But the first two were observational and found only an association between such low sodium intake and cardiovascular risk, not a cause-and-effect relationship.

前两项研究属于观察性研究，仅发现低钠摄入量与心血管疾病风险存在一种联系，但并非因果关系。

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But the first two were observational and found only an association between such low sodium intake and cardiovascular risk, not a cause-and-effect relationship.

前两项研究属于观察性研究，仅发现低钠摄入量与心血管疾病风险存在一种联系，但并非因果关系。

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