Climate change may be associated with human morbidity and mortality through direct and indirect effects. Ahvaz is one of the hottest cities in the world. The aim of this study was to investigate the relation between physiological Equivalent Temperature (PET) and non-accidental, cardiovascular and respiratory disease mortality in Ahvaz, Iran. Distributed Lag Non-linear Models (DLNM) combined with quasi-Poisson regression were used to investigate the effect of PET on death. The effect of time trend, air pollutants (NO₂, SO₂ and PM₁₀), and weekdays were adjusted.The results showed that in cold stress [1st percentile of PET (2.7 °C) relative to 25th percentile (11.9 °C)] the risk of total respiratory mortality, respiratory mortality in men, and mortality in people under 65 year olds, significantly decreased in the cumulative lags of 0–2, 0–6 and 0–13; but the risk of respiratory mortality increased in the elderly and in the final lags. In contrast, heat stress [99th percentile of PET (44.9 °C) relative to 75th percentile (43.4 °C)] significantly increased the risk of total cardiovascular mortality (CVD), cardiovascular mortality in men, ischemic heart disease and cerebrovascular disease mortality in lags 0 and 0–2. It seems that high PET values increase the risk of cardiovascular mortality, while low PET values increase respiratory mortality only among the elderly in Ahvaz.

气候变化可能通过直接和间接影响与人类发病率和死亡率有关。阿瓦士是世界上最热的城市之一。本研究的目的是调查生理等效温度 (PET) 与伊朗阿瓦士的​​非意外、心血管和呼吸系统疾病死亡率之间的关系。分布式滞后非线性模型 (DLNM) 结合准泊松回归用于研究 PET 对死亡的影响。时间趋势、空气污染物（NO ₂、SO ₂和 PM ₁₀) 和工作日进行了调整。结果表明，在冷应激 [PET 的第 1 个百分位 (2.7 °C) 相对于第 25 个百分位 (11.9 °C)] 的总呼吸系统死亡率、男性呼吸系统死亡率和人死亡率的风险65岁以下，0-2、0-6和0-13的累积滞后显着减少；但在老年人和最后的滞后期中，呼吸系统死亡的风险增加了。相比之下，热应激 [PET 的第 99 个百分位 (44.9 °C) 相对于 75 个百分位 (43.4 °C)] 显着增加了总心血管死亡率 (CVD)、男性心血管死亡率、缺血性心脏病和脑血管疾病死亡率的风险滞后 0 和 0–2。似乎高 PET 值会增加心血管死亡率的风险，而低 PET 值只会增加阿瓦士老年人的呼吸系统死亡率。