Which age group has the most deaths? An analysis of mortality rates

September 25, 2025 •

4 min read

Data from public health sources like the CDC reveal a striking fact: age is the most influential predictor of death, and the group aged 85 and older consistently has the highest crude death rates. But the answer to which age group has the most deaths is far more nuanced, with mortality rates fluctuating significantly throughout a human lifespan.

Quick Summary

The highest crude death rates consistently occur among the oldest age groups, particularly individuals aged 85 and older, largely driven by chronic diseases. However, infant mortality is also a significant factor, while rates generally follow a J-shaped curve, rising steeply in old age.

Key Points

Highest Rate in Oldest Adults: The age group 85 and older consistently has the highest crude death rates, driven primarily by chronic diseases like heart disease and cancer.
Significant Infant Mortality: The risk of death is also high during the first year of life, especially in the first few days, due to factors like perinatal events and congenital conditions.
A J-shaped Mortality Curve: Death rates follow a J-shaped pattern across the lifespan, starting high in infancy, dipping in childhood, and rising exponentially in adulthood.
Causes Shift with Age: Leading causes of death change dramatically across age groups, from external injuries in adolescents and young adults to chronic illnesses in middle and older age.
Prevention is Possible: Many causes of premature death are preventable. Lifestyle choices like diet, exercise, and abstaining from smoking can significantly reduce risk and promote healthy aging.
Palliative Care's Role: Palliative care is important for managing symptoms and improving quality of life for those with serious illness, regardless of age or prognosis.

Understanding the J-shaped mortality curve

Mortality rates across the human lifespan are not a straight line but rather follow a distinctive J-shaped curve. This pattern illustrates that the risk of death is high during the first year of life (infancy), drops to its lowest point during childhood, and then begins to rise again through adolescence and adulthood, increasing exponentially into old age. This curve is a fundamental concept in demography and public health, reflecting the different vulnerabilities and primary threats to life at each stage of development.

Infant mortality: The vulnerable beginning

The first year of life is a period of high risk. Death rates are highest on the day of birth, influenced by complications, trauma, and sepsis. The CDC reports that in 2023, there were 560.2 infant deaths per 100,000 live births in the United States, a rate that, while historically low, highlights this initial vulnerability. The leading causes of infant death are markedly different from those in other age groups, primarily including congenital malformations, low birth weight, and sudden infant death syndrome (SIDS). However, the risk declines sharply after the first few months as infants' immune systems develop, with most infant deaths occurring within the first 70 days.

Childhood and young adulthood: External causes and a rising curve

After the high-risk infant stage, death rates plummet to their lowest levels during early childhood (ages 5–9) before rising again during adolescence and young adulthood. For individuals aged 5–24, the leading causes of death are often external or injury-related, such as unintentional injuries, suicide, and homicide. Among the 25–44 age group, unintentional injuries remain the leading cause, frequently driven by factors like opioid overdoses and car accidents. Suicide and homicide are also significant contributors in these age brackets. This pattern underscores the societal and behavioral factors that contribute to mortality in younger populations.

The exponential rise in older adulthood

As individuals progress through middle age and into older adulthood, the mortality curve begins its exponential ascent. Chronic diseases become the dominant cause of death, replacing external causes. For those aged 45–64, heart disease and cancer become the most prominent threats, followed by other chronic conditions like liver disease and stroke. This shift reflects the accumulation of life-long risk factors and the physiological decline associated with aging. This trend becomes even more pronounced in the oldest age groups.

The highest mortality in the oldest age groups

For those aged 65 and older, chronic illnesses like heart disease and cancer account for the vast majority of deaths. The CDC reports that heart disease and cancer have been the top two causes of death for seniors for decades. However, the highest crude death rates of all are found among those aged 85 and older. This age group has the highest rates across almost all leading causes of death. A study published in the Journal of the American Geriatrics Society identified heart failure, dementia, and chronic lower respiratory disease as major contributors to death in this population. This reflects the high prevalence of multimorbidity, where the presence of multiple chronic diseases accelerates the risk of death.

