英译中，来自翻译练习

·英译中：

原文：

The study found that people with chronic insomnia -- trouble sleeping at least three days a week for three months or more -- had a 40% higher risk of developing mild cognitive impairment or dementia than those without insomnia, which is the equivalent of 3.5 additional years of aging. The study does not prove that insomnia causes brain aging, it only shows an association.

译文：

研究发现，慢性失眠（即每周至少三天入睡困难且持续三个月以上）的人，患轻度认知障碍或痴呆的风险比未失眠者高40%，相当于早衰3.5年。不过，这项研究仅能证明两者存在相关性，并不能说明失眠直接导致大脑衰老。