Statins Against Bushfire Smoke

The goal of this clinical trial is to test whether statins can protect the heart and brain from the biological stress and inflammatory responses caused by breathing bushfire smoke in healthy adult volunteers aged 18-64 years. The main questions it aims to answer are:

1. Does short-term statin use (2 days) reduce bushfire smoke-induced changes in heart rate variability, blood pressure, arterial stiffness, inflammation and oxidative stress markers, and cognitive function? 2. Does long-term statin use (≥12 months) reduce bushfire smoke-induced changes in heart rate variability, blood pressure, arterial stiffness, inflammation and oxidative stress markers, and cognitive function?

The study includes two streams:

Stream 1:short-term statin use (2 days) where participants receive either statin tablets (80mg atorvastatin) or placebo; Stream 2: long-term statin use (≥12 months) where participants include those already taking statins (≥12 months) with statin-naïve individuals.

Participants will:

* Attend two 3½-hour visits to a Climate Hut, which are approximately 4 weeks apart, where they will spend 2 hours exposed to either filtered air or simulated dilute bushfire smoke (average particulate matter (PM2.5) concentration of 300μg/m\^3) in randomised order; * Have continuous heart monitoring with ECG leads and blood pressure checks every 15 minutes during each visit * Provide urine, saliva, and nose swab samples before and after each exposure, plus follow-up samples the next morning * Complete cognitive tests (reaction time, memory tasks) and postural balance measurements during exposure * Complete questionnaires about anxiety levels, symptoms, diet, and health status * Have blood samples collected and pulse wave velocity measurements (assessing arterial stiffness) immediately after each exposure session.

Potential risks include time commitment, muscle pain from statins, eye irritation or throat discomfort from smoke exposure, and minor discomfort from blood collection.