Chronic exposure to high levels of interleukin-6 was associated with a significantly lower likelihood of healthy aging, according to a study in CMAJ (Canadian Medical Association Journal).
Interleukin-6 is marker of inflammation, and chronic inflammation has been linked to a variety of age-related diseases, such as diabetes, heart disease and cognitive decline. Diet, chronic disease, smoking and other factors can cause inflammation. However, studies on chronic inflammation have generally looked at inflammation at only one point in time.
Researchers analyzed data on 3044 civil servants aged 35 years from the Whitehall II study in the United Kingdom to better understand the link between chronic inflammation and aging. They used 2 measures of interleukin-6 and assessed these about 5 years apart; they then linked these measurements to the presence or absence of cardiovascular disease, death from noncardiovascular causes and successful aging during a 10-year follow-up.
The researchers categorized participants into four groups: (1) successful aging characterizaed by absence of chronic diseases and disability combined with optimal cognitive, physical, respiratory and cardiovascular functioning (24%); (2) nonfatal or fatal cardiovascular disease (11%); (3) death from other diseases (5%); and (4) normal aging (61%).
High levels of interleukin-6 at the start of the study as well as at 2 intervals within a 5-year period were associated with lower odds of reaching successful aging, remaining free of diabetes and having good respiratory and musculoskeletal functioning 10 years later.
"Chronically high levels of interleukin-6 halved the odds of successful aging 10 years later and was associated with increased odds of future cardiovascular disease and death from noncardiovascular causes in a dose-response fashion," writes Dr. Tasnime Akbaraly, INSERM (Institut National de la Santé et de la Recherche Médicale), Montpellier, France and University College London, United Kingdom, with coauthors. "These associations were independent of socioeconomic factors, health behaviours (smoking, physical activity), conditions such as obesity, acute inflammation and use of anti-inflammatory drugs."
The authors note that additional research in other populations is needed because their study was composed of exclusively middle-aged civil servants living in England.
"We were able to show that chronic inflammation, as ascertained by repeat measurements of interleukin-6, was related to a range of unhealthy aging phenotypes and a decreased likelihood of successful aging. Maintaining a low interleukin-6 level may facilitate successful aging by reducing the likelihood of impaired musculoskeletal functioning and increasing the likelihood of remaining free of diabetes."
"If confirmed, these results shed new light on the importance of assessing long-term chronic inflammation in geriatric clinical practice, not only to target individuals at risk of unhealthy aging but also to promote ideal health by managing long-term chronic inflammation," conclude the authors.