(NewsNation) — A new study out of Denmark challenges claims that aluminum in childhood vaccines poses health risks.

Over a span of 24 years, researchers reviewed health data for more than 1.2 million children. According to the study released on Monday in the Annals of Internal Medicine, no evidence was found linking aluminum exposure from vaccines to an increased risk of chronic conditions like asthma, autism, or autoimmune diseases.

Aluminum salts are commonly used in vaccines as adjuvants to enhance immune response, according to the Children’s Hospital of Philadelphia.

Although some have expressed worries about the health impacts of aluminum, the research established no connection between aluminum from vaccines and any of the 50 chronic conditions studied. This includes 36 autoimmune diseases, nine allergy or asthma-related conditions, and five neurodevelopmental disorders.

The study utilized Denmark’s comprehensive registry to trace the vaccination history and health outcomes of children born from 1997 to 2018, with follow-ups until the end of 2020. Researchers evaluated aluminum exposure by age 2 and analyzed outcomes across different exposure levels, excluding unvaccinated children from the study.

Only 1.2% of children received no “aluminum-adsorbed vaccines” before age 2. The rest received varying doses, with total aluminum exposure ranging from 0.125 mg to 1.00 mg per dose. The median exposure across the cohort was approximately 3 mg.

Researchers acknowledge they can’t completely rule out the possibility of a small increased risk for rare disorders.