For numerous years, my colleagues and I have been intrigued by people like Mrs. L. R., who possess an impressive resilience to illnesses. In 2008, we launched a research initiative named “Wellderly,” aimed at examining individuals who were at least eighty years old and had never experienced chronic illness or significant health issues. It took nearly six years for us at Scripps Research to identify fourteen hundred individuals who met this strict criterion of healthy aging and agreed to participate, which involved providing a blood sample for the sequencing of all three billion letters of their genome. Our hypothesis was that there would be something in their genetic makeup explaining their remarkable health span. I refer not to lifespan or longevity, which quantify total years lived, but to health span, which denotes the years lived in optimal health, unburdened by disease or disability.
Ultimately, we discovered we were mistaken. Despite the challenging and costly endeavor of sequencing and interpreting whole genomes several years back, their DNA did not reveal much to explain healthy aging. Their genetic risk markers for Alzheimer’s and heart disease were only slightly lower than those of the general population. In stark contrast to the absence of new genomic discoveries, this demographic, with an average age of eighty-four, was noticeably lighter, by nearly thirty pounds, engaged in more physical activity, and had higher education levels compared to the wider population of older Americans. The research nurse who enrolled and interviewed the participants* noted that the Wellderly exhibited a remarkably positive demeanor. Many enjoyed social activities such as bridge, dancing, and maintaining a network of friends; numerous individuals were active in community service. Well into their nineties, some were so engaged that scheduling an appointment for enrollment was challenging. Each had their distinct explanation for their robust health, despite the fact that some continued to smoke, consuming up to two packs daily. While our extended study did not clarify the genetic influences on achieving a prolonged health span, it broadened our perspectives on additional factors.
In contrast to our Wellderly cohort of healthy aging exceptions are the majority, whom we might refer to as the Illderly. In the United States, 60 percent of adults (ages eighteen and older) have at least one chronic disease, with 40 percent suffering from two or more. Among those aged sixty-five and over, 80 percent have two or more chronic conditions, 23 percent have three or more, and about 7 percent have five or more. If you or someone you know has a chronic illness, it’s likely one of the major four: diabetes, heart disease, cancer, or some form of neurodegeneration. In addition to these, chronic lung and kidney diseases are prevalent.
Who wouldn’t desire a long life? The pursuit of longevity captivates many of us. However, living longer with chronic ailments like Alzheimer’s, serious strokes, or significant frailty doesn’t appear to be very appealing. What we genuinely seek is for the extra years in life to be substantially free from disease. The encouraging news is that optimizing years of healthy living has become increasingly attainable. This book focuses on how we can maximize our health span, transitioning from being Illderly to remaining on the Wellderly trajectory.
This can be achieved through two distinctly different routes: either by preventing or postponing age-related diseases or by slowing down the aging process. The former builds on our current understanding and represents a considerable opportunity for progress in the near future. The latter, fundamentally altering aging, poses a greater challenge. Mrs. L. R. successfully avoided major chronic diseases, a feat achieved by only 19 percent of over four hundred centenarians (aged 97–119 years) studied in the New England Centenarian Study. The majority, 81 percent, developed comorbidities and were categorized as either “survivors,” diagnosed with age-related illnesses before the age of eighty, or “delayers,” diagnosed at eighty and beyond. Preventing or significantly postponing age-related diseases, thus extending health span, is the primary focus of this book.