Photo by S L on Unsplash Human biology is systems biology; perturb one aspect of human biology and it will have downstream effects, which can be noted throughout the body. As you know sleep is critical for brain health; if you have poor sleep hygiene you are putting yourself at greater risk of developing dementia when you get older. Why? In this study of cognitively normal older Chinese adults, spinal fluid soluble TREM2 (sTREM2) was associated with self-reported poor sleep hygiene using the Pittsburgh Sleep Quality Index. sTREM2 is shed from activated microglia or macrophages and is thought to be a marker of microglial activation. The implications are that this association may be causal, i.e. poor sleep is pro-inflammatory, both in the periphery and central nervous system and the latter contributes to driving neurodegeneration. Could improved sleep hygiene be anti-inflammatory? Or is the microglial activation simply a response to poorer clearance of CNS debris, which occurs when...