Terminology for Exceptional Longevity
Officially, a 105-year-old is called a semi-supercentenarian. This term is used in the fields of demography and gerontology to categorize individuals who have achieved exceptional longevity. While the more common word for anyone over the age of 100 is a centenarian, the more granular term is used for research purposes because the mortality rates and characteristics of people in this age bracket differ from those of younger centenarians.
The Definition of a Semi-Supercentenarian
A semi-supercentenarian is any person aged between 105 and 109 years old. This group is statistically much smaller and rarer than the general population of centenarians, which includes all individuals who have reached the age of 100 or more. A 2015 study in Japan showed that only about 6.1% of centenarians fell into the 105-109 age group, illustrating their relative rarity.
Expanding the Gerontology Lexicon
In addition to the common terms, demographers and researchers have developed a more precise vocabulary to discuss different stages of exceptional longevity. Here are some key terms related to extreme old age:
- Nonagenarian: Someone in their 90s, specifically between 90 and 99 years old.
- Centenarian: An individual who has reached the age of 100.
- Semi-supercentenarian: A person aged 105 through 109.
- Supercentenarian: An individual who has lived to be 110 years or older. This milestone is achieved by only about one in 1,000 centenarians.
Comparison: Centenarian vs. Semi-Supercentenarian vs. Supercentenarian
Understanding the subtle differences in these classifications is key to appreciating the scientific study of extreme longevity. The following table highlights the distinctions based on research data.
| Feature | Centenarian (100-104) | Semi-Supercentenarian (105-109) | Supercentenarian (110+) |
|---|---|---|---|
| Incidence (relative) | Most common type of person over 100. | Extremely rare; significantly fewer individuals exist than younger centenarians. | Exceptionally rare; only a fraction of semi-supercentenarians reach this age. |
| Health Profile | More variation in health, with some experiencing age-related diseases earlier in life. | Tend to have delayed age-related diseases until much later in life. | Many exhibit a “compression of morbidity,” meaning they remain in good health until very close to the end of their lives. |
| Mortality Rate | Declines over the age of 80, but remains higher than semi-supercentenarians. | Appears to plateau after age 105, meaning the risk of death does not significantly increase with each passing year. | Follows a similar mortality rate plateau as semi-supercentenarians. |
| Genetic Influence | While genetics play a role, the influence of inherited traits for exceptional longevity is less pronounced than at older ages. | Genetic factors are more influential than in centenarians. | The genetic influence on survival is strongest at these extreme ages. |
The Significance of Studying Semi-Supercentenarians
Researching semi-supercentenarians is important for understanding the limits of the human lifespan. Studies have found that after the age of 105, the risk of death levels off, a phenomenon known as the “mortality plateau”. This suggests that individuals who survive this long have a certain biological resilience that allows them to defy typical age-related declines. By studying this highly select group, scientists hope to discover the genetic and environmental factors that protect against age-related diseases.
For example, researchers have compared the health histories and genomic data of semi-supercentenarians and supercentenarians to look for clues about exceptional longevity. The New England Centenarian Study found that many semi-supercentenarians and supercentenarians exhibit a compression of morbidity, indicating they live healthier lives for longer. This is crucial for understanding how to promote healthier aging in the general population, not just increase overall lifespan.
Conclusion: More Than Just a Number
In conclusion, while a 105-year-old can simply be called a centenarian, the more precise and scientific term is a semi-supercentenarian. This distinction is not merely a technicality but reflects a deeper understanding of the biology of extreme longevity. Individuals who reach this remarkable age represent a highly resilient population, and their continued health and survival hold valuable information for researchers studying how to age well. Celebrating these milestones not only honors the individual's long and eventful life but also recognizes their place among the world's most exceptional survivors. Their existence challenges previous assumptions about the maximum human lifespan and offers a roadmap for studying and promoting healthy aging for all.
