We would like to thank you for the opportunity to respond to the issues raised in the letter by Drs Guo, Lan, Zhou and Liu [1]. The authors raise the concern that the long follow-up of our cohort study has affected the robustness of the study results. The data used from the Nurses' Health Study have the advantage of repeated dietary measurements over a long study period. Therefore, the cumulative average of dietary magnesium intake was assessed in association with frailty incidence since this best reflects long-term intake [2]. However, due to the strong increase in supplement intake over the years, we used a different approach for the supplemental magnesium intake and considered the most recent supplemental magnesium intake before frailty onset or the end of follow-up. Additionally, when no specific supplement brand was given, the supplemental magnesium intake was estimated as well as possible based on the most frequently used supplement on the market in the year the food frequency questionnaire was returned.

The authors of the letter are right that supplement users may be more likely to already have a deteriorated functional status. We have addressed this by repeating the analysis excluding women who were prefrail and by excluding women with cancer, diabetes, or heart disease at baseline; the association between supplemental magnesium and frailty remained non-significant.

We agree that social workers are important players in supporting the needs of older adults and more research is needed to understand how supplement use can improve health among older adults. Older adults for whom healthy eating can be a challenge due to dental problems, chewing difficulties, high costs of healthy foods or loss of appetite, a multivitamin supplement including magnesium may be of benefit to reach an adequate nutrient intake [3].

The main message of our study is that, for most older adults, an optimal palatable diet pattern that provides enough minerals, as well as an optimal macronutrient composition, is likely to help prevent the development of geriatric syndromes.

我们要感谢您有机会回应 Guo、Lan、周 和 Liu 博士在信中提出的问题 [1]。作者提出了担忧，即我们队列研究的长期随访影响了研究结果的稳健性。护士健康研究中使用的数据具有在长期研究期间重复饮食测量的优势。因此，膳食镁摄入量的累积平均值与虚弱发生率相关进行评估，因为这最能反映长期摄入量 [2]。然而，由于多年来补充剂摄入量的大幅增加，我们对镁的补充摄入量采用了不同的方法，并考虑了在虚弱发作或随访结束前最近的镁补充剂摄入量。此外，当没有给出特定的补充剂品牌时，根据返回食物频率问卷当年市场上最常用的补充剂，尽可能估计镁的补充剂摄入量。

这封信的作者是对的，补充剂使用者可能更有可能已经处于恶化的功能状态。我们通过重复分析排除了早期虚弱的女性以及排除了基线时患有癌症、糖尿病或心脏病的女性来解决这个问题;补充镁与虚弱之间的关联仍然不显著。

我们同意社会工作者是支持老年人需求的重要参与者，需要更多的研究来了解补充剂的使用如何改善老年人的健康。对于由于牙齿问题、咀嚼困难、健康食品成本高或食欲不振而可能面临健康饮食挑战的老年人，包括镁在内的多种维生素补充剂可能有助于达到足够的营养摄入 [3]。

我们研究的主要信息是，对于大多数老年人来说，提供足够矿物质和最佳宏量营养素成分的最佳可口饮食模式可能有助于预防老年综合征的发展。