Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Central Norway Regional Health Authority Norwegian Health Association Introduction Cardiovascular disease (CVD) is the leading cause of death worldwide. Several studies have shown that low cardiorespiratory fitness (CRF) is a major risk factor for CVD and is suggested to be a stronger predictor of CVD morbidity and mortality than established cardiovascular risk factors. CRF quantified as maximal oxygen uptake (VO2max) has a strong genetic component, estimated to be ~50%. Unfortunately, current studies on genetic markers for CRF are limited by small sample sizes. In addition, there are few studies on directly measured VO2max, as most of the previous studies are based on estimated CRF. To overcome these limitations, we performed a large-scale systematic screening for genetic variants associated with VO2max aiming to provide awaited insight to this complex trait and discover possible links between VO2max and CVD. Purpose To identify and validate genetic factors associated with VO2max. Methods The genotypes of 70,000 participants from the Trøndelag Health study (HUNT) were imputed providing information on 25 million single-nucleotide polymorphisms (SNPs). We conducted a genome-wide association study (GWAS) including 4,525 participants with directly measured VO2max from the HUNT3 Fitness study. The GWAS was performed using BOLT-LMM, adjusted for age, gender, physical activity, principal components, and genotyping batch. In addition, we ran a GWAS with the same covariates except physical activity. Further, gender specific analyses were conducted. For validation, similar analyses were performed in the United Kingdom Biobank (UKBB). In the UKBB, CRF was assessed through a submaximal bicycle test. The analyses of UKBB included ~60,000 participants and over 90 million SNPs. Functional analyses of the GWAS results were examined by functional mapping and annotation (FUMA). Results Two GWAS-significant (p < 5×10-8) SNPs associated with VO2max were identified in the total population, two in the male population, and 24 in the female population in HUNT. Two of the 24 SNPs found in the female population were nominally significant in the UKBB. One of the validated SNPs in the female population is located inside PIK3R5, that is shown to be of importance in cardiac function and CVD. In addition, the functional analyses in the total- and male population revealed candidate SNPs in a gene previously found to be associated with endurance, PPP3CA. Conclusions We have identified 28 novel SNPs associated with VO2max in the HUNT cohort. Two of these SNPs were nominally validated in females in UKBB. One of the validated SNPs resides within a gene previously reported to be related to heart function and CVD. In addition, the functional analyses in the total- and male population revealed candidate SNPs in a gene previously found to be associated with endurance. Further functional analyses using bioinformatic approaches may provide more information on the physiological importance of these findings and their relation to CVD.

中文翻译：

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GWAS 确定的 VO2max 水平的新遗传决定因素：HUNT 研究

资金致谢 资金来源类型：公共拨款——仅限国家预算。主要资金来源： 挪威中部地区卫生局 挪威卫生协会 引言 心血管疾病 (CVD) 是全球主要的死亡原因。几项研究表明，低心肺健康（CRF）是心血管疾病的主要危险因素，并且被认为是心血管疾病发病率和死亡率的更强预测因子，而不是既定的心血管危险因素。量化为最大摄氧量 (VO2max) 的 CRF 具有很强的遗传成分，估计约为 50%。不幸的是，目前关于 CRF 遗传标记的研究受到样本量小的限制。此外，很少有关于直接测量 VO2max 的研究，因为之前的大多数研究都是基于估计的 CRF。为了克服这些限制，我们对与 VO2max 相关的遗传变异进行了大规模系统筛选，旨在为这一复杂性状提供期待已久的见解，并发现 VO2max 和 CVD 之间可能的联系。目的 识别和验证与 VO2max 相关的遗传因素。方法 对来自 Trøndelag 健康研究 (HUNT) 的 70,000 名参与者的基因型进行了估算，提供了 2500 万个单核苷酸多态性 (SNP) 的信息。我们进行了一项全基因组关联研究 (GWAS)，包括 4,525 名参与者，他们直接测量了来自 HUNT3 Fitness 研究的 VO2max。GWAS 使用 BOLT-LMM 进行，并针对年龄、性别、身体活动、主要成分和基因分型批次进行了调整。此外，我们运行了一个具有相同协变量的 GWAS，除了身体活动。此外，还进行了针对性别的分析。为了验证，在英国生物银行（UKBB）进行了类似的分析。在 UKBB，通过次最大自行车测试评估 CRF。UKBB 的分析包括约 60,000 名参与者和超过 9000 万个 SNP。通过功能映射和注释 (FUMA) 检查 GWAS 结果的功能分析。结果在 HUNT 中，在总人群中鉴定出两个与 VO2max 相关的 GWAS 显着 (p < 5×10-8) SNP，两个在男性群体中，24 个在女性群体中。在女性人群中发现的 24 个 SNP 中有两个在 UKBB 中具有名义上的显着性。女性群体中经过验证的 SNP 之一位于 PIK3R5 内，这被证明对心脏功能和 CVD 很重要。此外，总人口和男性人口的功能分析揭示了先前发现与耐力相关的基因中的候选单核苷酸多态性，PPP3CA。结论 我们在 HUNT 队列中确定了 28 个与 VO2max 相关的新型 SNP。其中两个 SNP 名义上在 UKBB 的女性中得到验证。其中一个经过验证的 SNP 位于先前报道的与心脏功能和 CVD 相关的基因中。此外，对总人口和男性人口的功能分析揭示了先前发现与耐力相关的基因中的候选 SNP。使用生物信息学方法进行的进一步功能分析可以提供更多关于这些发现的生理重要性及其与 CVD 关系的信息。其中两个 SNP 名义上在 UKBB 的女性中得到验证。其中一个经过验证的 SNP 位于先前报道的与心脏功能和 CVD 相关的基因中。此外，对总人口和男性人口的功能分析揭示了先前发现与耐力相关的基因中的候选 SNP。使用生物信息学方法进行的进一步功能分析可以提供更多关于这些发现的生理重要性及其与 CVD 关系的信息。其中两个 SNP 名义上在 UKBB 的女性中得到验证。其中一个经过验证的 SNP 位于先前报道的与心脏功能和 CVD 相关的基因中。此外，对总人口和男性人口的功能分析揭示了先前发现与耐力相关的基因中的候选 SNP。使用生物信息学方法进行的进一步功能分析可以提供更多关于这些发现的生理重要性及其与 CVD 关系的信息。