Short‐Term Exposure to Air Pollution and Biomarkers of Oxidative Stress: The Framingham Heart Study

Background: Short‐term exposure to elevated air pollution has been associated with higher risk of acute cardiovascular diseases, with systemic oxidative stress induced by air pollution hypothesized as an important underlying mechanism. However, few community‐based studies have assessed this association. Methods and Results: Two thousand thirty‐five Framingham Offspring Cohort participants living within 50 km of the Harvard Boston Supersite who were not current smokers were included. We assessed circulating biomarkers of oxidative stress including blood myeloperoxidase at the seventh examination (1998–2001) and urinary creatinine‐indexed 8‐epi‐prostaglandin F2α (8‐epi‐PGF 2α) at the seventh and eighth (2005–2008) examinations. We measured fine particulate matter (PM 2.5), black carbon, sulfate, nitrogen oxides, and ozone at the Supersite and calculated 1‐, 2‐, 3‐, 5‐, and 7‐day moving averages of each pollutant. Measured myeloperoxidase and 8‐epi‐PGF 2α were loge transformed. We used linear regression models and linear mixed‐effects models with random intercepts for myeloperoxidase and indexed 8‐epi‐PGF 2α, respectively. Models were adjusted for demographic variables, individual‐ and area‐level measures of socioeconomic position, clinical and lifestyle factors, weather, and temporal trend. We found positive associations of PM 2.5 and black carbon with myeloperoxidase across multiple moving averages. Additionally, 2‐ to 7‐day moving averages of PM 2.5 and sulfate were consistently positively associated with 8‐epi‐PGF 2α. Stronger positive associations of black carbon and sulfate with myeloperoxidase were observed among participants with diabetes than in those without. Conclusions: Our community‐based investigation supports an association of select markers of ambient air pollution with circulating biomarkers of oxidative stress

Discordantly normal ApoB relative to elevated LDL-C in persons with metabolic disorders: A marker of atherogenic heterogeneity

Objective: A significant proportion of persons with metabolic syndrome (MetS), prediabetes, or type 2 diabetes (T2D) do not develop atherosclerotic cardiovascular disease (ASCVD).We sought to determine whether discordantly normal apolipoprotein B (ApoB) relative to elevated LDL-C may help to explain heterogeneity in ASCVD risk among persons with metabolic disorders. Methods: There were 278 Bogalusa Heart Study participants with MetS (n=95), prediabetes (n=233), or T2D (n=31) and LDL-C ≥100 mg/dL who were free of carotid plaque at baseline (2001-02) and underwent carotid ultrasound at follow-up (2013-16). Multivariable modified Poisson regression estimated the long-term absence of carotid plaque for lower ApoB, continuously and categorically. Results: Participants were on average 36.1 years old at baseline, 61.5% were women, and 31.7% were black. A total of 50.7% had discordantly normal ApoB (<90 mg/dL) and the mean ApoB and LDL-C concentrations were 91.6 mg/dL and 137.7 mg/dL, respectively. In addition to having higher HDL-C and lower triglyceride values, individuals with ApoB <90 were more likely to maintain persistent absence of plaque compared to those with ApoB ≥90 (73.1% versus 58.4%, p=0.01). Contrastingly, there was no significant difference in the proportion of individuals who remained free of plaque with increasing LDL-C (p=0.45). Independent of traditional risk factors including LDL-C, each 10 mg/dL lower ApoB (RR=1.11, 95% CI: 1.03-1.19) and ApoB <90 (RR=1.22, 95% CI: 1.00-1.43) were significantly associated with the persistent absence of carotid plaque. Conclusions: One-half of young persons with metabolic disorders and elevated LDL-C had discordantly normal ApoB and a low burden of carotid atherosclerosis over 13 years, suggesting that ApoB better represents the atherogenic lipid burden compared to LDL-C in this patient population. These results suggest a utility for assessing whether routine ApoB measurement can improve ASCVD risk stratification in young persons with metabolic disorders who have high triglycerides and low HDL-cholesterol

Short-Term Exposure to Ambient Air Pollution and Biomarkers of Systemic Inflammation: The Framingham Heart Study

OBJECTIVE: The objective of this study is to examine associations between short-term exposure to ambient air pollution and circulating biomarkers of systemic inflammation in participants from the Framingham Offspring and Third Generation cohorts in the greater Boston area. APPROACH AND RESULTS: We included 3996 noncurrent smoking participants (mean age, 53.6 years; 54% women) who lived within 50 km from a central air pollution monitoring site in Boston, MA, and calculated the 1- to 7-day moving averages of fine particulate matter (diameter \u3c 2.5 microm), black carbon, sulfate, nitrogen oxides, and ozone before the examination visits. We used linear mixed effects models for C-reactive protein and tumor necrosis factor receptor 2, which were measured up to twice for each participant; we used linear regression models for interleukin-6, fibrinogen, and tumor necrosis factor alpha, which were measured once. We adjusted for demographics, socioeconomic position, lifestyle, time, and weather. The 3- to 7-day moving averages of fine particulate matter (diameter \u3c 2.5 microm) and sulfate were positively associated with C-reactive protein concentrations. A 5 microg/m3 higher 5-day moving average fine particulate matter (diameter \u3c 2.5 microm) was associated with 4.2% (95% confidence interval: 0.8, 7.6) higher circulating C-reactive protein. Positive associations were also observed for nitrogen oxides with interleukin-6 and for black carbon, sulfate, and ozone with tumor necrosis factor receptor 2. However, black carbon, sulfate, and nitrogen oxides were negatively associated with fibrinogen, and sulfate was negatively associated with tumor necrosis factor alpha. CONCLUSIONS: Higher short-term exposure to relatively low levels of ambient air pollution was associated with higher levels of C-reactive protein, interleukin-6, and tumor necrosis factor receptor 2 but not fibrinogen or tumor necrosis factor alpha in individuals residing in the greater Boston area

Residential proximity to major roads, exposure to fine particulate matter and aortic calcium: the Framingham Heart Study, a cohort study

Objectives: Traffic and ambient air pollution exposure are positively associated with cardiovascular disease, potentially through atherosclerosis promotion. Few studies have assessed associations of these exposures with thoracic aortic calcium Agatston score (TAC) or abdominal aortic calcium Agatston score (AAC), systemic atherosclerosis correlates. We assessed whether living close to a major road and residential fine particulate matter (PM2.5) exposure were associated with TAC and AAC in a Northeastern US cohort. Design: Cohort study. Setting: Framingham Offspring and Third Generation participants residing in the Northeastern USA. Participants and outcome measures Among 3506 participants, mean age was 55.8 years; 50% female. TAC was measured from 2002 to 2005 and AAC up to two times (2002–2005; 2008–2011) among participants from the Framingham Offspring or Third Generation cohorts. We first assessed associations with detectable TAC (logistic regression) and AAC (generalised estimating equation regression, logit link). As aortic calcium scores were right skewed, we used linear regression models and mixed-effects models to assess associations with natural log-transformed TAC and AAC, respectively, among participants with detectable aortic calcium. We also assessed associations with AAC progression. Models were adjusted for demographic variables, socioeconomic position indicators and time. Results: There were no consistent associations of major roadway proximity or PM2.5 with the presence or extent of TAC or AAC, or with AAC progression. Some estimates were in the opposite direction than expected. Conclusions: In this cohort from a region with relatively low levels of and variation in PM2.5, there were no strong associations of proximity to a major road or PM2.5 with the presence or extent of aortic calcification, or with AAC progression