Heart disease is the single most likely cause of death for the average person. Globally, it kills 9.1 million people per year, accounting for 13% of all deaths. In the United States, heart disease claimed 683,037 lives in 2024, followed by cancer at 619,812. Together, these two conditions account for roughly 40% of all American deaths. But your specific risk depends heavily on your age, sex, and lifestyle.
Your Age Changes the Answer Dramatically
The leading killer shifts as you move through life. For children under 5, complications around birth are the top cause of death. From age 5 through 44, the number one killer isn’t a disease at all. It’s unintentional injury: car crashes, drug overdoses, drownings, and falls. This surprises many people who assume cancer or heart disease dominates every age group.
Between 45 and 64, cancer takes over as the leading cause of death. After 65, heart disease becomes the clear frontrunner, killing at a rate of roughly 1,089 per 100,000 people in that age group. If you’re young, your biggest statistical threat is an accident. If you’re middle-aged, it’s cancer. If you’re older, it’s your heart.
Suicide is the second leading cause of death for people aged 10 to 34 in the United States. That ranking holds across three separate age brackets (10 to 14, 15 to 24, and 25 to 34), making it one of the most significant causes of premature death in the country.
The Full US Top 10
Based on 2024 data from the CDC, here are the leading causes of death in the United States:
- Heart disease: 683,037 deaths
- Cancer: 619,812
- Unintentional injury: 196,488
- Alzheimer’s disease: 166,783
- Chronic lower respiratory diseases: 145,612
- Stroke: 116,016
- Chronic liver disease and cirrhosis: 94,382
- Suicide: 55,070
- Kidney disease: 52,259
- Diabetes: 48,683
Some of these have been climbing fast. Kidney disease was the 19th leading cause of death globally in 2000. By 2021, it had risen to 9th, with deaths increasing 95% over that period. Diabetes saw a similar 95% jump. These aren’t sudden epidemics. They reflect decades of rising rates of high blood pressure, high blood sugar, and obesity slowly compounding into organ damage.
What Kills Men vs. Women
Men die younger than women, and the gap isn’t just about biology. Men have higher death rates from heart disease, cancer, stroke, diabetes, liver disease, kidney disease, and accidents. But the biggest contributors to the gap between male and female lifespans aren’t chronic diseases. They’re traumatic deaths.
Homicide, suicide, and accidents account for roughly one-third of the life-expectancy gap between men and women among white and Black Americans, and half the gap among Latino Americans. Among white Americans, suicide alone accounts for 15% of the difference in years of life lost between men and women. Among Black Americans, homicide is responsible for 19% of that gap. Ischemic heart disease (the type caused by clogged arteries) is the second largest contributor, accounting for 11% to 23% of the gap depending on racial and ethnic group.
For women specifically, breast and gynecologic cancers represent a unique risk that doesn’t apply to men. For men, lung cancer is a major driver of excess deaths, accounting for 15% to 17% of the life-years gap among white and Black men compared to women.
What “Heart Disease” Actually Means
Heart disease is a broad category, and not all of it carries equal risk. Coronary heart disease, where the arteries supplying blood to the heart become narrowed or blocked, accounts for 40.3% of all cardiovascular deaths in the US. Stroke accounts for 17.5%. High blood pressure contributes to 13.4%, and heart failure to 9.1%.
Coronary heart disease is the specific condition most people will encounter if heart disease eventually kills them. It develops over decades as fatty deposits build up in artery walls, gradually restricting blood flow until a heart attack occurs. This is the process that makes blood pressure, cholesterol, smoking, and blood sugar levels so important long before any symptoms appear.
Which Cancers Are Most Deadly
Cancer is not one disease. The type matters enormously for survival. Lung cancer is by far the deadliest worldwide, causing 1.8 million deaths in 2022 and accounting for nearly 19% of all cancer deaths. Colorectal cancer is second at 9.3%, followed by liver cancer (7.8%), breast cancer (6.9%), and stomach cancer (6.8%).
Lung cancer’s dominance on this list is partly because it’s often caught late, when treatment options are limited. It’s also tightly linked to smoking, which remains the single most preventable cause of cancer death globally.
What “Unintentional Injury” Really Means
The third leading cause of death in the US, unintentional injury, is a category that hides some important specifics. The biggest component is poisoning, which in practice overwhelmingly means drug overdoses, particularly from opioids. Motor vehicle crashes are the second largest contributor, followed by falls and drownings.
For young adults, overdose deaths have reshaped the mortality landscape over the past two decades. Unintentional poisoning is now the leading type of accidental death in the US, surpassing car accidents. Falls are the dominant injury risk for older adults and a major cause of death after age 65.
The Risk Factors You Can Control
The 2021 Global Burden of Disease study identified the top modifiable risk factors driving death and disability worldwide. Air pollution (specifically fine particulate matter) ranked first, contributing 8% of the global disease burden. High blood pressure was second at 7.8%, followed by smoking at 5.7% and high blood sugar at 5.4%.
What’s striking about this list is how much overlap exists. High blood pressure damages arteries, increasing the risk of heart disease, stroke, kidney disease, and dementia. High blood sugar drives diabetes, kidney failure, and cardiovascular damage. Smoking causes lung cancer, worsens heart disease, and accelerates chronic lung disease. These risk factors don’t operate in isolation. They stack on top of each other, and the diseases they cause account for most of the top 10 killers.
The practical takeaway is that your most likely cause of death isn’t fixed. Blood pressure management, not smoking, physical activity, and maintaining a healthy weight don’t just reduce risk for one condition. They shift your odds across the entire list of leading killers simultaneously. The people who die of heart disease at 55 and those who die at 90 often differ less in genetics than in decades of accumulated risk factor exposure.