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Electrocardiogram (ECG) outcomes serve as early manifestations of cardiovascular functional or structural changes. While temperature fluctuation has been demonstrated to be a risk factor for cardiovascular diseases, few epidemiological studies have reported its relationship with ECG outcomes. In this study, we employed temperature anomaly (TA) as an innovative indicator of temperature fluctuation to quantify its detrimental impacts on ECG outcomes. A longitudinal study design was conducted using the repeated ECG records of the China National Stroke Screening Survey from 2013 to 2019. Only individuals undergoing at least two ECG tests were included. The daily temperature was assimilated by combining three kinds of data: in situ observations, satellite remote sensing measurements and weather research forecast simulations. We used generalized estimating equations to control for autocorrelation among repeated records and to estimate the association between TA and the risk of ECG abnormalities. We found 6837 events of ECG abnormalities in 47,286 individuals with 102,030 visits. Each unit increment of TA increased the risk of ECG abnormalities [odds ratio (OR) = 1.009, 95% confidence interval (CI): 1.001–1.017] and the risk of myocardial ischemia (OR = 1.061, 95% CI: 1.012–1.111). Hierarchic analyses presented a similar association of TA with both ECG abnormalities (OR = 1.017, 95% CI: 1.008–1.026) and myocardial ischemia (OR = 1.061, 95%CI: 1.011–1.114) in Northern China, but not in Southern China. The exposure-response relationship was estimated as a U-shaped curve centered at the TA value of zero. Sudden warming tended to increase the risk of ECG abnormalities and myocardial ischemia, and sudden cooling tended to increase the risk of atrial fibrillation. All these detrimental effects of TA could be modified by specific individual characteristics. In summary, ambient temperature fluctuation increased the risk of ECG abnormalities. This result indicated that regular ECG tests could be an early-warning measure for monitoring the adverse health effects of temperature fluctuations. • Temperature anomaly (TA) is an innovative index reflecting temperature fluctuations. • Each unit increment of TA increases the risk of ECG abnormalities. • The exposure-response curve is U-shaped which centered at the TA value of zero. • ECG tests can be used to monitor the health effects of temperature fluctuations. [ABSTRACT FROM AUTHOR]

The health effects of urbanization are controversial. The association between urbanization and reversible subclinical risks of cardiovascular diseases (e.g., electrocardiogram (ECG) abnormalities) has rarely been studied. This study aimed to assess the association between urbanization and ECG abnormalities in China based on the China National Stroke Screening Survey (CNSSS). We used changes in the satellite-measured impervious surfaces rate and nighttime light data to assess the level of urbanization. Every interquartile increment in the impervious surfaces rate or nighttime light was related to a decreased risk of ECG abnormalities, with odds ratios of 0.894 (95% CI, 0.869–0.920) or 0.809 (95% CI, 0.772–0.847), respectively. And we observed a U-shaped nonlinear exposure–response relationship curve between the impervious surfaces rate and ECG abnormalities. In conclusion, the current average level of urbanization among the studied Chinese adults remains a beneficial factor for reducing cardiovascular risks. [ABSTRACT FROM AUTHOR]

Ambient ozone (O 3) pollution has been associated with an increased risk of cardiovascular diseases. However, few studies have addressed the effect of O 3 exposure on electrocardiogram (ECG) abnormalities, a subclinical indicator of early damage to the cardiovascular system. This study aimed to examine the association between short-term exposure to O 3 and ECG abnormalities. We included 102,027 visits of 47,290 participants over 40 years old who had a normal ECG at baseline and then visited again at least once from the China National Stroke Screening Survey (CNSSS). Short-term ozone exposure concentrations were measured as averages of maximum daily 8-h O 3 concentrations over the two weeks prior to ECG measurements. The generalized estimation equations models were used to evaluate the association between O 3 exposure and ECG abnormalities. For every 10 µg/m3 increment in short-term O 3 concentration, the odds ratio of any ECG abnormality was 1.055 (95% confidence interval [CI] 1.045–1.064). For ECG-diagnosed cardiac arrhythmia, the odds ratio was 1.062 (95% CI 1.052–1.072). A nonlinear analysis showed a sublinear relationship between O 3 exposure and risk for ECG abnormalities. The association between O 3 exposure and ECG abnormalities varied by subpopulation. Our study provided new epidemiological evidence on the association between short-term O 3 exposure and ECG abnormalities. There is an urgent need to control ambient O 3 pollution to prevent cardiovascular events. [Display omitted] • Electrocardiogram abnormality as a subclinical indicator can reflect the early injury of cardiovascular system. • Short-term exposure to ozone is positively associated with ECG abnormalities in a large Chinese population. • Cardiovascular diseases should be prevented by reducing the occurrence of ECG abnormalities. [ABSTRACT FROM AUTHOR]

• Annual PM 2.5 constituent exposure was associated with abnormal ECG outcomes. • Per IQR increase of sulfate related to a 26% increased risk of ECG abnormalities. • Differential toxicity of PM 2.5 constituents on ECG may inform policy making. Electrocardiogram (ECG) abnormalities are known to have prognostic value for heart conditions, while evidence on the relationship between long-term exposure to PM 2.5 constituents and electrocardiographic (ECG) abnormalities is limited. This study aimed to quantify the association between long-term exposure to PM 2.5 constituents and changes in ECG diagnoses. We designed a longitudinal study among participants with repeated records of ECG examination based on the China National Stroke Screening Survey 2013–2018. Logistic regressions with multiple adjustment, estimated by the generalized estimating equation to incorporate repeated measurements, were used to assess the associations between the occurrence of any physician-diagnosed ECG abnormalities and long-term exposure to PM 2.5 constituents. We included 61,094 participants with 132,249 visits. All five constituents (sulfate, nitrate, ammonium, organic matter, and black carbon) were significantly associated with an increased risk of ECG abnormalities. The excess risk of ECG abnormalities per interquartile-range increase in exposure was the highest for sulfate (26%, 95% confidence interval [CI] 23–29%), followed by ammonium (22%, 19–26%), nitrate (21%, 17–24%), black carbon (16%, 13–10%) and organic matter (9%,6%-11%). We also found that atrial fibrillation patients might be susceptible to the adverse effects of PM 2.5 constituents on ECG. Differential associations between various constituents of PM 2.5 and ECG abnormalities were found. The unequal toxicities for different chemical constituents of ambient particles on cardiovascular electrophysiological endpoints should be taken into consideration when considering the biological pathways linking PM 2.5 and cardiovascular conditions. [ABSTRACT FROM AUTHOR]