What’s behind the alarming rise of ‘old age’ diseases in younger Americans?
Chronic diseases — once considered the ailments of old age — are increasingly striking younger people.
Nearly half of new colorectal cancer cases in the U.S. now occur in adults under 65, the American Cancer Society reported on Monday. About one in five heart attacks affect people younger than 40, and the share of 18- to 54-year-olds who died of a severe first heart attack rose by nearly 60% in the past decade, according to a study published last month. Meanwhile, rates of high blood pressure, high cholesterol and obesity are rising fastest among younger adults, according to data from the Centers for Disease Control and Prevention.
These studies illuminate a generational shift in health, with ripple effects that reach beyond individual patients, impacting health care systems and the broader economy. If the pattern continues, researchers worry that as more people spend longer portions of their lives managing conditions once largely confined to older age, today’s younger generations may face higher risks of disability, medical costs and shortened life expectancy.
While the trend is affecting people across the country, the burden is not evenly shared: people with lower incomes, those living in rural communities and some racial and ethnic minority groups are significantly more likely to develop chronic conditions.
Chronic diseases in the US
Chronic disease — heart disease, cancer, diabetes and other conditions that last longer than a year and require ongoing medical attention — is the leading cause of illness, disability and death in the U.S.
Roughly 60% of Americans — more than 200 million people — live with at least one chronic disease; about 40% have two or more conditions, according to the CDC.
The financial toll is enormous.
Direct medical costs to treat chronic diseases, including mental health conditions, account for some 90% of the nation’s health care spending, or roughly $3.7 trillion every year, not to mention indirect costs from missed workdays, diminished productivity or early retirement. The CDC estimated that heart disease and stroke cost the U.S. about $240 billion annually when considering productivity losses.
Given that chronic diseases often require lifelong management, economists warn that earlier onset could significantly increase personal medical costs and the overall burden on the U.S. health system.
Chronic disease in younger adults
While common chronic diseases such as high blood pressure, diabetes and heart disease are still more common among older adults — for instance, 55% of adults older than 65 had high cholesterol in 2023 compared with 16% of 18- to 34-year-olds — they are increasing more quickly among younger adults, according to data from the CDC.
The share of 18- to 34-year-olds with obesity rose by 5.2% between 2013 and 2023, the most recent year for which data is available, while that number only grew by 4.5% among 35- to 64-years-old and 3.8% among those older than 65. During the same time period, the portion of younger adults with high cholesterol and high blood pressure increased while the percentage of older adults with those conditions declined or remained steady.
At least six different types of cancer are also rising faster in younger adults, according to a large, multi-country study published late last year. Physicians and epidemiologists are particularly concerned about colorectal cancer. In North America, Europe and Australia, about 1 in 10 cases already occur in people younger than 50. It is now the leading cause of cancer-related death among young adults. Some researchers estimated that by 2030, cases could rise sharply among younger adults — increasing by about 90% among those ages 20 to 34 and by 46% among those ages 35 to 49.
National health organizations have lowered the recommended ages for some cancer screenings in recent years, meaning more people are being tested earlier in life. The U.S. Preventive Services Task Force reduced the starting age for colorectal cancer screening from 50 to 45 and now recommends all women begin breast cancer screening at age 40 rather than 50.
Different types of health care providers are also becoming involved in screening. Some dentists test patients for diabetes during dental exams, while more eye doctors are checking blood pressure during appointments.
Earlier screening may partly explain why more young people are being diagnosed with cancer and other chronic diseases: as testing expands, more cases are likely to be detected.
After the colorectal screening age was lowered, screening among adults ages 45 to 49 increased by 62% while diagnoses in that age group rose by about 50%, according to separate studies by researchers at the American Cancer Society published in the Journal of the American Medical Association.
Earlier detection and improvements in cancer treatment have helped lower mortality for some cancers. Between 1991 and 2023, the overall cancer death rate fell 34%, even as the number of people diagnosed with cancer grew. But at least two cancers — colorectal and uterine — are bucking that trend among younger people.
What’s driving the rise?
Researchers do not know entirely what is behind the rise of chronic diseases in younger people. Genetics may be partly responsible: About 20% of colorectal cancer patients under 50 have an inherited genetic mutation that causes their cancer.
Lifestyle factors — poor diet, lack of physical activity and drug or alcohol use — are also significant contributors. Today, more than 70% of Americans are overweight or obese and fewer than 25% meet national physical activity guidelines that call for at least 150 minutes of moderate exercise or 75 minutes of vigorous activity each week, along with twice-weekly muscle-strengthening activities.
A rise in mental health conditions such as depression may also be a factor. According to CDC data, about 25% of adults aged 18 to 34 report depression, compared with about 15% of adults older than 65. Several meta-analyses reported that depression increases the risk of cardiovascular disease by roughly 40% to 60%. Living with chronic illness can also increase the risk of depression, creating an interconnected cycle.
Income, geography and race
Chronic diseases do not affect all Americans equally. A growing body of research shows that income, race, geography and education strongly shape who develops chronic illness and when. Studies have found that people with lower socioeconomic status tend to develop multiple chronic conditions earlier in life, often after longer exposure to risk factors such as poor nutrition, environmental stress and limited access to preventive health care.
Racial and ethnic disparities are particularly striking. Longitudinal studies have found that Black Americans tend to enter middle age with a higher burden of chronic illness and reach the threshold of having multiple chronic diseases several years earlier than white Americans.
Geographic and economic differences play a role as well: People living in rural or poorer communities often have higher rates of chronic conditions and face greater barriers to health care, widening the gap in long-term health outcomes.
The burden of chronic disease also differs between men and women.
The February study on heart attacks in young adults found that while more men than women have heart attacks, a higher percent of women died from them. The researchers also reported that women were more likely to have diabetes, obesity and chronic kidney disease. Nationwide, more girls and women live in poverty than men and boys, at rates of about 12% versus 10%.
Cancer incidence among women younger than 50 was about 82% higher than among men the same age in 2021, up from a 51% difference in 2002, according to the American Cancer Society.
But risks vary by cancer type. For instance, men have about a 50% higher risk of developing colorectal cancer than women while women aged 18 to 44 years who have colorectal cancer have better chances of survival than men of the same age.
Taken together, the emerging body of research on chronic disease burden and its drivers suggests that the country’s declining health is more than a medical challenge. Chronic diseases are appearing earlier in life and falling hardest on those with fewer economic and social resources — a pattern that could leave millions of Americans living longer with illness while deepening existing health and economic divides across the country.
Ella Rae Greene, Editor In Chief
