Okinawa Centenarian Study

The Okinawa Centenarian Study is a study of the elderly people of Okinawa, Japan. The study, funded by Japan's ministry of health, is the largest of its kind ever carried out. Over the years, the scientists involved have had access to more than 600 Okinawan centenarians.

The elderly of Okinawa enjoy what may be the longest life expectancy in the world, and are also known for enjoying the relatively good health while doing so. The three leading killers in the West—coronary heart disease, stroke, and cancer—occur in Okinawans with the lowest frequency in the world.

The goal of the study is to find out why this is the case.

Compared to Westerners, the islanders age slowly and are about 80% less likely to get heart disease. They are also a quarter less likely to get breast or prostate cancer. In addition, they have half the risk of getting colon cancer and are less likely than Westerners to get dementia. On average they spend 97% of their lives free of any disabilities.

Current studies

Article title

Demographic, phenotypic, and genetic characteristics of centenarians in Okinawa and Japan: Part 1-centenarians in Okinawa

Introduction

The Okinawa Centenarian Study was conducted by D. Craig Willcox, Bradley J. Willcox, Wen-Chi Hsueh, and Makoto Suzuki and published on January 2, 2024.

Research Methodology

Participant Selection and Verification The selection of participants and verification of their ages are foundational to the study's credibility. Thorough demographic reviews, with researchers consulting official records such as birth certificates and family registers (koseki) to verify the ages of the subjects. This verification is essential to accurately identify centenarians and reduce the possibility of age misreporting. The study's sample includes a significant proportion of the centenarian population in Okinawa, nearly one-third.

Data Collection and Home Assessments Data acquisition for the OCS is performed by in-home assessments; this method aims to lessen stress and facilitate ease for elderly individuals, which is believed to aid in collecting more consistent and precise data.

The assessments encompass several facets of health and well-being:

- Cognitive Functioning

- Physical Health

- Functional Status

Genetic Analysis and Biomarkers Investigating genetic elements related to longevity is a critical component of the study. Attention is given to specific genetic markers, including the APOE gene variants, focusing on the APOE2 allele. The study also examines telomere length, mitochondrial DNA variations, and the interplay between genetics and environmental factors.

A selection of biomarkers is measured to gain insights into various health aspects:

- Inflammatory Markers: These include CRP, interleukins, and tumor necrosis factors, indicative of immune function and chronic inflammation levels.

- Metabolic and Cardiovascular Indicators: The assessment of lipid profiles, fasting glucose, and insulin sensitivity is conducted to understand metabolic health and cardiovascular risk factors.

- Hormonal Profiles: Hormones such as DHEAS, estrogen, testosterone, and other growth factors are measured to explore their roles in the aging process.

- Oxidative Stress Markers: The study measures the activity of antioxidant enzymes and the presence of oxidative damage, which can shed light on cellular aging mechanisms.

Data Collection and Home Assessments

Data collection within the OCS is conducted through direct in-home assessments, which provide a comfortable and familiar setting for participants. This approach is designed to minimize stress and inconvenience for the elderly subjects, thereby facilitating more accurate and reliable data collection. The assessments cover various domains, including: Cognitive Functioning,Physical Health,Functional Status and interviews are utilized to gather information on participants' psychological well-being, social networks, and perceived life satisfaction. These comprehensive assessments provide a multi-dimensional picture of the centenarians' health and lifestyle.

Genetic Analysis and Biomarkers

The Okinawa Centenarian Study investigates genetic factors contributing to longevity, focusing on various genetic markers, such as APOE alleles, especially APOE2, which is linked to a lower risk of Alzheimer's and a higher likelihood of longevity. Researchers also analyze telomere length, mitochondrial DNA variations, and how genes interact with environmental factors to influence lifespan. Key biomarkers measured include: Inflammatory Markers: To assess immune function and chronic inflammation, levels of C-reactive protein (CRP), interleukins, and tumor necrosis factors are measured. Metabolic and Cardiovascular Indicators: Lipid profiles, fasting glucose, and insulin sensitivity are evaluated to understand metabolic health and cardiovascular risk. Hormonal Profiles: Hormones like dehydroepiandrosterone sulfate (DHEAS), estrogen, testosterone, and various growth factors are quantified for their role in aging. Oxidative Stress Markers: Activities of antioxidant enzymes and markers of oxidative damage provide insight into cellular aging processes.

Lifestyle Factors Influencing Longevity

Article title

Blue Zones

Introduction

This article is written by Dan Buettner and Samantha Skemp and published in the American Journal of Lifestyle Medicine in 2016.

The exceptional longevity of Okinawa's centenarians can be attributed to a combination of lifestyle choices and cultural practices. Notably, the concept of "Hara Hachi Bu," which advocates eating only until one is 80% full, is a common practice among Okinawans. This practice promotes caloric restriction, which has been linked to longer lifespan in various studies.

Another integral aspect of Okinawan culture is "Ikigai," or a sense of purpose. It is believed that having a clear sense of purpose can contribute to overall well-being and longevity. This cultural ethos fosters strong social ties and community engagement, which are essential components of healthy aging. These lifestyle factors are seen not only as habits but as ingrained cultural practices that contribute to the high life expectancy in Okinawa.

Dietary Habits and Nutritional Biomarkers

Article title

Nutrition in Centenarians

Introduction

This Study was conducted by researchers D.B. Hausman, J.G. Fischer, and M.A. Johnson and published in the journal Maturitas in March 2011.

Dietary Habits and Nutritional Biomarkers

The dietary patterns of Okinawan centenarians are characterized by a high intake of vegetables, whole grains, soy products, and a moderate consumption of fish, with a low reliance on meat and processed foods. The traditional Okinawan diet is low in calories yet nutritionally dense, particularly rich in antioxidants and other phytonutrients. Key nutritional biomarkers for longevity among Okinawans include lower levels of homocysteine and higher levels of antioxidant vitamins, which are indicative of a diet rich in folate, vitamin B12, and vitamin D. These biomarkers suggest a reduced risk for chronic diseases such as cardiovascular disease and certain cancers.