Lower Serum Klotho Correlates with Longer Sleep Duration in Older People
Higher levels of klotho slow aging in animal models, most likely largely a result of improved kidney function in later life. Klotho upregulation also slows cognitive aging, which may be downstream of effects on the kidneys, given the importance of kidney function to many organs. The correlation reported here between klotho and sleep duration is interesting enough to comment on, but it seems likely to be very indirect. Altered sleep duration with age is an emergent consequence of countless changes and dysfunctions. The path through mammalian biochemistry that leads from klotho to sleep is likely a winding one.
The sleep duration recommended by the National Sleep Foundation in 2015 was as follows: 7-9 hours in young people and adults, and 7-8 hours in elderly people. Excessive or insufficient sleep duration is disadvantageous for health. Previous studies have shown that sleep duration is associated with cardiovascular disease, cognitive decline, and metabolic syndrome, and aging.
Klotho protein is a multifunctional protein encoded by the klotho gene, and its expression level is associated with aging. It was found that mice lacking klotho suffer from premature aging syndrome, the lack of klotho in serum is also associated with heart aging, and decreased klotho levels are found in patients with various aging-related diseases, such as metabolic syndrome, cancer, and hypertension. In contrast, high level of klotho prolongs lifespan.
Aging is an inevitable process for human being, but the speed of aging is affected by many factors. Aging is affected by environmental, genetic, and epigenetic factors. On the other hand, the expression level of klotho may be potentially involved in the relationship between sleep duration and aging. Sleep disorders and aging are common public health problems, and the potential association between sleep duration and the anti-aging protein klotho is largely unexplored. Therefore, the purpose of this study was to investigate the potential association between them using the data of the National Health and Nutrition Examination Survey (NHANES) from 2007 to 2016. Our hypothesis is that sleep duration is associated with the serum anti-aging protein klotho concentration.
Sleep duration was non-linearly associated with the level of klotho protein in the serum, with a negative association between sleep duration and serum klotho concentration after adjusting for confounding variables. Serum klotho of the participants in the highest tertile (more than 7.5 hours) was 21.9 pg/mL lower than those in the lowest tertile (less than 5.5 hours). Thus our results revealed that people who sleep more than 7.5 hours per night have decreased levels of the anti-aging protein klotho in their serum, thus being more at risk of aging-related syndromes.