Preventing and managing age-related mortality

While age is the most significant risk factor for death, many age-related health declines and morbidities can be mitigated through public health initiatives and personal lifestyle choices. Strategies for healthy aging, promoted by organizations like the CDC, include maintaining a balanced diet, engaging in regular physical activity, and staying socially and mentally active. For older adults, regular health screenings and managing chronic conditions are critical. Furthermore, palliative care plays a crucial role in improving the quality of life for seriously ill patients and their families at all stages of disease, not just at the end of life.

Leading causes of death: A comparison by age group


Age Group	Top Causes of Death (examples)	Dominant Risk Factors	Primary Prevention Focus
Under 1 year	Perinatal events, congenital abnormalities, SIDS	Biological vulnerability, birth complications	Prenatal care, infant health support
5–24 years	Unintentional injury, suicide, homicide	External factors, behavioral risks	Safety education, mental health support
25–44 years	Unintentional injury (overdoses), heart disease, suicide	Behavioral risks, substance use, chronic disease onset	Substance abuse programs, chronic disease prevention
45–64 years	Cancer, heart disease, chronic liver disease	Lifestyle factors, accumulated risk	Cancer screenings, managing risk factors
65+ years	Heart disease, cancer, stroke, Alzheimer's disease	Multimorbidity, physiological decline	Chronic disease management, healthy aging

Strategies for promoting health and longevity

Embrace Regular Physical Activity: Exercise helps protect against age-related issues like cardiovascular disease, diabetes, and bone loss. Both aerobic and resistance training offer significant benefits throughout adulthood.
Maintain a Balanced Diet: Proper nutrition is key to preventing malnutrition and managing chronic conditions. Adequate protein, micronutrients, and hydration are particularly important for older adults.
Regular Health Screenings: Routine check-ups, cancer screenings, and vaccinations are essential for detecting and treating health problems early. This is especially important for managing chronic conditions. For more information on health initiatives, consult the Centers for Disease Control and Prevention.
Prioritize Mental and Emotional Well-being: Stress management, social engagement, and sufficient sleep are vital for overall health. Palliative care and support systems can help manage the psychosocial aspects of serious illness.
Avoid Harmful Habits: Quitting smoking and moderating alcohol consumption can significantly reduce the risk of many chronic diseases and premature death at any age.

Conclusion: Age and the landscape of mortality

Ultimately, age is the single greatest determinant of mortality rates, with the oldest age groups having the highest likelihood of death. However, this fact masks the complex and evolving causes of mortality across the lifespan, from biological vulnerabilities in infancy to external risks in young adulthood and the rise of chronic diseases in older age. By understanding these patterns, we can develop targeted public health interventions and make informed personal choices to promote health and extend a higher quality of life across all age groups.

Frequently Asked Questions

While it varies by country and population size, the highest overall number of deaths typically occurs in the oldest age groups because of the increased vulnerability to chronic diseases and physiological decline.

Yes, they are fundamentally different. Younger adults and adolescents are more likely to die from external causes like unintentional injuries, suicide, and homicide, whereas older adults are predominantly affected by chronic illnesses such as heart disease and cancer.

Infants are highly vulnerable during their first year of life, particularly in the initial days and weeks. Their health is at greater risk from birth complications, infections, and congenital issues before their bodies fully develop.

For middle-aged adults (45-64), the primary causes of death typically transition from external injuries to chronic diseases, with cancer and heart disease becoming the dominant threats.

Strategies for reducing mortality risk in older age include maintaining a healthy lifestyle, managing chronic conditions through regular check-ups, staying physically active, and focusing on preventive care and screenings.

Mortality risk does not rise continuously. It first dips to its lowest point during childhood before rising again during adolescence and young adulthood, and then it increases exponentially throughout older adulthood.

Palliative care helps to improve the quality of life for those with serious illnesses by managing symptoms and providing emotional support. While it doesn't prevent death, it addresses the significant suffering often associated with life-limiting diseases, particularly among older adults.

Both U.S. and global mortality trends generally follow the J-shaped curve, with high infant mortality and exponentially increasing rates in older adults. However, regional differences exist, particularly in rates among children and younger adolescents.