Okereke Olivia, Hankinson Susan E, Hu Frank B, Grodstein Francine
Division of Aging, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Mass, USA.
Arch Intern Med. 2005 Jul 25;165(14):1651-6. doi: 10.1001/archinte.165.14.1651.
Growing evidence suggests that type 2 diabetes mellitus and hyperinsulinemia may be related to diminished cognition. To help differentiate between the effects of diabetes and insulin, we examined the relation of insulin to cognitive function among nondiabetic participants of the Nurses' Health Study.
We measured the C peptide level, representing insulin secretion, in blood samples provided by 718 women from June 14, 1989, to October 4, 1990, when they were aged 61 to 69 years. We administered telephone interviews an average of 10 years after blood collection, testing general cognition, verbal memory, category fluency, and attention; second cognitive assessments were conducted 2 years later. The primary outcomes were global cognitive function across all tests and verbal memory. We used regression models to estimate multivariable-adjusted mean differences in cognitive function and cognitive decline, and odds of cognitive impairment, across C peptide levels.
Cognitive function was worse among women in the fourth C peptide quartile compared with those in the first quartile (eg, on the global score combining all cognitive tests, the multivariable-adjusted mean difference was -1.7 standard units [95% confidence interval, -2.9 to -0.6 standard units]; P = .002); the odds of cognitive impairment (defined as the worst 10% of the distribution) were 3-fold higher among women in the fourth vs first quartile (95% confidence interval, 1.3-7.8). On verbal memory, women in the fourth quartile scored significantly worse than those in the first quartile; the odds of impairment were 2.8-fold higher (95% confidence interval, 1.1-7.0). Consistent findings were observed for cognitive decline.
Higher insulin secretion may be related to worse cognition, even among those without diabetes.
越来越多的证据表明，2型糖尿病和高胰岛素血症可能与认知能力下降有关。为了帮助区分糖尿病和胰岛素的影响，我们在护士健康研究的非糖尿病参与者中研究了胰岛素与认知功能的关系。
我们测量了1989年6月14日至1990年10月4日期间718名年龄在61至69岁的女性提供的血液样本中的C肽水平，该水平代表胰岛素分泌。在采血平均10年后，我们进行了电话访谈，测试一般认知、言语记忆、类别流畅性和注意力；2年后进行了第二次认知评估。主要结局是所有测试的整体认知功能和言语记忆。我们使用回归模型来估计不同C肽水平下认知功能和认知衰退的多变量调整后平均差异，以及认知障碍的几率。
与第一四分位数的女性相比，第四C肽四分位数的女性认知功能更差（例如，在综合所有认知测试的总体评分上，多变量调整后的平均差异为-1.7个标准差单位[95%置信区间，-2.9至-0.6个标准差单位]；P = 0.002）；第四四分位数的女性认知障碍（定义为分布最差的10%）几率比第一四分位数的女性高3倍（95%置信区间，1.3-7.8）。在言语记忆方面，第四四分位数的女性得分明显低于第一四分位数的女性；障碍几率高2.8倍（95%置信区间，1.1-7.0）。在认知衰退方面也观察到了一致的结果。
即使在没有糖尿病的人群中，较高的胰岛素分泌也可能与较差的认知有关。
