A report by the Centers for Disease Control and Prevention predicts that cancer will soon surpass heart attack as the leading cause of death in the United States.

In fact, it will happen in two years. Data collated from the past 12 years by the National Center for Health Statistics Multiple Cause of Death mortality files revealed that from 2003 to 2015, more counties across the country reported cancer as the leading cause of death.

"Recent data suggest that the United States is in the midst of an epidemiologic transition in the leading cause of death," wrote the researchers. "How the epidemiologic transition from heart disease to cancer is occurring in regions of the United States with different levels of economic development, and by racial/ethnic group, is unclear."

Cancer To Become The Leading Cause Of Death In The US

The report revealed that in 2003, 79 percent of the participating counties disclosed that the top killer for the year was heart disease. The rest of the counties stated that cancer was the leading cause of death among citizens.

In comparison, in 2015, only 59 percent of counties said that heart disease was the leading cause of death. The rest said it was cancer.

The Disease Transition Theory

This is in line with the decade-old theory that predicted a periodic shift in the health and disease pattern in the United States. In the last century, diseases such as tuberculosis and flu were claiming the lives of many Americans.

The shift happened by the latter part of the 100-year period. Deaths due to heart disease and cancer became more common.

The theory predicted that the shift is dictated by economic and social conditions — an idea backed by the new report from the CDC. The report revealed that from 2003 to 2015, the rates of mortality linked to heart diseases declined by 22 percent in low-income counties and 30 percent in high-income counties. Meanwhile, the rates of mortality linked to cancer declined 11 percent in low-income counties and 18 percent in high-income counties during the same time period.

The researchers further added that the introduction of effective but expensive cancer therapies might further affect the shift, contributing to the social inequalities of cancer survival. The effects of genetic testing, screening, and personalized treatment on cancer are still unclear as of the moment.