Data for: Evaluating the impact of physical frailty during ageing in wild chimpanzees (Pan troglodytes schweinfurthii)

While declining physical performance is an expected consequence of aging, human clinical research has placed increasing emphasis on physical frailty as a predictor of death and disability in the elderly. We examined non-invasive measures approximating frailty in a richly-sampled longitudinal dataset on wild chimpanzees. Using urinary creatinine to assess lean body mass, we demonstrated moderate but significant declines in physical condition with age in both sexes. While older chimpanzees spent less of their day in the trees and feeding, they did not alter activity budgets with respect to travel or resting. There was little evidence that declining lean body mass had negative consequences independent of age. Old chimpanzees with poor lean body mass rested more often but did not otherwise differ in activity. Males, but not females, in poor condition were more likely to exhibit respiratory illness. Poor muscle mass was associated acutely with death in males, but it did not predict future mortality in either sex. While there may be some reasons to suspect biological differences in the susceptibility to frailty in chimpanzees versus humans, our data are consistent with recent reports from humans that lean, physically active individuals can successfully combat frailty.

尽管身体机能衰退是衰老过程中可预见的必然结果，但人类临床研究愈发重视将身体虚弱作为老年人死亡与残疾的预测因子。我们基于一份针对野生黑猩猩的高密度采样纵向数据集，探究了可近似反映虚弱状态的无创检测指标。通过尿肌酐（urinary creatinine）评估瘦体重（lean body mass），我们证实两性的身体状况均随年龄增长出现了中度但显著的衰退。尽管老年黑猩猩每日在树上活动与进食的时长更短，但它们在移动或休息的活动时间分配上并未发生改变。几乎没有证据表明，瘦体重下降会在年龄因素之外独立产生负面影响。瘦体重偏低的老年黑猩猩休息频次更高，但在其余活动维度上并无差异。身体状况较差的雄性黑猩猩（而非雌性）更易罹患呼吸道疾病。肌肉量偏低与雄性个体的急性死亡存在关联，但无法预测任一性别的未来死亡率。尽管有理由推测黑猩猩与人类在虚弱易感性方面存在生物学差异，但我们的数据与近期人类研究的结论一致：瘦体重正常且经常进行身体活动的个体能够有效对抗虚弱。