Chinese labs approaching Alzheimer's from a proactive perspective

There are several places in Shanghai that carry the Huashan name. The one I wanted, the neurology center off Wulumuqi Road, sits behind a wall of plane trees that in late April were shedding their fuzzy seed over everything, and I sneezed my way through the gate. A guard pointed me toward a low building where, he said, they study forgetting. I have been turning that phrase over for weeks.

What they actually study is timing. The neurologists here, at the National Center for Neurological Disorders inside Huashan Hospital, part of Fudan University, have spent most of the past decade pushing the moment of diagnosis earlier and earlier. For a long time Alzheimer's was something you found only once it had already taken the upper floors of a person, and often you confirmed it at autopsy. The clinicians I met want to catch it while the lights are still on, sometimes fifteen or twenty years before anyone in the family notices a name gone missing.

The reason they can even try is a change in what a vial of blood will show you. A researcher walked me through it at a pace plainly calibrated for visitors who did poorly in chemistry. Floating in the plasma are fragments of tau, a protein that tangles inside failing neurons, and one fragment called p-tau217 rises early and tracks the disease with unnerving fidelity. Huashan runs one of the larger cohorts in the world testing this, alongside a long-running study out in the city's older neighborhoods. Draw the blood, and you get a number that used to require a PET scanner and a small fortune.

So the question stops being how do we treat this and starts being how early are you willing to know. That is a stranger question than it sounds. The two infused anti-amyloid drugs that made headlines in the West slow the decline of already-sick patients by a modest margin and carry real risk, and nobody here talked about them with much heat. Their attention was further upstream, on the years when a person is technically fine and quietly, biochemically, is not.

So the question stops being how do we treat this and starts being how early are you willing to know.

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Jin-Tai Yu, a neurologist here whose name sits on a great deal of the prevention research coming out of China, led a review a few years back that gathered hundreds of observational studies and clinical trials to ask something blunt: what actually lowers your risk. The answers are almost insultingly ordinary. Treat high blood pressure in midlife. Keep learning things. Look after your hearing. Manage diabetes, weight, mood. Move your body. None of it is a cure, and most of it is dull, which may be part of why it took so long to be taken seriously as medicine.

I sat in on a clinic morning. The waiting hall smelled of instant coffee and floor cleaner, and the chairs were the kind that tip if you lean wrong, which I did. An older man came in with his daughter, who did most of the talking. He corrected her twice, sharply, about his own history, and a doctor told me afterward that the corrections are themselves a kind of reading, that how a person guards their own story tells you something. The visit was less about handing down a verdict than about placing him somewhere on a curve and arguing over how quickly he was sliding along it.

I kept wanting a clean figure, a percentage, something tidy for the notebook. I mostly did not get one, and I have come to think the reluctance was honest rather than evasive. Someone explained that population studies here are still catching up to the size of the problem, that China is aging faster than almost anywhere and that the data to say precisely how much of its dementia could be headed off is being assembled right now, one cohort at a time. Estimates exist. They are wide. A large share of cases, perhaps a third or more, is thought to trace to risk factors you could in principle change, though nobody I met would defend a single number down to the decimal.

There is a shadow over all of it that the enthusiasm does not quite cover. If you can tell a healthy fifty-year-old that a protein in their blood is drifting the wrong way, and you cannot yet offer a drug that reliably stops the drift, what exactly have you handed them. One of the younger researchers admitted, half to me and half to the window, that this is the part that keeps the field awake. The instruments to see are running well ahead of the instruments to fix. For now the answer in Shanghai is to give people the dull list and a reason to take it seriously, and to keep drawing the blood and watching the numbers move.

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Outside, the plane trees were still shedding. A woman swept the fuzz into little drifts that the wind undid behind her. Around the corner a wet market was loud with the ordinary business of a Tuesday, and I bought a bag of loquats I did not want, because the vendor and I had run out of shared words and it felt rude to leave with nothing.

I ate one on the metro back into the city. The man from the clinic and his daughter had gone before me, him still correcting her, her letting him. I never learned what his number was. I don't think, that afternoon, it was the most important thing in the room.