The logistic function or logistic growth curve is an "S" shape (sigmoid curve) that has been applied to numerous fields, including geology, physics, biology, mathematics, chemistry, economics, sociology, oncology, and statistics. The S-curve initiates with exponential growth, followed by slowing of growth as saturation occurs, and completion of growth at maturity. The S-curve follows the law of natural growth with a limiting factor, whether it be a competition for resources, investigation and demand for new products, or an economic bubble. The concept of the S-curve has been utilized in medicine to describe the advancements in the 20th century based on the diagnosis and treatment of disease (the "illness" curve [first S-curve]) and predict the future focused on disease prevention and health promotion (the "wellness" curve [second S-curve]). Herein, we propose a third S-curve that we are labeling the "longevity" curve.
Keywords: Discontinuity; Healthcare; Longevity; Public health; S-curve.
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