In adults aged 65 and older, higher levels of a blood marker for inflammation (C-reactive protein) are linked to greater feelings of loneliness, and higher loneliness is also linked to later...

We analyzed the available evidence and found that in adults aged 65 and older, higher levels of C-reactive protein — a blood marker of inflammation — are linked to greater feelings of loneliness, and higher loneliness is also linked to later increases in this same marker [1]. This suggests a possible two-way connection between inflammation and loneliness, where each may influence the other over time. What we’ve found so far is based on one assertion that supports this idea, with no studies in our review contradicting it. The pattern points to a reciprocal relationship: as loneliness increases, CRP levels tend to rise later, and as CRP levels are higher, feelings of loneliness also appear stronger. This doesn’t mean loneliness causes inflammation or that inflammation causes loneliness — only that the two seem to move together in a way that could feed into each other. We don’t yet know why this link exists. It could be related to behaviors like reduced physical activity, poor sleep, or social isolation that often accompany loneliness and may affect the body’s inflammatory response. Or it could involve biological pathways we haven’t fully mapped. The evidence we’ve reviewed is limited to a single assertion, so we can’t say how strong or consistent this pattern is across different groups of older adults. For now, the evidence we’ve reviewed leans toward a back-and-forth connection between loneliness and inflammation in older adults. If you’re concerned about this, staying socially connected and managing stress may help — not because they “fix” inflammation, but because they support overall well-being in ways that might ease both emotional and physical strain.