Fight Aging!

Modern hunter-gatherer populations such as the Tsimane, Hazda, and others, are increasingly of interest to researchers following publications of recent years indicating that these groups exhibit very little cardiovascular disease in comparison to populations in wealthier parts of the world. One might look at high and sustained levels of physical activity as a primary cause of this difference, although diet may also play a role. It is one of the better examples of the degree to which lifestyle influences the progression of aging, even while it fails to extend life out beyond the usual limits.

In today's research materials, the authors focus on differences in inflammation between first world populations and hunter-gatherers. One lesson that we might take away from this is that not all inflammation is the same: the hunter-gatherers exhibit higher levels of inflammation in youth, perhaps due to a greater burden of infectious disease, but nonetheless that burden of inflammation does not increase meaningfully into later life as it does in wealthier populations. As noted above the hunter-gatherers exhibit a far, far lower burden of cardiovascular diseases, age-related conditions well known to be driven by the chronic inflammation of aging.

Researchers analyzed data from four populations: two industrialized groups - the Italian InCHIANTI study and the Singapore Longitudinal Aging Study (SLAS) - and two Indigenous, non-industrialized populations - the Tsimane of the Bolivian Amazon and the Orang Asli of Peninsular Malaysia. While the inflammaging signature was similar between the two industrialized populations, it did not hold in the Indigenous groups, where inflammation levels were largely driven by infection rather than age.

Interestingly, while the indigenous populations, particularly the Tsimane, had high constitutive levels of inflammation, these did not increase with age and, crucially, did not lead to the chronic diseases that plague industrialized societies. In fact, most chronic diseases - diabetes, heart disease, Alzheimer's, etc. - are rare or largely absent in the Indigenous populations, meaning that even when young Indigenous people have profiles that look similar on the surface to those of older industrialized adults, these profiles do not lead to pathological consequences.

Inflammaging, an age-associated increase in chronic inflammation, is considered a hallmark of aging. However, there is no consensus approach to measuring inflammaging based on circulating cytokines. Here we assessed whether an inflammaging axis detected in the Italian InCHIANTI dataset comprising 19 cytokines could be generalized to a different industrialized population (Singapore Longitudinal Aging Study) or to two indigenous, nonindustrialized populations: the Tsimane from the Bolivian Amazon and the Orang Asli from Peninsular Malaysia. We assessed cytokine axis structure similarity and whether the inflammaging axis replicating the InCHIANTI result increased with age or was associated with health outcomes.

The Singapore Longitudinal Aging Study was similar to InCHIANTI except for IL-6 and IL-1RA. The Tsimane and Orang Asli showed markedly different axis structures with little to no association with age and no association with age-related diseases. Inflammaging, as measured in this manner in these cohorts, thus appears to be largely a byproduct of industrialized lifestyles, with major variation across environments and populations.