The World's Oldest Identical Twins: Umeno Sumiyama and Koume Kodama
On September 20, 2021, the world received official confirmation of the oldest identical twins ever verified by Guinness World Records. The prestigious title was awarded to Japanese sisters Umeno Sumiyama and Koume Kodama, who were 107 years and 300 days old at the time of their certification. Born on November 5, 1913, on Shodo Island, they were the third and fourth of 11 siblings. Their achievement surpassed the previous record, also held by Japanese sisters Kin Narita and Gin Kanie.
Despite being separated for long periods, their eventual reconnection speaks to the powerful and enduring bond of identical twins. As children, Kodama moved away from the island to live with an uncle, and they rarely saw each other until the age of 70, when they reconnected and began making Buddhist pilgrimages together. This special relationship is often cited as a key factor in twin longevity, and their story underscores the importance of social connections in aging.
The Longevity Advantage: Why Twins May Live Longer
Recent research has shed light on why twins, and especially identical twins, tend to live longer than the general population. While the genetic component is significant, several non-genetic factors play a crucial role. A study published by researchers at the University of Washington explored mortality data from thousands of Danish twins and found that both identical and fraternal twins showed a survival advantage over the general population, with the benefit being slightly greater for identical pairs. The primary driver behind this phenomenon is believed to be the unique social and emotional bond they share.
The Twin Protection Effect
This benefit, coined the "twin protection effect," is thought to function similarly to the well-documented "marriage protection effect," where married people often exhibit better health and longer lives than unmarried adults. Unlike marriage, however, twinhood is not a choice, which eliminates the possibility of a selection bias (i.e., healthier people being more likely to get married). For twins, this built-in social support system provides several benefits:
- Built-in Accountability: A twin can offer constant encouragement and act as a reliable partner in maintaining a healthy lifestyle, such as regular exercise or healthy eating habits.
- Emotional Support: The profound bond between twins, particularly identical ones, provides a unique level of emotional and psychological support during difficult or stressful times. This support can act as a buffer against loneliness and stress, which are known to negatively impact health.
- Reduced Risky Behavior: The close relationship can sometimes discourage risky behaviors. Researchers noted that this effect was particularly pronounced in male twins, who are statistically more prone to risky behavior than females.
Unraveling the Impact of Nature vs. Nurture
Twin studies have long been a valuable tool for understanding the contributions of genetics versus environment on human traits. In the case of longevity, while identical twins share nearly 100% of their DNA, environmental factors and lifestyle choices diverge over time. This leads to a concept known as "epigenetic drift," where environmental influences can cause changes in how genes are expressed without altering the DNA sequence itself.
This means that even among genetically identical individuals, one twin might age differently than the other based on varying life experiences. Research from the University of Virginia further supports this, linking accelerated epigenetic aging in one identical twin to a higher rate of memory decline, with early-life socioeconomic disadvantage also playing a role. Such findings emphasize that while genes are a foundation, lifestyle and environment are the blueprints that ultimately shape our health and longevity.
Comparison of Identical and Fraternal Twin Longevity
| Feature | Identical Twins (Monozygotic) | Fraternal Twins (Dizygotic) |
|---|---|---|
| Genetic Similarity | Nearly 100% | Around 50% (like any other siblings) |
| Longevity Advantage | Consistently show a stronger survival advantage over the general population. | Also show a survival advantage, but less pronounced than identical twins. |
| Strength of Social Bond | Often report a more intense and intuitive bond, which likely contributes to their greater longevity advantage. | Social bond varies, but may not be as intense as that of identical twins. |
| Epigenetics | Differences in epigenetic aging due to environmental factors are more easily studied, providing clearer insights. | Epigenetic differences are influenced by both genetics and environment, making it harder to isolate the impact of environment alone. |
The Ever-Changing World of Age Records
While Umeno Sumiyama and Koume Kodama hold the record for the oldest identical twins ever verified, the record for the oldest living identical twins is a dynamic one. As of September 2025, other twins have surpassed the centenarian milestone, and documentation from geriatric societies often tracks potential candidates. However, official confirmation of identical twin status is not always immediate or publicly available. A search of gerontology databases reveals several pairs over 100 years old, but their twin type (identical vs. fraternal) is not always confirmed. Regardless of who holds the title today, the stories of these remarkably long-lived individuals offer invaluable lessons on the combination of genetics, strong social bonds, and lifestyle choices in achieving a long and healthy life.
Final Thoughts: The Broader Lessons for Healthy Aging
The stories of Umeno and Koume and the insights from twin longevity studies offer a powerful message for everyone. While we cannot choose our genes, we have significant control over our environment and social relationships. Cultivating strong, supportive bonds, engaging in mutual care, and maintaining a healthy lifestyle are strategies that can enhance longevity for anyone, whether you are a twin or not. The resilience and close relationship demonstrated by the world's oldest identical twins serve as a compelling testament to the profound impact of social connection on human health and happiness.
For more on the benefits of social connection and longevity, consult research from the University of Washington and other experts Longevity in Identical Twins.
