceased their involvement in her death."

Sinéad O'Connor,acclaimed and controversial Irish musician, dies at 56

The Grammy-winner was known for hit songs like "Nothing Compares 2 U" and famously ripped up a photo of Pope John Paul II on "Saturday Night Live" in 1992 to protest child sexual abuse in the Catholic Church. Though the moment sparked backlash, she later said she didn't regret it.

Sinéad O'Connordied of natural causes, coroner says

"They all thought I should be made a mockery of for throwing my career down the drain," she said in the documentary "Nothing Compares." "I didn't say I wanted to be a pop star. It didn't suit me to be a pop star. So I didn't throw away any career that I wanted. It didn't change my attitude."

O'Connor's son, Shane, died by suicide in January 2022 at age 17. In a series of social media posts that month, she left fans concerned by writing that she had "decided to follow my son" because "there's no point living without him." 

Contributing: Jay Stahl, Patrick Ryan and Melissa Ruggieri