Background Short-term exposure to ambient temperature is linked to various health outcomes, raising public health concern in the context of climate change. We aimed to investigate longitudinal associations of temperature exposure with inflammation-related proteins among Swedish young adults.

Methods We conducted three repeated measurements (2020-2022) by collecting self-sampled volumetric dry blood spots (DBS) from 807 participants from the Swedish BAMSE cohort (mean age 25.9 years). We estimated individual-address level daily temperature using a high-resolution spatiotemporal model. Inflammation-related proteins were measured using the Olink’s Explore Inflammation panel. Temperature-related proteins were identified using mixed-effect model adjusting for potential covariates, with potential effect modification by sex, smoking, asthma and air pollution explored. We further linked the temperature-related proteins to lung function, blood pressure and HbA1c. In addition, we built an inflammation-proteomic aging clock using a machine-learning approach and estimated the association between temperature exposure and proteomic age acceleration.

Findings we found that 58 (16%) of the 365 studied inflammation-related proteins were significantly associated with short-term exposure to ambient temperatures (P<0.05 after correcting for multiple comparison). The impact of temperature exposure was modified by sex, smoking, asthma, and concurrent exposure to air pollution. A total of five, three and three temperature-related proteins were found to be associated with lung function, blood pressure, and HbA1c, respectively and validated in the UK Biobank. Peak temperature exposure (both cold and heat) was associated with significantly increased proteomic age acceleration.

Interpretation Our findings suggest that ambient temperature exposure may cause adverse health effects through perturbating inflammation-related proteins.

Synopsis This study reports significant effects of ambient temperature exposure on inflammation-related proteins, highlighting potential health impacts from ambient temperature exposure.

The authors have declared no competing interest.

The study received funding from the Swedish Research Council (grant no. 2020-01886, 2022-06340, 2024-02345), the Swedish Research Council for Health, Working Life and Welfare (FORTE grant no.2017-01146, no.2023-01213), the Swedish Heart-Lung Foundation, Karolinska Institute (no. 2022-01807) and Region Stockholm (ALF project for cohort and database maintenance).

I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.

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The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

This study was approved by the Swedish Ethical Review Authority (approval 2020-02922), and all participants gave written informed consent.

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The datasets analyzed during the current study are not publicly available due to legal and ethical regulations, but the derived data supporting the findings of this study are available from the PI of the BAMSE cohort (Professor Erik Melén erik.melenki.se) upon reasonable request.