Birth weight, an indicator of fetal growth, is associated with cognitive outcomes in early life (which are predictive of cognitive ability in later life) and risk of metabolic and cardiovascular disease across the life course. Brain health in older age, indexed by MRI features, is associated with cognitive performance, but little is known about how variation in normal birth weight impacts on brain structure in later life. In a community dwelling cohort of participants in their early seventies we tested the hypothesis that birth weight is associated with the following MRI features: total brain (TB), grey matter (GM) and normal appearing white matter (NAWM) volumes; whiter matter hyperintensity (WMH) volume; a general factor of fractional anisotropy (gFA) and peak width skeletonised mean diffusivity (PSMD) across the white matter skeleton. We also investigated the associations of birth weight with cortical surface area, volume and thickness. Birth weight was positively associated with TB, GM and NAWM volumes in later life (β ≥ 0.194), and with regional cortical surface area but not gFA, PSMD, WMH volume, or cortical volume or thickness. These positive relationships appear to be explained by larger intracranial volume, rather than by age-related tissue atrophy, and are independent of body height and weight in adulthood. This suggests that larger birth weight is linked to more brain tissue reserve in older life, rather than age-related brain structural features, such as tissue atrophy or WMH volume.

出生体重是胎儿生长的一个指标，与生命早期的认知结果（可预测晚年的认知能力）以及整个生命过程中代谢和心血管疾病的风险有关。由 MRI 特征索引的老年大脑健康与认知能力相关，但对于正常出生体重的变化如何影响晚年的大脑结构知之甚少。在一个 70 岁出头的社区居住队列中，我们检验了出生体重与以下 MRI 特征相关的假设：全脑 (TB)、灰质 (GM) 和正常出现的白质 (NAWM) 体积；白质高信号 (WMH) 体积；白质骨架的分数各向异性 (gFA) 和峰宽骨架化平均扩散率 (PSMD) 的一般因素。我们还调查了出生体重与皮质表面积、体积和厚度的关系。出生体重与晚年的 TB、GM 和 NAWM 体积呈正相关（β ≥ 0.194），并且与区域皮质表面积呈正相关，但与 gFA、PSMD、WMH 体积或皮质体积或厚度无关。这些积极的关系似乎是由较大的颅内容积来解释的，而不是与年龄相关的组织萎缩，并且与成年期的身高和体重无关。这表明较大的出生体重与老年人更多的脑组织储备有关，而不是与年龄相关的脑结构特征，如组织萎缩或 WMH 体积。和区域皮质表面积，但不包括 gFA、PSMD、WMH 体积或皮质体积或厚度。这些积极的关系似乎是由较大的颅内容积来解释的，而不是与年龄相关的组织萎缩，并且与成年期的身高和体重无关。这表明较大的出生体重与老年人更多的脑组织储备有关，而不是与年龄相关的脑结构特征，如组织萎缩或 WMH 体积。和区域皮质表面积，但不包括 gFA、PSMD、WMH 体积或皮质体积或厚度。这些积极的关系似乎是由较大的颅内容积来解释的，而不是与年龄相关的组织萎缩，并且与成年期的身高和体重无关。这表明较大的出生体重与老年人更多的脑组织储备有关，而不是与年龄相关的脑结构特征，如组织萎缩或 WMH 体积。