Every day, we are exposed to things such as pollution that can increase our risk of illness. Many people take on additional risks—due to tobacco smoke, fast food, or alcohol, for example. But there’s a less-recognized exposure that is even more common than smoking and increases the risk of heart disease, diabetes, cancer, chronic lung diseases, sexually transmitted infections, chronic pain, and mental illness, and reduces one’s life by as much as 20 years. This public health hazard that hides in plain sight is childhood adversity: experiences such as physical abuse, sexual abuse, and neglect. Childhood Adversity Is Common In the United States, more than two-thirds of children reported at least one traumatic event by age 16, according to the Substance Abuse and Mental Health Services Administration. In Canada, one child in three is physically or sexually abused, or witnesses violence between adults in their home. Other adversities such as emotional neglect, living in an unsafe neighborhood, or experiencing prejudice and bullying are …