BACKGROUND Hyponatremia is a common condition with unspecific symptoms and a complicated etiology. The impact of outdoor temperature on hyponatremia is not well-studied and varies depending on the climate and location. This study aimed to investigate the association between outdoor temperature and the prevalence of severe hyponatremia. METHODS This retrospective register-based cohort study based on the Stockholm Sodium Cohort investigated the association between ambient temperatures and severe hyponatremia (<125 mmol/L) in adults. Prevalence rates of severe hyponatremia were calculated as the number of days of severe hyponatremia divided by person-days at risk for the same temperature, using mean daily temperatures at the area of residence of each study participant to calculate exposure time. A prediction model incorporating changes in demographics and climate was used to estimate the burden of severe hyponatremia in Stockholm by 2050. RESULTS We identified 51,143 episodes of severe hyponatremia in 21,924 adults. A near linear modest increase in prevalence with rising temperatures was observed up to 20°C, followed by rapidly increasing rates at higher temperatures. The prevalence was higher with older age, reaching >100 days of hyponatremia per million person-days among +80-years-olds at temperatures over 22°C. Women experienced twice the rate observed in men. Temperature rises of 1°C or 2°C by the year 2050 are expected to be associated with higher prevalence rates by 66% and 73%, respectively. CONCLUSIONS There was a strong association between high temperatures and severe hyponatremia. The higher prevalence of severe hyponatremia was most pronounced among elderly.

中文翻译：

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室外温度与严重低钠血症的关联：一项基于斯德哥尔摩钠队列的研究。


背景 低钠血症是一种常见病，症状不明确，病因复杂。室外温度对低钠血症的影响尚未得到充分研究，并且因气候和地点而异。本研究旨在探讨室外温度与严重低钠血症患病率之间的相关性。方法 这项基于斯德哥尔摩钠队列的基于注册的回顾性队列研究调查了环境温度与成人严重低钠血症 （<125 mmol/L） 之间的关联。严重低钠血症的患病率计算为严重低钠血症的天数除以相同温度下有风险的人天数，使用每个研究参与者居住地区的日平均温度来计算暴露时间。一个结合人口统计和气候变化的预测模型被用来估计到 2050 年斯德哥尔摩严重低钠血症的负担。结果 我们在 51,143 名成人中确定了 21,924 次严重低钠血症发作。观察到患病率在高达 20°C 时随着温度升高而近线性适度增加，随后在较高温度下迅速增加。患病率随着年龄的增长而更高，在温度超过 22°C 的 +80 岁人群中，低钠血症的患病率达到 >100/百万人日。 女性的发病率是男性的两倍。预计到 2050 年，气温上升 1°C 或 2°C 将与患病率增加分别增加 66% 和 73% 相关。结论 高温与严重低钠血症之间有很强的相关性。严重低钠血症的患病率在老年人中最为明显。