Short height and long life have a direct connection in Japanese men, according to new research based on the Kuakini Honolulu Heart Program (HHP) and the Kuakini Honolulu-Asia Aging Study (HAAS).
"We split people into two groups - those that were 5-foot-2 and shorter, and 5-4 and taller," said Dr. Bradley Willcox, one of the investigators for the study and a Professor in the University of Hawai`i (UH) John A. Burns School of Medicine's Department of Geriatric Medicine. "The folks that were 5-2 and shorter lived the longest. The range was seen all the way across from being 5-foot tall to 6-foot tall. The taller you got, the shorter you lived."
Researchers at the Kuakini Medical Center, the UH John A. Burns School of Medicine and U.S. Veterans Affairs worked on the study, which was recently published in PLOS ONE, a peer-reviewed medical journal.
The researchers showed that shorter men were more likely to have a protective form of the longevity gene, FOXO3, leading to smaller body size during early development and a longer lifespan. Shorter men were also more likely to have lower blood insulin levels and less cancer.
"This study shows for the first time, that body size is linked to this gene," said Dr. Willcox. "We knew that in animal models of aging. We did not know that in humans. We have the same or a slightly different version in mice, roundworms, flies, even yeast has a version of this gene, and it's important in longevity across all these species."
Dr. Willcox noted that there is no specific height or age range that should be targeted as a cut-off in the study, in part because "no matter how tall you are, you can still live a healthy lifestyle" to offset having a typical FOXO3 genotype rather than the longevity-enhancing form of the FOXO3 gene.
The Kuakini HHP started in 1965 with 8,006 American men of Japanese ancestry born between the years 1900 and 1919. The lifestyles and health conditions of these men were closely followed and studied by the researchers through the years. The Kuakini HHP is the only longitudinal study of Japanese-American men that has included epidemiological and clinical data of the cohorts for almost 50 years. From a worldwide perspective, it is the only research program that maintains a comprehensive, longitudinal database of demographic, lifestyle and medical information, as well as biological specimens collected, from such a large cohort of aging men.
"One of the reasons why Honolulu is perfect for this kind of study is that we have the longest-lived state in the country, combined with a population that has remained, for the most part, in Hawaii. This has helped us maintain one of the longest-running, largest studies of aging men in the world, in the Kuakini Honolulu Heart Program," Dr. Willcox said.
Approximately 1,200 men from the study lived into their 90s and 100s, and approximately 250 of those men are still alive today.