Cognitive decline may start in middle age, a study finds

If you’re waiting for old age to see signs of cognitive decline, don’t hold your breath. A study finds that brain function could start falling off in middle age.

Researchers gave a number of cognitive tests to 5,198 men and 2,192 women ages 45 to 70 three times over the course of 10 years. The study participants were assessed on memory, reasoning, vocabulary and aural and visual comprehension.

Declines were seen in all areas except for vocabulary, and as people got older there was a faster drop. Over the 10 years, men ages 45 to 49 saw a 3.6% decline in mental reasoning. Those 65 to 70 saw a 9.6% drop. In women the declines were 3.6% for those 45 to 49 and 7.4% for those 65 to 70. Researchers controlled for different education levels.

Previous studies suggested that cognitive declines don’t happen until later in life, about age 60. But the authors of this paper said that if those declines are happening sooner, maintaining a healthful lifestyle earlier in life is paramount. Recent studies have linked conditions such as diabetes and cardiovascular disease with a higher risk of dementia and Alzheimer’s disease.

“Life expectancy continues to increase,” they wrote, “and understanding cognitive ageing will be one of the challenges of this century.” More study is needed, they add, to better comprehend the mechanism of cognitive decline and how risk factors could be modified.

The study was released Thursday in the British Medical Journal.