Medical history

Medical History of Cancer or Diabetes: Mortality Risks and Life Expectancy

Introduction

Having a medical history of cancer or diabetes significantly impacts mortality risk and life expectancy. Both conditions represent major public health challenges, with substantial effects on longevity that vary based on age at diagnosis, treatment approaches, and comorbidities. This report synthesizes current understanding of how these conditions affect mortality outcomes.

Impact of Diabetes on Life Expectancy

Age at Diagnosis and Life Expectancy Reduction

The age at which diabetes is diagnosed plays a crucial role in determining its impact on life expectancy:

Type 2 diabetes diagnosis at age 30 can reduce life expectancy by up to 14 years¹
Diagnosis at age 50 reduces life expectancy by approximately 6 years¹²
Every decade of earlier diagnosis is associated with about 3-4 years of lower life expectancy³

This creates a clear dose-response relationship, with earlier diagnosis linked to greater life years lost. A 50-year-old with diabetes diagnosed at age 30, 40, or 50 died on average 14, 10, or 6 years earlier, respectively, than individuals without diabetes³.

Gender Differences in Diabetes Mortality

There are notable gender differences in diabetes mortality:

Women with type 2 diabetes have a 60% higher risk of premature death and live approximately 5 years less than women without diabetes⁴
Men with type 2 diabetes have a 44% higher risk of premature death and live 4.5 years less than men without diabetes⁴
After adjusting for socioeconomic factors, women with diabetes still have 60% higher mortality risk compared to 44% for men⁴

Compounding Risk Factors

Several factors can compound the mortality risk associated with diabetes:

Smoking has the most dramatic impact, reducing life expectancy by 10 years in people with diabetes compared to the general population⁴
A woman with diabetes who smokes and was diagnosed before age 65 has 3.75 times higher risk of premature death and lives 15 years less than the average woman⁴
Those diagnosed with diabetes before age 65 have a 93% higher risk of premature death and live more than 8 years less than age-matched individuals without diabetes⁴

Cancer History and Mortality

Survival Trends and Mortality Risks

Cancer survival rates have improved significantly over time, but a history of cancer still impacts mortality risk:

Cancer mortality has decreased by 22.6% in the last three decades, with approximately 70% of patients now surviving five years after diagnosis, compared to 57% in 1990⁵
Even without functional deficits, cancer survivors have a 1.3 to 1.4-fold increased risk of mortality compared to cancer-free individuals⁶
Cancer survivors with functional deficits have even higher mortality risks, ranging from 1.6 to 2.0-fold increased risk⁶

Life Expectancy After Cancer Diagnosis

Life expectancy changes over time after cancer diagnosis:

The greatest difference in patients' life expectancy compared to the general population occurs immediately after diagnosis⁷
Life expectancy progressively increases in patients surviving the first years after diagnosis⁷
Years of life lost due to cancer are highest at younger ages of diagnosis, with greater impact for aggressive cancers like lung and ovarian (>20 years lost) compared to less aggressive cancers like thyroid and melanoma (<6 years lost)⁷

Diabetes and Cancer Comorbidity

The relationship between diabetes and cancer creates particularly complex mortality patterns:

Type 2 diabetes is associated with poorer prognosis after cancer diagnosis (HR 1.09)⁸
Cancer mortality is particularly increased in diabetic patients with breast (HR 1.32) and prostate cancer (HR 1.19)⁸
Interestingly, lung cancer mortality is decreased in diabetic patients (HR 0.84)⁸
Early onset type 2 diabetes (diagnosed <40 years) is associated with significantly higher all-cause mortality (HR 3.16) compared to individuals without diabetes⁹

Mechanisms of Increased Mortality

Diabetes Complications

Several complications contribute to the reduced life expectancy in diabetes:

Cardiovascular disease: Diabetic patients triple their risk of dying from ischemic heart disease¹⁰¹¹
Nephropathy: People with diabetes triple their risk of dying from kidney diseases¹⁰¹¹
Hepatic complications: Diabetes triples the risk of dying from liver diseases¹⁰¹¹
Cancer risk: Diabetes doubles the risk of liver and colorectal cancer¹⁰¹¹

Cancer and Functional Age

Cancer survivors often experience accelerated functional aging:

Long-term cancer survivors have an "older functional age" compared to age-matched individuals without cancer history⁶
Cancer survivors have more deficits in geriatric assessment domains, including physical function limitations, comorbidities, and poor general health⁶
The risk of mortality increases with the number of geriatric assessment deficits, with higher risk among cancer survivors regardless of the number of deficits⁶

Conclusion

Both cancer and diabetes significantly impact mortality risk and reduce life expectancy, with greater effects when diagnosed at younger ages. While cancer survival rates have improved substantially over recent decades, cancer survivors still face elevated mortality risks. For diabetes, the relationship between age at diagnosis and reduced life expectancy is particularly striking, with each decade of earlier diagnosis associated with 3-4 fewer years of life. These findings highlight the importance of prevention, early detection, and effective management strategies to mitigate the impact of these conditions on longevity.