Table_1_Dietary Acid Load and Bone Health: A Systematic Review and Meta-Analysis of Observational Studies.DOCX

Findings on the association between dietary acid load (DAL) and bone health are conflicting. This study aimed to summarize available studies on the association between DAL and risk of fractures or bone mineral density (BMD) in adults. Online databases including PubMed, Scopus, and Embase were searched for relevant studies published up to June 2021, using pertinent keywords. We identified observational studies (cohort, case-control, and cross-sectional) investigating the association between DAL and risk of fractures or BMD, then selected studies following these reported criteria: RRs with corresponding 95% CIs for the relationship between DAL and fracture risk; correlation coefficients for the association between DAL and BMD; and mean ± SD of BMD values across the categories of DAL. Overall, 17 studies with 80545 individuals were included. There was no significant relationship between the PRAL and fracture risk (Pooled RR: 1.18; 95% confidence interval 0.98 to 1.41, I2 = 60.6%). Moreover, a similar association was observed between the NEAP and fracture risk (Pooled RR: 1.41, 95% CI: 0.79 to 2.52, I2 = 54.1%). The results of five studies from four publications revealed no significant association between dietary PRAL score and femoral and spinal BMD (WMD femoral = −0.01, 95% confidence interval: −0.02 to 0.01, I2 = 76.5%; WMD spinal = −0.01, 95% CI: −0.03 to 0.01, I2 = 56.7%). However, being in the highest category of NEAP was significantly associated with a lower femoral and spinal BMD (WMD femoral = −0.01, 95% CI: −0.02 to −0.00, I2 = 82.1%; WMD spinal = −0.02, 95% CI: −0.03 to −0.01, I2 = 93%). It was showed that adopting diets high in acidity was not associated with risk of fractures. We also found a significant negative relationship between NEAP and BMD. However, DAL based on PRAL was not associated with BMD.

目前关于膳食酸负荷（dietary acid load, DAL）与骨骼健康之间的关联，现有研究结论尚存争议。本研究旨在汇总现有针对成人群体中膳食酸负荷与骨折风险或骨密度（bone mineral density, BMD）关联的相关研究。我们通过PubMed、Scopus及Embase等在线数据库，以相关关键词检索了截至2021年6月发表的相关文献。最终筛选出探讨膳食酸负荷与骨折风险或骨密度关联的观察性研究（包括队列研究、病例对照研究及横断面研究），并依据以下标准完成文献遴选：用于表征膳食酸负荷与骨折风险关联的相对危险度（relative risk, RR）及其对应95%置信区间（confidence interval, CI）；用于反映膳食酸负荷与骨密度关联的相关系数；以及不同膳食酸负荷分层下骨密度值的均值±标准差（mean ± standard deviation, SD）。最终共纳入17项研究，涉及80545名研究对象。潜在肾酸负荷（Potential Renal Acid Load, PRAL）与骨折风险未呈现显著关联（合并RR=1.18，95%CI：0.98~1.41，I²=60.6%）。此外，净内源性酸产生（Net Endogenous Acid Production, NEAP）与骨折风险亦未见显著相关性（合并RR=1.41，95%CI：0.79~2.52，I²=54.1%）。来自4项文献的5项研究结果显示，膳食PRAL评分与股骨及脊柱骨密度无显著关联（股骨加权均数差（weighted mean difference, WMD）=-0.01，95%CI：-0.02~0.01，I²=76.5%；脊柱WMD=-0.01，95%CI：-0.03~0.01，I²=56.7%）。然而，处于最高分层的NEAP摄入与较低的股骨及脊柱骨密度显著相关（股骨WMD=-0.01，95%CI：-0.02~-0.00，I²=82.1%；脊柱WMD=-0.02，95%CI：-0.03~-0.01，I²=93%）。本研究表明，高酸性膳食与骨折风险无显著关联。同时我们发现，NEAP与骨密度存在显著负相关关系；但基于PRAL计算的膳食酸负荷与骨密度并无关联。