Report illuminates dementia’s causes

Commission finds preventable factors in all stages of life.

More than 1 in 3 cases of Alzheimer’s disease and other forms of dementia can be traced to factors — such as inadequate education, obesity, hearing loss and smoking — that simply don’t need to be, according to a new report.

These challenges first present themselves in childhood, and they continue to make their presence felt all the way through one’s senior years. But if all of these problems could be fixed, at least 35 percent of seniors who lose their independence and their pasts would instead retain their dignity and their memories until they died of something else, the Lancet Commission on Dementia Prevention, Intervention and Care has concluded.

This would require doctors, communities and governments around the world to implement things like universal preschool and senior visiting clubs; rebuild cities to encourage exercise and healthy diets; and expand preventive health care. And that’s just a start.

It’s a tall order, the commission acknowledged in a report published Thursday in the medical journal Lancet. But it would be worth it.

For countries bracing for a tsunami of citizens needing wraparound care in their final years, a 35 percent reduction in dementia would reduce a crushing burden on productivity, government spending and economic growth.

In 2015, roughly 47 million people were thought to be living with dementia, and $818 billion was spent worldwide on their care. The number of dementia sufferers is expected to triple by 2050, and that growth is likely to be greatest in low- and middle-income countries such as China, India, Brazil and Indonesia.

Dr. Lon Schneider, an Alzheimer’s Disease specialist at USC’s Keck School of Medicine and one of the report’s senior authors, said the commission has produced a road map to reducing the global burden of dementia. The avenues it suggests are rarely solutions to dementia alone, he added: whether the recommendation is to keep kids in school, manage high blood pressure in midlife or reduce seniors’ social isolation, such initiatives pay other dividends as well.

New research on the links between air pollution and Alzheimer’s risk might even nudge the power of preventable factors in dementia still higher, Schneider said.

The good news is that many of the world’s most affluent countries — the United States, United Kingdom, Sweden, Canada, the Netherlands — are already on the right path.

In recent years, all those countries have seen unexpected declines either in the number of dementia patients or the rates at which seniors are developing the condition.

The commission found that stunted educational attainment — specifically, the failure to complete more than eight years of school — is childhood’s most potent risk factor for dementia.

In midlife, the commission found that one of the most powerful — and fixable — drivers of dementia risk is hearing loss. In fact, as much as 9 percent of lifetime risk for dementia lies with hearing loss during midlife.