Obesity, depression, high blood pressure, asthma: These are just a few of the chronic health conditions that are now affecting almost 40 million Americans between the ages 18 and 34, new federal data shows.

Overall, the 2019 data found that more than half of young adults (nearly 54%) now deal with at least one chronic health issue. Almost one in every four (22%) have two or more of these conditions, according to a team of researchers from the U.S. Centers for Disease Control and Prevention.

"The most prevalent conditions were obesity (25.5%), depression (21.3%), and high blood pressure (10.7%)," said a team led by Kathleen Watson, of the CDC's National Center for Chronic Disease Prevention and Health Promotion.

High cholesterol levels affected about 10% of adults under 35, asthma affected over 9%, and about 6% had arthritis, the study found.

Unhealthy lifestyles were often a part of the mix for people with chronic conditions. Young adults "with a chronic condition were more likely than those without one to report binge drinking, smoking or physical inactivity," Watson's team found.

The data is based on telephone surveys conducted in 2019 among more than 67,000 18- to 34-year-olds across the United States.

Certain factors seemed to raise a person's odds for the leading chronic health condition, obesity. For example, about one-third of young adults living in rural areas were obese, compared to about one-quarter of city dwellers. Black Americans were somewhat more likely to be dealing with obesity than whites—33.7% versus 23.9%, respectively.

Depression tended to affect young adult women (27%) more than men (about 16%), the report found, and depression rates were especially high among the unemployed (about 31%).

None of this bodes well for the health of Americans as they age, the CDC team warned.

"Because chronic conditions become more prevalent with age, a focus on prevention and risk factors is essential for health across the life span," Watson's team wrote. They noted that obesity, chronic high blood pressure and high cholesterol are all potent risk factors for diseases like heart disease and diabetes that can arise in later years.

All of this means that "addressing health behaviors and intermediate conditions among young adults can help improve long-term health and well-being over the life course," the team concluded.

More than half of young U.S. adults have a chronic health condition...